Patent Publication Number: US-3880601-A

Title: Method of preparing a continuously cast ingot for rolling or the like

Description:
United States Patent Wii&#39;nnenberg et al.  
 METHOD OF PREPARING A CONTTNUOUSLY CAST INGOT FOR ROLLING OR THE LIKE Inventors: Klaus Wiinnenberg; Josef Kleinen,  
 both of Duisburg, Germany Mannesmann AG, Dusseldorf, Germany Filed: Dec. 20, 1973 Appl. No.1 426,659  
 Assignee:  
 Foreign Application Priority Data Dec, 19. 1972 Germany 2262978 US. Cl. 29/187; 29/203 Int. Cl. B2lb 1/08 Field of Search 164/70; 29/527.6, 527.7,  
 2/1970 Gross 72/203 6/1971 Mitchell 72/203 Primary Examiner-Lowell A. Larson Attorney, Agent, or FirmRalf H. Siegemund [57] ABSTRACT An ingot has been produced by continous casting and cutting a length of the casting. The ingot is presumed to be used for being rolled into a product having particular profile and to be obtained by rolling different portions of the ingot differently as far as reduction in local thickness is concerned. The end faces of the ingot are provided with arch-shaped recesses in those regions of the ingot, which will undergo a higher degree in reduction than the remainder, so that the ingot in turn can have dimensions more suitable for continuous casting, while such dimensions do not have detrimental effect on rolling due to the recesses.  
 6 Claims, 2 Drawing Figures METHOD OF PREPARING A CONTINUOUSLY CAST INGOT FOR ROLLING OR THE LIKE BACKGROUND OF THE INVENTION The present invention relates to continuously cast ingots and to the preparation of such an ingot for further working such as rolling.  
  Upon continuously casting ingots. it has been found practical to provide already the ingot with a contour outlining the particular profile of the final product. into which the ingot is to be worked. In particular. the ingot is cast in a more or less matching cross-sectional contour. but with greather thickness dimensions transverse to the end-to-end dimension of the ingot section. As the ingot is worked (rolled) subsequently. it must be necessary to obtain different degrees of deformation in different portions of the cross-section of the ingot section (uniformly, of course. in the length dimension). Another method has ingots cast with such a cross-section. so that all portions have the same thickness in relation to each other the corresponding thickness relations will have in the subsequently rolled. final product.  
  It is common practice. for example. to provide for a five-fold deformation (reduction); the ingot should be five-fold thicker accordingly in that case. However. it was found that casting and rolling are quite difficult to match. if these dimensional rules are being observed. In other words, it was found difficult in cases to cast an ingot. so that all portions can be rolled down similarly. In such a case one attempts to match the casting procedure for the ingot to the rolling process on the basis of the desired profile of the rolled product. Problems are encountered here concerning feeding of the molten metal to the mold and distributing the metal therein uniformly to make sure that the texture of the casting will be a uniform one. On the other hand. if one tries to match rolling to casting. starting with a casting process on the basis that uniformity of texture is the dominant criterium. then rolling becomes rather difficult as the ingot will not be uniformly reduced. particularly on the first pass through the different mill-stands.  
  The problem will be specified for a particular case. Take the casting of a double T. I beam or flange beam ingot. also called dog bones. From the point of view of casting. the metal should be fed in the region of the stem or web portion of this particular I-profile. Depending on the throughput of casting. it is necessary here to maintain a minimum thickness of that stem of at least I mm (about 2.5 inches). This way one can use a charging chamber, dipping into the mold and having submerged feeder ports. while the open surface of the metal in the mold is covered with a slag producing powder. These various features permit production of high quality ingots (see for example U.S. Pat. Nos. 3,587,719; 3,648,761; 3.669.]81). However. a central web or stem thickness of 2.5 inches or moreis a much larger dimension than rolled billets can be expected to have. Upon rolling the ingot in an intermediate stand and in a subsequent edging stand. the web has to be deformed considerably more than the cross-bar portions or flanges of the double T, so that large tongues form in longitudinal direction at the ends of the ingot. which may severely disturb the rolling process.  
 SUMMARY OF THE INVENTION It is an object of the present invention to avoid the difficulties as outline above and to suggest a prepala tion for an ingot. which reconciles the demands made on casting and rolling so as to match the two processes without impairment of either.  
  In accordance with the invention, it is suggested to continuously cast an ingot with a particular profile in a manner most favorable for obtaining high quality texture in a manner known per se. This continuously cast ingot is cut into sections or predetermined lengths. In accordance with the specific feature of the invention. those portions of that length. which will be deformed more than others during subsequent working, e.g. rolling. will be provided with arched recesses at the ends, extending axially therefrom, i.e. in the direction towards each other, along the direction of end-to-end dimension of the ingot. Depending on the length of the profile. the depth of such arch-shaped indentation is to be 0.2 to 2 times larger than the thickness of the ingot at that point.  
