LU81187A1 - IMPROVEMENTS IN METHODS OF HEAT TREATING METAL SHEET - Google Patents

Description

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Brevet N ° ...... O i l Ö / du 54 i.vril IS 79 Minister Jÿ 54¾ of the National Economy and the Middle Classes T.ue dJ.vre. ..... ............ ϊχ ';' Industrial Property Service

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M / liai. ^ w f () Invention Patent Application I. CEHTBB PE RESEARCH Request. MEmLliaSIffffiS ..- Non-profitmaking organization - yeraniging goadcg vinstoo £, mark - 47 rus “îoôtoyei ÏOfôÔ BntsciÎea, Belgium, reprasentéa par EïMcyar * & E.?r&ylinger, Ingvcöns.fes pröpr, l?; 4'iV“ ^ 6 ' ty® ............ (Z) du ... Ciaati & re ”-Luxecibourg r - agi ss? nt çuali té de - inonda t & ires ......................................... ...............

drop off ........ this April 24th new cover ................... (3) at „15.® ° ...... Γ .... hours, to the Ministry of National Economy and the Middle Classes, in Luxembourg: 1. the present request for the obtaining of a patent of invention concerning: „“ Perfectioaiteuepta to the processing procedures estai -............... (4) league “” ........................... .: ................................................ .................................................. .................................................. ......................

declare, assuming responsibility for this declaration, that the inventor (s) is (are): 41frM ... PEÇ.KER, ..... 15 ..., rua. .E.silôuXj.XîÆourg ^ .. ..B.algiqtia .................................... .................................................. ............. (5) 2. the Delegation of power, dated ........ B.îTtriMllCS .............. ............... on ...... U- £ StiL127S ................

3. description in language ...... JftÂTlçels · .................................... of the invention in two copies; 4 ............ “................. drawing boards, in two copies; 5. the receipt of the taxes paid to the Luxembourg Registration Office, the yxîigtrçustrft ..... s. \ 'Ril..ni.l .... nfeu £ -cr; .rit -.- ®oixant- e-dLS - new · ........................................... ............................. — ......- claims for the above patent application the priority of one ( of) requested) of (6) ............................. — ............ ................................................ filed) in (7) ......................... m .................... .................................................. .................................- the ............... .................................................. .................................................. .................................................. .................................................. .................................................. ...... (8) in the name of ...................................... ......................... (9) * elect domicile for him and her. if appointed, for its representative, in Luxembourg --.................................

46 rue I-tr; y, -. Bourg ....................................... .................................................. ............................................ dO) - requests delivery an invention patent for the subject described and represented in the abovementioned appendices, - with deferment of this issue to .d:.; p “ir.î £ t ............ .... months.

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i s Improvements to heat treatment procedures t I of metal sheets t f i i!

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.1 METALLURGICAL RESEARCH CENTER

.i CENTRUM VOOR RESEARCH IN DE METALLURGIE

Non-profit association | Vereniging zonder winstoogmerk I 47 rue Montover ir I 1040 Brussels I Belgium • i: y ', i v f C 1955/7904.

\ METALLURGICAL RESEARCH CENTER -CENTRUM VOOR RESEARCH IN DE METALLURGIE,

Non-profit association - vereniging zonce winstoogmerk in BRUXELLES, (Belgium).

Improvements to thermal treatment processes for metal sheets.

The present invention relates to per-fectionnexnents to the methods of heat treatment of metal sheets. They are applicable to heat treated sheets in continuous lines.

Among the heat treatment processes applied in continuous lines to metal sheets, one can cite that which consists in immersing, continuously, / / 1 2.- i ►! j a steel sheet dar3 an aqueous bath at boiling temperature.

This immersion lasts for the time necessary to achieve a controlled lowering of the temperature of the sheet, for example so that the allotropic transformation of the metal starts, continues or ends according to a determined program.

s With this in mind, however,

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lose sight of the fact that there is generally an interest in increasing the speed of movement of the sheets, in order to increase the productivity of the entire installation.

