VARIABLE FLANGE BEAM BLANK AND METHOD OF CONTINUOUS CASTING

Abstract: A beam blank and a method of continuously casting beam blanks suited for rolling as-cast into an entire range of product sizes within a family of structural products without the need for altering the as-cast geometry in a Breakdown Mill prior to finish rolling.

Description: VARIABLE FLANGE BEAM BLANK AND METHOD OF CONTINUOUS CASTING BACKGROUND OF THE INVENTION This invention relates to continuous cast beam blanks from which structural beam products are rolled, and in particular, it relates to a method of continuously casting variable flange beam blanks suited for rolling into an entire range of finished beam shapes within a family of structural beam products without the need for altering the as-cast geometry in a Breakdown Mill prior to finish rolling. Kawasaki Steel Technical Report No. 3, dated September 1981, discloses that state of the art beam blanks are continuously cast to shapes which conform as close as possible to their final rolled beam size. This casting practice was established because it improves both the quality and yield of the finished beam products. This improvement is realized because the small dimensional changes required to roll the finished beam product reduces many rolling mill problems such as tongue elongation, end cropping loss, and irregular flange thickness. These rolling problems are normally encountered because of an improper understanding of the volumetric relationship between the various components of the cast beam blank and the finished beam product. Because the state of the art continuous cast beam blank is sized as close as possible to its finished beam size, it can only be universally rolled, as-cast, into a small number of selected finished beam products. To further emphasize this point, we refer to a paper entitled "The Continuous Casting of Beam Blanks at the Algoma Steel Corp., Ltd." given at the 77th General Meeting of the American Iron and Steel Institute, (ΛISI). The AISI publication teaches that Algoma has continuously cast and used the beam blanks A through C shown in Figure 1. Algoma discloses that its beam blank A is suited for rolling into 14 finished beam product sizes, beam blank B yields 12 finished beam products, and beam blank C can be rolled into 7 finished product sizes. In all cases, Algoma _ as-cast beam blanks must first be rolled in a conventional Breakdown Mill to substantially alter the as-cast geometry prior to finish rolling in a Universal Mill. As the state of the cast beam blank art advanced, the industry began to recognize the need to consider the relationship between cast beam blanks and their corresponding finished beam products. It also recognized a need to provide adjustable casting molds to increase production and yield. United States Patent No. 5,082,746 granted to Forward, et al. addresses the relational need by disclosing an as-continuously cast beam blank that, 1) appro -imates the finished shape and configuration of the beam or other structural shape desired, 2) minimizes the number of rolling passes or that must be undergone to reach the desired final size, and 3) controls the relationship between web thickness and flange thickness to effect control over both required working and minimize tearing of flanges and undesired elongation and/or buckling of web portions of the beam blank. Forward further discloses providing a continuously cast beam blank wherein the web of the blank has an average thickness of no greater than 3 inches, and the ratio of the average thickness of the flange precursor portions to the average thickness of the web portion is between 0.5:1 to about 2:1. Although Forward teaches a need to balance the thickness ratio between the web and flange portions of his cast beam blank, he fails to recognize the need to balance the web/flange cross-sectional area ratio. He has also failed to recognize the need to correlate such web/flange ratios with their corresponding ratios in the desired finished product. Strucbel, et al. addresses the need for an adjustable continuous casting mold in his