湘钢中小棒56*100.5平面矩形扁钢轧制工艺研究

Research on Rolling Process of 56*100.5 Right-angle Flat Bar in Small and Medium Bar Plant at Xiangtan Steel

湖南华菱湘潭钢铁有限公司棒材厂中小棒材厂在圆钢的基础上开发56×100.5平面矩形扁钢,采用圆-平-平-立-平-立-平的模式,同宽度系列的矩形孔型共用,最大限度发挥产能优势,其中K2、K4专用立轧孔型;K4孔无槽底凸度,侧壁斜度α=10°,槽底宽度b_(k4)=58mm,槽口宽度B_(k4)=68 mm,辊缝20 mm,槽高78mm。K2孔无槽底凸度,侧壁斜度α=3°,槽底宽度b_(k2)=56.8 mm,槽口宽度B_(k4)=60.98 mm,辊缝20 mm,槽高99.7 mm。通过低温开轧和冷床缓冷工艺轧制52CrMoV4平面矩形扁钢,其抗拉强度为1511-1494 MPa,硬度在330-342 HB,延伸率为11%。52CrMoV4脱碳层深度为0.245-0.25 mm,组织为珠光体和黑色针状下贝氏体,并有少量马氏体和少量的粒状贝氏体及屈氏体。

Small and Medium Bar Plant of Hunan Valin Xiangtan Iron and Steel Co.,Ltd.develops 56*100.5 right-angle flat bar based on their round steel.The circle-flat-flat-vertical-flatvertical-flat pattern was adopted.Rectangular design hole patterns of the same width series were shared to make full use of the advantages of production capacity.Among them,K2 and K4 are special vertical rolling passes;K4 hole has no groove bottom convexity and the sidewall slopeα=10°,groove bottom width b_(K4)=58 mm,groove width B_(K4)=68 mm,roll gap is 20 mm and groove height is 78 mm.K2 hole has no groove bottom convexity and sidewall slopeα=3°,groove bottom width b_(K2)=56.8 mm,groove width B_(K4)=60.98 mm,roll gap is 20 mm and groove height is 99.7 mm.Through the low temperature rolling and slow cooling process on the cooling bed,the 52CrMoV4 right-angle flat bar was rolled.Its tensile strength is 1511-1494 MPa,the surface hardness is 330-342 HB,and the elongation is 11%.The decarburization layer depth of 52CrMoV4 is 0.245-0.25 mm.The microstructure is pearlite and black acicular lower bainite,and there is a small amount of martensite and a small amount of granular bainite and troostite.