US2028244A - Steel ingot - Google Patents

Description

` Jan.21, 1936. J, E PERRY EAL 2,028,244

STEEL INGOT Drgnal Filed July 5, 1923 2 Sheets-Sheet 1` 2@ Liv 3 age A M A oRNEY Jan. 2,1, 1936. J. E. PERRY Er AL STEEL meow original Filed, July 5, 192s 2 sheets-sheet 2 f ATTORNEY l s 4W 3 p0, j M, .n I

UNITED STATES PATENT .oFFlcE STEEL INGOT John E. Berry, Youngstown, and William Haig Ramage, Girard, Ohio, assgnors to Valley Mould and Iron Corporation, Hubbard, Ohio, a corporation of New York Original application July 5, 1928, Serial lNo. 290,329. Divided and this application August g929, Serial No. 388,293. In Canada July 24,

9 Claims. (Cl. 22-218) The present inventio'n relates broadly to the metallurgy of steel and more especially to a steel ingot. The present application comprises a division of our application Serial No. 290,329, led July 5, 1928.

The `presentl invention relates to an ingot of steel having corrugated surfaces ofv a novel characteristic and wherein the surface cracks and defects adjacent the surface of the ingot are eliminated and wherethe corrugations in the ingot are arranged particularly with reference to facilitatingrolling of the ingot.

Ingots of the prior art having relatively high salients of small cross section formed on small radii not only tend to' trap segregates when the ingot is frozen, but also have weakness caused -by entangled columnar crystals `in the salients.

i wherein the curvature of the salients and of the valleys between the salients are such that when the ingot is being cast, columnar crystals in the ingot which grow at right angles to the surface of the mold do not tend to focus Within the zone of direct chill in the ingot produced from the cold walls of the mold. The axes of the radii upon which the salients and the valleys o'r non-salient portions of the surface of the ingot are formed are such that the columnar crystals in the ingot, if extended, do come to a focus within the zones of axial crystals and the inner ends of the columnar crystals do not overlap or intersect with each other. Therefore, the ingot does not contain concentrates which are trapped by the ends of the columnar crystals as would be the case if these crystals did actually intersect and focus within their own zones.

From a crystallinastandpoint, the radii of the non-salient portions of the surface of the ingot is not so important as the radii of the salient portions, but in practice, it has been found that the valleys or non-salient portions should be such as td avoid surface' defects, which may occur in working the ingot when the valleys are on very columnar crystals without bringing the inner ends of these crystals into interlacing contact with each other. The inner ends of these columnar crystals comprise. a wavy zone surrounding and securely locked to the zone ofl axial crystals in the center portion of the ingot.

Another important feature of the invention resides in the arrangement of the salients on the ingots in that the initial roll contacting tops of the salients are parallel to each other and to center planes at right angles to the mid sections of the ingot surface. This results in the salients running in a straight line under the rolls of a rolling mill and thus prevents any cross or diagonal rolling on the surface of the ingot. The dimensions of the salients on the surface of the ingot are formed throughout the length of the ingot, and this also obviates rolling strains on the salients and permits uniform heating of the salients when the ingot is in the soaking pit. Where the surfaces of the ingot are tapered as may be the case in rectangular ingots, the maintaining of the salients and valleys throughout the length of the ingot may be accomplished by providing small at narrow rectangular areas on the sides of the ingots adjacent the corners and which areas are lo'cate'd between the corner curved surfaces of the adjacent salients on the ingot. Increased height of salients on the ingot gives increased strength to the-ingot skin. In rolling practice, however, there is a maximum height which is allowable for any given cross sectional sizes of ingot. However, the size of the ingot determines the number of proper salients which may be placed in a side thereof. Using this ,proper number of salients with the form of curvature such as will result in correct crystallization in the ingot, the maximum height of the salient is obtained by having the areas of the valleys between the salients relatively small.

Other and further objects of the present invention `will in part be'lobvious and will in part be pointed out hereinafter by reference to the accompanying drawings, forming a part of this specification. l

Realizing that the present .invention may be embodied in structures other than those specifically disclosed, it is to be `understood that the disclosure herewith is illustrative and not in the limiting sense.

