CA1040077A - Method and apparatus continuously quenching moving electrolytic tin-plated steel strip - Google Patents
Method and apparatus continuously quenching moving electrolytic tin-plated steel stripInfo
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- CA1040077A CA1040077A CA212,654A CA212654A CA1040077A CA 1040077 A CA1040077 A CA 1040077A CA 212654 A CA212654 A CA 212654A CA 1040077 A CA1040077 A CA 1040077A
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- quenching
- strip
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- liquid
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
- C25D5/50—After-treatment of electroplated surfaces by heat-treatment
- C25D5/505—After-treatment of electroplated surfaces by heat-treatment of electroplated tin coatings, e.g. by melting
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- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electroplating Methods And Accessories (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An improved process and apparatus are provided, in order to brighten the surface of tin-plated layer of steel strip which has been tin-plated on a commonly known continuous electrolytic tin-plating line. The strip is first heated in a traditional continuous heating furnace for rapid fusion of its tin-plated layer. Then it is promptly quenched for solidification. In such quenching, the quenching is carried out in two stages aiming at obtaining excellent corrosion resistance as well as tending to prevent the occurence of quench stains. Thus, there is first maintained a relatively low quenching rate by spraying quenching liquid mist or a stream of high-pressure quenching liquid on both sides of the strip across the entire width, uniformly on the same horizontal level, in the air above the surface of quenching liquid in the quenching tank immediately following the heating furnace. Then the strip is passed into a quenching liquid in the quenching tank. There is maintained a relatively higher quenching rate by spraying a larger quantity of quenching liquid under high pressure onto both sides of the strip across the entire width, uniformly on the same horizontal level, beneath the surface of quenching liquid in the quenching tank. In this manner there is almost complete prevention of quench stains, improved corrosion resistance of the tin plated strip due to the formation of a uniform and dense alloy layer in the tin plated layer and there is a high speed quenching operation.
An improved process and apparatus are provided, in order to brighten the surface of tin-plated layer of steel strip which has been tin-plated on a commonly known continuous electrolytic tin-plating line. The strip is first heated in a traditional continuous heating furnace for rapid fusion of its tin-plated layer. Then it is promptly quenched for solidification. In such quenching, the quenching is carried out in two stages aiming at obtaining excellent corrosion resistance as well as tending to prevent the occurence of quench stains. Thus, there is first maintained a relatively low quenching rate by spraying quenching liquid mist or a stream of high-pressure quenching liquid on both sides of the strip across the entire width, uniformly on the same horizontal level, in the air above the surface of quenching liquid in the quenching tank immediately following the heating furnace. Then the strip is passed into a quenching liquid in the quenching tank. There is maintained a relatively higher quenching rate by spraying a larger quantity of quenching liquid under high pressure onto both sides of the strip across the entire width, uniformly on the same horizontal level, beneath the surface of quenching liquid in the quenching tank. In this manner there is almost complete prevention of quench stains, improved corrosion resistance of the tin plated strip due to the formation of a uniform and dense alloy layer in the tin plated layer and there is a high speed quenching operation.
Description
~ ~4~'7~
This in~ention relates to a method and apparatus for quenching continuously electrolytic tin-plate steel strip to tend to prevent the occurrence of stains on the surface of its tin-plated layer while carry-ing out steps to brighten its tin-plated layer by continuously heating and quenching the moving s-~eel strip.
The surface of the plated layer of a tin-plated steel strip produced by a commonly known continuous electrolytic tin-plating méthod is dull and has no gloss. In order to impart gloss to the surface of the thus tin-plated layer, the prior art traditionally teaches the method of heating the strip in a continuous heating furnace to cause rapid fusion of the tin-plated layer, and then immediately directing the strip in~to a quenching tank to quench it for the solidification of the tin-pla-ted layer.
If the quenching is improperly applied, however, dirt patterns which loolc like dried stains of dirty water (hereinafter referred to as "quench stain") are produced on the surface of tin-plated layer of the strip, conslderably reducing the commercial value of the strip.
The quench st~in is believed to be produced by an unevenly quenched tin-plated layer due to the irregular quenching rate caused by a non-uniform contact between the strip and the quenching liquid. This is believed to be brought about by surface turbulence of the quenching liquid in the quenching tank on introducing the strip into it, by splashes of quenching liquid onto the strip, and by uneven deposit of steam film, which is generated by quenching, on the strip.
Also, the tin-plated layer of the strip produces an alloyed layer of tin and iron at its fusion. It is necessary to make such alloyed layer uniform and dense in order to obtain excellent corrosion resistance. For this purpose, there should be a certain duration in time sufficient to cause progressive development of the alloyed layer.
In other words, slowing down of the quenching rate of the strip is required to a certain degree. On the other hand, however, increasing the quenching rate is required for accelerating the quenching line operation~
' -- 1 - 5~
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~ V4~717 In order to solve these problems, there have been a number of proposals. In a method disclosed in United States Patent No. 3,358,980 issued December 19, 1967 to H. L. Taylor, for instance, two compartments with a hood and spaced plates are installed in a quenching tank, and surface turbulence on the surface of the quench-ing liquid in the quenching tank caused by the incoming strip is pre~
vented by the use of the said spaced plates. Besides, a narrow region is confined by the spaced plates, and the heated strip is directed into this narrow region. The quenching liquid first fed into such compart-ments flows down into the quenching tank by gravity along the both sidesof the strip, in the same direction as the travel of the strip, and almost ill parallel with the strip, in the narrow region, and after filling up the quenching tank, the quenching liquid overflows. Initially, the ætrip, brought into contact with the quenching liquid in the narrow region, is quenched at a relatively slow quenching rate, and then is moved into the quenching tank, being quenched down to the prescribed temperature. Further, a temperature sensing device is provided in the narrow reglon to control the quenching liquid temperature.
Accordlng to the above-mentioned method, no surface turbul~nce is produced on the surface of the quenching liquid in the quenching tank on introducing the strip into it, so that the tin-plated layer is quenched uniformly, tending to prevent the formation of quench stains.
~lowever, in this method, because the quenching liquid comes into contact with the strip while flowing down in the narrow region by gravity, the^
impact of the quenching liquid against the strip is small. Nevertheless, with the recent speeding-up of a continuous electrolytic tin-plating line, the moving speed of the strip has been accelerated up to some 300 - 450 mlmin. Accordingly, quenching capacity obtained only by a stream of quenching liquld by flowing gravity as is the case of this method is insufficient. With an insufficient quenching capacity, steam generating at the interface between the strip and the quenching liquid accompanies the strip, being deposited on the surface of the strip. As a result, irregularities are found in the quenching rate of the tin-plated layer, which is not uniformly quenched, so that it is impossible com-pletely to prevent the occurrence of quench stains. In other words, this method is not applicable to a high-speed continuous electrolytic tin-plating llne. Besides, it is necessary to provide the quenching tank with a hood, spaced plates and co~partments, leading to increased costs of quenching facilities.
Further, in the method disclosed in United States Patent No.
3,410,734 issued November 12, 1968 to H. L. Taylor, an elongated conduit section of rectangular cross-section is included which provides a restricted quench channel extending upwardly from a quenching tank. The quenching liquid supplied into the quenching tank after filling up the quenching tank, comes up in the restricted quench channel and flows over its upper end into a trough. Closely adjacent the upper end of the restricted quench channel, a plurality of submerged jet or spray units are provided for directing streams of quenching liquld toward the strip across the entire width thereof. The heated steel strlp moves downwardly Erom the heating furnace and enters the restrlcted quench channel where it is immediately immersed in the upward-ly flowing stream oE quenching liquid. In addition, the submerged jetor spray units direct streams oE quenching liquid against the strip in a direction generally normal to the strip. The submerged jet or spray units use a large quantity of quenching liquid with a relatively low .
pressure of 1.4 - 2.1 kg/cm2.
According to the above-mentioned method, the strip can be quenched ove~ the entire width uniformly and at a high rate. Therefore, this method is applicable, in particular, for obtaining strips having martensitic microstructure and superior flatness. However, this method includes no special regard for the prevention of quench stains and for the achievement of excellent corrosion resistance. Particularly, no regard is paid to such points as developing, in the tin-plated layer, an alloyed layer necessary for obtaining an excellent corFosion resistance, .
in other words, making the quenching rate in the initial stage of quench-ing relatively slower. The method has ~nother disadvantage of req~iring a complicated quenching device which increases installation costs.
A method is also known to fuse electrolytically deposited tin in a heating furnace aiming at improving the corrosion resistance on either the upper or the under surface of continuously electrolytic tin-plate steel strip, then to spray quenching liquid on either the upper or the under surEace of the strip, in the air of beneath the surface of the quenching liquid in the quenching tank, and, by quenching while holding a temperature difference between the both sides, to coarsen the grain size of tin on one side of the strip.
The method, though better in slow quenching in the initial stage of quenching, has no regard to uniform quenching of the strip over the entire width and quenching capacity. That is, in this method, increasing the pressure or the volume of water of submerged spray in the quenching tank in an attempt to lmprove the quenching capacity brings more serious surface turbulence of the quenching liquid in the quenching tanlc without permittlng unLform quenching of the strip over the entire width, resultlng in the impossibility of preventing the production of quench stalns. Moreover, quenching in the air by this method aims merely at controlling the tin crystals, with no regard to uniform quenching of the strip over the entire width.
As described above, it is desired to obtain continuously elec-trolytic tin-plated steel strip excellent in corrosion resistance as well as being glossy and with substantially no quench stain, but a method and apparatus to obtain strip with these properties have not as yet been proposed.
Therefore, it is an object of a main aspect of this invention to provide a strip quenching method and apparatus tending to prevent the production o~ quench stains on the surface of the tin-plated layer of co~tinuously electrolytic tin-plated steel strip, tending to eliminate the above-mentioned disadvantages of the conventional methods and devices.
An objec-t oF another aspect of -this invention is to provide a quenching method and appara-tus for such steel strip in order to give excellent corrosion resistance to con-tinuously electrolytic tin-plated steel strip.
By a broad aspect of this invention, a continuous quenching method is provided for quenching con-tinuously moving electrolytic tin-plated steel strip, comprising the steps of: (1) maintaining a relatively low quenching ra-te by spraying a quenching fluid mist onto continuously moving electrolytic tin-plated steel strip with its tin-plated layer fused thereto with heat in the air above the surface of a quenching liquid maintained in a quenching zone; (2) passing said strip into said quenching zone containing said quenching liquid;
and (3) maintainirlg a relatively higher quenching rate by spraying a larger quantity of quenching liquid under high pressure onto said strip beneath the surface of said quenching liquid in said quenching zone.
By another aspect, a method is provided of continuously quenching a Fused layer oF tin electrolytically plated on the surface oF a moving strip of steel issuing from a continuous hea-ting furnace wh:ich process coMprises passing said strip in-to a quenching apparatus and in a first quenching step, spraying a quenching liquid onto the tin-plated steel strip, and immediately af-ter tha-t, in a second quenching step, spraying quenching liquid at a pressure of from 2 to 20 Kg/cm onto the said strip benea-th the surface of quenching liquid in a quenching tank, -the quan-ti-ty of quenching liquid sprayed in said second quenching step being greater than that sprayed in said first quenching step.
By one yarian-t thereof, the first s-tep quenching includes spraying quenching liquid mist onto said strip.