United Stales Patent No. 5,036,902. He teaches adjusting the end walls of a continuous casting mold to vary the flange th ' c n-ss of a beam blank. However, Struebel fails to either teach or even suggest varying his cast beam blank flange thickness to effect a desired web/flange area ratio which substantially equals a corresponding ratio in a desired finished product. In most instances, in the absence of such teaching, Struebel's cast beam blanks will realize poor product yield and incur considerable rolling problems as described above. Because of the current state of die cast beam blank art, manufactures are unable to cast beam blanks which are suited for rolling into an entire family of structural beam products without first making significant modifications to die as-cast beam blank in a Breakdown Mill. A family of structural beam products is the entire range of beam sizes having the same beam depth (d). For example, all the finished beam products falling within the W36x300 tiirough W36xl35 range of wide flange beam sizes as listed in "Bethlehem Structural Shapes", Catalog 3277 and Catalog Insert 3277A. SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a single continuous cast variable flange beam blank suited for rolling any finished beam size within an entire family of finished beam products without making significant modifications to the as-cast beam blank in a Breakdown Mill. It is a further object of Uiis invention to greatly reduce the amount of tongue elongation during the rolling of the finished beam product. It is still a further object of this invention to minimize variations in either the flange thickness or web thickness during the rolling of the finished beam product. And finally, it is a further object of this invention to provide a method for continuously casting a variable flange beam blank suited for rolling into any finished beam size within an entire family of finished beam products. We have discovered that the foregoing objects can be attained with a method fo continuously casting a beam blank having a flange width (bf) greater than the largest (bf) in family of finished beam products, a web depth (dw) close to the roll width of a Universal Rollin Mill, and a web area to flange area ratio (Λw/Λf) substantially equal to the (Λw/Λf) of th desired finished beam size within a family of beam products. BRIEF DESCRIFITON OF TIIE DRAWING The drawing figure is a cross-sectional end view of an adjustable continuous caster mol and a continuously cast beam blank strand. _, DETAILED DESCRIPTION OF TIIE INVENTION Referring to the drawing figure, ti e cross-section of a continuously cast beam blank stran 1, shown within a continuous caster mold 10, comprises a web portion 2 identified by the cros sectioned area Aw, and two flange portions 3 identified by the cross-sectioned areas Λf. Vario structural steel manufactures are currently rolling finished beam products from continuously ca beam blanks having the general configuration shown in the drawing. However, it has be discovered that these state of the art beam blanks can only be rolled, as cast, into a few, limit finished beam sizes. In most instances it is necessary to significantly modify such beam blan in a Breakdown Mill prior to finish Universal Mill rolling. These limitations are primarily result of an industry wide lack of understanding concerning the volumetric relationship betwe the various segments of the cast beam blank and their correlation with their correspondi segments in the finished beam product. As shown in the above patents, and in particular as disclosed in U.S. 5,082,746, t current state of the cast beam blank art teaches a need to balance the thickness relationsh between the web and flange portions of the beam blank to overcome the aforementioned proble experienced during rolling operations. To this end, Forward specifically teaches casting a bea blank having a 0.5:1 to about 2:1 flange to web thickness ratio. However, when cast beam blan are based upon such thickness criteria, they must either be cast within tightly defined dimension limits, or be significantly