CN114686646A - Solid solution heat treatment device and method for large thin-wall stainless steel structural member - Google Patents
Solid solution heat treatment device and method for large thin-wall stainless steel structural member Download PDFInfo
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- CN114686646A CN114686646A CN202210406073.5A CN202210406073A CN114686646A CN 114686646 A CN114686646 A CN 114686646A CN 202210406073 A CN202210406073 A CN 202210406073A CN 114686646 A CN114686646 A CN 114686646A
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 119
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 91
- 239000010935 stainless steel Substances 0.000 title claims abstract description 91
- 239000006104 solid solution Substances 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims abstract description 18
- 239000000243 solution Substances 0.000 claims abstract description 50
- 238000001816 cooling Methods 0.000 claims abstract description 46
- 238000003825 pressing Methods 0.000 claims abstract description 25
- 230000000712 assembly Effects 0.000 claims abstract description 7
- 238000000429 assembly Methods 0.000 claims abstract description 7
- 238000007664 blowing Methods 0.000 claims description 18
- 229910000831 Steel Inorganic materials 0.000 claims description 11
- 229910001566 austenite Inorganic materials 0.000 claims description 11
- 239000010959 steel Substances 0.000 claims description 11
- 238000004321 preservation Methods 0.000 claims description 6
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 claims description 4
- 239000000835 fiber Substances 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 3
- 230000003647 oxidation Effects 0.000 claims description 3
- 238000007254 oxidation reaction Methods 0.000 claims description 3
- 230000006032 tissue transformation Effects 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims 1
- 230000001174 ascending effect Effects 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
- C21D11/005—Process control or regulation for heat treatments for cooling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
- Furnace Details (AREA)
Abstract
The invention provides a solid solution heat treatment device and a solid solution heat treatment method for a large thin-wall stainless steel structural member, which comprises a cushion mounting bottom plate assembly for clamping and fixing the whole stainless steel structural member; the outer flanges at the bottom ends of the outer cylinder and the inner cylinder of the stainless steel structural member are respectively fixed at the top of the base plate assembly through a plurality of uniformly distributed pressing plate assemblies; the stainless steel structural member is integrally placed in a special solid solution treatment furnace after being clamped by the base plate and bottom plate assembly, and corresponding solid solution heat treatment is carried out. The heating or cooling rate can be controlled according to requirements when the solution heat treatment is carried out, the full circulation of the atmosphere in the furnace is ensured during the heating or cooling, the temperature difference of each point of the workpiece is reduced, and the deformation is reduced.
Description
Technical Field
The invention relates to the technical field of thin-wall stainless steel structural member processing, in particular to a solid solution heat treatment device and method for a large thin-wall stainless steel structural member.
Background
In a certain order accepted by the company, a gas turbine diffuser (shown in figures 1 and 2) is a large thin-wall stainless steel structural member and is an important component of a certain type of gas turbine of the company, the outline dimension phi 2360 (+ -1) is multiplied by 1102.5 (+ -1), the weight is about 730Kg, the main structure comprises an inner cylinder body, an outer cylinder body, a guide ring, a support plate, rib plates and the like, all the inner cylinder body, the outer cylinder body, the guide ring and the rib plates are processed and welded by 316L stainless steel plates, the plate thicknesses of the inner cylinder body, the outer cylinder body, the guide ring and the rib plates are 5mm, and the plate thickness of the support plate is 8 mm. After welding, solution heat treatment is needed. The diffuser has large size, thin plate thickness and strict deformation requirement. In the solution heat treatment, 6 heel thermocouples were placed on the workpiece at the locations where the temperatures were expected to be higher and lower, which were required to meet the corresponding temperature profile.
Due to the extremely high requirements of the solution heat treatment of the diffuser, the trial production of a company in global suppliers is not successful, and the reason is that the temperature control cannot meet the requirement of the temperature curve. In the upper half of the temperature curve, the temperature difference between each point on the workpiece during heating and cooling is small, and the cooling rate is controlled according to the curve during cooling, and 3 cooling rates are required in the cooling curve of the temperature curve. As a skilled artisan will appreciate, the cooling rate of the prior art heat treatment furnaces is much lower than the required 160-170 ℃ per hour at furnace cold. If the part is discharged for air cooling when the part is cooled to 900 ℃, firstly, the cooling rate is difficult to control, and secondly, the temperature difference between the inside and the outside of the part is rapidly increased when the part is discharged for air cooling, so that the requirement of a temperature curve is not met. The internal and external temperature difference is increased, and larger thermal stress is generated, so that the deformation of the part is increased, and the size requirement of the part is not met.
After the diffuser trial production task of a company is carried out by our company, the car-type heat treatment is adopted for carrying out the solution heat treatment, the deformation of the workpiece is large, and the temperature recording curve does not meet the requirement. The technical requirements of the solution heat treatment are analyzed, and it is considered that a heat treatment device capable of effectively controlling the temperature during heating and cooling needs to be designed and manufactured, the furnace temperature is ensured to be uniform, and the production requirements are met by formulating a proper heat treatment process.
Disclosure of Invention
The invention aims to provide a solid solution heat treatment device and a solid solution heat treatment method for a large thin-wall stainless steel structural member, which can control the heating or cooling rate according to requirements when the solid solution heat treatment is carried out, ensure the full circulation of the furnace atmosphere when in heating or cooling, reduce the temperature difference of each point of a workpiece and reduce the deformation.