By another variant -thereof, the first step quenching includes spraying high-pressure quenching liquid along a guide plate onto said strip.
By s-till another variant, the high-pressure quenching liquid used for said second step quenching is at a pressure of between 4 ~g/cm2 and 10 kg/cm2.
By a preferred variant, the quenching fluid is water.
By another aspect of this invention a method is provided for continuously quenching a continuously moving electrolytic tin-plated steel strip, the method comprising (1) maintaining a relatively low quenching rate of from 500 to 900C. per second by spraying a quenching liquid mist onto a continuously moving tin-plated steel s-trip with its tin-plated layer fused thereto with heat, in the air above -the surface of a quenching liquid maintained in a quenching tank, with a quantity of said quenching liquid of from 0.002 to 0.08 liter per square meter per minute; (2) passing said s-trip into said quenching tank containing said quenching liquid; and (3) maintaining a relatively higher quench-ing rate o:F from 1,100 to 1,300C. per second by spraying a larger quantity of quenching liquid oF a-t leas-t 1.2 li-ters per square meter per minute under a h:igh pressure on-to said strip beneath said surface in said quenching tank.
By still ano-ther aspect, such a method is provided comprising:
(1) rnaintaining a relatively low quenching ra-te of from 500 to 900C.
per second by spraying a quenching liquid at high pressure along a guide pla-te on-to a con-tinuously moving tin-plated steel s-trip wi-th its tin-pla-ted layer :Fused thereto with hea-t, in the air above -the surface of a quenching liquid maintained in a quenching tank, wi-th a quantity of said liquid of from 0.2 to 0.8 liter per square me-ter per minute, followed by (2) passing said strip into said quenching -tank containing said quenching liq~uid, and (3) maintaining a rela-tively higher quenching rate of from 1,100 to 1,300C, per second by spraying a ' .-4(~77 larger quantity of quenching liquid of at least 1.2 liters per squaremeter per minu-te under a high pressure on-to said strip beneath said surface in said quenching -tank.
By one variant thereof, the mist is so sprayed in (1) onto both sides of said strip from a plurali-ty of spray nozzles positioned on both sides of said strip across the entire width thereof and substantially on the SaJle horizontal level with each othèr.
By another variant, the liquid is so sprayed in (3) onto both sides of said strip from a plurality of spray nozzles positioned on both sides of said strip across the entire width thereof and substant-ially on the same horizontal level with each other.
By still another variant, the quenching liquid sprayed in (1) is at a pressure between 2 kg/cm2 and 20 kg/cm2, and in (3) is between 4 kg/cm2 and 10 kg/cm2.
By a fur-ther aspec-t, such method comprises the steps of:
moving said strip in a subs-tantially vertical direction -through the atmosphere; spraying a firs-t quantity of a quenching liquid mist towards sa.icl strip from both sides thereof and at substantially the same horizon-tal :Level, said spraying being directed at an angle within the range between a right angle and 45 in an upward direction relative to said substantially vertically moving strip; thereafter passing said strip in a subs-tantially vertical direc-tion into a quenching tank conrtaining a quenching liquid; and -then spraying a second quan-tity of a quenching liquid at high pressure toward said strip from both sides thereof below -the surface of -the quenching liquid in said quenching tank and at substantially -the same horizon-tal level below -the surface of the quenching liquid in said quenching -tank 7 said high-pressure spraying being direc-ted at an angle wi-thin -the range between a right angle and ~5 in an upward direc-tion rela-tive -to said substantially vertically moving strip, said second quantity of quenching liquid being -5b-. .
7~
greater than said firs-t quan-ti-ty.
By a still further ~spect, such method comprises the s-teps of: moving said strip in a substantially vertical direction through said atmosphere between a-t least a pair of guide plates; spraying a first quantity of high-pressure quenching liquid toward said strip from bo-th sides -thereof, and at substantially the same horizontal level, said spraying being directed at an angle within the range between an upwardly directed parallel direction and ~5 in an upward direction relative to said substantially vertically moving strip, at least a portion of said high-pressure quenching liquid spray being directed toward said guide plates; deflecting with said guide plates said portion of said high-pressure quenching liquid spray directed thereon toward said strip, the uppermost par-t of said guide plates being curved toward said strip, the curved uppermost parts ending substantially at -the same horizontal level; thereafter passing said strip in a substan-tially vertical direction into a quenching tank containing a quenching liquid; and then spraying a second quantity o:F a high-press~re quenching liquid toward said strip from bo-th sides thereof below the sur.Face o:F -the quenching liquid in said quenching tank and at substantially the same horizon-tal level below the surface of the quenching liquid in said quenching tank, said high~pressure spraying being directed at an angle within the range between a right angle and 45 in an upward direction relative to said substantially vertically moving strip, and said second quantity being greater than said firs-t quantity.
~ y ano-ther aspect of -this invention, a quenching apparatus is provided for con-tinuously quenching a continuously moving electro-lytic tin-pla-ted steel strip, comprising:(l) a quenching tank adap-ted to con-tain quenching liquid; (2) means for spraying fluid on both sides of said strip, on the same horizon-tal level above -the surface of -5c-'-`` lV~0()77 quenching fluid in said quenching tank, against said strip at an angle between 90 and 45 upwardly, with respect to the vertical, thereby to direct liquid over the entire width of said strip; and (3~ means for spraying high-pressure quenching liquid, on the same horizontal level below the surface of quenching liquid in said quenching tank, at an angle between 90 and 45 upwardly, with respect to the vertical, thereby to direct liquid over the entire width of said strip.
By another aspect, such an apparatus is provided for continuously quenching a fused layer of tin electrolytically plated on the surface of a moving strip of steel issuing from a continuous heating furnace, which apparatus comprises: a quenching tank for containing quenching liquid, a plurality of first spray nozzles, on each side of the said strip, on the same horizontal level above the intended working surface of quenching liquid in the said quenching tank, directed at an angle within the range from 90 to 45 against the direction of motion of said strip and adapted to direct quenching liquid over the entire width of the strip; a pair of quenching liquid supply tubes; and a plurality of second nozzles arranged for spraying quenching liquid, installed on the said pair of quenching liquid supply tubes, on each side of the said strip, on the same horizontal level beneath the intended working surface of quenching liquid in the said quenching tank, directcd a-t an angle within the range from 90 to 45 against the direction of motion of the said strip and adapted to direct quenching liquid over the entire width of the strip.
By a variant thereof, -the first spray nozzles are connected to a pair of compressed air reservoirs whereby said nozzles spray a mist of quenching liquid.
By another Yariant the first spray nozzles are connected to a pair of pressurized quenching liquid supply tubes, whereby '`~;
~ -6-said spray pressurized quenching liquid.
By another aspect, such an apparatus is provided comprising:
a quenching tank adap-ted to contain quenching liquid; a pair of high-pressure quenching liquid supply tubes; a plurality of spray nozzles adapted -to spray high-pressure quenching liquid, installed on said pair of high-pressure quenching liquid supply -tubes, on both sides of said s-trip, on the same horizontal level above the surface of quenching liquid in said quenching tank, in such a manner as to - form an angle within the range of between substantially parallel to said strip and 45 upwardly, with respect to the vertical, against said strip, thereby to direct liquid over the entire width of said strip; a pair of guide plates, installed on said pair of high-pressure quenching liquid supply tubes, on both sides of said strip, and adapted to direct said high-pressure quenching liquid sprayed through said spray nozzles onto said s-trip, said guide plates being wider than said strip, with the top end of said plates being curved toward said s-trip and with the topmost part of said plates each ending on the same horizontal level; a pair of high-pressure quenching liquid supply tubes adaptecl to be submerged below the surEace of liquid in said tan]c; and a plurality oF nozzles adap-ted to be submerged below -the surlace of liquid in saicl tank, and adapted -to spray high-pressure quenching liquid, installed on said pair of high-pressure quenching liquid supply tubes, on both sides oE said strip, on the same horizontal level w:ithin said quenching tank, in such a manner as to form an angle within -the range of between 90 and 45 upwardly, with respect to the yer-tical ? agains-t said strip, thereby -to direct liquid oyer the entire wid-th of said strip.
By s-till another aspec-t, such an appara-tus is provided comprising: a quenching tank containing a quenching liquid; a pair of compressed-air~ reservoirs; a source of quenching liquid; a ~ ~ -6a-$77 plurality of spray nozzles for spraying quenching liquid mist coupled to said quenching liquid source and said compressed-air reservoirs, said-. nozzles being positioned on both sides of said strip and on substantially the same horizontal level above the surface of the quenching liquid in said quenching tank, said nozzles forming an angle within the range between a right angle and 45 in an upward direction relative to said strip which moves substan-tially vertically in the vicinity of sai~-~ nozzles, -thereby to direct quenching liquid over the entire width of said strip; a pair of high-pressure quenching ... .
liquid supply -tubes submerged in said tank; and a plurality of sub-merged nozzles for spraying submerged high-pressure quenching liquid coupled to said submerged high-pressure quenching liquid supply tubes, sa.id submerged nozzles being positioned on both sides of said strip and on subs-tantially the same horizontal level benea-th the surface of the quenching liquid in said quenching tank, sa.id submerged nozzles forming an angle within the range be-tween a righ-t angle and 45 in an upward direct:ion relative to said strip which moves substantially vertically in the vicinity of said submerged nozzles, thereby to direct quenching liquid over the entire width of said s-trip.
By yet a further aspect, such an apparatus is provided comprising: a quenching tank containing a quenching liquid; a pair of high-pressure quenching liquid supply -tubes; a plurality of spray nozzles coupled to said high-pressure quenching liquid supply tubes for spraying high-pressure quenching liquid, said nozzles being positioned on bo-th sides of said strip and on substan-tially the same horizontal level above the surface of the quenching liquid in said quenching tank~ said nozzles forming an angle within the range be-tween an upwardly directed parallel position and 45 in an upward direction relative to said strip which moves substantially vertically in the vicinity of said spray nozzles, -thereby to direct quenching ~ -6b-~ r~
liquid over -the en-tire width of said s-tripj a pair of guide plates positioned adjacent a respective high-pressure quenching liquid supply tube; one guide pla-te being located on opposite sides of said s-trip, said guide plates being wider than said s-trip, sai~-~ guide pla-tes having upper ends which are above said spray nozzles and which are curved toward said strip, said guide pla-tes having their -topmost parts ending on substantially the same horizontal level for directing said high-pressure quenching liquid sprayed through said spray nozzles onto said strip; a pair of high-pressure quenching liquid supply o tubes submerged in said tank; and a plurality of submerged nozzles for spraying submerged high-pressure quenching liquid coupled to said submerged high-pressure quenching liquid supply tubes, said submerged nozzles being posi-tioned on both sides of said strip and on substant~
ially the same horizontal level beneath the surface of the quenching liquid in said quenching tank, said submerged:nozzles forming an angle wi-thin the range be-tween a right angle and ~5 in an upward direc-tion relative -to said s-trip which moves substantially vertically in the vi.cinity of said submerged nozzles, thereby to direc-t quenching liquid over -the entire width of said strip.