 DESCRIPTION OF THE DRAWINGS While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention. it is believed that the invention. the objects and features of the invention and further objects. features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which:  
  FIG. I shows a cross section through a continuously cast ingot with double T cross-section and profile: and  
  FIG. 2 is a side view of such ingot. prepard at one end in accordance with the teaching of this invention.  
  Proceeding now to the detailed description of the drawing the particular ingot shown in FIG. 1 has a stem or web portion 1 of the cross-sectional profile and cross-bars or flanges 2 to obtain I-beam contour characteristics or dog bone contour. The stem or web 1 is much thicker than the flanges are. because continuous casting requires such thick web; the central portions of the casting must be sufficiently thick for reasons of uniformity of metal flow in the mold, so that the metal may be distributed properly for obtaining uniform texture in the ingot.  
  Upon rolling this particular ingot. a product is usually desired in which the web thickness is equal to the thickness of the flanges (in the final product) or even thinner. Consequently, the ingot has to be deformed by the rolling process rather strongly in the stem and web region, and less in the flange portions of the ingot.  
  The ingot was continuously cast and a certain section has then been cut from the casting. Each end of such a section is defined by a plane of cutting such as 3. Now. in accordance with the invention, it is suggested to provide. (i.e. to cut) an arch-shaped indentation or recess 4 into the portion 1 of the ingot expected to experience the highest deformation upon rolling.  
  The arch of the recess extends in a plane transverse to the thickness dimension of the web, and the two recesses at the two ends extend towards each other along the end-to-end dimension of the ingot. Due to the symmetry of the ingot profile. the arches have their apices on a center line and plane of the ingot. along which the shortest longitudinal dimension of the ingot is established therewith.  
  The indentation 4 can be cut in the same manner and by the same tool and, possibly. at the same time the section is cut from the casting, as it is withdrawn from the mold. Cutting may be performed by conventional equipment as used for cutting sections from a casting. such as cutting torches. a mechanical or hydraulical shearing cutter or other cutters with appropriate profiles. etc.  
  The particular cutting plane 3 illustrates and defines the end faces of flanges 2 at one end of the ingot and without modifications. so that the axial length of the section is reduced by the recess in stem and web por tion 1 of the ingot only with maximum thickness reduction during subsequent rolling resulting in the center. corresponding to the apex of the arch 4. The height 5 of that arch apex relative to plane 3 is illustrated to be about equal to the thickness of the web thereat. the thickness being measured transverse to the arch. i.e. in the plane of the drawing of FIG. 1. Such a lzl ratio is well within the range stated above (0.2 to 2.0). However. in the specific case of ingots for making I beams or flanged beams. a 0.5 ratio was found to be preferred. so that the drawings are not to be interpreted to be on scale for this preferred example of practicing the invention.  
 The drawing depicts. as stated above, an ingot sec- -tion to be prepared in that manner for a subsequent rolling process. reducing the thickness of flanges 2 as well as the stem portion 1, but the latter more than the former. Consequently, excess&#34; material will flow into the arches. (there being one on either end). As these arches are provided. the rolling process can proceed because flow space is provided for within the contour of the final profile.  
  The invention is not limited to the embodiments described above but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be included.  
 We claim:  
 . 1. The method of preparing an ingot for forming. working and shaping such as rolling, which ingot has been produced by continuous casting and by cutting a section of particular length from the casting. the ingot having two end faces. comprising the step. providing an arch-shaped recess in at least one of these end faces extending in the direction of extension of the ingot as between the end faces and into that portion of the ingot. which will be subjected to a higher degree of deforming during the said subsequent forming than the remainder of the ingot. the recess to be bounded by said end faces.  
  2. The method as set forth in claim 1, wherein the depth of the arch-shaped recess is 0.1 to 2 fold the value of the thickness of the ingot at the region of the recess. the thickness being measured transversely to the extension of the arch.  
  3. The method as in claim 1, wherein the end faces are planar and the ingot has portions which are relatively thick and other portions which are thinner than the relatively thick portions. the recess being cut into the relatively thick portions. while end face portions adjacent to thinner ingot portions are left planar.  
  An ingot as an intermediate product to be rolled and having been produced by continuous casting and by cutting a length of the casting and having an archshaped recess in at least one of its planar end faces, the recess extending into that portion of the ingot. which will be deformed by rolling more than the remainder of the ingot.  
  &#39;5. An ingot as set forth in claim 4. wherein the depth of the arch is 0.2 to 2 fold the thickness of the ingot of that portion into which the recess extends.  
  6. An ingot as in claim 4, wherein the recess extends into a portion of the ingot, which is thicker than the remaining portion or portions of the ingot.