US2317233A - Method and apparatus for hardening steel rolls - Google Patents

Description

April 20, 1943. J. A. TAYLOR A METHC AND APPARATUS FOR HARDENING STEEL ROLLS Filed Aug. 5, 1940 2 Sheets-Sheet 2 April 20, 1943. J. A. TAYLOR METHOD AND APPARATUS FOR HARDENING STEEL ROLLS Filed- Aug. 3, 1940 2 Sheets-Sheet 1 31m-mtos Jaluz A Patented Apr. 20,

UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR HARDENING STEEL ROLLS John A. Taylor, Bethlehem, Pa.,

assigner to Bethlehem Steel Company, a corporation of Penn- Sylvania Application August 3, t s claims. (ci. 14s- 21) This invention relates to new and useful improvements in the art of hardening and tempering cylindrical or tubular metal objects, and more specically it relates to a method and apparatus for the4 quenching of steel rolling-mill rolls whereby greater depth of hardening and higher and more uniform surface hardness are more' it is necessary to begin' the quenching as a flood quench, the entire hot roll being submerged in water, and in a few seconds, after the scale has been removed, to change to a spray quench.

vBy this method, steam formed inthe ood quench removes the scale and` commences the 'hardening process, and vthe spray quench then continues the hardening process;

resulting not 1940, Serial No. 350,168

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patent, and pump 4 pumps water from reservoir 5 through pipes 6 and 1, open valve 8, and pipe 9 into deep cylindrical quenching tank II). The tankis thereby. lled with water to the level II-I I, which in order to allow for the displacement produced by the roll is somewhat below the n overflow outlet pipe I2. With the pump running, but with outlet valve 2 closed, the roll I3 which has previously been heated in a furnace slightly above its critical temperature range is rapidly lowered by means of hanger I4 into the tank I0 until totallyimmersed in the Water and suspended from turntable I5 with'its lower end supported by tubular center I6 and dash-pot I1.

'Rotation of the turntable, by means of motor I8 and gearing connections, is immediately begun; the spray vpipes 3, fed through supply pipe I9, are brought into position adjacent to the roll surface. By this time, some twenty c`- thirty seconds, the roll surface is completely freed of scale, whereupon outlet valve 2 is opened by means of the controlling valve 20 and the water is allowed to drain from the tank to the level 2 I-2I. The balance of the quench thereafter is continued by means of the spray pipes 3, in the -manner described in 'the aforementioned United States Letters Patent No. 2,146,793.

onlyin the elimination of soft spots from the surface of the nished rolls, but also in a considerable increase in general surface hardness over that which could be obtained by using either a ood quench or a spray quench alone. This hardness increase 'as actually measured is from three to five points on the scleroscope, and the depth of hardness is correspondingly greater.

Having thus given a 'general description of the objects and advantages of my invention, I shall now in order to make the same more clear refer to the annexed two sheets or' drawings forming a part of this specication and in which like characters ci' reference indicate like parts.

Figure l' is a vertical longitudinal section of a hardening apparatus such as is shown and described in United States Letters Patent No. 2,146,793, granted to George J. Buckner, with my improvements shown in connection therewith;

Figure 2 is a transverse section taken on the line 2 2 ci Flgure 1, and showing the retractable spray pipes; and

Figure 3 is an enlarged detail view o the bottom portion of the apparatus shown in Figure i.

In operating the quenching machine i, outlet valve 2 is closed, spray pipes 3 are retracted in the manner described 'Ihe quenching uid preferably used with my method and apparatus will be water, but I may use other quenching media, 'or chemical solutions, of the same or diiferent temperatures, singly'or in combination, if I so desire.

And although I have shown and described my Y invention in considerable detail, I do not Wish to be'limited to the exact and specific details shown and described, but may use such substitutions,

in the above mentioned 55 modifications or equivalents thereof, as are embraced within the scope of my invention, or as are pointed out in the claims.

Having .thus described my invention, what I claim as new and desire to secure by Letters Patent is:

i. In a machine for uniformly hardening without soft spots metallic rolls or the like, comprising a quenching tank, a turntable mounted on the quenching tank having means for suspending and supporting the upper end of a heated roll disposed in a vertical position, yielding means for supporting the lower end of the roll, means for rotating the turntable, means orsupplying a quenching luid to the quenching tank to initially descale and nood quench the roll, means for discharging the nocd quenching fluid from the quenching tank after said floodA quenching operation, and means for completing the operation of quenching the heated roll by a continuous sheet spray. g

2. A machine for uniformly hardening and preventing soft spots in a heated metal article, comprising a tank, means for supplying a ilood quenching fluid to the tank, means for brieily Y suspending the article in vthe flood quenching iluid to descale the article, means for discharging the flood quenching fluid from the tank after descaling and flood quenching the article, and means for subjecting the article to a Spray to complete the quenching operation.

3. A machine for descaling and uniformly hardening without soft spots heated metal rolls or the like, comprising a deep cylindrical tank,

means for supplying a descaling and i1o0d` l quenching fluid to the tank, a turntable mounted on the tank, means on the turntable for supporting the upper end of the roll adapted to suspend said roll in the descaling and flood-quenching fluid, means for rotating the turntable, means for removing the descaling and flood-quenching fluid from the tank after descaling and oodquenching the roll, and means for subjecting the` roll to a continuous sheet spray to complete the the roll from the turntable, a dash-pot for re siliently and rotatably supporting the lower end of the roll, retractable spraying members for applying a continuous sheet spray to the roll, and a manually-operated valve for controlling the volumeof the spray quench.

5. A machine for removing scale from a heated metal roll or the like and uniformly hardening the same free of soft spotsrcomprising a tank for containing a scale removingand quenching uid,

a pump for supplying said fluid to thev tank, an outlet pipe for draining excess fluid opening on the tank above the level of the iluid wherein said roll is immersed, an outlet valfve connected to said outlet pipe adapted for rapid drainage' of the scale-removing and quenching fluid from the tank after flood quenching the roll, a turntable for suspending and rotating the roll in the scaleremoving and quenching fluid, means for rotat-V ing the turntable, and means for subjecting the roll to a spray to complete the quenching operation.

6. The method of preventing soft spots due to scale on a heated metal roll or the'lke, which consists in taking the roll'heated slightly above its critical temperature range, briefly subjecting the rollt'o a steam-producingscale-removing and flood-quenching fluid, withdrawing said steamproducing scale-removing. and flood-quenching fluid from the roll surfaces and then completing the vquenching operation by applying to the roll aY continuous sheet spray. y

7. The method of uniformly hardeningA without soft spots a vertically suspended heated metal roll which consists in taking the roll heated above its upp'r critical temperature, removing scale therefrom by briefly flood-quenching said roll to evolve steam to remove surface scale while rotating the roll rapidly, quickly removing the iioodquenching fluid from the roll, and thereafter applying to said roll a continuoussheet spray.

8. The method of uniformly hardening without soft spotsa metal roll or the like consisting of rst heating-the roll above the upper critical temperature, then briefly immersing the heated roll in a flood-quench fluid to evolve steam and thereby remove the scale from the surface of the roll, removing the nood-quenching iluid from the roll, and then spray quenching the roll.

9. The meth'od ofuniforlnly hardening without soft spots a metal roll or the like consisting in subjecting the roll heated slightly above its upper critical temperature to a flood-quenching y fluid for approximately thirty seconds to produce steam and to remove all patches of scale from the roll, removing theilood quenching iluid from the roll, and then spray quenching the roll until cool.

. JOHN A. TAYLOR.

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