In order to achieve the technical features, the invention is realized as follows: a solid solution heat treatment device for a large thin-wall stainless steel structural member is characterized by comprising a cushion bottom plate assembly for clamping and fixing the whole stainless steel structural member;
the outer flanges at the bottom ends of the outer cylinder and the inner cylinder of the stainless steel structural member are respectively fixed at the top of the base plate assembly through a plurality of uniformly distributed pressing plate assemblies;
the stainless steel structural member is integrally placed in a special solid solution treatment furnace after being clamped by the base plate and bottom plate assembly, and corresponding solid solution heat treatment is carried out.
The base plate and bottom plate assembly comprises a bottom plate, the top of the bottom plate is fixedly provided with a top plate through a plurality of uniformly distributed vertical plates, a first central hole is processed in the central part of the top plate, and a second central hole is processed in the central part of the bottom plate; an inner cylinder positioning ladder used for positioning the inner cylinder of the stainless steel structural member is processed at the top of the top plate and positioned at the periphery of the first central hole;
inner ring threaded holes are uniformly distributed in the inner ring of the inner cylinder positioning step, and the inner ring threaded holes fix the inner cylinder through the pressing plate assembly;
the outer ring of the inner cylinder positioning ladder is provided with uniformly distributed outer ring threaded holes, and the outer ring threaded holes fix the outer cylinder through the pressing plate assembly.
The vertical plates are arranged along the radial direction of the bottom plate.
A plurality of vent holes are uniformly and annularly processed on the top plate and positioned between the inner ring threaded hole and the outer ring threaded hole; and the vent hole is positioned between the inner cylinder and the outer cylinder.
The pressing plate assembly comprises an L-shaped pressing plate, a bolt hole is machined in a top plate of the L-shaped pressing plate, a long bolt penetrates through the bolt hole, and the bottom end of the long bolt is fixedly connected to an inner ring threaded hole and an outer ring threaded hole in the corresponding position of the top plate through threads; and a gasket is arranged between the long bolt and the L-shaped pressing plate.
The special solid solution treatment furnace comprises a furnace body, wherein the furnace body is a cylindrical pit-type resistance furnace, a furnace body shell is arranged on the periphery of the furnace body and is made of steel plates, a furnace lining is an aluminum silicate fiber module, a heating element resistance belt is arranged on the inner side of a hearth, and a heat-resistant steel furnace bottom plate is arranged at the bottom of the hearth; the top of the furnace body is provided with a furnace cover through a guide rod in a lifting way; the furnace body is connected with an air inlet device for supplying air; and an exhaust device is arranged at the bottom of the furnace body.
The air inlet device comprises an air blower, an L-shaped air inlet pipe is installed at an air outlet of the air blower, a plurality of short pipes are arranged on a vertical pipe of the L-shaped air inlet pipe at equal intervals, an air inlet valve is installed on each short pipe, the other end of each short pipe is connected with an annular air inlet pipe, the annular air inlet pipe is arranged around the periphery of the furnace body, the inner side of the annular air inlet pipe is connected with air blowing pipes of a plurality of uniform distribution, the air blowing pipes are arranged along the tangential direction of the hearth and are communicated with the inside of the hearth, and the air blowing direction is guaranteed to be tangent to the inner side of the hearth.
The exhaust device comprises an air outlet hole formed in the center of the heat-resistant steel furnace bottom plate, an exhaust pipe is connected to the air outlet hole, an exhaust valve is mounted on the exhaust pipe, and the tail end of the exhaust pipe is connected with an exhaust vertical pipe.
The special solid solution treatment furnace is controlled in 5 areas, the rated power is 520KW, the rated temperature is 1100 ℃, the rated voltage is 380V, the effective heating area is phi 3000 multiplied by 1600, and the furnace temperature uniformity is +/-10 ℃.
