US1687825A - Die block and method of treating steel for use in the manufacture thereof - Google Patents

Description

Oct. 16, 1928. 1,687,825

H. A. 'BRASSERT DIE BLOCK AND METHOD OF TREATING STEEL FOR USE IN THE MANUFACTURE THEREOF Filed Oct. 14, 1926 HWY-' Inwniir Patented Oct. 16, 1928.

UNITED STATES,

PATENT OFFICE.

HERMAN A. BBAS SERT, 0F KENILWOIRTH, ILLINOIS.

DIE BLOCK AND METHOD or TREATING STEEL FOR USE IN THEREOF.

THE MANUFACTURE Application filed October 14, 1926. Serial 'No. 141,679.

My invention relates to the manufacture of die blocks and other special steel products requiring a steel which retains a high elastic limit in every direction under conditions of it and reduce its cross section, which produces a fibrous structure lengthwise or parallel with the longitudinal axis of the ingot.

It is a well known fact that the physical results obtained in testing steel are not the same in a test made parallel to the fibre as in one made transversely to the fibre. In the manufacture of die blocks it is cusfomary, after the block has been suitably annealed to make the die impressions in a surface of the block which is parallel with the fibre created by the elongation or reductionof the piece by rolling or forging. One reason for this has been that the centerv of an ingot shows a less dense structure than the outer layers, which is due to the more rapid cooling off and chilling of the rim which produces a closer structure therein, whereas the slow cooling of the center develops a coarser or less dense structure. The larger the ingot, the more pronounced is this condition and the more marked is the difference, but it is present in all ingots. This uneven density between surface and center is only partially counteracted in the process of reducing and by heat treatment which refines the grain but is not able to give a homogeneous structurefrom the surface to the center. The result is that the number of drop forgings obtainable from successive die sinkings, while satisfactory in the first few sinkings, becomes smaller as the center of the block is approached, is very unsatis-,

factory near the center, and increases again after the center is passed and the opposite surface approached. Since the resinking of dies is a very expensive operation, it can readily be understood that an important economy is to be gamed by making the gram structure uniform throughout the block and equal 111 qual ty to that of the outer layers. While the desirability of such savingshas long been recognized,p'rior to the present invention no satisfactory method has been proposed by which they could be realized.

I have found that I can overcome the lack of uniformity in the grain structure, and

also produce a more compact grain structure throughout the block,by causing the blooms or billets which have been rolled or for ed from the original ingot, and which, w en necessary, have been cut into multiple pieces of approximately the weight of the finished die block, to be forged endwise or against the longitudinal fibre,that is, in. a direc tion perpendicularto that of the original forging or rolling, which is naturally in the direction of the length of the ingot. In the practice of my invention the endwise forging, or what is generally termed upsetting,

must be carried far enough so that theefl'ect penetrates to the very center of the block. In 7 other Words, the center of the block must be sub ected to the same mechanical refinement as the outer layers, as a slight upsetting of course does not materially affect the grain structure of the block, since it does not extend to any appreciable depth. That the desirable results referred tocan be accomplished by my method, has been'proven by physical tests of pieces of dieblocks so forged, which show the same results as to ultimate strength, elastic limit, elongation, and reduction of area in their longitudinal and their trans verse test pieces. Itis well known that with the present method of forging the longitudinal tests'arealways superior to the transverse tests.

'As a result of the uniform structure throughout the piece which I accomplish, I can with safety use one or the other of the faces at the upset ends for sinking the dies. This not only has the advantage that there. is no. reduction in the density of the structure reached in successive sinkings, but also the die impressions, are cut across and not with the originalfibre of the block, thereby obviating the yielding or flowing of the laminated fibrous structure under the great stress of impact and heat where the die impression is made inalongitudinal surface of the boom In the use of my die block the continued impact of the drop forging hammer continues the refining action upon the block with the Fig. 3 is a'perspective view of ablock out from the billet shown in Fig. 1, illustrating diagrammatically the oldpracticeof sinking dies in the block parallel with the longitudr nal fibres thereof. Fig. 4- is a view illustrating a billet cut to the weight'required for a die block and arranged in position for forging, as a step in my improved process. Fig. 5 is a view of the billetshown in Fig. 4= after it has been reduced by endwise forging or upsetting to thesize required for a die block, an'd'Fi 6 is a view of the block shown in Fig. 5 with the die sunk in one of the upset ends of the block which are at right angles to the main axis of the original ingot. In all the views the shade linesare intended to repre-,