modified in a Breakdown Mill in order for them to be successfull rolled into a few desired finished beam sizes. The present invention, which is directed to a beam blank cast to a shape having a we area to flange area ratio (Aw/Af) substantially equal to the web area to flange area ratio (Aw/A of a desired finished beam product, eliminates the need to cast a beam blank to tightly define thickness dimensions. It has also been discovered that if the casting mold is adjusted to vary t flange area thereby maintaining a substantially equal (Aw/Af) ratio between the cast beam blan and desired finished product, such continuously cast beam blanks can be rolled into any finishe beam size within an entire family of beam products. Additionally, because the (Aw/Af) rati are equal, the need for a Breakdown Mill is eliminated and rolling elongation between the flan and web portions is equalized. As a result, tongue elongation and end cropping is greatl reduced, and both the product quality and yield are improved. To better illustrate the inherent differences between a continuous cast beam blank havin its dimensional properties based upon a web thickness to flange thickness ratio (tw/tf) and t same cast beam blank having its dimensions based upon an (Aw/Af) ratio, we refer to the enti family of finished 36 inch deep wide flange beam products produced by Bethlehem Ste Corporation. As shown in Table 1, a finished W36x393 beam, has an overall depth (d) of 37. inches and comprises a web depth (dw) of 33.400 inches, a web thickness (tw) of 1.220 inche a flange width (bf) of 16.830 inches and a (tw/tf) ratio of 0.555. According to Forward teaching, his continuous cast beam blank is based upon two criteria. The first criterion requir the beam blank to be cast into a shape which approximates the shape of the finished bea product, and the second criterion requires the (tw/tf) ratio of his beam blank to fall within a ran of 0.5:1 to about 2:1. Let us now consider what will occur if we continuously cast a family of beam blanks using Forward's teaching to adjust die casting mold to vary the flange thickness (tf) of the beam blanks. Because we want to cast a blank which will approximate the finished product, we will assume our mold will be sized to duplicate the geometry of the largest beam size in the W36 family. The adjustable end walls 11 of the caster mold 10 are set to cast a (tf) of 2.200 inches to match the finished product, and as shown in Table 1, the geometry of this cast beam blank closely matches the finished product. Therefore we should be able to cast and directly roll this beam blank in a Universal Mill with few or no problems. Continuing with Forward's teaching, and remembering that we are unable to adjust eithe the web opening 12 or flange width 13 of the caster mold 10, we adjust the mold end walls 11 to increase or decrease of the (tf) of the beam blank flanges 3 as we move through the range o beam sizes listed in the W36 family of finished beam products. As further shown in Table 1 when the (tf) of a cast beam blank is varied to match the (tf) of a desired beam size, the cas beam blanks fall within the scope of Forward's teaching in that the beam blanks approximate th shape of the finished product, and the (tw/tf) ratios of the beam blanks fall within a 0.5:1 to 2: ratio range. Even though the thickness ratios fall within Forward's range, Table 1 shows that problem will occur when the beam blanks are rolled into the finished beam size. For example, if w compare the web and flange cross-sectional areas of the W36x393 beam, we find that both th web and flange portions elongate equally during the rolling of the as-cast beam blank into it finished product, i.e., (web 40.748/40.748 = 1, flange 37.026/37.026 = 1). This is verified by th equal (Aw/Af) ratio of 1.101 shown in the table. However, if we continue to apply Forward' teaching to both the as-cast beam blank and its finished product for the other beam sizes withi the W36 family we find that the as-cast (Aw/Af) ratio is no longer equal to the (Aw/Af) ratio o the finished product. For example, in the case