US2171074A - Process for improving the texture of rolled products - Google Patents

Description

Aug. 29, 1939. F. BARTSCHERER Y 2,171,074

rnocsss FOR IMPROVING THE'TEXTURE 6F ROLLED PRODUCTS Filed Febizs, 1957 Hy. B312 Patented Aug. 29, 1939- UNITED STATES (PATENT OFFICIE Franz Bartscherer, Duisburg-Hamborn,

- Germany Application February 23, 1937, Serial No. 127,280 In Germany February 27, 1936 a 4 Claims. Experiments have shown that, by employing 'very high degrees of compression during the rolling out of the puddle ingots, a practically parallel fcrystallite arrangement of the surface of the rolled products can be obtained. The degree of compression to be employed in a pass is 50 to 80%. The bending test pieces taken from thqtranscrystalli'zation zone showed, that bending strengths exceeding'100% with at the same time considerable enlargement of the bending angle could be obtained by employing these high degrees of compression, as compared with normally 'rolled products of similar character. This process of employing high degrees of compression is, as regards its employment, restricted to relatively low rolled products, as particularly in the case of high girder sections the difllculty arises, that this measure not only requires more passes than in the case of the rolling process hitherto employed and results in losses in temperature, but that the puddle ingot dimensions became such that they could no longer be treated by rolling. For example, for producing an I-girder SOcentimetres in height it would be necessary to use, with a compression degree of 75%, a puddle i'ngot at least 1 .5 metres in height. Such dimensions cannot, however, be worked tp-day in any rolling mills; It has been found, however, that the employment bi high degrees of compression should at the same time preferably be chosen so that, during the compressing of the same notonly the direction of the transcrystallization extends practically parallel to the surface of the ingot,"

but that no technical defects of rolling, such as overrolling or the like can occur. Therefore, the

protrusions formed by the additional material are preferably of triangular cross-section. On the other hand it issufilcient to provide these protrusions only in two opposite sides of the'ingot, for example for the middle of the flanges in the case of girders, for the base surface and the head of rails. The two other sides, which form the web of the sections, are worked through so strongly during the rolling process that the ininevertheless becomes possible in that atthe- The shape of the local additional material tially existing primary structure almost completely disappears in the finished product.

In itself it is not necessary to provide the additional material on the puddle ingot. The rolls may also be calibrated in such a manner that the local protrusions of .additional material are formed in an intermediate pass and then during the next pass such high pressure is exerted that these protrusions disappear and moreover the height of the section is reduced. It is, however, preferable to produce the protrusions in the puddle ingot as the ingot can easily be produced in correspondingly shaped chills, and the local protrusions can be arranged so that they disappear at a certain distance from one of the ends of the block, which, it evident, facilitates the feeding, as the rolls first grip the smooth'part of theingot and only thereafter work the protrusions.

The drawing shows, by way of example, a manner of carrying out the process in connection with the production of rails, and in which the displacement of the surface crystallites into a parallel position relatively to the surface takes place on the rail head and on the rail base surface. 1

Fig. 1 shows a puddle ingot a with the local protrusions 1) formed by additional material.

' After the first pass the ingot has assumed the shape c indicated by dash lines, whereas the hatching shows the places at which the head and base surfaces are situated in the finished product and in which therefore the crystallites are arrangedparallel to the surface.

Figs. 2 to 13 show the appearance of the ingot after each additional pass, Fig. 13 showing the finished rail. In all these figures the position of the portions subsequently forming the head and base surfaces are indicated by shaded portions.

The rolling of I-girders is'carried out in sub-. stantially the same manner. The grooved rolls for the shaping of the ingot according to Figs. 1 to 4 are provided on the blooming mill, the remaining passes on the finishing rolls. Up to the ingot shape shown ,in Fig. 4 the grooving is practically the same also for I-girders, and for the passes on the finishing rolls it is the well known one.

It is evident, that not more passes are-necessary than in the'known rolling processes.

I claim:

l. A method of producing and treating rolled articles, more particularly rails and-shaped iron sections for improving the texture and structure thereof, consisting in forming local protrusions of additional material on at least two opposite sides of an ingot, said protrusions being formed on those sides which are to have a crystallite arrangement substantially parallel to the surface of the finished article, said protrusions being spaced from one end of the ingot to facilitate the feeding of the ingot to the rollers, and rolling the ingot to'reduce the local protrusions and to produce the parallel crystallite arrangement.

2. A method of producing rolled articles more particularly rails and shaped iron sections while improving their structure by disposing the surface crystallites at particular positions in the material being rolled in a position practically parallel to the surface, consisting in forming local protrusions of additional material on twoopposite sides of the ingot, the protrusions being so shaped and located that they disappear at such a distance from one end of the ingot as to facilitate the insertion of the ingot between the

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