高性能特厚板的研发

Development of Ultra-thick High-Performance Steel Plate

现有特厚板强度较低,低温韧性较差。研发了一种碳质量分数为0.065%的120 mm特厚钢板。研究了轧制加热温度和非再结晶区轧制总压下率对钢板奥氏体晶粒尺寸、显微组织和力学性能的影响。结果表明:在1200℃以下加热的钢板奥氏体晶粒长大不明显;在1250℃加热的钢板奥氏体晶粒平均尺寸为111μm,最大为295μm;随着非再结晶区轧制总压下率的增大,钢板铁素体增多,组织细化。通过控制加热温度和非再结晶区轧制总压下率试制的120 mm厚钢板屈服强度大于390 MPa,抗拉强度大于510 MPa,-60℃冲击吸收能量大于200 J,表面和表面以下50 mm处韧-脆转变温度低于-80℃。

The existing ultra-thick steel plate is lower in strength and poor in low-temperature toughness.A type of 120-mm-ultra-thick steel plate which contained 0.065%C by mass was developed.The effects of the heating temperature before rolling and the total rolling reduction in the non-recrystallized zone on the size of austenite grains,microstructure and mechanical properties of the steel plate were investigated.The results showed that(a)the steel plate heated at temperatures below 1200℃had no considerably grown austenite grain;(b)the size of austenite grains was average of 111μm and maximum of 295μm in the steel plate heated at 1250℃;(c)as the total rolling reduction in the non-recrystallized zone increased,the ferrite amount increased and the microstructure become finer.The 120-mm-thick steel plate trial-produced by controlling both the heating temperature and total rolling reduction in the non-recrystallized zone exhibited yield strength greater than 390 MPa,tensile strength greater than 510 MPa,impact absorption energy greater than 200 J at-60℃,and ductile-brittle transition temperature below-80℃at the surface and 50 mm from the surface.