Fig. 1 is a longitudinal view of the exterior of one side of a rectangular ingot in accordance with the present invention.

Fig. 2 is a view similar to Fig. 1 and showing a portion of the ingot broken away to clearly illustrate the relation between the columnar and axial crystals.

Fig. 3 is a cross sectional plan view taken on line 3 3 of Fig. 1.

Fig. 4 illustrates a detail portion comprising a section adjacent one side of an ingot in accordance with the present invention and with the salients joined byv long non-salient portions.

Fig. 5 is a view similar to Fig. 4 showing these face 2, and joined at the mid-section of the side wall of the ingot by a non-salient or valley 4. The salients I have their top-most portions extending parallel throughout the length of the ingot, as indicated by lines 5 and 6 of Fig. 1. 'I'he ingots may be tapered slightly with the bottom width of the side being slightly greater than the top width thereof, and flat surfaces 'I and 8 (shown in Fig. 1 in dotted lines in exaggeration) occur between the corner surfaces 2 and the adjacent salient ribs I. These surfaces I and 8 are referred to as hat but it is to be understood that the term flat is merely relative. These surfaces may be somewhat curved, and the feature which is emphasized is that the salient ribs I are made with their initial roll contacting top portions parallel without distortion of the corner surfaces, and with the salient ribs I being substantially the same width and height throughout the length of the ingot. An extremely important feature of the present ingot is that the ribs I and the valleys 4 are formed upon such curvature (when considered in cross section) that the growth of columnar crystals, when the ingot is freezing, is such as not to focus within the zone of chill produced by the chill mold wall in which the ingot is cast. In the preferred embodiment of the invention the axes 9 of the radii I0 on which the salient ribs are formed are in the zone A of axial crystals of the ingot, and within the zone B of the normal effect of chill of the mold on the crystallization of the steel of the ingot. An ingot in accordance with this construction has a crystalline structure wherein the columnar crystals occur at substantially right angles to the surface of the ingot, but do not come to focus within the zone B and, therefore, the ingot is free from inclusions which otherwise would occur at about this zone.

A further advantage of an ingot in accordance with the present invent1on is that the zone represented by the dotted line C, Figs. 2 and 3, where the columnar crystals meet the axial crystals, is such that these two types of crystals interlock with each other in such manner as to thoroughly tie the two types of crystals together. n It is to be understood that while this interlocking zone between the columnar crystals and the axial crystals is indicated by dotted line C, the zone is of substantial width so that this dotted line indicates the general location of the zone rather than the absolute definite limits of the zone. The radii II of the corners are preferably of such length that the' axes I2 of these corner radii are also wel] within the zone A of axial crystallization, and the corners 2 are preferably rounded on uniform radii for the full length of the ingot.

Fig. 4 is a detailed sectional portion of the side of an ingot taken at right angles to the salient ribs and shows the salients I4 and I5, which are on radii of the same length, being. joined by a relatively long radius non-salient portion I6, which is tangent at its extremities to the curves of the salients I4 and I5. The axes I I of the radii I8 are located well within the zone of axial crystals A. In this construction the general tend of the growth of columnar crystals is in accordance with the lines I9 and it will be observed that these lines do not focus within the zone B, representing the normal depth of the chill in the ingot due to the eect of the mold in which the ingot is cast.

Fig. 5 is a view similar to Fig. 4 with the salients 20 and 2| formed upon the same radii as the salients shown in Fig. 4, but with the nonsalient portion 22 on a much shorter radius than the non-salient portion IG of Fig. 4. In the type of ingot shown in Fig. 5 a much deeper salient is provided in that the tangents on each side of the non-salient portion where this portion joins the salients are closer together than in the construction shown in Fig. 4. In other words, the side wall length of the salients is extended further than 'the side wall of the salients in Fig. 4. This produces a stiffer ingot during the time the ingot is freezing and also produces a somewhat longer surface skin on the side of the ingot. The lines 24 illustrate the general direction of the columnar crystals under the construction shown in Fig. 5 and while more crystals are directed toward the axes on which the salients are formed, none of these lines 24 come to a focus within the zone B representing the mold wall chill and consequently there is no tendency of trapping inclusions in the zone between the axial and the columnar crystals.

