US2371356A - Method of producing steel billets - Google Patents

Description

March1 3, 1945. ARROWE 2,371,356

METHOD OF PRODUCING STEEL BILLETS Filed July 20, 1943 I MQQ fTi Patentod Mar; 13, 1945 METHOD OF PRODUCING STEEL BILLETS Andrew Rowe, MoKeesport, Pa assignor to National Tube Company, Pittsburgh, Pa., a corporation of New Jersey Application July 20, 1943, SerialNo. 495,471

2 Claims.

The invention relates to the production of steel "billets that are substantially rectangular in cross section, having rounded corners, and which are subsequently rolled or otherwise worked to form various sections, seamless tubing, forgings and the like.

The prevailing practice in producing suchbillets is to roll ingots into blooms on a reversing blooming mill which may be. a two-high or a fourhigh mill whose working rolls are supported by backing rolls. and then on the same heat to roll the blooms singly on a reversing three-high mill or on a continuous mill which is used primarily for producing the smaller size billets. The work ing rolls of such billet mills are provided with grooved passes that are formed between deep collars that not infrequently spell and break, making it necessary to regrind the rolls or substitute new ones.

Before ,being rolled or otherwise worked, it is necessary to condition the four rolled surfaces oi each such singly rolled billet, as by chipping, grinding, i iame cutting or scarflns, which requires a substantial amount of time, and not infrequently is attended by a substantial loss of metal required to be removed.

-'1'he object of the invention is to provide an improved method of producing steel billets of the type explained, whereby the direct cost of production is materially reduced and substantial indirect savings are attained by reduction in the wear and breakage of rolls and roll collars.

In-the practice of my improved method steel billets are produced in multiple from an ingot which is first rolled on a slabbing mill to form a slab having a thickness which is substantially equal to the thickness of desired billets and having a width which is a multiple of that of desired billets. Any well known or desired procedure may be followed-to roll such slabs from east ingots. They may be rolled on eithertwo or four-high reversing slabbing mills having vertical edging rolls in line with horizontal slabbing'rolls, but preferably the slabbing rolls are provided r with one or more edging passes and the working tables adjacent to them are equipped to-turn the slabs on their edges and properly guide them through the passes. v v

Aftera slab of the desired width and thickness has thus been produced it is, on the same heat, flat rolled in a closed pass to form desired rounded corners at its longitudinal edges. and also simultaneously to form narrow shallow grooves on the upper andlow'er faces or the slab, the grooves 7 upper'being opposed to those on the lower face. These grooveshave rounded corners and they are spaced from each other and from the edges of the slab the width of desired billets. While this grooving and corner-rounding pass may be formed in the rolls of a special mill stand,

it is preferably formed in the working rolls of the slabbing mill. p

when the thus grooved slab has been formed it is flame cut'in the plane of the opposed grooves to form a plurality of billets, the flame cutting being done by oxyacetylene or oxyhydrogen torches which simulttaneously finish the flame cut faces of the billets and make it unnecessary subsequently to condition them.

tive view of a grooved slab being flame out to produce a plurality of billets.

As shown in Fig.1, the faces of upper slabbing roll Iii and lower slabbing roll it are provided with a slabbing-pass i, a preliminary edging pass 2, a final edging pass 3 and a closed slab-grooving and corner-rounding pass 4, Upper roll I is shown in its lowermost position, land is adapted to be I collars I on the faces of rolls Ill and ii.

outer portion 0 of each of these' collars is curved elevated in any desired manner by rollbalances which urge it against screw-downs which are turned to the required vertical position to form any desired pass spread. An ingot is. reduced to a slab by giving it the required number of passes in slabbing pass I and edging pass 2. When As shown in F18. 1, pass 4 is shaped to provide two grooves in the upper and two'in the lower i'ace of a slab, the grooves being formed by small to correspondingly form a rounded base at the bottom of each groove, and, between the outer portions of each collarand the adjoining cylindrlcal roll faces, eachroll is curved as at I to form rounded corners at the outer portions of the grooves. 'The edgesof pass 4 are iormed by collars it which are curved as at It to form rounded corners at the longitudinal edges or a grooved slab. The curvatures it of pass 4 may be of slightly less radius than the corresponding curvatures l8 in final edging pass 3 to provide an initial underflll at the comers or pass 4. In rolling a slab in pass 4 these corner underfllls are filled by the displacement of metal incident to the forming of grooves by collar 1. Thus in pass 4 there is nooverfill, and consequent formation of fins, in the plane of the meeting faces of the rolls at the-edges of the pass.