of the W36X256 beam size, we find that the we portion and the flange portion elongate unequally during the rolling of the as-cast W36X25 beam blank into its finished product, i.e., (web 40.748/32.611 = 1.250, flange 37.009/21.132 1.751). This is because in the absence of metal cross flow during finish rolling, the web portio of the W36X256 as-cast beam blank will attempt to finish 1.402 times longer than its flang portion, i.e., (1.751/1.250 = 1.402). This unequal elongation between the web and flange portion increases the tendency for web buckling and/or flange thinning during the finish rolling of th product, and such rolling problems are difficult, if not impossible to control. It is very difficul to effect a high degree of metal cross flow in a Universal Mill. In order to achieve a hig volume metal cross flow, the as-cast beam blank must first be reshaped in a Breakdown Mil before being sent to the finish rolling operations of the Universal Mill. Even then, much of th excess material will form into elongated tongues and will be lost during end cropping of th Breakdown Mill product. Therefore, Forward's as-cast beam blank cannot be sent directly t a Universal Mill, and the process of reshaping his as-cast beam blank in a Breakdown Mill wil result in substantial product loss due to uneven elongation and cropping. As clearly shown in Table 1, if the (tf) of a beam blank is systematically varied to matc the (tf) of a desired finished beam product, and even though the beam blank geometry falls withi the taught (tw/tf) ratio range, unequal distribution of metal between the flange and web portion of beam blank is a reoccurring problem throughout the entire beam family. The present invention is directed to a heretofore unknown method for continuously castin an improved variable flange beam blank which can be rolled into any finished beam size withi a given family of beam products. The finished beam sizes can be rolled directly in the Universa Mill without any flange unevenness, tongue elongation, or cropping loss. To continuously ca an improved beam blank, three criteria must be met. The first criterion requires that the flang width opening 13 of the continuous caster mold 10 must be larger than the flange width (bf) o TABLE 1 W36 WIDE FLANGE BEAM FAMILY and CAST BEAM BLANK BASED UPON FLANGE THICKNESS SECTION d dw br tf t Af Aw tw/tf Aw/Af NUMBER Inches Inches inches Inches inches sq. In. sq. In. raUo ratio W36_393 Beam 37.80 33.400 16.830 2.200 1.220 37.026 40.748 0.555 1.101 Cast Beam Blank 33.400 16.830 2.200 1.220 37.026 40.748 0.555 1.101 36 359 Beam 37.40 33.380 16.730 2.010 1.120 . 33.627 37.386 0.557 1.112 Cast Beam Blank 33.400 16.830 2.189 1.220 36.841 40.748 0.557 1.205 W_«_328 Beam 37.09 33.390 16.630 1.850 1.020 30.766 34.058 0.551 1.107 Cast Beam Blank 33.400 16.830 2.213 1.220 37.245 40.748 0.551 1.309 W36_3O0 Beam 36.74 33.380 16.655 1.680 0.945 27.980 31.544 0.563 1.127 Cast Beam Blank 33.400 16.830 2.169 1.220 36.504 40.748 0.563 1.441 W3____0 Beam 36.52 33.380 16.595 1.570 0.885 26.054 29.541 0.564 1.134 I Cast Beam Blank 33.400 16.830 2.164 1.220 36.420 40.748 0.564 1.542 W-__2-0 Beam 36.26 33.380 16.550 1.440 0.840 23.832 28.039 0.583 1.177 Cast Beam Blank 33.400 16.830 2.091 1.220 35.192 40.748 0.583 1.681 W3-X256 Beam 37.43 33.970 12.215 1.730 0.960 21.132 32.611 0.555 1.543 Cast Beam Blank 33.400 16.830 2.199 1.220 37.009 40.748 0.555 1.400 W3-X245 Beam 36.08 33.380 16.510 1.350 0.800 22.289 26.704 0.593 1.198 Cast Beam Blank 33.400 16.830 2.059 1.220 34.653 40.748 0.593 1.793 W3-X232 Beam 37.12 33.980 12.120 1.570 0.870 19.028 29.563 0.554 1.554 Cast Beam Blank 33.400 16.830 2.202 1.220 37.060 40.748 0.554 1.542 W- _x230 Beam 35.90 33.380 16.470 1.260 0.760 20.752 25.369 0.603 1.222 Cast Beam Blank 33.400 16.830 2.023 1.220 37.076 40.748 0.603 1.922 W3.