-6c-In the accompanying drawings, Figure 1 is a normal sec-~ional schematic sketch showing an example of a device usable for putting the method of an aspect of this invention into practice;
Figure 2 is a sectional sketch along line A-A' of Figure l;
. Figure 3 is a sec-tional view showing an example of a nozzle to pulverize and spray quenching liquid;
Figure 4 is a normal sectional schematic sketch showing another example of a device usable for putting the method of an aspect of this invention into practice; and Figure 5 is a sec-tional view along line B-B of Figure 4.
In order to impart a gloss to the tin-plated layer of ,~ , -7-1~34U~ '7 continuousl~ electrol~tic tin-plated steel strip, as mentioned above, the strip is usually heated in a continuous heating furnace to fuse the tin-plated layer rapidly, and by quenching the strip immediately after that, the tin-plated layer is solidified. Unless the strip is quenched uniformly over the entire width, the tin-plated layer is not quenched uniformly, tending to cause the occurrence of quench stains on the sur-face of the tin-plated layer. These quench stains are produced in the initial stage of the above-mentioned quenching. Corrosion resistance of continuously electrolytic tin-plated steel strip, on the other hand, improves by achieving a uniform and dense alloyed layer of iron and tin produced on heating the strip and fusing the tin-plated layer. For the purpose of achieving excellent corrosion resistance, therefore, it is desirable to slow down the quenching rate of the strip in the initial stage of quenching, to cause progressive development of the alloyed layer.
By the method of an aspect of this invention, taking notice of the Eact described above, after fusing the tin-plated layer of continu-ously electrolytic tln-plated steel strip in a continuous heating furnace, a Eirst-step quenching at a low rate is carried out, in the initial stage oE quenchLng, and then in the later stage oE quenching, a second-step quenching at a high rate is carried out.
By the method of an aspect of this invention, the plurality of spray nozzLes are respectively installed on the same horizontaI level above the surface of quenching liquid in the quenching tank which is installed below the continuous heating furnace, against both sides of the incoming strip. The above-described first-step quenching :Ls carried out in the following manner: before the strip, with its tin-plated layer fused by the continuous heating furnace, moves almost vertically down-wardly into quenching liquid in the quenching tank, quenching liquid mist or a stream of high-pressure quenching liquid is sprayed through the spray nozzles on both sides of the strip across the entire width, uniform-ly on the same horizontal level, :in the air above the surface of the quenching liquid.
_ ~ _ '77 Also, according to the method of an aspect of this invention, the plural number of submerged nozzles are respectively installed on the same horizontal level beneath the surface of quenching liquid in the quenching tank, against the both sides of the incoming strip. The second-step quenching is carried out by spraying a large quantity of high-pressure quenching liquid through the submerged nozzles on both sides of the strip across the entire width, uniformly on the same hori-zontal level, in the quenching liquid when the strip, which has undergone the first-step quenching, enters the quenching liquid in the quenching tank.
- In carrying out the method of an aspect of this invention, any of water, oil and other liquid quenching media may be used as quenching liquid, but water is practical. To obtain a good result, high-pressure quenching liquid having a pressure of 2 - 20 kg/cm2 in the high-pressure quenching liquid supply tube is recommended for the first-step quenching, and for the second-step quenching, a pressure preferably used is between 10 kg/cm2 - ' A~ mentioned above, quench stains are believed to be attribut-able to the non-unlEorm quenching in the initial stage of quenchlng, which is brought about by, for instance, surface turbulence of quenching liquid in the quenching tank caused by the entering strip, by splashing of quenching liquid on the strip, and by the unevenly deposited steam film on the strip. In the first-step quenching step of the method of an aspect of this invention,.however, because the both sides of the strip are quenched uniformly over the entire width on the same horizontal level with uniform quenching obtained in the initial stage, the produc-tion of quench stains is substantially completely prevented. Also, a low quenching rate in the first-step quenching does not impair the develop-ment of an alloyed layer in the tin-plated layer, making it possible to obtain excellent corrosion resistance.
Further particulars concerning aspects of this invention are given below, as described in the examples, and by reference to drawings.
4(~(~77 EX~PLE 1 Example 1 is an example in which the above-mentioned first-step quenching is carried out with quenching liquid mist; and ~igures 1, 2 and 3 are its sketches. In Figures 1, 2 and 3, 1 represents con-tinuously electrolytic tin-plated steel strip which moves in the direc-tion of arrow; 2 indicates a continuous heating furnace; and 3, a quenching tank comprising an entry 3a and an exit 3b for quenching liquid. Quenching liquid is supplied through entry 3a and quenching liquid having filled quenching tank 3 flows over exit 3b. 4 is a sinker roll supported bv watertight bearings on the quenching tank 3. 5 (Fig-ure 3) stands for a tube supplying quenching liquid to be dispersed into - mist, and 6 a compressed air reservoir comprising a co~pressed air blasting tube 6a (Figure 3). 7 represents a spray nozzle to spray quen^hing liquid mist. As shown in Figure 3, compressed air is sent through compressed air blowing tube 6a to compressed air reservoir 6.
On the other hand, quenching liquid is supplied through quenching liquid supply tube 5 to the spray noæzle 7. Quenching liquid is dispersed by compressed alr in the spray nozzle 7, and quenching liquid mist takes the orm of high-speed ~et stream under the pressure of compressed air to be sprayed by spray nozzle 7. Several spray nozzles 7 are respec-~ively installed on the pair of compressed air reservoirs 6, on both sides of the strip 1, on the same horizontal level above the surface of quenching liquid in the quenching tank 3, in such a manner as to form an angle within the range of between right angles (i.e., 90) and 45 upwardly,with respect to the vertical, against moving strip 1. Figure 2 shows an example of three spray nozzles 7 installed on one side. The number of spray nozzles 7 can '~e properly chosen so as to spray quenching liquid mist uniformly onto both sides of the strip 1 across the entire width. 8 is a submerged high-pressure quenching liquid supply tube to submerged nozzles 9 spraying high-pressure quenching liquid. A plurality of submerged nozzles 9 are respectively installed on the pair of high-pressure quenching liquid supply tubes 8 on both sides of the strip 1, on 04U1~77 the same horizontal level beneath the surface of quenching liquid in the quenching tank 3, in such a manner as to form an angle within the range of between right angles (i.e. 90) and 45 upwardly, with respect to the vertical, against moving strip 1. The number of submerged nozzles can be properly chosen as lS the case of spray nozzle 7 Now, continuously electrolytic tin-plated steel strip 1, after its tin-plated layer has been fused by heating in the continuous heating furnace 2 at 240C. - 300C., descends nearly vertically and the first-step quenching, i.e., quenching in the initial stage, is applied to the strip 1 with quenching liquid mist sprayed through spray nozzles 7, in - the air above the surface of quenching liquid in the quenching tank 3.
Spray nozzles 7, as mentioned above, are installed on both sides of fitrip 1 on the same horizontal level, so that very finely divided quenching liquid is sprayed onto both sides of strip 1 uniformly across the entire width on the same horizontal level. Both sides of strip 1 are uniformly quenched over the entire width without significant uneven-ness in the lnitial stage quenching, thus substantially completely pre-venting the productlon of quench stains. Also, as the quenching is done ln the air~ the quenchlng rate ls low, the development of an unalloyed layer in the tln-plated layer is not substantially hindered. As a result, lt ls posslble to obtain excellent corrosion resistance.
Then, strip 1 immediately enters quenching liquid in the quenching tank 3, and is quenched to a prescribed temperature at a high quenching rate by the application of the second-step quenching, namely, the final quenching, beneath the surface of the quenching liquid, a large quantity of high-pressure quenching liqu-d being sprayed out from sub-merged noæzles 9. Then, strip 1, moving outside quenching tank 3 by way of sinker roll ~, is sent to the following process. It has been confirmed that 2 - 20 kg/cm2, preferably ~ - 10 kg/cm2 pressure of the high-pressure and large quantity quenching liquid in submerged high-pressure quenching liquid supply tube 8 brings about a good result. As described above, submerged nozzles 9 are installed on both sides oE strip 1 on the same . . .
horizontal level. In the second-step quenching, therefore, strip 1 comes in contact with a large quantit~ of high-pressure quenching liquid sprayed through submerged nozzles 9 in addition to quenching liquid in the quenching tank 3. Accordingly, strip 1 is quenched at a high quenching rate to permit high-speed operation of the quenching line. In addition, because it is after the flrst-step quenching, namely, quenching in the initial stage, when quench stains are produced, acceleration of the quenching rate does not threaten the production of quench stains and adverse effects on the corrosion resistance. It is possible further to increase the quenching effect by adjusting the quenching liquid mist - sprayed from spary nozzles 7 to be lower in temperature than the sub-merged high-pressure quenching liquid sprayed from submerged nozzles ~, as the case requires.
Example 2 is an example in which the above-mentioned first-step quenching is done with high-pressure quenching liquid, Figurcs 4 and 5 being its sketches. Example 2 is the same as Example 1, except for the first-step quenching with quenching liquid mist in Example 1 replaced by the first-step quenching with high-pressure quenchlng liquid. The follow-ing explanation centers around points different from Example 1.
In Figures l~ and 5, 61 is a high-pressure quenching liquid supply tube, and 71, a spray nozzle to spray high-pressure quenching liquid. ~ plurality of spray nozzles 71 are respectively installed on the pair of high-pressure quenching supply tubes 61, on both sides of strip 1, on the same horizontal level abw-e the surface of quenching liquid in the quenching tank 3, in such a manner as to form an angle within the range of between an upwardly parallel position (i.e. almost vertical) and ~5 upwardly, with respect to the vertical, against strip 1, which strip is adapted to move nearly vert:ically. Figure 5 shows an example of three spray nozzles 71 installed on one side, and the number of spray nozzles 71 can be properly chosen so as to spray high--pressure quenching liquid uniformly onto both sides of the strip 1 across the entire width. It has been confirmed that 2 - 20 kglcm2 pressure in the high-pressure quenching liquid supply t'ube 61 brings about a good resuL~.
72 stands for a guide'plate for high-pressure quenching liquid sprayed through spray nozzles 71. Guide plate 72, as illustrated in Figure 4, has its top end curved toward strip 1, which strip is adapted to move nearly vertically, and topmost part oE each guide plate ends on the same horizontal level. The width of guide plate 72, as shown in Figure 5, is a little wider than that of the strip 1. Further, guide plates 72 are symmetrically fixed on high-pressure quenching liquid supply tube 61, one for each, on both sides of strip l.
Now, continuously electrolytic tin-plated steel strip l, after its tin-plated layer has been fused by heating iD the continuous heating furnace 2 at 240C. - 300C., descends nearly vertically and the first-step quenching~ namely, quenching in the initial stage, is applied to the strip 1 with high-pressure quenching liquid sprayed through spray nozzles 71, in the air above tha surface of quenching liquid in the quenching tank 3. ~ligh-pressure quenching liquid is sprayed~through spray nozzles 71 onto both sides of strip 1 uniformly across the entire width on the same horizontal level, without splashing directed by guide plate 72 ~u~t as one smooth plate, so that strip 1 is quenched uniformly over the entire width without unevenness in the initlal stage quenching, thus substantially completely preventing the production of quench stains.
Also, as the quenching is done in the air, the quenching rate is low, not impairing the development of an alloyed layer in the tin-plated layer.
~s a result, it is possible to obtain excellent corrosion resistance.