With regard to the heat treatment phase, this increase in speed normally results in a reduction in the residence time of the sheet in the aqueous bath.

It is therefore necessary to be certain that the desired cooling is still operating well during this residence time and consequently, that the heat transmission coefficient causing this cooling is certainly the highest possible, but at least sufficient to obtain the desired result. This translates into i | practiced by a boiling state, in which must be | the liquid cooling throughout the course of the sheet in the bath considered. If, by the force of circumstances, the residence time cannot be reduced, it only remains to lengthen the trajectory of the sheet in the bath, which most often leads to increasing the dimensions of the tank which contains it.

With the obvious aim of reducing the horizontal size of these installations, it is normally conceivable to arrange, along the vertical, the reservoir or tank containing the aqueous bath in which the sheet moves during its cooling phase, the major part of this movement then takes place in the vertical direction, first by going down, then by going up.

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In such vertical installations / it must be ensured that for relatively large tank heights, for example 25 m or 30 m, the pressure existing in the lower zone of the tank due to the height of the existing water column, is not opposed to the fact that the bath, at a substantially equal temperature, is there and remains there at boiling point; In order to get there, one can imagine in particular an additional heating of the part of the bath being in the lower zone of the tank. We understand that this solution can only be very expensive and would only lead to results as heterogeneous as not reproducible.

The present invention specifically relates to a method applicable in the above-mentioned case and which overcomes, in a very large proportion, the drawbacks mentioned above.

The process, object of the present invention, in which, in a continuous heat treatment line, a steel sheet is introduced into an aqueous bath at boiling temperature, is essentially characterized in that the bath in at least two separate tanks, arranged one above the other, as close as possible to each other, in that the sheet is passed from top to bottom successively, from tank in a tank, up to the lowest disposed tank, in which the sheet metal makes a U-turn to start a journey from bottom to top and successively cross all the tanks, or at least most of them, starting with their bottom, until the sheet temperature has reached the desired value. The passage of the sheet, from reservoir to reservoir, is advantageously made through holes of appropriate dimensions, threatened in the bottoms thereof. *

According to the invention, the part of the aqueous bath which flows from reservoir to reservoir, through the holes in these bottoms through which the sheet passes, is recovered in a tarpaulin, ^ warmed to boiling temperature and recycled in one,. Γ * ✓; i 4.-

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Ϊ ϊ several or all of the superimposed tanks, which makes it possible to maintain the boiling temperature in the baths contained i, in all the tanks. These tanks, whose own height j is no more than a fraction of that which a tank i would have had! unique with the same capacity as the sum of the capacities of the tanks ί! superimposed, are all appreciably at atmospheric pressure and the bath which they contain is no longer subject to variations of: pressure the importance of which could cause the disadvantages! mentioned above.

i! The remedy for these disadvantages is therefore found! * and these are therefore deleted.

Constructively, the openings intended to leave; . the passage to the sheets, either in the downward path, or in the upward path, are preferably arranged one above the other, substantially along the vertical and their dimensions I. determined to minimize water leakage.

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Claims (4)

1. A method of heat treatment of metal sheets in which / in a continuous heat treatment line, the sheet is introduced into an aqueous bath at boiling temperature, characterized in that the bath is distributed in at least two separate tanks, arranged one above the other, as close as possible to each other, in that the sheet is passed from top to bottom successively from tank to tank, up to lowest tank, in which the sheet metal makes a half turn to start a journey from bottom to top and successively cross all the tanks or most of them, starting with their bottom, until the temperature of the sheet has reached the desired value. 2. Method according to claim 1, characterized in that the sheet is passed from reservoir to reservoir, through holes of appropriate dimensions, formed in the bottoms of the reservoirs. 3. Method according to either of claims 1 and 2, characterized in that the part of the aqueous bath which flows from reservoir to reservoir through the holes in the bottoms through which the sheet passes, is recovered in a tarpaulin, heated to boiling point and recycled in one, several or all stacked tanks. ^ 4. Processes as described above. T ·, / /. · - f · ^ if, · fi. * / y -y "s //