新日铁于 2 0 0 1年 3月 6日宣布 ,已开发成功可降低焊接费用的高层大楼底层钢柱用的厚板新品种。新产品名为“建筑钢结构用高热对应、高 HAZ韧性钢”,用于高层大楼底层的钢柱。因需强度较高 ,故采用 4 0～ 1 0 0 mm厚板焊成箱形结构。但是用老产品焊接时 ,高温下钢的晶粒由数 On March 6, 2001, Nippon Steel announced that it has developed a new variety of slabs for steel columns on the ground floor of high-rise buildings that can reduce welding costs. The new product, titled “Building Steel Structures with High Heat, High-HAZ Toughness Steel,” is used for steel columns on the ground floor of high-rise buildings. Due to the higher strength, so the use of 4 0 ~ 1 0 0 mm thick welded into box-shaped structure. But with the old product welding, the high temperature steel by the number of grains