Next, strip 1 enters quenching liquid in the quenching tank 3 and undergoes the second-step quenching, namely, the final quenching, but since the quenching method and apparatus in this second step are the same as in the case of Exa~ple 1, their explanation is omitted. ~lso, the fact'that the quenching effect can be further increased by adiusting the temperature of the high-pressure quenching liquid to be sprayed through spray nozzles 71 to below that of the submerged high-pressure quenching liquid to be sprayed th ~ ~h4su~me ged nozzle 9 is the same as in the case of Example 1.
As mentioned above, according to the method and apparatus of aspects of this invention, it is possible, on quenching continuously electrolytic tin-plated steel strip with its tin-plated layer fused by heating, substantially completely to prevent the production of quench stains and to give excellent corrosion resistance as well as a beautiful gloss to the tin-plated layer of the strip. Further, there are other industrial advantages such as, for example, the realiæation of the high-speed quenching line and simple facilities at relatively low installationcosts. .
This in~ention relates to a method and apparatus for quenching continuously electrolytic tin-plate steel strip to tend to prevent the occurrence of stains on the surface of its tin-plated layer while carry-ing out steps to brighten its tin-plated layer by continuously heating and quenching the moving s-~eel strip.
The surface of the plated layer of a tin-plated steel strip produced by a commonly known continuous electrolytic tin-plating méthod is dull and has no gloss. In order to impart gloss to the surface of the thus tin-plated layer, the prior art traditionally teaches the method of heating the strip in a continuous heating furnace to cause rapid fusion of the tin-plated layer, and then immediately directing the strip in~to a quenching tank to quench it for the solidification of the tin-pla-ted layer.
If the quenching is improperly applied, however, dirt patterns which loolc like dried stains of dirty water (hereinafter referred to as "quench stain") are produced on the surface of tin-plated layer of the strip, conslderably reducing the commercial value of the strip.
The quench st~in is believed to be produced by an unevenly quenched tin-plated layer due to the irregular quenching rate caused by a non-uniform contact between the strip and the quenching liquid. This is believed to be brought about by surface turbulence of the quenching liquid in the quenching tank on introducing the strip into it, by splashes of quenching liquid onto the strip, and by uneven deposit of steam film, which is generated by quenching, on the strip.
Also, the tin-plated layer of the strip produces an alloyed layer of tin and iron at its fusion. It is necessary to make such alloyed layer uniform and dense in order to obtain excellent corrosion resistance. For this purpose, there should be a certain duration in time sufficient to cause progressive development of the alloyed layer.
In other words, slowing down of the quenching rate of the strip is required to a certain degree. On the other hand, however, increasing the quenching rate is required for accelerating the quenching line operation~
' -- 1 - 5~
.
~ V4~717 In order to solve these problems, there have been a number of proposals. In a method disclosed in United States Patent No. 3,358,980 issued December 19, 1967 to H. L. Taylor, for instance, two compartments with a hood and spaced plates are installed in a quenching tank, and surface turbulence on the surface of the quench-ing liquid in the quenching tank caused by the incoming strip is pre~
vented by the use of the said spaced plates. Besides, a narrow region is confined by the spaced plates, and the heated strip is directed into this narrow region. The quenching liquid first fed into such compart-ments flows down into the quenching tank by gravity along the both sidesof the strip, in the same direction as the travel of the strip, and almost ill parallel with the strip, in the narrow region, and after filling up the quenching tank, the quenching liquid overflows. Initially, the ætrip, brought into contact with the quenching liquid in the narrow region, is quenched at a relatively slow quenching rate, and then is moved into the quenching tank, being quenched down to the prescribed temperature. Further, a temperature sensing device is provided in the narrow reglon to control the quenching liquid temperature.
Accordlng to the above-mentioned method, no surface turbul~nce is produced on the surface of the quenching liquid in the quenching tank on introducing the strip into it, so that the tin-plated layer is quenched uniformly, tending to prevent the formation of quench stains.
~lowever, in this method, because the quenching liquid comes into contact with the strip while flowing down in the narrow region by gravity, the^
impact of the quenching liquid against the strip is small. Nevertheless, with the recent speeding-up of a continuous electrolytic tin-plating line, the moving speed of the strip has been accelerated up to some 300 - 450 mlmin. Accordingly, quenching capacity obtained only by a stream of quenching liquld by flowing gravity as is the case of this method is insufficient. With an insufficient quenching capacity, steam generating at the interface between the strip and the quenching liquid accompanies the strip, being deposited on the surface of the strip. As a result, irregularities are found in the quenching rate of the tin-plated layer, which is not uniformly quenched, so that it is impossible com-pletely to prevent the occurrence of quench stains. In other words, this method is not applicable to a high-speed continuous electrolytic tin-plating llne. Besides, it is necessary to provide the quenching tank with a hood, spaced plates and co~partments, leading to increased costs of quenching facilities.
Further, in the method disclosed in United States Patent No.
3,410,734 issued November 12, 1968 to H. L. Taylor, an elongated conduit section of rectangular cross-section is included which provides a restricted quench channel extending upwardly from a quenching tank. The quenching liquid supplied into the quenching tank after filling up the quenching tank, comes up in the restricted quench channel and flows over its upper end into a trough. Closely adjacent the upper end of the restricted quench channel, a plurality of submerged jet or spray units are provided for directing streams of quenching liquld toward the strip across the entire width thereof. The heated steel strlp moves downwardly Erom the heating furnace and enters the restrlcted quench channel where it is immediately immersed in the upward-ly flowing stream oE quenching liquid. In addition, the submerged jetor spray units direct streams oE quenching liquid against the strip in a direction generally normal to the strip. The submerged jet or spray units use a large quantity of quenching liquid with a relatively low .
pressure of 1.4 - 2.1 kg/cm2.
According to the above-mentioned method, the strip can be quenched ove~ the entire width uniformly and at a high rate. Therefore, this method is applicable, in particular, for obtaining strips having martensitic microstructure and superior flatness. However, this method includes no special regard for the prevention of quench stains and for the achievement of excellent corrosion resistance. Particularly, no regard is paid to such points as developing, in the tin-plated layer, an alloyed layer necessary for obtaining an excellent corFosion resistance, .
in other words, making the quenching rate in the initial stage of quench-ing relatively slower. The method has ~nother disadvantage of req~iring a complicated quenching device which increases installation costs.
A method is also known to fuse electrolytically deposited tin in a heating furnace aiming at improving the corrosion resistance on either the upper or the under surface of continuously electrolytic tin-plate steel strip, then to spray quenching liquid on either the upper or the under surEace of the strip, in the air of beneath the surface of the quenching liquid in the quenching tank, and, by quenching while holding a temperature difference between the both sides, to coarsen the grain size of tin on one side of the strip.
The method, though better in slow quenching in the initial stage of quenching, has no regard to uniform quenching of the strip over the entire width and quenching capacity. That is, in this method, increasing the pressure or the volume of water of submerged spray in the quenching tank in an attempt to lmprove the quenching capacity brings more serious surface turbulence of the quenching liquid in the quenching tanlc without permittlng unLform quenching of the strip over the entire width, resultlng in the impossibility of preventing the production of quench stalns. Moreover, quenching in the air by this method aims merely at controlling the tin crystals, with no regard to uniform quenching of the strip over the entire width.
As described above, it is desired to obtain continuously elec-trolytic tin-plated steel strip excellent in corrosion resistance as well as being glossy and with substantially no quench stain, but a method and apparatus to obtain strip with these properties have not as yet been proposed.
Therefore, it is an object of a main aspect of this invention to provide a strip quenching method and apparatus tending to prevent the production o~ quench stains on the surface of the tin-plated layer of co~tinuously electrolytic tin-plated steel strip, tending to eliminate the above-mentioned disadvantages of the conventional methods and devices.
An objec-t oF another aspect of -this invention is to provide a quenching method and appara-tus for such steel strip in order to give excellent corrosion resistance to con-tinuously electrolytic tin-plated steel strip.
By a broad aspect of this invention, a continuous quenching method is provided for quenching con-tinuously moving electrolytic tin-plated steel strip, comprising the steps of: (1) maintaining a relatively low quenching ra-te by spraying a quenching fluid mist onto continuously moving electrolytic tin-plated steel strip with its tin-plated layer fused thereto with heat in the air above the surface of a quenching liquid maintained in a quenching zone; (2) passing said strip into said quenching zone containing said quenching liquid;
and (3) maintainirlg a relatively higher quenching rate by spraying a larger quantity of quenching liquid under high pressure onto said strip beneath the surface of said quenching liquid in said quenching zone.
By another aspect, a method is provided of continuously quenching a Fused layer oF tin electrolytically plated on the surface oF a moving strip of steel issuing from a continuous hea-ting furnace wh:ich process coMprises passing said strip in-to a quenching apparatus and in a first quenching step, spraying a quenching liquid onto the tin-plated steel strip, and immediately af-ter tha-t, in a second quenching step, spraying quenching liquid at a pressure of from 2 to 20 Kg/cm onto the said strip benea-th the surface of quenching liquid in a quenching tank, -the quan-ti-ty of quenching liquid sprayed in said second quenching step being greater than that sprayed in said first quenching step.
By one yarian-t thereof, the first s-tep quenching includes spraying quenching liquid mist onto said strip.
By another variant -thereof, the first step quenching includes spraying high-pressure quenching liquid along a guide plate onto said strip.
By s-till another variant, the high-pressure quenching liquid used for said second step quenching is at a pressure of between 4 ~g/cm2 and 10 kg/cm2.
By a preferred variant, the quenching fluid is water.
By another aspect of this invention a method is provided for continuously quenching a continuously moving electrolytic tin-plated steel strip, the method comprising (1) maintaining a relatively low quenching rate of from 500 to 900C. per second by spraying a quenching liquid mist onto a continuously moving tin-plated steel s-trip with its tin-plated layer fused thereto with heat, in the air above -the surface of a quenching liquid maintained in a quenching tank, with a quantity of said quenching liquid of from 0.002 to 0.08 liter per square meter per minute; (2) passing said s-trip into said quenching tank containing said quenching liquid; and (3) maintaining a relatively higher quench-ing rate o:F from 1,100 to 1,300C. per second by spraying a larger quantity of quenching liquid oF a-t leas-t 1.2 li-ters per square meter per minute under a h:igh pressure on-to said strip beneath said surface in said quenching tank.
By still ano-ther aspect, such a method is provided comprising:
(1) rnaintaining a relatively low quenching ra-te of from 500 to 900C.
per second by spraying a quenching liquid at high pressure along a guide pla-te on-to a con-tinuously moving tin-plated steel s-trip wi-th its tin-pla-ted layer :Fused thereto with hea-t, in the air above -the surface of a quenching liquid maintained in a quenching tank, wi-th a quantity of said liquid of from 0.2 to 0.8 liter per square me-ter per minute, followed by (2) passing said strip into said quenching -tank containing said quenching liq~uid, and (3) maintaining a rela-tively higher quenching rate of from 1,100 to 1,300C, per second by spraying a ' .-4(~77 larger quantity of quenching liquid of at least 1.2 liters per squaremeter per minu-te under a high pressure on-to said strip beneath said surface in said quenching -tank.
By one variant thereof, the mist is so sprayed in (1) onto both sides of said strip from a plurali-ty of spray nozzles positioned on both sides of said strip across the entire width thereof and substantially on the SaJle horizontal level with each othèr.