The method for carrying out the solution heat treatment on the large thin-wall stainless steel structural member by adopting the solution heat treatment device comprises the following steps:
step one, clamping a large thin-wall stainless steel structural part: fixedly mounting an inner cylinder and an outer cylinder of a stainless steel structural member to be processed on the top of a base plate assembly through a plurality of groups of pressing plate assemblies in sequence;
step two, hoisting the stainless steel structural member integrally into a furnace: hoisting the clamped stainless steel structural member into a special solid solution treatment furnace, covering the furnace cover, and inputting a solid solution heat treatment process;
step three, primarily heating the stainless steel structural part: when heating is started, a small amount of air is introduced along the inner side of the hearth through the air blowing pipe, the air blowing direction is tangent to the inner side of the hearth to form annular airflow along the inner side of the hearth, the annular airflow is heated after the annular airflow exchanges heat with the heating elements arranged on the inner side of the hearth, the annular airflow moves upwards to form spiral ascending annular airflow, the spiral ascending annular airflow is reflected after reaching the top of the furnace, the exhaust pipe is arranged at the bottom of the furnace, and the airflow is guided to move towards the bottom of the furnace and is exhausted out of the furnace; when the furnace atmosphere flows, the furnace atmosphere exchanges heat with the inner cylinder and the outer cylinder of the stainless steel structural member simultaneously, so that the stainless steel structural member is heated, and the inner part and the outer part of the stainless steel structural member are kept at the same temperature; adjusting the air inflow according to the actual temperature difference between the inner cylinder and the outer cylinder of the stainless steel structural member, if the temperature difference between the inner cylinder and the outer cylinder of the stainless steel structural member is larger, increasing the air inflow, accelerating the atmosphere circulation in the furnace, and reducing the temperature difference between the inner cylinder and the outer cylinder of the stainless steel structural member;
step four, carrying out solution heat treatment on the stainless steel structural part: in the heating stage, the stainless steel structure is rapidly heated to reduce the oxidation of the stainless steel structure, wherein the heating rate is 200-300 ℃ per hour, the heating rate is 500-950 ℃ per hour, and the heating rate is 175-275 ℃ per hour; the heating rate is 250-300 ℃ per hour from 950 ℃ to 1040 +/-10 ℃; keeping the temperature at 500 ℃ and 950 ℃ for 10-15 minutes respectively, ensuring that the temperature of the parts is as uniform as possible during heating, and reducing the deformation; because the thickness of the part is thin, the heat preservation temperature of 1040 +/-10 ℃ is only required to be kept for 30 minutes;
the cooling rate is required to be controlled in the cooling stage, the cooling rate is required to be 160-170 ℃ per hour from the heat preservation temperature of 1040 +/-10 ℃ to 900 ℃, and the rapid cooling is required to be carried out from 900 ℃ to 600 ℃ to form an austenite structure, the cooling rate is 300-600 ℃ per hour, and the process is finished within 30-60 minutes; no tissue transformation from 600 ℃ to room temperature, no cooling rate control;
step five, discharging and cooling the stainless steel structural member: when the temperature is cooled to below 600 ℃, the heating power supply is turned off, the air inlet pipe and the exhaust pipe are turned off, furnace cooling is carried out, the temperature recording instrument is kept to work continuously, and the furnace can be discharged when the temperature is cooled to below 200 ℃;
step six, checking: and (3) opening the tool after the stainless steel structural member is cooled to room temperature, and checking whether the deformation, the metallographic structure and the temperature recording curve meet the requirements or not, wherein the deformation requirement is less than 2 mm.
The invention has the following beneficial effects:
1. the invention designs and manufactures the cushion bottom plate assembly, the cushion bottom plate assembly needs to ensure the strength, and a panel in contact with a workpiece adopts a 316L stainless steel plate to prevent the workpiece from being polluted by the contact with the workpiece at high temperature. The center of the backing bottom plate is provided with a hole, and the size of the hole is slightly smaller than that of the inner cylinder of the workpiece. The part clamped by the inner cylinder and the outer cylinder on the stainless steel panel is provided with air holes, so that the furnace atmosphere can fully flow when the stainless steel panel enters the furnace. And after welding and forming, the cushion bottom plate is subjected to stress relief treatment and machined to be smooth, so that the workpiece is prevented from generating additional deformation. The part is placed on the cushion bottom plate and is pressed tightly by the L-shaped pressing plate, so that the workpiece is prevented from moving during hoisting. The diffuser is of a symmetrical round table structure and is formed by welding 316L stainless steel sheets, a plurality of symmetrical supporting plates and rib plates are arranged between the inner cylinder and the outer cylinder, the structure is firm, if the temperature difference of the atmosphere in the furnace is small during the solution heat treatment, the deformation caused by heating is symmetrical, and the deformation can be uniformly recovered during the subsequent cooling, so that reinforcing ribs for limiting the deformation do not need to be welded inside a workpiece during the solution heat treatment, and the early preparation of the solution heat treatment is simplified.
2. The special solid solution treatment furnace manufactured by the invention is a cylindrical well type resistance furnace. The furnace body is provided with an air inlet device and an exhaust pipe. The air inlet device is composed of an air blower, an air inlet pipe and an air inlet valve, the air inlet pipe is divided into 4 annular air inlet pipes from top to bottom outside the furnace body, each annular air inlet pipe is provided with 6 uniformly distributed air inlets for blowing air to the furnace, and the blowing direction is tangent to the inner side of the furnace. The furnace bottom is provided with a phi 500 air outlet hole which is connected with an exhaust pipe, and the exhaust pipe is provided with an exhaust valve. When heating, the air inlet pipe introduces air along the inner side of the hearth, the blowing direction is tangent to the inner side of the hearth to form annular airflow along the inner side of the hearth, after the annular airflow exchanges heat with the heating elements arranged on the inner side of the hearth, the annular airflow is heated and moves upwards to form spirally-rising annular airflow which is reflected after reaching the top of the furnace, and the exhaust pipe is arranged at the bottom of the furnace to guide the airflow to move towards the bottom of the furnace and then be exhausted out of the furnace. When the atmosphere in the furnace flows, the heat exchange is simultaneously carried out with the inside and the outside of the workpiece, so that the workpiece is heated, and the temperature inside and outside the workpiece is equalized. The air inlet pipe air inflow can be adjusted according to the actual temperature difference between the inside and the outside of the workpiece, if the temperature difference between the inside and the outside of the workpiece is large, the air inflow can be increased, the atmosphere circulation in the furnace is accelerated, the temperature difference between the inside and the outside of the workpiece can be reduced, and therefore the deformation is reduced.