__.10 Beam 36.69 33.970 12.180 1.360 0.830 16.565 28.195 0.610 1.702 Cast Beam Blank 33.400 16.830 1.999 1.220 33.643 40.748 0.610 1.780 W3__194 Beam 36.49 33.970 12.115 1.260 0.765 15.265 25.987 0.607 1.702 Cast Beam Blank 33.400 16.830 2.099 1.220 33.811 40.748 0.607 1.922 W3.X182 Beam 36.33 33.970 12.075 1.180 0.725 14.249 24.628 0.614 1.728 Cast Beam Blank 33.400 16.830 1.986 1.220 33.424 40.748 0.614 2.052 W36xl70 Blank 36.17 33.970 12.030 1.100 0.680 13.233 23.100 0.618 1.746 Cast Beam Blank 33.400 16.830 1.974 1.220 33.222 40.748 0.618 2.201 W-6xl60 Beam 36.01 33.970 12.000 1.020 0.650 12.240 22.080 0.637 1.804 Cast Beam Blank 33.400 16.830 1.914 1.220 32.213 40.748 0.637 2.374 W36_150 Beam 35.85 33.970 11.975 0.940 0.625 11.257 21.231 0.655 1.886 Cast Beam Blank 33.400 16.830 1.835 1.220 30.883 40.748 0.655 2.576 W36_135 Beam 35.55 33.970 11.950 0.790 0.600 9.4410 20.382 0.759 2.159 Cast Beam Blank 33.400 16.830 1.606 1.220 27.029 40.748 0.759 3.065 J the largest beam size in the family of beam products. Second, the web opening 12 of the caster mold must be sized to cast a beam blank having a web depth (dw) close to the Universal Mill roll width. And third, the end walls 11 of tiie caster mold must be adjusted to cast a beam blank having an (Aw/Af) ratio substantially equal to the (Aw/Af) ratio of the desired finished beam size. Referring to Table 2 and the drawing figure, in order to meet the first criterion we observe that the largest finished beam size in the W36 family is the W36x393 beam. This beam has a (bf) of 16.830 inches and a web thickness (tw) of 1.220 inches. Knowing that the (bf) for the W36X393 is 16.830 inches, we can now furnish a properly sized flange width opening 13 in our caster mold 10 by providing a (bf) opening having a greater width than the largest (bf) in the W36 family of beams. For example, (16.830" largest W36 bf) + 1.000" = (17.830" caster mold bf). To meet the second criterion, and insure that the web depth (dw) of the improved beam blank is properly sized to fit the roll width of the Universal Mill, we simply set the (dw) of the web opening 12 to the common (dw) listed for the beam family. In this case the (dw) opening is 33.380 inches. In conjunction with the selection of the (dw), the web thickness of the mold opening 12 must also be considered. The (tw) of the as-cast beam blank must be greater than the (tw) of the finished beam product. However, the selection of the (tw) should also be based upon metallurgical properties desired in the finished product. Accordingly, the (tw) should be sized to permit a rolling reduction rate which will impart a proper grain structure to the finished product. In this case, a (tw) of 5.000 inches has been selected to give a reduction rate of 4.1:1, a common reduction rate for most structural products. It should be remembered however, that depending upon the composition of the material being rolled and the desired grain structure of the finished product, reduction rates can have a wide range of variations. Therefore, the important criterion is to provide an as-cast beam blank having a (tw) greater than the (tw) of its finished product. Thus the first and second criteria have been met in that the improved cast beam blank wi have a (bf) greater than the largest (bf) listed in the W36 beam family, and its (dw) will fit withi the Universal Mill rolls. Both the caster mold web opening 12 and flange width opening 13 a fixed dimensions which cannot be adjusted to vary the geometry of the cast beam blank. The third criterion, directed to tiie (Aw/Λf) ratio, is adjustable to permit varying t improved beam blank (Aw/Λf) ratio to equal the (Aw/Af) ratio of a finished beam product. shown in the drawing, mold end walls 11 are capable of adjustment toward or away from the X axis of caster mold 10. Such end wall adjustment permits a wide variation of the cros sectional flange area (Af) of the cast improved beam blank strand. Knowing that the cros section of web opening 12 is 166.90 square inches, it is a simple matter to calculate that e walls 11 must be adjusted to cast an improved beam blank having an (Af) of 151.59 squa inches to provide a matching 1.101 (Aw/Λf) ratio. To calculate the required end wall adjustment necessary for achieving a beam blank flan area of 151.59 square inches, we again refer to the drawing. Beam blank flanges 3 comprise tapered