By another variant, the liquid is so sprayed in (3) onto both sides of said strip from a plurality of spray nozzles positioned on both sides of said strip across the entire width thereof and substant-ially on the same horizontal level with each other.
By still another variant, the quenching liquid sprayed in (1) is at a pressure between 2 kg/cm2 and 20 kg/cm2, and in (3) is between 4 kg/cm2 and 10 kg/cm2.
By a fur-ther aspec-t, such method comprises the steps of:
moving said strip in a subs-tantially vertical direction -through the atmosphere; spraying a firs-t quantity of a quenching liquid mist towards sa.icl strip from both sides thereof and at substantially the same horizon-tal :Level, said spraying being directed at an angle within the range between a right angle and 45 in an upward direction relative to said substantially vertically moving strip; thereafter passing said strip in a subs-tantially vertical direc-tion into a quenching tank conrtaining a quenching liquid; and -then spraying a second quan-tity of a quenching liquid at high pressure toward said strip from both sides thereof below -the surface of -the quenching liquid in said quenching tank and at substantially -the same horizon-tal level below -the surface of the quenching liquid in said quenching -tank 7 said high-pressure spraying being direc-ted at an angle wi-thin -the range between a right angle and ~5 in an upward direc-tion rela-tive -to said substantially vertically moving strip, said second quantity of quenching liquid being -5b-. .
7~
greater than said firs-t quan-ti-ty.
By a still further ~spect, such method comprises the s-teps of: moving said strip in a substantially vertical direction through said atmosphere between a-t least a pair of guide plates; spraying a first quantity of high-pressure quenching liquid toward said strip from bo-th sides -thereof, and at substantially the same horizontal level, said spraying being directed at an angle within the range between an upwardly directed parallel direction and ~5 in an upward direction relative to said substantially vertically moving strip, at least a portion of said high-pressure quenching liquid spray being directed toward said guide plates; deflecting with said guide plates said portion of said high-pressure quenching liquid spray directed thereon toward said strip, the uppermost par-t of said guide plates being curved toward said strip, the curved uppermost parts ending substantially at -the same horizontal level; thereafter passing said strip in a substan-tially vertical direction into a quenching tank containing a quenching liquid; and then spraying a second quantity o:F a high-press~re quenching liquid toward said strip from bo-th sides thereof below the sur.Face o:F -the quenching liquid in said quenching tank and at substantially the same horizon-tal level below the surface of the quenching liquid in said quenching tank, said high~pressure spraying being directed at an angle within the range between a right angle and 45 in an upward direction relative to said substantially vertically moving strip, and said second quantity being greater than said firs-t quantity.
~ y ano-ther aspect of -this invention, a quenching apparatus is provided for con-tinuously quenching a continuously moving electro-lytic tin-pla-ted steel strip, comprising:(l) a quenching tank adap-ted to con-tain quenching liquid; (2) means for spraying fluid on both sides of said strip, on the same horizon-tal level above -the surface of -5c-'-`` lV~0()77 quenching fluid in said quenching tank, against said strip at an angle between 90 and 45 upwardly, with respect to the vertical, thereby to direct liquid over the entire width of said strip; and (3~ means for spraying high-pressure quenching liquid, on the same horizontal level below the surface of quenching liquid in said quenching tank, at an angle between 90 and 45 upwardly, with respect to the vertical, thereby to direct liquid over the entire width of said strip.
By another aspect, such an apparatus is provided for continuously quenching a fused layer of tin electrolytically plated on the surface of a moving strip of steel issuing from a continuous heating furnace, which apparatus comprises: a quenching tank for containing quenching liquid, a plurality of first spray nozzles, on each side of the said strip, on the same horizontal level above the intended working surface of quenching liquid in the said quenching tank, directed at an angle within the range from 90 to 45 against the direction of motion of said strip and adapted to direct quenching liquid over the entire width of the strip; a pair of quenching liquid supply tubes; and a plurality of second nozzles arranged for spraying quenching liquid, installed on the said pair of quenching liquid supply tubes, on each side of the said strip, on the same horizontal level beneath the intended working surface of quenching liquid in the said quenching tank, directcd a-t an angle within the range from 90 to 45 against the direction of motion of the said strip and adapted to direct quenching liquid over the entire width of the strip.
By a variant thereof, -the first spray nozzles are connected to a pair of compressed air reservoirs whereby said nozzles spray a mist of quenching liquid.
By another Yariant the first spray nozzles are connected to a pair of pressurized quenching liquid supply tubes, whereby '`~;
~ -6-said spray pressurized quenching liquid.
By another aspect, such an apparatus is provided comprising:
a quenching tank adap-ted to contain quenching liquid; a pair of high-pressure quenching liquid supply tubes; a plurality of spray nozzles adapted -to spray high-pressure quenching liquid, installed on said pair of high-pressure quenching liquid supply -tubes, on both sides of said s-trip, on the same horizontal level above the surface of quenching liquid in said quenching tank, in such a manner as to - form an angle within the range of between substantially parallel to said strip and 45 upwardly, with respect to the vertical, against said strip, thereby to direct liquid over the entire width of said strip; a pair of guide plates, installed on said pair of high-pressure quenching liquid supply tubes, on both sides of said strip, and adapted to direct said high-pressure quenching liquid sprayed through said spray nozzles onto said s-trip, said guide plates being wider than said strip, with the top end of said plates being curved toward said s-trip and with the topmost part of said plates each ending on the same horizontal level; a pair of high-pressure quenching liquid supply tubes adaptecl to be submerged below the surEace of liquid in said tan]c; and a plurality oF nozzles adap-ted to be submerged below -the surlace of liquid in saicl tank, and adapted -to spray high-pressure quenching liquid, installed on said pair of high-pressure quenching liquid supply tubes, on both sides oE said strip, on the same horizontal level w:ithin said quenching tank, in such a manner as to form an angle within -the range of between 90 and 45 upwardly, with respect to the yer-tical ? agains-t said strip, thereby -to direct liquid oyer the entire wid-th of said strip.
By s-till another aspec-t, such an appara-tus is provided comprising: a quenching tank containing a quenching liquid; a pair of compressed-air~ reservoirs; a source of quenching liquid; a ~ ~ -6a-$77 plurality of spray nozzles for spraying quenching liquid mist coupled to said quenching liquid source and said compressed-air reservoirs, said-. nozzles being positioned on both sides of said strip and on substantially the same horizontal level above the surface of the quenching liquid in said quenching tank, said nozzles forming an angle within the range between a right angle and 45 in an upward direction relative to said strip which moves substan-tially vertically in the vicinity of sai~-~ nozzles, -thereby to direct quenching liquid over the entire width of said strip; a pair of high-pressure quenching ... .
liquid supply -tubes submerged in said tank; and a plurality of sub-merged nozzles for spraying submerged high-pressure quenching liquid coupled to said submerged high-pressure quenching liquid supply tubes, sa.id submerged nozzles being positioned on both sides of said strip and on subs-tantially the same horizontal level benea-th the surface of the quenching liquid in said quenching tank, sa.id submerged nozzles forming an angle within the range be-tween a righ-t angle and 45 in an upward direct:ion relative to said strip which moves substantially vertically in the vicinity of said submerged nozzles, thereby to direct quenching liquid over the entire width of said s-trip.
By yet a further aspect, such an apparatus is provided comprising: a quenching tank containing a quenching liquid; a pair of high-pressure quenching liquid supply -tubes; a plurality of spray nozzles coupled to said high-pressure quenching liquid supply tubes for spraying high-pressure quenching liquid, said nozzles being positioned on bo-th sides of said strip and on substan-tially the same horizontal level above the surface of the quenching liquid in said quenching tank~ said nozzles forming an angle within the range be-tween an upwardly directed parallel position and 45 in an upward direction relative to said strip which moves substantially vertically in the vicinity of said spray nozzles, -thereby to direct quenching ~ -6b-~ r~
liquid over -the en-tire width of said s-tripj a pair of guide plates positioned adjacent a respective high-pressure quenching liquid supply tube; one guide pla-te being located on opposite sides of said s-trip, said guide plates being wider than said s-trip, sai~-~ guide pla-tes having upper ends which are above said spray nozzles and which are curved toward said strip, said guide pla-tes having their -topmost parts ending on substantially the same horizontal level for directing said high-pressure quenching liquid sprayed through said spray nozzles onto said strip; a pair of high-pressure quenching liquid supply o tubes submerged in said tank; and a plurality of submerged nozzles for spraying submerged high-pressure quenching liquid coupled to said submerged high-pressure quenching liquid supply tubes, said submerged nozzles being posi-tioned on both sides of said strip and on substant~
ially the same horizontal level beneath the surface of the quenching liquid in said quenching tank, said submerged:nozzles forming an angle wi-thin the range be-tween a right angle and ~5 in an upward direc-tion relative -to said s-trip which moves substantially vertically in the vi.cinity of said submerged nozzles, thereby to direc-t quenching liquid over -the entire width of said strip.
-6c-In the accompanying drawings, Figure 1 is a normal sec-~ional schematic sketch showing an example of a device usable for putting the method of an aspect of this invention into practice;
Figure 2 is a sectional sketch along line A-A' of Figure l;
. Figure 3 is a sec-tional view showing an example of a nozzle to pulverize and spray quenching liquid;
Figure 4 is a normal sectional schematic sketch showing another example of a device usable for putting the method of an aspect of this invention into practice; and Figure 5 is a sec-tional view along line B-B of Figure 4.
In order to impart a gloss to the tin-plated layer of ,~ , -7-1~34U~ '7 continuousl~ electrol~tic tin-plated steel strip, as mentioned above, the strip is usually heated in a continuous heating furnace to fuse the tin-plated layer rapidly, and by quenching the strip immediately after that, the tin-plated layer is solidified. Unless the strip is quenched uniformly over the entire width, the tin-plated layer is not quenched uniformly, tending to cause the occurrence of quench stains on the sur-face of the tin-plated layer. These quench stains are produced in the initial stage of the above-mentioned quenching. Corrosion resistance of continuously electrolytic tin-plated steel strip, on the other hand, improves by achieving a uniform and dense alloyed layer of iron and tin produced on heating the strip and fusing the tin-plated layer. For the purpose of achieving excellent corrosion resistance, therefore, it is desirable to slow down the quenching rate of the strip in the initial stage of quenching, to cause progressive development of the alloyed layer.
By the method of an aspect of this invention, taking notice of the Eact described above, after fusing the tin-plated layer of continu-ously electrolytic tln-plated steel strip in a continuous heating furnace, a Eirst-step quenching at a low rate is carried out, in the initial stage oE quenchLng, and then in the later stage oE quenching, a second-step quenching at a high rate is carried out.
By the method of an aspect of this invention, the plurality of spray nozzLes are respectively installed on the same horizontaI level above the surface of quenching liquid in the quenching tank which is installed below the continuous heating furnace, against both sides of the incoming strip. The above-described first-step quenching :Ls carried out in the following manner: before the strip, with its tin-plated layer fused by the continuous heating furnace, moves almost vertically down-wardly into quenching liquid in the quenching tank, quenching liquid mist or a stream of high-pressure quenching liquid is sprayed through the spray nozzles on both sides of the strip across the entire width, uniform-ly on the same horizontal level, :in the air above the surface of the quenching liquid.