Fig. 6 illustrates small salients 25 upon radii 26 formed on axes 21 and also small non-salient portions 28. This produces the side wall on the ingot in which the height of the salients is rela.- tively low. It will be observed that the axes 2l for the salients are located very close to the edge of the chill zone B. While, as above specified, columnar crystals tend to grow at substantially right angles to the ingot side wall, the actual growth of these crystals or location of these crystals in the ingot is influenced by the surface on the ingot, as for example, in Fig. 6, the columnar crystals 29 from the salients 25 are ini'luenced by the relation ofthe columnar crystals from the non-salients 28. Under these conditions the columnar crystals 30 beneath the nonsalients 28 spread out fanwise with plenty of space to grow in and therefore relieve the concentration pressure on the inner ends of the columnar crystals 29. In this way practically none of the crystals directly under the salients tends to focus within the zone chill but on the other hand tends to focus, as expanded, between the point 3| and the axis 2l on which the small sa.- lients are formed. This condition obviates the formation of any cleavage plane by the focusing of the columnar crystals and consequently the crystallization in the ingot is not detrimental to the ingot. On the other hand, an ingot surface is provided which may stretch under rolling without breaking and furthermore, the small salients support the ingot during the freezing thereof.

The present invention produces ingots not only having improved skin surfaces, but which are also better ingots from a metallurgical standpoint in that the curvatures of the salients on the surface of the ingots are such as to permit proper freezing and crystallizationot the steel without the trappingof harmful inclusions at the juncture between the columnar crystals and the axial crystals. Furthermore, since the tops of the salients are parallel throughout the length of the ingot, there is no cross rolling when the ingot passes through the rolling mill.

1. An article of manufacture comprising an ingot of steel tapering from one end toward the other and having salient portions on the longitudinal surfaces thereof, said salient portions on each side being parallel to salient portions on the same side andextending the full length of said ingot, said salient portions being remote from the corners of said ingot.

2.-An article of manufacture comprising an ingot of steel tapering from one end toward the other and having salient portions extending the full length of said ingot, said salient portions being of the same width throughout the length of the ingot, said salient portions being remote from the corners of the ingot.'

-3. An article of manufacture comprising an y lthe depth of said salient portions on a side being uniform throughout their length.

5. As an article of manufacture, an ingot of steel having longitudinal taper and with salient portions .on the sides of said ingot, the, salient portions on each side being parallel to other salient portions onthe same side, the corners of said ingot being rounded on a uniform radius throughout the length ofthe ingot, and with narrow triangular areas extending lengthwise of the ingot adjacent to said corners.

6."As an article of manufacture, an ingot of steel tapering from one end toward the other and with salient portions on thesides of said ingot, the salient portions on each side being parallel to other salient portions on the same side, the corners of said ingot being rounded throughout the length of the ingot, the salient portions and said corners comprising surfaces generated on radii of a length greater than the depth of the columnar crystalline zone of the ingot,

7. As an article oi' manufacture, a steel ingot tapering from one end toward the other and having salients on the sides thereof, said salients being formed upon radii having axes extending parallel to the surface of the ingot and parallel to each other axis on the same side of the ingot, and non-salients formed on radii of a lesser length than the radii of the salients. v

8. As an article of manufacture, an ingot of steel having longitudinally tapered sides and with portions being formed on radii of uniform length and having axes extending parallel to the surface of the ingot and with said axes being located in theJ zone of axial crystals of the ingot. i 9. A longitudinally tapered metallic ingot having a substantially rectangular cross section with rounded corners and salients superimposed on the sides of said ingot comprising segments of cylinders extending lengthwise of said ingot.

JOHN E. PERRY. WILLIAM HAIG amen.

' salient portions on the sides thereof, said salient

Images