4 Pass 4 may be formed to provide any desired number of properly spaced grooves in the upper and lower faces of a slab so that the slab may later be flame cut into any desired number of billets of a given size. By way of example, and

not of limitation, the details of a' suitable pro- 4 cedure will be explained for rolling slabs in multiples of three billets that are 4 1-: 4 inches in cross section.- Starting witha steel ingot about 23 x 26 inches and weighing about 12,500 pounds, it is first given about ten passes in slabbing pass I to reduce it to a slab about 20 x 11 inches, as shown in Fig. 2. The slab is then turned on its edge and is given four ed ng passes in edging pass 2 to reduce it to about 15 x 12 inches, as shown in Fig. 3. The thus edged blank is then given four passes in slabbing pass I to reduce it to about 19 x 5 inches, as shown in Fig. 4, and is then-turned on its edge and given one or two edgin passes in final edging and comerrounding pass 3 to shape it to the form shown in Fig. 5 which is about 14 1: 4 inches. The slab is finally given one or more passes in closed groove-forming pass 4 to provide its upper and lower faces with opposed narrow shallow grooves 20. These grooves may suitably be about threesixteenths of an inch wide at their bases and one-half inch in depth. After the slab is thus rolled and grooved it is flame cut by torches 2i which burn slits through the slab of about threesixteenths of an inch in width and leave the corners of the billets rounded to the same curvature as the rounded edges of groove 20.

In the example given the tonnage rate or production oi grooved slabs of the form shown in Figs. 6 and 7 is three times "greater than that of rolling billets singly according to the prevailing practice explained above. In other words, thirty tons of slabs of the form shown in Figs.

6 and 7 can be rolled in the time required for 5 practice. The overall 'cost or flame cutting grooved slabs and conditioning their rolled faces is not more than that of conditioning all four .faces of billets rolled singly according to the prevailing practice, and is usually less with an at- 10 tendant saving in cost oi billet production. In

addition to these direct savings in the cost or billet production, there is less spalling and breakage of the shallow groove-forming collar I and of the working rolls than in the case of rolls which 16 are provided with deep collars for rolling all four faces of billetssingly. This indirect reduction in cost of producing billets is substantial.

According to the rovisions of the patent statutes, I have explained the principle and mode 20 or operation of my invention, have illustrated the preferred way of practicing it, and have given a specific example of one procedure. However. I desire to have it understood that, within the scope of the appended claims the invention may be practiced otherwise than specifically illustrated and described.

Iclaim; I

l. The method of producing steel billets in multiple i'rom an ingot, comprising rolling an ingot to form a slab having a thickness which is rooves in the upper and lower faces thereof,

such grooves having rounded corners and being spaced from each other and from the edges of the slab the width of desired billets, and flame cuttingthe slab in the planes of said opposed grooves to form a plurality of billets and simultaneously to finish the so cut faces of the billets. 2. The method of producing steel billets from an ingot, comprising rolling an ingot on a slabblng mill to form a slab having a thickness which is substantially equal to and a. width which is a multiple or that or desired billets, rolling the slab in a closed pass provided inthe rolls of said slabbing mill to form rounded comers atthe lonw gltudinaledges of the slab and opposed grooves in the upper and lower races thereof. such grooves having rounded corners and being spaced from each other and from the edges' of the slab the width or desired billets, and flame cutting the slab in the planes or said opposed grooves to form I. plurality of billets and simuitaneously to finish the so cut faces of the billets.

. ANDREW REED ROWE.

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