_ ~ _ '77 Also, according to the method of an aspect of this invention, the plural number of submerged nozzles are respectively installed on the same horizontal level beneath the surface of quenching liquid in the quenching tank, against the both sides of the incoming strip. The second-step quenching is carried out by spraying a large quantity of high-pressure quenching liquid through the submerged nozzles on both sides of the strip across the entire width, uniformly on the same hori-zontal level, in the quenching liquid when the strip, which has undergone the first-step quenching, enters the quenching liquid in the quenching tank.
- In carrying out the method of an aspect of this invention, any of water, oil and other liquid quenching media may be used as quenching liquid, but water is practical. To obtain a good result, high-pressure quenching liquid having a pressure of 2 - 20 kg/cm2 in the high-pressure quenching liquid supply tube is recommended for the first-step quenching, and for the second-step quenching, a pressure preferably used is between 10 kg/cm2 - ' A~ mentioned above, quench stains are believed to be attribut-able to the non-unlEorm quenching in the initial stage of quenchlng, which is brought about by, for instance, surface turbulence of quenching liquid in the quenching tank caused by the entering strip, by splashing of quenching liquid on the strip, and by the unevenly deposited steam film on the strip. In the first-step quenching step of the method of an aspect of this invention,.however, because the both sides of the strip are quenched uniformly over the entire width on the same horizontal level with uniform quenching obtained in the initial stage, the produc-tion of quench stains is substantially completely prevented. Also, a low quenching rate in the first-step quenching does not impair the develop-ment of an alloyed layer in the tin-plated layer, making it possible to obtain excellent corrosion resistance.
Further particulars concerning aspects of this invention are given below, as described in the examples, and by reference to drawings.
4(~(~77 EX~PLE 1 Example 1 is an example in which the above-mentioned first-step quenching is carried out with quenching liquid mist; and ~igures 1, 2 and 3 are its sketches. In Figures 1, 2 and 3, 1 represents con-tinuously electrolytic tin-plated steel strip which moves in the direc-tion of arrow; 2 indicates a continuous heating furnace; and 3, a quenching tank comprising an entry 3a and an exit 3b for quenching liquid. Quenching liquid is supplied through entry 3a and quenching liquid having filled quenching tank 3 flows over exit 3b. 4 is a sinker roll supported bv watertight bearings on the quenching tank 3. 5 (Fig-ure 3) stands for a tube supplying quenching liquid to be dispersed into - mist, and 6 a compressed air reservoir comprising a co~pressed air blasting tube 6a (Figure 3). 7 represents a spray nozzle to spray quen^hing liquid mist. As shown in Figure 3, compressed air is sent through compressed air blowing tube 6a to compressed air reservoir 6.
On the other hand, quenching liquid is supplied through quenching liquid supply tube 5 to the spray noæzle 7. Quenching liquid is dispersed by compressed alr in the spray nozzle 7, and quenching liquid mist takes the orm of high-speed ~et stream under the pressure of compressed air to be sprayed by spray nozzle 7. Several spray nozzles 7 are respec-~ively installed on the pair of compressed air reservoirs 6, on both sides of the strip 1, on the same horizontal level above the surface of quenching liquid in the quenching tank 3, in such a manner as to form an angle within the range of between right angles (i.e., 90) and 45 upwardly,with respect to the vertical, against moving strip 1. Figure 2 shows an example of three spray nozzles 7 installed on one side. The number of spray nozzles 7 can '~e properly chosen so as to spray quenching liquid mist uniformly onto both sides of the strip 1 across the entire width. 8 is a submerged high-pressure quenching liquid supply tube to submerged nozzles 9 spraying high-pressure quenching liquid. A plurality of submerged nozzles 9 are respectively installed on the pair of high-pressure quenching liquid supply tubes 8 on both sides of the strip 1, on 04U1~77 the same horizontal level beneath the surface of quenching liquid in the quenching tank 3, in such a manner as to form an angle within the range of between right angles (i.e. 90) and 45 upwardly, with respect to the vertical, against moving strip 1. The number of submerged nozzles can be properly chosen as lS the case of spray nozzle 7 Now, continuously electrolytic tin-plated steel strip 1, after its tin-plated layer has been fused by heating in the continuous heating furnace 2 at 240C. - 300C., descends nearly vertically and the first-step quenching, i.e., quenching in the initial stage, is applied to the strip 1 with quenching liquid mist sprayed through spray nozzles 7, in - the air above the surface of quenching liquid in the quenching tank 3.
Spray nozzles 7, as mentioned above, are installed on both sides of fitrip 1 on the same horizontal level, so that very finely divided quenching liquid is sprayed onto both sides of strip 1 uniformly across the entire width on the same horizontal level. Both sides of strip 1 are uniformly quenched over the entire width without significant uneven-ness in the lnitial stage quenching, thus substantially completely pre-venting the productlon of quench stains. Also, as the quenching is done ln the air~ the quenchlng rate ls low, the development of an unalloyed layer in the tln-plated layer is not substantially hindered. As a result, lt ls posslble to obtain excellent corrosion resistance.
Then, strip 1 immediately enters quenching liquid in the quenching tank 3, and is quenched to a prescribed temperature at a high quenching rate by the application of the second-step quenching, namely, the final quenching, beneath the surface of the quenching liquid, a large quantity of high-pressure quenching liqu-d being sprayed out from sub-merged noæzles 9. Then, strip 1, moving outside quenching tank 3 by way of sinker roll ~, is sent to the following process. It has been confirmed that 2 - 20 kg/cm2, preferably ~ - 10 kg/cm2 pressure of the high-pressure and large quantity quenching liquid in submerged high-pressure quenching liquid supply tube 8 brings about a good result. As described above, submerged nozzles 9 are installed on both sides oE strip 1 on the same . . .
horizontal level. In the second-step quenching, therefore, strip 1 comes in contact with a large quantit~ of high-pressure quenching liquid sprayed through submerged nozzles 9 in addition to quenching liquid in the quenching tank 3. Accordingly, strip 1 is quenched at a high quenching rate to permit high-speed operation of the quenching line. In addition, because it is after the flrst-step quenching, namely, quenching in the initial stage, when quench stains are produced, acceleration of the quenching rate does not threaten the production of quench stains and adverse effects on the corrosion resistance. It is possible further to increase the quenching effect by adjusting the quenching liquid mist - sprayed from spary nozzles 7 to be lower in temperature than the sub-merged high-pressure quenching liquid sprayed from submerged nozzles ~, as the case requires.
Example 2 is an example in which the above-mentioned first-step quenching is done with high-pressure quenching liquid, Figurcs 4 and 5 being its sketches. Example 2 is the same as Example 1, except for the first-step quenching with quenching liquid mist in Example 1 replaced by the first-step quenching with high-pressure quenchlng liquid. The follow-ing explanation centers around points different from Example 1.
In Figures l~ and 5, 61 is a high-pressure quenching liquid supply tube, and 71, a spray nozzle to spray high-pressure quenching liquid. ~ plurality of spray nozzles 71 are respectively installed on the pair of high-pressure quenching supply tubes 61, on both sides of strip 1, on the same horizontal level abw-e the surface of quenching liquid in the quenching tank 3, in such a manner as to form an angle within the range of between an upwardly parallel position (i.e. almost vertical) and ~5 upwardly, with respect to the vertical, against strip 1, which strip is adapted to move nearly vert:ically. Figure 5 shows an example of three spray nozzles 71 installed on one side, and the number of spray nozzles 71 can be properly chosen so as to spray high--pressure quenching liquid uniformly onto both sides of the strip 1 across the entire width. It has been confirmed that 2 - 20 kglcm2 pressure in the high-pressure quenching liquid supply t'ube 61 brings about a good resuL~.
72 stands for a guide'plate for high-pressure quenching liquid sprayed through spray nozzles 71. Guide plate 72, as illustrated in Figure 4, has its top end curved toward strip 1, which strip is adapted to move nearly vertically, and topmost part oE each guide plate ends on the same horizontal level. The width of guide plate 72, as shown in Figure 5, is a little wider than that of the strip 1. Further, guide plates 72 are symmetrically fixed on high-pressure quenching liquid supply tube 61, one for each, on both sides of strip l.
Now, continuously electrolytic tin-plated steel strip l, after its tin-plated layer has been fused by heating iD the continuous heating furnace 2 at 240C. - 300C., descends nearly vertically and the first-step quenching~ namely, quenching in the initial stage, is applied to the strip 1 with high-pressure quenching liquid sprayed through spray nozzles 71, in the air above tha surface of quenching liquid in the quenching tank 3. ~ligh-pressure quenching liquid is sprayed~through spray nozzles 71 onto both sides of strip 1 uniformly across the entire width on the same horizontal level, without splashing directed by guide plate 72 ~u~t as one smooth plate, so that strip 1 is quenched uniformly over the entire width without unevenness in the initlal stage quenching, thus substantially completely preventing the production of quench stains.
Also, as the quenching is done in the air, the quenching rate is low, not impairing the development of an alloyed layer in the tin-plated layer.
~s a result, it is possible to obtain excellent corrosion resistance.
Next, strip 1 enters quenching liquid in the quenching tank 3 and undergoes the second-step quenching, namely, the final quenching, but since the quenching method and apparatus in this second step are the same as in the case of Exa~ple 1, their explanation is omitted. ~lso, the fact'that the quenching effect can be further increased by adiusting the temperature of the high-pressure quenching liquid to be sprayed through spray nozzles 71 to below that of the submerged high-pressure quenching liquid to be sprayed th ~ ~h4su~me ged nozzle 9 is the same as in the case of Example 1.
As mentioned above, according to the method and apparatus of aspects of this invention, it is possible, on quenching continuously electrolytic tin-plated steel strip with its tin-plated layer fused by heating, substantially completely to prevent the production of quench stains and to give excellent corrosion resistance as well as a beautiful gloss to the tin-plated layer of the strip. Further, there are other industrial advantages such as, for example, the realiæation of the high-speed quenching line and simple facilities at relatively low installationcosts. .
Claims (22)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for continuously quenching a continuously moving electrolytic tin-plated steel strip, comprising the steps of:
(1) maintaining a relatively low quenching rate by spraying a quenching fluid onto a continuously moving electrolytic tin-plated steel strip with its tin-plated layer fused thereto with heat in the air above the surface of a quenching liquid maintained in a quenching zone;
(2) passing said strip into said quenching zone containing said quenching liquid and (3) maintaining a relatively higher quenching rate by spraying a larger quantity of quenching fluid under a high pressure onto said strip beneath the surface of said quenching liquid in said quenching zone.
(1) maintaining a relatively low quenching rate by spraying a quenching fluid onto a continuously moving electrolytic tin-plated steel strip with its tin-plated layer fused thereto with heat in the air above the surface of a quenching liquid maintained in a quenching zone;
(2) passing said strip into said quenching zone containing said quenching liquid and (3) maintaining a relatively higher quenching rate by spraying a larger quantity of quenching fluid under a high pressure onto said strip beneath the surface of said quenching liquid in said quenching zone.
