US1450699A - Process for seamless-tube drawing - Google Patents

Description

Apr. 3, i923. 1,450,699

A. c. MGRSE ET AL.

PROCESS FOR SEAMLESS TUBE DRAWING FiledSept. 15, 1921 Tube Drawing, of which the following is a Patented Apr. 3, i923.

ALONZO CLAY HORSE AND HARRY RICHARD LEWIS, JR, OF SHELBY,

OHIG.

PROCESS FOR SEAIBiLESS-TUBE DRAWING.

Application filed September 13, 1:92 11. Serial No. 500,414. 3

To all wliom it may concern: I

Be it known that AIDNZO CLAY Morse and HARRY RICHARD LEWIS, Jr., citizens of the United States of America, residing at Shelby, in the county of Richland and State of Ohio, have invented certain new and useful Improvements in Processes for Seamlessspecification. 1

This invention relates to an improvement in the process of seamless tube drawing, wherein through a definite step of heattreatment, the'qualit-ies and capabilities of the material for the. specific purpose outlined, are materially increased.

In the ordinary method of tube making the billets are pierced white hot and rolled over plugs while hot, then pointed and pickled and cold drawnthrough a die over a mandrel. The product is then annealed in a furnace, at from thirteen hundred to fifteen hundred degrees F., and cooled. The pickling step is then repeated, and the material cold drawn over a. mandrel. The opera-- tions from the annealing step being succes-' sively repeated until the tubing has reached the desired size.

The improved step to'be introduced into the process outlined above, is that of heattreatment of the material to a point just above the critical point of the particular material being'used and in accordance with the properties desired and quenching the heated material in a proper cooling medium, This particular heatetreatment step results in a tempering-s'o calledof the grain of the material, with the obvious advantage of a much greater tensile strength for the same ductility; a more uniform and better grain structure; presents a tubing capable of bet ter and more perfect machining; and produces less scale in annealing, hence requiring less acid and time in pickling and cold drawlifter the tube is quenched, the temper is drawn by reheating to a temperature below that of the temperature at which quenching is had, this drawing temperature, say of a minimum of 300 F. being determined by the required characteristics of the final product, that is the'required degree of softness, ductility or other physical properties of the tubedesired. The tube is then allowed to cool and the ordinary operations of making its carbon desired size of tube is seamless drawn tubing repeated, until the obtained.

The use of this additional heat-treatment i step is not confined to any particular period of the complete process, as the usual proc- .css can be followed to any desired size of cold drawn tube, the improved heat-treatment step carr1ed out, and the original or other steps employed to complete the tube' formation.

Of course it is to be understood that the v The accompanying drawing illustrates a.

there-can be no specific inagnified section of material", that in Fig. l i 5 showing the fiber construction of the material following the old and usual process; and

Fig-2 showing the same material following 1 the introduction of the heat-treatment step I of-the new process.

. The heat treatment, or grain refining step, may, of course, 'be used in a particular operation as often as desired ornecessai'y; can be performed at any time, after any heating precess of the material; or may be carried outaft-er several steps or treatments of the tube. In other words there is no practical limitation to the application of the new step.

Fig. 2 of the drawings, in comparison with Fig. 1, clearly indicates the fiber change in cident to the use of the new step, and the advantages of the resultant fiber arrangement will be obvious to one skilled in tubedrawing processes.

The tube result-ant from the use of the new step is essentially stronger, that is of greater tensile strength, than the tube resultant from the old or usual process. Therefore, the tube under the new process can be made of much as was required in the old process. The possibility of lower annealing heat prevents a large proportion of otherwise usual scale' accumulation, and also avoids the possibility of burning the fibers of the material. As a direct result of these conditions, the material can be worked at a much lower heat and much longer.

i nealin Having thus described the invention, What we cla m as new, 1s:--

The close knitting of the fibers of the ma.- teriel resultant directly from the new step of the process, permits a. much better ms.-

and capable of finer drawing, and one requiring less operations to perfect, and providing a better finished article, primarily incident tothe permitted use of a lower/an- .temperuture.

1. A step in the process of seamless tube drawing, consisting in a refinement of the grain of the metal by heat-treatment. to u predetermined degree and then quenching.

- 2. A step in the process of seamless tube drawing, consisting in heating the'material to the upper critical point and quenching intermediate the drewingsteps. I

3. A step in the process of seamless tube drawing, including heat treatment and ally refining the quenching prior to theannealing step.

4. A step in the process of seamless tube drswin consisting in annealin the materinhrs eating to the upper critical point, quenching, and then tempering for additionu g grain of the metal over that oftlie'nnnealing treatment.

5. A step in the process of seamless tuberirawing including heat treatment and quenching immediately following any independent heating step of the usual process.

6..Thatstep in a seamless-tube drawing process consistingin heating the material to s teupersture jfiist above the critical point end i on quenc ing.

before or between any of the drawing steps.

9. A step in a cold drawing tube process directed toward extreme refinement of the grain of the metel, consisting in heating the material to the critical point and quenching in a cooling medium and thereafter anneal- %0. A- process for drawing seamless tubing consisting of piercing and drawing said billet over a. plugin a heated state, then pointjust above the critical point, then quenching same in a cooling medium; then re-heating to a temperature below the upper critical point depending on the character or quality of the steel desired and then allowing same to cool and repeating the usual operations until the size required is produced.

I 11. A process for drawing seamless tubing consisting of piercing a billet and drawing said billet over a plugin e hectedstet'e, then,

pointing-same, then heating same to a tempereture just above the critical point, then quenching some in s cooling medium. then reheating same to a temperature between 300 F. and the upper critical point, de ending on the character or quality of the tu e desired, and then allowing same to cool and repeating the usual operation of drawing the tube until the tube is finished to the size desired.

In testimony whereof we aflix our signatures.

. ALONZO CLAY MORSE.

HARRY RICHARD LEWIS, JR.

mg same, then heatin same to a temperature

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