3. After the diffuser is subjected to solution heat treatment, the metallographic structure is greatly improved. The metallographic structure before the solution heat treatment is austenite plus a small amount of ferrite, and black grain-shaped compounds are distributed in the austenite. The metallographic structure after the solution heat treatment was austenite, and black grain compounds in the austenite disappeared.
4. The diffuser solution heat treatment process has extremely high requirements, strict temperature control is required at each stage of the process, 6 following parts of thermocouples are uniformly distributed inside and outside a workpiece for temperature measurement, and 3 cooling rates are required during cooling. This requires that the solution heat treatment furnace ensure a small temperature difference in the furnace and that the heating and cooling rates can be controlled. The solid solution heat treatment furnace designed and manufactured by the invention solves the problem.
5. During the cooling of the solution heat treatment, the workpiece is generally required to be hoisted out of the furnace for quick cooling, and the workpiece is difficult to be hoisted out at high temperature.
Drawings
The invention is further illustrated by the following examples in conjunction with the drawings.
FIG. 1 is a right side view of the diffuser to be treated in the present invention.
FIG. 2 is a front view of a diffuser to be treated in the present invention.
FIG. 3 is a structural view of the stainless steel structural member to be treated in the present invention clamped and fixed to the backing plate assembly.
Fig. 4 is a front cross-sectional view of the mat-mounted base assembly of the present invention.
FIG. 5 is a top view of the cushioned baseplate assembly of the present invention.
FIG. 6 is a front cross-sectional view of an L-shaped platen according to the present invention.
FIG. 7 is a top view of an L-shaped platen according to the present invention.
FIG. 8 is a main sectional view of the special solution treatment furnace of the present invention.
FIG. 9 is a view A-A of the solution treatment furnace of FIG. 8 according to the present invention.
FIG. 10 is a schematic view showing the circulation of the atmosphere in the solution heat treatment furnace of the present invention.
FIG. 11 is a graph of dimensional inspection data of diffusers of the present invention after solution heat treatment.
FIG. 12 shows a metallographic structure of 500 before the solution heat treatment of the present invention.
FIG. 13 shows a metallographic structure after solution heat treatment of the present invention is 500.
FIG. 14 is a temperature profile of the solution heat treatment of the present invention.
Wherein: the furnace body comprises a stainless steel structural part 1, a bottom end outer flange 2, a long bolt 3, a gasket 4, an L-shaped pressing plate 5, a vertical plate 6, a top plate 7, a bottom plate 8, an outer ring threaded hole 9, an inner cylinder positioning ladder 10, an inner ring threaded hole 11, a first central hole 12, a second central hole 13, a vent hole 14, a bolt hole 15, a furnace body shell 16, a furnace cover 17, a furnace lining 18, a guide rod 19, an air inlet valve 20, an L-shaped air inlet pipe 21, a heat-resistant steel furnace bottom plate 22, an exhaust pipe 23, an exhaust valve 24, an air blower 25, a short pipe 26, an annular air inlet pipe 27, an air blow pipe 28 and an exhaust vertical pipe 29.
Detailed Description
Embodiments of the present invention will be further described with reference to the accompanying drawings.
Example 1:
referring to fig. 3-14, a solution heat treatment device for a large thin-wall stainless steel structural member comprises a cushion bottom plate assembly for clamping and fixing the whole stainless steel structural member 1; the outer flanges 2 at the bottom ends of the outer cylinder and the inner cylinder of the stainless steel structural member 1 are respectively fixed at the top of the base plate assembly through a plurality of uniformly distributed pressing plate assemblies; the stainless steel structural member 1 is integrally placed in a special solid solution treatment furnace after being clamped by the base plate and bottom plate assembly, and corresponding solid solution heat treatment is carried out. By adopting the treatment device of the invention to realize rapid uniform temperature cooling in the solid solution heat treatment furnace, the problems of solid solution heat treatment and deformation are solved. In the specific treatment process, a cushion mounting bottom plate assembly is manufactured, a workpiece is placed on the cushion mounting bottom plate assembly and is pressed tightly by a pressing plate assembly; the special solid solution heat treatment furnace is manufactured, the structure is a cylindrical well type resistance furnace, a furnace body is provided with an air inlet device and an exhaust pipe, the air blowing direction is tangent to the inner side of a hearth to form spiral ascending annular airflow which is reflected after reaching the top of the furnace, and the exhaust pipe is arranged at the bottom of the furnace to guide the airflow to move towards the bottom of the furnace and be exhausted out of the furnace. The temperature difference between the inside and the outside of the workpiece can be adjusted by controlling the air inflow, and the cooling rate can be controlled.
Further, the base plate and bottom plate assembly comprises a bottom plate 8, a top plate 7 is fixedly installed at the top of the bottom plate 8 through a plurality of uniformly distributed vertical plates 6, a first central hole 12 is machined in the central part of the top plate 7, and a second central hole 13 is machined in the central part of the bottom plate 8; an inner cylinder positioning ladder 10 for positioning the inner cylinder of the stainless steel structural member 1 is processed at the top of the top plate 7 and positioned at the periphery of the first central hole 12; inner ring threaded holes 11 are uniformly distributed in the inner ring of the inner cylinder positioning step 10, and the inner ring threaded holes 11 fix the inner cylinder through a pressing plate assembly; the outer ring of the inner cylinder positioning ladder 10 is provided with uniformly distributed outer ring threaded holes 9, and the outer ring threaded holes 9 fix the outer cylinder through the pressing plate assembly. The base plate bottom plate component can be used for stably and reliably clamping and fixing the inner cylinder and the outer cylinder of the diffuser to be treated.