2. The method for continuously quenching a fused layer of tin electrolytically plated on the surface of a moving strip of steel issuing from a continuous heating furnace as claimed in claim 1, which process com-prises passing said strip into a quenching apparatus and in a first quench-ing step, spraying a quenching liquid onto said strip, and immediately after that, in a second quenching step, spraying quenching liquid at a pressure of from 2 to 20 kg/cm2 onto said strip beneath the surface of a quenching liquid in a quenching tank, the quantity of quenching liquid sprayed in said second quenching step being greater than that sprayed in said first quenching step.
3. The method of claim 2 wherein said first-step quenching in-cludes spraying a quenching liquid mist onto said strip.
4. The method of claim 2 wherein said first-step quenching in-cludes spraying a high-pressure quenching liquid along a guide plate onto said strip.
5. The method of claims 1, 2 or 4 wherein said high-pressure quenching liquid used for said first-step quenching is at a pressure of between 2 kg/cm2 and 20 kg/cm2, and for said second-step quenching, at a pressure of between 4 kg/cm2 and 10 kg/cm2.
6. The method of claim 3 wherein said high-pressure quenching liquid used for said second-step quenching is at a pressure of between 4 kg/cm2 and 10 kg/cm2.
7. The method of claims 1, 2 or 3 wherein said quenching fluid or said quenching liquid is water.
8. The method for continuously quenching a continuously moving electrolytic tin-plated steel strip as claimed in claim 1, which comprises the steps of:
(1) maintaining a relatively low quenching rate of from 500 to 900°C. per second by spraying a quenching liquid mist onto a continuously moving tin-plated steel strip with its tin-plated layer fused thereto with heat, in the air above the surface of a quenching liquid maintained in a quenching tank, with a quantity of said quenching liquid of from 0.002 to 0.08 liter per square meter per minute;
(2) passing said strip into said quenching tank containing said quenching liquid; and (3) maintaining a relatively higher quenching rate of from 1,100 to 1,300°C. per second by spraying a larger quantity of quenching liquid of at least 1.2 liters per square meter per minute under a high pressure onto said strip beneath said surface in said quenching tank.
(1) maintaining a relatively low quenching rate of from 500 to 900°C. per second by spraying a quenching liquid mist onto a continuously moving tin-plated steel strip with its tin-plated layer fused thereto with heat, in the air above the surface of a quenching liquid maintained in a quenching tank, with a quantity of said quenching liquid of from 0.002 to 0.08 liter per square meter per minute;
(2) passing said strip into said quenching tank containing said quenching liquid; and (3) maintaining a relatively higher quenching rate of from 1,100 to 1,300°C. per second by spraying a larger quantity of quenching liquid of at least 1.2 liters per square meter per minute under a high pressure onto said strip beneath said surface in said quenching tank.
9. The method for continuously quenching a continuously moving electrolytic tin-plated steel strip as claimed in claim 1, comprising the steps of:
(1) maintaining a relatively low quenching rate of from 500 to 900°C. per second by spraying a quenching liquid at a high pressure along a guide plate onto a continuously moving tin-plated steel strip with its tin-plated layer fused thereto with heat, in the air above the surface of a quenching liquid maintained in a quenching tank, with a quantity of said liquid of from 0.2 to 0.8 liter per square meter per minute;
followed by (2) passing said strip into said quenching tank containing said quenching liquid; and (3) maintaining a relatively higher quenching rate of from 1,100 to 1,300°C, per second by spraying a larger quantity of quenching liquid of at least 1.2 liters per square meter per minute under a high pressure onto said strip beneath said surface in said quenching tank.
(1) maintaining a relatively low quenching rate of from 500 to 900°C. per second by spraying a quenching liquid at a high pressure along a guide plate onto a continuously moving tin-plated steel strip with its tin-plated layer fused thereto with heat, in the air above the surface of a quenching liquid maintained in a quenching tank, with a quantity of said liquid of from 0.2 to 0.8 liter per square meter per minute;
followed by (2) passing said strip into said quenching tank containing said quenching liquid; and (3) maintaining a relatively higher quenching rate of from 1,100 to 1,300°C, per second by spraying a larger quantity of quenching liquid of at least 1.2 liters per square meter per minute under a high pressure onto said strip beneath said surface in said quenching tank.
10. The method of claims 1, 8 or 9 wherein said quenching li-quid mist or said high-pressure quenching liquid is so sprayed in step (1) onto both sides of said strip from a plurality of spray nozzles positioned on both sides of said strip across the entire width thereof and substanti-ally on the same horizontal level with each other.
11. The method of claims 1, 8 or 9 wherein said high-pressure quenching liquid is so sprayed in (3) onto both sides of said strip from a plurality of spray nozzles positioned on both sides of said strip across the entire width thereof and substantially on the same horizontal level with each other.
12. The method of claim 8 wherein said high-pressure quenching liquid sprayed in (3) is at a pressure of between 4 kg/cm2 and 10 kg/cm2.
13. The method of claim 9 wherein said high-pressure quenching liquid sprayed in (1) is at a pressure of between 2 kg/cm2 and 20 kg/cm2, and in (3) at a pressure of between 4 kg/cm2 and 10 kg/cm2.
14. The method for continuously quenching a continuously moving electrolytic tin-plated steel strip, as claimed in claim 8, comprising the steps of:
moving said strip in a substantially vertical direction through the atmosphere;
spraying a first quantity of a quenching liquid mist toward said strip from both sides thereof and at substantially the same horizontal level, said spraying being directed at an angle within the range of be-tween a right angle and 45° in an upward direction relative to said sub-stantially vertically moving strip;
thereafter passing said strip in a substantially vertical di-rection into a quenching tank containing a quenching liquid; and then spraying a second quantity of a quenching liquid at a high pressure toward said strip from both sides thereof below the surface of the quenching liquid in said quenching tank and at substantially the same horizontal level below the surface of the quenching liquid in said quench-ing tank, said high-pressure spraying being directed at an angle within the range of between a right angle and 45° in an upward direction relative to said substantially vertically moving strip, said second quantity of quenching liquid being greater than said first quantity.
moving said strip in a substantially vertical direction through the atmosphere;
spraying a first quantity of a quenching liquid mist toward said strip from both sides thereof and at substantially the same horizontal level, said spraying being directed at an angle within the range of be-tween a right angle and 45° in an upward direction relative to said sub-stantially vertically moving strip;
thereafter passing said strip in a substantially vertical di-rection into a quenching tank containing a quenching liquid; and then spraying a second quantity of a quenching liquid at a high pressure toward said strip from both sides thereof below the surface of the quenching liquid in said quenching tank and at substantially the same horizontal level below the surface of the quenching liquid in said quench-ing tank, said high-pressure spraying being directed at an angle within the range of between a right angle and 45° in an upward direction relative to said substantially vertically moving strip, said second quantity of quenching liquid being greater than said first quantity.
15. The method for continuously quenching a continuously moving electrolytic tin-plated steel strip as claimed in claim 9, com-prising the steps of:
moving said strip in a substantially vertical direction through said atmosphere between at least a pair of guide plates;
spraying a first quantity of a high-pressure quenching liquid toward said strip from both sides thereof, and at substantially the same horizontal level, said spraying being directed at an angle within the range of between an upwardly directed parallel direction and 45° in an upward direction relative to said substantially vertically moving strip, at least a portion of said high-pressure quenching liquid spray being directed to-ward said guide plates;
deflecting with said guide plates said portion of said high-pressure quenching liquid spray directed thereon toward said strip, the uppermost part of said guide plates being curved toward said strip, the curved uppermost parts ending substantially at the same horizontal level;
thereafter passing said strip in a substantially vertical direction into a quenching tank containing a quenching liquid; and then spraying a second quantity of a high-pressure quenching li-quid toward said strip from both sides thereof below the surface of the quenching liquid in said quenching tank and at substantially the same hori-zontal level below the surface of the quenching liquid in said quenching tank, said high-pressure spraying being directed at an angle within the range of between a right angle and 45° in an upward direction relative to said substantially vertically moving strip, and said second quantity being greater than said first quantity.
moving said strip in a substantially vertical direction through said atmosphere between at least a pair of guide plates;
spraying a first quantity of a high-pressure quenching liquid toward said strip from both sides thereof, and at substantially the same horizontal level, said spraying being directed at an angle within the range of between an upwardly directed parallel direction and 45° in an upward direction relative to said substantially vertically moving strip, at least a portion of said high-pressure quenching liquid spray being directed to-ward said guide plates;
deflecting with said guide plates said portion of said high-pressure quenching liquid spray directed thereon toward said strip, the uppermost part of said guide plates being curved toward said strip, the curved uppermost parts ending substantially at the same horizontal level;
thereafter passing said strip in a substantially vertical direction into a quenching tank containing a quenching liquid; and then spraying a second quantity of a high-pressure quenching li-quid toward said strip from both sides thereof below the surface of the quenching liquid in said quenching tank and at substantially the same hori-zontal level below the surface of the quenching liquid in said quenching tank, said high-pressure spraying being directed at an angle within the range of between a right angle and 45° in an upward direction relative to said substantially vertically moving strip, and said second quantity being greater than said first quantity.
16. An apparatus for continuously quenching a continuously moving electrolytic tin-plated steel strip, comprising:
(1) a quenching tank adapted to contain a quenching liquid;
(2) means for spraying a quenching fluid on both sides of said strip, on substantially the same horizontal level above the surface of a quenching fluid in said quenching tank, against said strip at an angle of between 90° and 45° upwardly, with respect to the vertical, thereby to direct said quenching fluid over the entire width of said strip;
and (3) means for spraying a high-pressure quenching liquid on both sides of said strip, on substantially the same horizontal level below the surface of the quenching liquid in said quenching tank, against said strip at an angle of between 90°
and 45° upwardly, with respect to the vertical, thereby to direct said high-pressure quenching liquid over the entire width of said strip.
(1) a quenching tank adapted to contain a quenching liquid;
(2) means for spraying a quenching fluid on both sides of said strip, on substantially the same horizontal level above the surface of a quenching fluid in said quenching tank, against said strip at an angle of between 90° and 45° upwardly, with respect to the vertical, thereby to direct said quenching fluid over the entire width of said strip;
and (3) means for spraying a high-pressure quenching liquid on both sides of said strip, on substantially the same horizontal level below the surface of the quenching liquid in said quenching tank, against said strip at an angle of between 90°
and 45° upwardly, with respect to the vertical, thereby to direct said high-pressure quenching liquid over the entire width of said strip.
17. The apparatus as claimed in claim 16 for continuously quench-ing a fused layer of tin electrolytically plated on the surface of a moving strip of steel issuing from a continuous heating furnace, which apparatus comprises: a quenching tank for containing a quenching liquid; a plurality of first spray nozzles, an each side of said strip, on substantially the same horizontal level above the intended working surface of a quenching liquid in said quenching tank, directed at an angle within the range of from 90° to 45° upwardly against the direction of motion of said strip and adapted to direct a quenching liquid over the entire width of said strip;
a pair of quenching liquid supply tubes; and a plurality of second nozzles arranged for spraying a quenching liquid, installed on said pair of quench-ing liquid supply tubes, on each side of said strip, on substantially the same horizontal level beneath the intended working surface of the quenching liquid in said quenching tank, directed at an angle within the range of from 90° -to 45° against the direction of motion of said strip and adapted to direct a quenching liquid over the entire width of the strip.
a pair of quenching liquid supply tubes; and a plurality of second nozzles arranged for spraying a quenching liquid, installed on said pair of quench-ing liquid supply tubes, on each side of said strip, on substantially the same horizontal level beneath the intended working surface of the quenching liquid in said quenching tank, directed at an angle within the range of from 90° -to 45° against the direction of motion of said strip and adapted to direct a quenching liquid over the entire width of the strip.