portion (tfl) adjacent the beam blank web 2, and a rectangular portion (tf2) adjacent t caster mold adjustable end wall 11. The tapered portion (tfl) has a fixed cross-sectional ar while the cross-sectional area portion (tf2) can be varied by adjusting the mold end walls 11. Common Universal Mill practice has established that the inside flange angle 14 of t beam blank portion (tfl) should fall within an angle of between 10° to about 20°. However, should be understood that almost any beam blank flange angle between 0 and 90 degrees can b used. A 15° angle has been selected for this example, and knowing tiiis angle we can calcula that the flange portion area bound by (tfl) has a fixed cross-section of 19.630 square inches. From this we know that end wall 11 must be adjusted to create a rectangular flange opening 131.96 square inches, i.e., (151.59 Af - 19.630 tfl = 131.96 square inches). Therefore, becau we know that the (bf) opening is 17.830 inches, we must adjust the (tf2) to 7.40 inches in ord TABLE 2 W36 WIDE FLANGE BEAM FAMILY and IMPROVED BEAM BLANK BASED UPON AREA RATIOS SECTION d dw bf tf tw Λr Aw tw/tf Λw/Af NUMBER Inches In. inches inches Inches sq. In. sq. In. ratio ratio W3_x393 Beam 37.80 33.400 16.830 2.200 1.220 37.026 40.748 0.555 1.101 Improved Blank 33.380 17.830 8.502 5.000 151.59 166.90 0.548 1.101 W36x359 Beam 37.40 33.380 16.730 2.010 1.120 33.627 37.386 0.557 1.112 Improved Blank 33.380 17.830 8.418 5.000 150.09 166.90 0.553 1.112 W3-X328 37.09 33.390 16.630 1.850 1.020 30.766 34.058 0.551 1.107 Improved Blank 33.380 17.830 8.456 5.000 150.77 166.90 0.551 1.107 W3-X300 Beam 36.74 33.380 16.655 1.680 0.945 27.980 31.544 0.563 1.127 Improved Blank 33.380 17.830 8.306 5.000 148.09 166.90 0.560 1.127 W3-X280 Beam 36.52 33.380 16.595 1.570 0.885 26.054 29.541 0.564 1.134 Improved Blank 33.380 17.830 8.255 5.000 147.18 166.90 0.563 1.134 W3-x260 Beam 36.26 33.380 16.550 1.440 0.840 23.832 28.039 0.583 1.177 Improved Blank 33.380 17.830 7.953 5.000 141.80 166.90 0.583 1.177 W3.X256 Beam 37.43 33.970 12.215 1.730 0.960 21.132 32.611 0.555 1.543 Improved Blank 33.380 17.830 6.067 5.000 108.17 166.90 0.748 1.543 W3.X245 Beam 36.08 33.380 16.510 1.350 0.800 22.289 26.704 0.593 1.198 Improved Blank 33.380 17.830 7.814 5.000 139.32 166.90 0.593 1.198 W3._232 Beam 37.12 33.980 12.120 1.570 0.870 19.028 29.563 0.554 1.554 Improved Blank 33.380 17.830 6.024 5.000 107.40 166.90 0.753 1.554 W36x230 Beam 35.90 33.380 16.470 1.260 0.760 20.752 25.369 0.603 1.222 Improved Blank 33.380 17.830 7.660 5.000 136.58 166.90 0.604 1.222 W3.X210 Beam 36.69 33.970 12.180 1.360 0.830 16.565 28.195 0.610 1.702 Improved Blank 33.380 17.830 5.500 5.000 98.061 166.90 0.817 1.702 W3-X194 Beam 36.49 33.970 12.115 1.260 0.765 15.265 25.987 0.607 1.702 Improved Blank 33.380 17.830 5.500 5.000 98.061 166.90 0.817 1.702 W3.X182 Blank 36.33 33.970 12.075 1.180 0.725 14.249 24.628 0.614 1.728 Improved Blank 33.380 17.830 5.417 5.000 96.586 166.90 0.829 1.728 W36xl70 Blank 36.17 33.970 12.030 1.100 0.680 13.233 23.100 0.618 1.746 Improved Blank 33.380 17.830 5.361 5.000 95.590 166.90 0.836 1.746 W3«xl6- Beam 36.01 33.970 12.000 1.020 0.650 12.240 22.080 0.637 1.804 Improved Blank 33.380 17.830 5.189 5.000 92.517 166.90 0.861 1.804 W3.XI50 Beam 35.85 33.970 11.975 0.940 0.625 11.257 21.231 0.655 1.886 Improved Blank 33.380 17.830 4.963 5.000 88.494 166.90 0.896 1.886 W3-X135 Blank 35.55 33.970 11.950 0.790 0.600 9.4410 20.382 0.759 2.159 Improved Blank 33.380 17.830 4.336 5.000 77.304 166.90 1.009 2.159 to achieve the required 131.96 inch cross-sectional area. As shown in Table 2, if end walls 11 are systematically adjusted to vary the (tf2) openin in accordance with the present invention, the (Aw/Af) ratios are matched throughout the entir beam family and the distribution of metal between the flange and web portions is equalized. Th (Aw/Λf) ratios for the W36 family fall within a ratio range from 1:1 to about 2: 1. In considerin a full line of I-beam or wide flange beam products starting with the W40 family through W family, it will be found that the finished product (Aw/Af) ratios fall within a ratio range fro about 0.4:1 to about 2.6:1. Such improved, continuously cast beam blanks facilitate rolling operations in that they ca be sent directly to the Universal Mill and they experience no tongue elongation or yield loss du to rolling in a Breakdown Mill. Additionally, as illustrated in Table 2, a single caster mold ca be used to cast an entire family of beam blanks, in this case 17 different beam sizes, and thereb increase the productivity of the industry. While this invention has been illustrated and described in accordance with a preferre embodiment, it is recognized that variations and changes may be made therein without departin from the scope of the invention as set forth in the claims. For example, the continuous castin method invention based upon (Aw/Af) ratios can be adapted to use a single adjustable mold f casting improved beam blanks suited for rolling the entire range of finished beam sizes fallin within two or more families of beam products. This new (Aw/Af) ratio method of continuou casting beam blanks can also be adapted for casting and rolling asymmetrical flanges on bea products when each of the two flanges are considered individually, as well as other structur products such as structural tees or rails.

Claims: AMENDED CLAIMS [received by the International Bureau on 1 November 1994 (01 . 1 1 .94) ; original claims 1 -10 cancel led _ and repl aced with new claims 1 - 15 (6 pages ) ] 1. A method of continuously casting beam blanks for direct finish rolling as-cast into any finished beam size within a beam family, the steps of the method comprising: a) providing a caster mold having: i) adjustable end walls , ii) a web opening extending through said caster mold, said web opening including a fixed cross-sectional area (Aw) within said caster mold, and iii) at least one flange opening extending through said caster mold, said flange opening adjacent said web opening and including a variable cross-sectional area (Af) within said caster mold, b) adjusting at least one end wall toward or away from said web opening to vary said cross- sectional area (Af) and provide an (Aw/Af) ratio equal to an (Aw/Af) ratio of a finished beam within said beam family, c) pouring liquid steel into said web opening and said flange opening extending through said caster mold, d) casting said beam blank, and e) rolling a finished beam having an (Aw/Af) equal to said (Aw/Af) ratio of said caster mold. 2. The invention described in claim 1 wherein said variable cross-sectional area (Af) comprises: a) a tapered portion (tfl) adjacent said web opening, said tapered portion (tf) having a fixed cross-sectional area, and b) a rectangular portion (tf2) adjacent at least one adjustable end wall of said caster mold, said rectangular portion (tf2) having a variable cross-sectional area. 3. The invention described in claim 2 wherein said tapered portion (tfl) comprises: a) a flange width (bf) greater than a largest flange width (bf) within a range of finished beam sizes of said beam family, and b) an inside flange angle within a range of 0° to 90°. 4. The invention described in claim 3 wherein said flange width (bf) of said tapered portion (tfl) is greater than a largest flange width (bf) within a range of finished beam sizes of said beam family. 5. The invention described in claim 4 wherein said flange width (bf) of said tapered portion (tfl) is greater than or equal to said largest flange width (bf) of said beam family. 6. The invention described in claim 1 wherein said fixed cross-sectional are (Aw) comprises: a) a web depth (dw) equal to a (dw) of said beam family, and b) a web thickness (tw) Φ a largest (tw) within a range of finished beam sizes of said beam family. 7. The invention described in claim 1 wherein said end walls of said caster mold are adjusted to provide a (Aw/Af) ratio within a range of (Aw/Af) ratios of said beam family. 8. The invention described in claim 2 wherein said end walls of said caster mold are adjusted to provide a (Aw/Af) ratio within a range of (Aw/Af) ratios of said beam family. 