Further, the vertical plate 6 is arranged along the radial direction of the bottom plate 8. The top plate 7 can be stably supported and fixed by the upright plate 6.
Furthermore, a plurality of vent holes 14 are uniformly and annularly processed on the top plate 7 and between the inner ring threaded hole 11 and the outer ring threaded hole 9; and the vent 14 is located between the inner and outer cylinders. The vent holes 14 ensure that hot air can enter between the inner barrel and the outer barrel in the heating process, and effectively prevent the problem of overlarge temperature difference between the inner barrel and the outer barrel.
Further, the pressing plate assembly comprises an L-shaped pressing plate 5, a bolt hole 15 is machined in a top plate of the L-shaped pressing plate 5, a long bolt 3 penetrates through the bolt hole 15, and the bottom end of the long bolt 3 is fixedly connected to an inner ring threaded hole 11 and an outer ring threaded hole 9 of the corresponding position of the top plate 7 through threads; a washer 4 is arranged between the long bolt 3 and the L-shaped pressure plate 5. The pressing plate assembly can reliably clamp and fix the inner cylinder and the outer cylinder of the stainless steel structural member 1.
Further, the special solid solution treatment furnace comprises a furnace body, wherein the furnace body is a cylindrical well-type resistance furnace, a furnace body shell 16 is arranged on the periphery of the furnace body, the furnace body shell 16 is made of steel plates, a furnace lining 18 is an aluminum silicate fiber module, a heating element resistance belt is arranged on the inner side of a hearth, and a heat-resistant steel furnace bottom plate 22 is arranged at the bottom of the hearth; the top of the furnace body is provided with a furnace cover 17 through a guide rod 19 in a lifting way; the furnace body is connected with an air inlet device for supplying air; and an exhaust device is arranged at the bottom of the furnace body. The solid-heat solution treatment of the stainless steel structural member 1 can be realized through the special solid-solution treatment furnace.
Further, air inlet unit includes air-blower 25, L type intake pipe 21 is installed to air outlet of air-blower 25, equidistant many stub pipes 26 of having arranged on the vertical pipe of L type intake pipe 21, all install admission valve 20 on every stub pipe 26, the other end of every stub pipe 26 links to each other with annular intake pipe 27, annular intake pipe 27 encircles the periphery of furnace body and arranges, the inboard of annular intake pipe 27 is connected with the gas blow pipe 28 of many equipartitions, gas blow pipe 28 arranges along the tangential of furnace to be linked together with furnace inside, guarantee that the direction of blowing is tangent with the furnace inboard. Referring to fig. 10, when the air inlet device is used for ensuring heating, air is introduced into the air inlet pipe along the inner side of the hearth, the blowing direction is tangent to the inner side of the hearth, annular airflow along the inner side of the hearth is formed, after the annular airflow exchanges heat with the heating element arranged on the inner side of the hearth, the annular airflow is heated and moves upwards to form spirally-rising annular airflow which is reflected behind the top of the furnace, and the exhaust pipe is arranged at the bottom of the furnace to guide the airflow to move towards the bottom of the furnace and exhaust the airflow out of the furnace. When the furnace atmosphere flows, the furnace atmosphere exchanges heat with the inside and the outside of the workpiece simultaneously, so that the workpiece is heated and the inside and the outside of the workpiece are equalized in temperature.
Further, the exhaust device comprises an air outlet hole formed in the center of the heat-resistant steel furnace bottom plate 22, an exhaust pipe 23 is connected to the air outlet hole, an exhaust valve 24 is mounted on the exhaust pipe 23, and the tail end of the exhaust pipe 23 is connected with an exhaust vertical pipe 29. Through foretell exhaust apparatus can guarantee to form hot gas circulation in the stove, and then guarantee the heating effect.
Furthermore, the special solid solution treatment furnace is divided into 5 zones for temperature control, wherein the rated power is 520KW, the rated temperature is 1100 ℃, the rated voltage is 380V, the effective heating zone is phi 3000 multiplied by 1600, and the furnace temperature uniformity is +/-10 ℃.