sent the trend. of the fibres. The views are of course'diagrammatic in character, but with the exception of Fig. 3 which shows the old' practice as above stated, they serve to illustrate the several steps of my improved process.

' In practicing my improved process I forge a billet 1 from the original ingot or rolled bloom in the usual manner, and cut the billet into multiples 2 of approximately the weight of the finished die block. These multiples are forged under the press, including anend- Wise forging against the longitudinal fiber resulting from the previous operations; in other words, the block's-are upset in this forging. For instance, a block of thirty inches in height may be upset to one of only eight.- een inches in height.

The forging is done while tlie'die block is hot, preferably. at a temperature from 2000 to 2100 Fahrenheit, although the temperature may vary considerably throughout a comparatively" wide range, and after the forging has been done the block 8 is annealed in any suitable way. The die a is then cut into one end 50f this block, facing the main axis of the original ingot. instead'of being parallel withit as is the current practice as shown at 6 in the made on each successive sinking is practically the same as on the first sinking, resulting in a much larger total number of forgings made from a given block.

In nial'iing die blocks according to the above described process I prefer to use a chromemolybdenuin-niclrel steel so treated as to be suitable for use in making die-blocks without being subjected to the usual or any treatment for hardening, because such a steel, besides having the necessary strength, durability and toughness, is not tooliard to be machined, or to be trimmed down for re-sinking after: it has been used to such an extent that re-sinking is necessary or desirable, but my invention may. well be applied to die blocks made of steels that require hardening, after the sinking,

of the die, and, therefore, it should be understood that the claims hereinaftermade are not intended to be restricted to the use of any particular alloy steel, or to the production of a die block material that essentially excludes hardening.

steel for various other uses besides that of'die block manufacture where a material of'uniform grain structure throughout its mass is desired.

, lVhat I claim as my invention and desire Furthermore, it should be understood that my improved process may be applied in the treatment of high grade Ice in the direction ofthe grain to substantially the fiDlSlIGCl dimensions and simultaneously refining the grain structure throughout the block, forming a die impression within the peripheral confines of a face transverse to'the originallongitudinal axis, and by the repeat-- ed impact of use, under a forging hammer further refining the remainder of the block.

2. A die block containing a die recess sunk into a face transverse to'the ori ginal'longitudinal. axis of the billet from which the block is made and'disposed within the pea ripheral confines of said face, said block having a grain refined byforging longitudinally. of the original fibers and capable of further refinement in use by repeated impact of the forginghammer in gaining impressions from the die.

3. A die block having a grain which has been refined throughout the entirelength of the block by forging endwise of the original longitudinal fibers and hav ng a forming. die recess sunk into an end face thereof across the originaltrend of the fibers and within the peripheral confines of said end face.

4-. A die block containing a forming die recess sunk into a face transverse to the original longitudinalaxis of the billet from which the block is made, said block having a grain refined by forging longitudinally ofthe original fibers and capable of further refinement in use by repeated impact of the forging hammer in gaining impressions from the die.

5. A body of metal suitable for use as a die block, comprising a block severed by a transverse cut from a billet which has a longitudinally extending grain, said block having a grain refined throughout by endwise forging and being adaptedthereby to have a forming die recess sunk in one end face thereof trans- 10 verse to the original longitudinal grain, and being capable of further refinement in use by repeated impact of the forging hammer in gaining impressions from the die.

HERMAN A. BRASSERT.

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