9. The invention described in claim 1 wherein said continuous cast beam blanks are suited for finish rolling as-cast into an entire range of finished beam sizes within two or more beam families. 10. The invention described in claim 1 wherein said caster mold includes a first flange opening adjacent a first end of said web opening and a second flange opening adjacent a second end of said web opening, said first and said second flange openings each including a variable cross-sectional area (Af) within said caster mold. 11. The invention described in claim 9 wherein said continuous cast beam blanks are suited for finish rolling as-cast into an entire range of finished beam sizes within a beam family. 12. The invention described in claim 9 wherein said continuous cast beam blanks are suited for finish rolling as-cast into an entire range of finished I-beam sizes within two or more I-beam families. 13. A method of continuously casting a beam blank for direct finish rolling as-cast into any finished beam size within a beam family, the steps of the method comprising: a) providing a caster mold having; i) adjustable end walls, ii) a web opening extending through said caster mold, said web opening including a fixed cross-sectional area (Aw) within said caster mold, and iii) at least one flange opening extending through said caster mold, said flange opening adjacent said web opening and including a variable cross-sectional area (Af) within said caster mold, b) pouring liquid steel into said web opening and said flange opening extending through said caster mold, c) adjusting at least one end wall toward or away from said web opening to vary said cross- sectional area (Af) and provide an (Aw/Af) ratio equal to an (Aw/Af) ratio of a finished beam within said beam family, d) casting said beam blank, and e) rolling a finished beam having an (Aw/Af) equal to said (Aw/Af) ratio of said caster mold. 14. A method of continuously casting a beam blank for direct finish rolling as-cast into any finished beam size within a beam family, the steps of the method comprising: a) providing a caster mold having; i) adjustable end walls, ii) a web opening extending through said caster mold, said web opening including a fixed cross-sectional area (Aw) within said caster mold, and iii) two flange openings extending through said caster mold, each said flange opening adjacent said web opening and each flange opening including a variable cross-sectional area (Af) within said caster mold, b) adjusting said end walls toward ' or any from said web opening to vary each said cross-sectional area (Af) and provide an (Aw/Af) ratio equal to an (Aw/Af) ratio of a finished beam within said beam family, c) pouring liquid steel into said web opening and said flange openings extending through said caster mold, d) casting said beam blank, and e) rolling a finished beam having an (Aw/Af) equal to said (Aw/Af) ratio of said caster mold. 15. A method of continuously casting a beam blank for direct finish rolling as-cast into any finished beam size within a beam family, the steps of the method comprising: a) providing a caster mold having; i) adjustable end walls, ii) a web opening extending through said caster mold, said web opening including a fixed cross-sectional area (Aw) within said caster mold, and iii) two flange openings extending through said caster mold, each said flange opening adjacent said web opening and each flange opening including a variable cross-sectional area (Af) within said caster mold, b) pouring liquid steel into said web opening and said flange openings extending through said caster mold, c) adjusting said end walls toward or away from said web opening to vary each said cross-sectional area (Af) and provide an (Aw/Af) ratio equal to an (Aw/Af) ratio of a finished beam within said beam family, d) casting said beam blank, and e) rolling a finished beam having an (Aw/Af) equal to said (Aw/Af) ratio of said caster mold.

Inventors: WILDE WILLIAM J, WILDE, WILLIAM, J.
Applicants: BETHLEHEM STEEL CORP, BETHLEHEM STEEL CORPORATION
Application year: 1993
Main classification: B22D11
IPC codes: B21B1, B22D11