18. The apparatus as claimed in claim 17 wherein said first spray nozzles are connected to a pair of compressed air reservoirs whereby said nozzles spray a mist of quenching liquid.
19. The apparatus as claimed in claim 17 wherein said first spray nozzles are connected to a pair of pressurized quenching liquid supply tubes, whereby said nozzles spray a pressurized quenching liquid.
20. The apparatus as claimed in claim 16 for continuously quench-ing a continuously moving electrolytic tin-plated steep strip, comprising:
a quenching tank adapted to contain a quenching liquid; a pair of high-pressure quenching liquid supply tubes; a plurality of spray nozzles adapted to spray a high-pressure quenching liquid, installed on said pair of high-pressure quenching liquid supply tubes, on both sides of said strip, on substantially the same horizontal level above the surface of a quenching liquid in said quenching tank, in such a manner as to form an angle within the range of between substantially parallel to said strip and 45° upwardly, with respect to the vertical, against said strip, thereby to direct said high-pressure quenching liquid over the entire width of said strip; a pair of guide plates, installed on said pair of high-pressure quenching liquid supply tubes, on both sides of said strip, and adapted to direct said high-pressure quenching liquid sprayed through said spray nozzles onto said strip, said guide plates being wider than said strip, with the top end of said plates being curved toward said strip and with the topmost part of said plates each ending on the same horizontal level; a pair of high-pressure quenching liquid supply tubes adapted to be submerged below the surface of the quenching liquid in said tank; and a plurality of nozzles adapted to be submerged below the surface of the quenching liquid in said tank, and adapted to spray a high-pressure quenching liquid, installed on said pair of submerged high-pressure quenching liquid supply tubes, on both sides of said strip, on substantially the same horizontal level beneath the surface of the quenching liquid in said quenching tank, in such a manner as to form an angle within the range of between 90° and 45° upwardly, with respect to the vertical, against said strip, thereby to direct said high-pressure quenching liquid over the entire width of said strip.
a quenching tank adapted to contain a quenching liquid; a pair of high-pressure quenching liquid supply tubes; a plurality of spray nozzles adapted to spray a high-pressure quenching liquid, installed on said pair of high-pressure quenching liquid supply tubes, on both sides of said strip, on substantially the same horizontal level above the surface of a quenching liquid in said quenching tank, in such a manner as to form an angle within the range of between substantially parallel to said strip and 45° upwardly, with respect to the vertical, against said strip, thereby to direct said high-pressure quenching liquid over the entire width of said strip; a pair of guide plates, installed on said pair of high-pressure quenching liquid supply tubes, on both sides of said strip, and adapted to direct said high-pressure quenching liquid sprayed through said spray nozzles onto said strip, said guide plates being wider than said strip, with the top end of said plates being curved toward said strip and with the topmost part of said plates each ending on the same horizontal level; a pair of high-pressure quenching liquid supply tubes adapted to be submerged below the surface of the quenching liquid in said tank; and a plurality of nozzles adapted to be submerged below the surface of the quenching liquid in said tank, and adapted to spray a high-pressure quenching liquid, installed on said pair of submerged high-pressure quenching liquid supply tubes, on both sides of said strip, on substantially the same horizontal level beneath the surface of the quenching liquid in said quenching tank, in such a manner as to form an angle within the range of between 90° and 45° upwardly, with respect to the vertical, against said strip, thereby to direct said high-pressure quenching liquid over the entire width of said strip.
21. The apparatus as claimed in claim 16 for continuously quench-ing a continuously moving electrolytic tin-plated steep strip, comprising:
a quenching tank comprising a quenching liquid;
a pair of compressed-air-reservoirs;
a source of quenching liquid; a plurality of spray nozzles for spraying quenching liquid mist coupled to said quenching liquid source and said compressed-air reservoirs, said nozzles being positioned on both sides of said strip and on substantially the same horizontal level above the surface of the quenching liquid in said quenching tank, said nozzles forming an angle within the range of between a right angle and 45° in an upward direction relative to said strip which moves substantially vertically in the vicinity of said nozzles, thereby to direct said quenching liquid mist over the entire width of said strip, a pair of high-pressure quenching liquid supply tubes submerged in said tank; and a plurality of submerged nozzles for spraying submerged high-pressure quenching liquid coupled to said submerged high-pressure quenching liquid supply tubes, said submerged nozzles being positioned on both sides of said strip and on substantially the same horizontal level beneath the surface of the quenching liquid in said quenching tank, said submerged nozzles forming an angle within the range of between a right angle and 45° in an upward direction relative to said strip which moves substantially vertically in the vicinity of said sub-merged nozzles, thereby to direct said submerged high-pressure quenching liquid over the entire width of said strip.
a quenching tank comprising a quenching liquid;
a pair of compressed-air-reservoirs;
a source of quenching liquid; a plurality of spray nozzles for spraying quenching liquid mist coupled to said quenching liquid source and said compressed-air reservoirs, said nozzles being positioned on both sides of said strip and on substantially the same horizontal level above the surface of the quenching liquid in said quenching tank, said nozzles forming an angle within the range of between a right angle and 45° in an upward direction relative to said strip which moves substantially vertically in the vicinity of said nozzles, thereby to direct said quenching liquid mist over the entire width of said strip, a pair of high-pressure quenching liquid supply tubes submerged in said tank; and a plurality of submerged nozzles for spraying submerged high-pressure quenching liquid coupled to said submerged high-pressure quenching liquid supply tubes, said submerged nozzles being positioned on both sides of said strip and on substantially the same horizontal level beneath the surface of the quenching liquid in said quenching tank, said submerged nozzles forming an angle within the range of between a right angle and 45° in an upward direction relative to said strip which moves substantially vertically in the vicinity of said sub-merged nozzles, thereby to direct said submerged high-pressure quenching liquid over the entire width of said strip.
22. The apparatus as claimed in claim 16 for continuously quench-ing a continuously moving electrolytic tin-plated steel strip comprising:
a quenching tank containing a quenching liquid;
a pair of high-pressure quenching liquid supply tubes;
a plurality of spray nozzles coupled to said high-pressure quenching liquid supply tubes for spraying high-pressure quenching liquid, said nozzles being positioned on both sides of said strip and on substanti-ally the same horizontal level above the surface of the quenching liquid in said quenching tank, said nozzles forming an angle within the range of between an upwardly directed parallel position and 45° in an upward direc-tion relative to said strip which moves substantially vertically in the vicinity of said spray nozzles, thereby to direct said high-pressure quench-ing liquid over the entire width of said strip; a pair of guide plates positioned adjacent a respective high-pressure quenching liquid supply tube;
one guide plate being located on opposite sides of said strip, said guide plates being wider the said strip, said guide plated having upper ends which are above said spray nozzles and which are curved toward said strip, said guide plates having their topmost parts ending on substantially the same horizontal level for directing said high-pressure quenching liquid sprayed through said spray nozzles onto said strip; a pair of high-pressure quenching liquid supply tubes submerged in said tank; and a plurality of submerged nozzles for spraying submerged high-pressure quenching liquid coupled to said submerged high-pressure quenching liquid supply tubes, said submerged nozzles being positioned on both sides of said strip and on sub-stantially the same horizontal level beneath the surface of the quenching liquid in said quenching tank, said submerged nozzles forming an angle within the range of between a right angle and 45° in an upward direction relative to said strip which moves substantially vertically in the vicinity of said submerged nozzles, thereby to direct said submerged high-pressure quenching liquid over the entire width of said strip.
a quenching tank containing a quenching liquid;
a pair of high-pressure quenching liquid supply tubes;
a plurality of spray nozzles coupled to said high-pressure quenching liquid supply tubes for spraying high-pressure quenching liquid, said nozzles being positioned on both sides of said strip and on substanti-ally the same horizontal level above the surface of the quenching liquid in said quenching tank, said nozzles forming an angle within the range of between an upwardly directed parallel position and 45° in an upward direc-tion relative to said strip which moves substantially vertically in the vicinity of said spray nozzles, thereby to direct said high-pressure quench-ing liquid over the entire width of said strip; a pair of guide plates positioned adjacent a respective high-pressure quenching liquid supply tube;
one guide plate being located on opposite sides of said strip, said guide plates being wider the said strip, said guide plated having upper ends which are above said spray nozzles and which are curved toward said strip, said guide plates having their topmost parts ending on substantially the same horizontal level for directing said high-pressure quenching liquid sprayed through said spray nozzles onto said strip; a pair of high-pressure quenching liquid supply tubes submerged in said tank; and a plurality of submerged nozzles for spraying submerged high-pressure quenching liquid coupled to said submerged high-pressure quenching liquid supply tubes, said submerged nozzles being positioned on both sides of said strip and on sub-stantially the same horizontal level beneath the surface of the quenching liquid in said quenching tank, said submerged nozzles forming an angle within the range of between a right angle and 45° in an upward direction relative to said strip which moves substantially vertically in the vicinity of said submerged nozzles, thereby to direct said submerged high-pressure quenching liquid over the entire width of said strip.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12336173A JPS549975B2 (en) | 1973-11-05 | 1973-11-05 | |
| JP12402073A JPS549976B2 (en) | 1973-11-06 | 1973-11-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1040077A true CA1040077A (en) | 1978-10-10 |
Family
ID=26460312
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA212,654A Expired CA1040077A (en) | 1973-11-05 | 1974-10-30 | Method and apparatus continuously quenching moving electrolytic tin-plated steel strip |
Country Status (5)
| Country | Link |
|---|---|
| CA (1) | CA1040077A (en) |
| DE (1) | DE2450365C3 (en) |
| FR (1) | FR2249977B1 (en) |
| GB (1) | GB1448340A (en) |
| IT (1) | IT1022961B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4367597A (en) * | 1979-12-13 | 1983-01-11 | Nippon Steel Corporation | Gas-liquid cooling apparatus |
| GB9306243D0 (en) * | 1993-03-25 | 1993-05-19 | Metal Box Plc | Process & apparatus for producing coated metal |
| KR102219717B1 (en) | 2016-06-09 | 2021-02-23 | 제이에프이 스틸 가부시키가이샤 | Electroplated steel sheet manufacturing method and manufacturing apparatus thereof |
-
1974
- 1974-10-14 GB GB4448274A patent/GB1448340A/en not_active Expired
- 1974-10-17 IT IT2853474A patent/IT1022961B/en active
- 1974-10-23 DE DE19742450365 patent/DE2450365C3/en not_active Expired
- 1974-10-30 FR FR7436340A patent/FR2249977B1/fr not_active Expired
- 1974-10-30 CA CA212,654A patent/CA1040077A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| IT1022961B (en) | 1978-04-20 |
| DE2450365B2 (en) | 1978-06-29 |
| DE2450365A1 (en) | 1975-05-15 |
| FR2249977A1 (en) | 1975-05-30 |
| DE2450365C3 (en) | 1979-02-22 |
| AU7388174A (en) | 1976-04-08 |
| GB1448340A (en) | 1976-09-02 |
| FR2249977B1 (en) | 1977-10-28 |
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