Furthermore, the outer shell of the furnace body is made of a Q235A steel plate with the thickness of 5mm, the furnace lining is an aluminum silicate fiber module with the thickness of 400mm, a phi 500 air outlet hole is formed at the bottom of the furnace,
example 2:
the method for carrying out the solution heat treatment on the large thin-wall stainless steel structural member by adopting the solution heat treatment device comprises the following steps:
step one, clamping a large thin-wall stainless steel structural part: fixedly mounting an inner cylinder and an outer cylinder of a stainless steel structural member 1 to be processed on the top of a base plate assembly through a plurality of groups of pressing plate assemblies in sequence;
step two, hoisting the stainless steel structural member 1 into the furnace integrally: hoisting the whole clamped stainless steel structural member 1 into a special solid solution treatment furnace, covering a furnace cover, and inputting a solid solution heat treatment process;
step three, primarily heating the stainless steel structural member 1: when heating is started, a small amount of air is introduced along the inner side of the hearth through the air blowing pipe 28, the air blowing direction is tangent to the inner side of the hearth to form annular air flow along the inner side of the hearth, after the annular air flow exchanges heat with the heating elements arranged on the inner side of the hearth, the annular air flow is heated and moves upwards to form spiral ascending annular air flow which is reflected after reaching the top of the furnace, the bottom of the furnace is provided with an exhaust pipe, and the air flow is guided to move towards the bottom of the furnace and is exhausted out of the furnace; when the furnace atmosphere flows, the furnace atmosphere exchanges heat with the inner cylinder and the outer cylinder of the stainless steel structural member 1 simultaneously, so that the stainless steel structural member 1 is heated, and the inner part and the outer part of the stainless steel structural member 1 are kept at the same temperature; adjusting air inflow according to the actual temperature difference of the inner cylinder and the outer cylinder of the stainless steel structural member 1, if the temperature difference of the inner cylinder and the outer cylinder of the stainless steel structural member 1 is larger, the air inflow is increased, and atmosphere circulation in the furnace is accelerated, so that the temperature difference of the inner cylinder and the outer cylinder of the stainless steel structural member 1 is reduced;
step four, carrying out solution heat treatment on the stainless steel structural part 1: in the heating stage, the stainless steel structural member 1 is rapidly heated to reduce the oxidation, wherein the heating rate is 200-300 ℃ per hour, the heating rate is 500-950 ℃ per hour, and the heating rate is 175-275 ℃ per hour; the heating rate is 250-300 ℃ per hour from 950 ℃ to 1040 +/-10 ℃; keeping the temperature at 500 ℃ and 950 ℃ for 10-15 minutes respectively, ensuring that the temperature of the part is as uniform as possible during heating, and reducing the deformation; because the thickness of the part plate is thinner, the part plate is required to be kept for only 30 minutes at the heat preservation temperature of 1040 +/-10 ℃;
the cooling rate is required to be controlled in the cooling stage, the cooling rate is required to be 160-170 ℃ per hour from the heat preservation temperature of 1040 +/-10 ℃ to 900 ℃, and the rapid cooling is required to be carried out from 900 ℃ to 600 ℃ to form an austenite structure, the cooling rate is 300-600 ℃ per hour, and the process is finished within 30-60 minutes; no tissue transformation from 600 ℃ to room temperature, no cooling rate control;
step five, discharging and cooling the stainless steel structural member 1: when the temperature is cooled to below 600 ℃, the heating power supply is turned off, the air inlet pipe and the exhaust pipe are turned off, furnace cooling is carried out, the temperature recording instrument is kept to work continuously, and the furnace can be discharged when the temperature is cooled to below 200 ℃;
step six, checking: and (3) after the stainless steel structural member 1 is cooled to room temperature, opening the tool, and checking whether the deformation, the metallographic structure and the temperature recording curve meet the requirements or not, wherein the deformation requirement is less than 2 mm.
Referring to fig. 11, the dimension detection data of the diffuser after the solution heat treatment is shown, and the detection result meets the drawing requirements.
Fig. 12 shows a metallographic structure before the solution heat treatment of the present invention × 500. Referring to fig. 13, the metallographic structure after the solution heat treatment of the present invention is × 500. The metallographic structure before the solution heat treatment was austenite + a small amount of ferrite of about 7%, and black grain-like compounds were distributed in the austenite. The metallographic structure after the solution heat treatment was austenite, and black grain compounds in the austenite disappeared.
Referring to fig. 14, the temperature profile for the solution heat treatment of the present invention is shown. The temperature profile conforms to the temperature control profile required by the customer.
Claims (10)
1. A solid solution heat treatment device for a large thin-wall stainless steel structural member is characterized by comprising a cushion bottom plate assembly for clamping and fixing the whole stainless steel structural member (1);
outer flanges (2) at the bottom ends of the outer cylinder and the inner cylinder of the stainless steel structural member (1) are respectively fixed at the top of the base plate assembly through a plurality of uniformly distributed pressing plate assemblies;
the stainless steel structural member (1) is integrally placed in a special solution treatment furnace after being clamped by the base plate and bottom plate assembly, and corresponding solution heat treatment is carried out.
2. The solution heat treatment device for the large thin-wall stainless steel structural member according to claim 1, wherein the backing plate and bottom plate assembly comprises a bottom plate (8), a top plate (7) is fixedly installed at the top of the bottom plate (8) through a plurality of uniformly distributed vertical plates (6), a first central hole (12) is machined in the central part of the top plate (7), and a second central hole (13) is machined in the central part of the bottom plate (8); an inner cylinder positioning ladder (10) used for positioning the inner cylinder of the stainless steel structural member (1) is processed at the top of the top plate (7) and positioned at the periphery of the first central hole (12);
inner ring threaded holes (11) are uniformly distributed in the inner ring of the inner cylinder positioning ladder (10), and the inner cylinder is fixed by the inner ring threaded holes (11) through a pressing plate component;
the outer ring of the inner cylinder positioning ladder (10) is provided with uniformly distributed outer ring threaded holes (9), and the outer ring threaded holes (9) fix the outer cylinder through the pressing plate assembly.
