Q255B/SM490 /热模合金钢SWRCH19A SWRCH20A SWRCH22A SWRCH10K SWRCH12K SWRCH15K SWRCH16K SWRCH17K SWRCH18K SWRCH20K SWRCH22K SWRCH24K SWRCH25K SWRCH27K SWRCH30K SWRCH33K SWRCH35K SWRCH38K SWRCH40K SWRCH41K SWRCH43K SWRCH45K SWRCH48K SWRCH50K SNB5-1 SNB7-2 SNB16-3 SNB21-1 SNB22-1 用于制作高耐磨性、高疲劳强度和相当大的强度、处理后尺寸精度高的氮化零件,如仿模、气缸套、齿轮、高压阀门、镗杆、蜗杆、磨床主轴等。但尺寸较大的零件不宜采用。