| 摘要 |
<p>An as-continuously cast beam blank (10) is described including a web portion (12) and a plurality of opposed flange precursor portions (14, 16, 18, 20) extending from opposite ends of the web portion (12), the web portion (12) having an average thickness of no greater than about 3 inches, each of said flange precursor portions (14, 16, 18, 20) having an average thickness of no greater than about 3 inches, wherein the ratio of the average thickness of the flange precursor portions (14, 16, 18, 20) to the average thickness of the web portion (12) preferably is between about .5:1 to about 2:1. The resulting beam blank (10) has a crystal grain structure of fine ferrite and pearlite, substantially free of acicular ferrite and grain boundary ferrite films.</p> |