3. Solution heat treatment device for large thin-walled stainless steel structural members according to claim 2, characterized in that the vertical plates (6) are arranged along the radial direction of the bottom plate (8).
4. The solution heat treatment device for the large thin-wall stainless steel structural member as claimed in claim 2, wherein a plurality of vent holes (14) are uniformly formed in the top plate (7) between the inner ring threaded hole (11) and the outer ring threaded hole (9) in an annular shape; and the vent hole (14) is positioned between the inner cylinder and the outer cylinder.
5. The solution heat treatment device for the large thin-wall stainless steel structural member according to claim 1, wherein the pressure plate assembly comprises an L-shaped pressure plate (5), a bolt hole (15) is formed in a top plate of the L-shaped pressure plate (5), a long bolt (3) penetrates through the bolt hole (15), and the bottom end of the long bolt (3) is fixedly connected to an inner ring threaded hole (11) and an outer ring threaded hole (9) of a corresponding part of the top plate (7) through threads; a washer (4) is arranged between the long bolt (3) and the L-shaped pressing plate (5).
6. The solution heat treatment device for the large thin-wall stainless steel structural member as claimed in claim 1, wherein the special solution treatment furnace comprises a furnace body, the furnace body is a cylindrical well type resistance furnace, a furnace body shell (16) is arranged at the periphery of the furnace body, the furnace body shell (16) is made of steel plates, a furnace lining (18) is an aluminum silicate fiber module, a heating element resistance belt is arranged at the inner side of a hearth, and a heat-resistant steel furnace bottom plate (22) is arranged at the bottom of the hearth; the top of the furnace body is provided with a furnace cover (17) through a guide rod (19) in a lifting way; the furnace body is connected with an air inlet device for supplying air; and an exhaust device is arranged at the bottom of the furnace body.
7. The solid solution heat treatment device for the large thin-wall stainless steel structural part according to claim 6, wherein the air inlet device comprises an air blower (25), an L-shaped air inlet pipe (21) is installed at an air outlet of the air blower (25), a plurality of short pipes (26) are equidistantly arranged in a vertical pipe of the L-shaped air inlet pipe (21), an air inlet valve (20) is installed on each short pipe (26), the other end of each short pipe (26) is connected with an annular air inlet pipe (27), the annular air inlet pipe (27) is arranged around the periphery of a furnace body, the inner side of the annular air inlet pipe (27) is connected with a plurality of uniformly distributed air blowing pipes (28), the air blowing pipes (28) are arranged along the tangential direction of a hearth and are communicated with the inside of the hearth, and the air blowing direction is guaranteed to be tangent to the inner side of the hearth.
8. The solution heat treatment device for the large thin-wall stainless steel structural member as claimed in claim 6, wherein the exhaust device comprises an air outlet hole formed in the central part of the heat-resistant steel furnace bottom plate (22), an exhaust pipe (23) is connected to the air outlet hole, an exhaust valve (24) is installed on the exhaust pipe (23), and the tail end of the exhaust pipe (23) is connected with an exhaust vertical pipe (29).
9. The solution heat treatment device for the large thin-wall stainless steel structural member according to claim 6, wherein the special solution treatment furnace is divided into 5 zones for temperature control, the rated power is 520KW, the rated temperature is 1100 ℃, the rated voltage is 380V, the effective heating zone is phi 3000 x 1600, and the furnace temperature uniformity is +/-10 ℃.
10. A method for solution heat treatment of large thin-walled stainless steel structural members using the solution heat treatment apparatus of any one of claims 1 to 9, comprising the steps of:
step one, clamping a large thin-wall stainless steel structural part: fixedly mounting an inner cylinder and an outer cylinder of a stainless steel structural member (1) to be processed on the top of a base plate assembly through a plurality of groups of pressing plate assemblies in sequence;
step two, integrally hoisting the stainless steel structural member (1) into a furnace: hoisting the clamped stainless steel structural member (1) into a special solid solution treatment furnace integrally, covering a furnace cover, and inputting a solid solution heat treatment process;
step three, primarily heating the stainless steel structural part (1): when heating is started, a small amount of air is introduced along the inner side of the hearth through the air blowing pipe (28), the air blowing direction is tangent to the inner side of the hearth to form annular air flow along the inner side of the hearth, after the annular air flow exchanges heat with the heating element arranged on the inner side of the hearth, the annular air flow is heated and moves upwards to form spiral rising annular air flow which is reflected after reaching the top of the furnace, and the exhaust pipe is arranged at the bottom of the furnace to guide the air flow to move towards the bottom of the furnace and exhaust the air flow out of the furnace; when the furnace atmosphere flows, the furnace atmosphere exchanges heat with the inner cylinder and the outer cylinder of the stainless steel structural member (1) simultaneously, so that the stainless steel structural member (1) is heated, and the inner part and the outer part of the stainless steel structural member (1) are kept at the same temperature; adjusting air inflow according to the actual temperature difference of the inner cylinder and the outer cylinder of the stainless steel structural member (1), if the temperature difference of the inner cylinder and the outer cylinder of the stainless steel structural member (1) is large, increasing the air inflow, accelerating the atmosphere circulation in the furnace, and reducing the temperature difference of the inner cylinder and the outer cylinder of the stainless steel structural member (1);
step four, solution heat treatment of the stainless steel structural part (1): in the heating stage, the stainless steel structural member (1) is rapidly heated to reduce the oxidation, wherein the heating rate is 200-300 ℃ per hour, the heating rate is 500-950 ℃ per hour, and the heating rate is 175-275 ℃ per hour; the heating rate is 250-300 ℃ per hour from 950 ℃ to 1040 +/-10 ℃; keeping the temperature at 500 ℃ and 950 ℃ for 10-15 minutes respectively, ensuring that the temperature of the parts is as uniform as possible during heating, and reducing the deformation; because the thickness of the part is thin, the heat preservation temperature of 1040 +/-10 ℃ is only required to be kept for 30 minutes;
the cooling rate is required to be controlled in the cooling stage, the cooling rate is required to be 160-170 ℃ per hour from the heat preservation temperature of 1040 +/-10 ℃ to 900 ℃, and the rapid cooling is required to be carried out from 900 ℃ to 600 ℃ to form an austenite structure, the cooling rate is 300-600 ℃ per hour, and the process is finished within 30-60 minutes; no tissue transformation from 600 ℃ to room temperature, no cooling rate control;
step five, discharging and cooling the stainless steel structural member (1): when the temperature is cooled to below 600 ℃, the heating power supply is turned off, the air inlet pipe and the exhaust pipe are turned off, furnace cooling is carried out, the temperature recording instrument is kept to work continuously, and the furnace can be discharged when the temperature is cooled to below 200 ℃;
step six, checking: and (3) after the stainless steel structural member (1) is cooled to room temperature, opening the tool, and checking whether the deformation, the metallographic structure and the temperature recording curve meet the requirements or not, wherein the deformation requirement is less than 2 mm.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5556593A (en) * | 1993-12-14 | 1996-09-17 | Grenier; Mario | Method and apparatus for heat treating metal parts |
| US20070107714A1 (en) * | 2004-08-25 | 2007-05-17 | Kiyobumi Kurita | Hot air circulation furnace |
| RU80849U1 (en) * | 2008-09-10 | 2009-02-27 | Открытое акционерное общество "Тамбовский завод "Комсомолец" имени Н.С. Артемова" | OVEN FOR THERMAL PROCESSING OF LARGE-SIZED PRODUCTS |
| CN203304930U (en) * | 2013-06-18 | 2013-11-27 | 南车戚墅堰机车车辆工艺研究所有限公司 | Machining tool for cylindrical thin-walled parts with flanges |
| CN203569150U (en) * | 2013-09-27 | 2014-04-30 | 江苏恒力炉业有限公司 | Well type thermal treatment furnace for ring piece |
| CN105196092A (en) * | 2015-10-23 | 2015-12-30 | 中核(天津)科技发展有限公司 | Clamping and fixing device for thin-walled cylindrical part |
| CN111500954A (en) * | 2020-04-29 | 2020-08-07 | 天津航天机电设备研究所 | Heat treatment process for large high-strength magnesium alloy thin-wall casting |
| CN211661551U (en) * | 2019-12-23 | 2020-10-13 | 湖南涉外经济学院 | Clamping tool for machining flange hole of conical component |
| CN214922445U (en) * | 2021-05-06 | 2021-11-30 | 大连恒基数控机床有限公司 | Special clamp for oil baffle ring products |
| CN217324198U (en) * | 2022-04-18 | 2022-08-30 | 宜昌船舶柴油机有限公司 | Solid solution heat treatment device for large thin-wall stainless steel structural member |
-
2022
- 2022-04-18 CN CN202210406073.5A patent/CN114686646B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5556593A (en) * | 1993-12-14 | 1996-09-17 | Grenier; Mario | Method and apparatus for heat treating metal parts |
| US20070107714A1 (en) * | 2004-08-25 | 2007-05-17 | Kiyobumi Kurita | Hot air circulation furnace |
| RU80849U1 (en) * | 2008-09-10 | 2009-02-27 | Открытое акционерное общество "Тамбовский завод "Комсомолец" имени Н.С. Артемова" | OVEN FOR THERMAL PROCESSING OF LARGE-SIZED PRODUCTS |
| CN203304930U (en) * | 2013-06-18 | 2013-11-27 | 南车戚墅堰机车车辆工艺研究所有限公司 | Machining tool for cylindrical thin-walled parts with flanges |
| CN203569150U (en) * | 2013-09-27 | 2014-04-30 | 江苏恒力炉业有限公司 | Well type thermal treatment furnace for ring piece |
| CN105196092A (en) * | 2015-10-23 | 2015-12-30 | 中核(天津)科技发展有限公司 | Clamping and fixing device for thin-walled cylindrical part |
| CN211661551U (en) * | 2019-12-23 | 2020-10-13 | 湖南涉外经济学院 | Clamping tool for machining flange hole of conical component |
| CN111500954A (en) * | 2020-04-29 | 2020-08-07 | 天津航天机电设备研究所 | Heat treatment process for large high-strength magnesium alloy thin-wall casting |
| CN214922445U (en) * | 2021-05-06 | 2021-11-30 | 大连恒基数控机床有限公司 | Special clamp for oil baffle ring products |
| CN217324198U (en) * | 2022-04-18 | 2022-08-30 | 宜昌船舶柴油机有限公司 | Solid solution heat treatment device for large thin-wall stainless steel structural member |
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