大口径P91无缝钢管低温形变退火

研究推制式生产和低温形变退火的大口径P91无缝热扩钢管的显微组织、晶粒度、非金属夹杂物和室温力学性能,并与原管和热扩后经正火+回火处理的热处理钢管进行对比。结果表明,推制式低温形变退火生产的热扩钢管显微组织为回火马氏体,晶粒度6级,纵向和横向屈服强度、抗拉强度、伸长率、布氏硬度分别达到565、740 MPa,25%,220 HB和540、730 MPa,24%,218 HB。P91无缝钢管在低温形变退火后,屈服强度、抗拉强度、硬度略微下降,显微组织、晶粒度和非金属夹杂物与低温形变退火前保持一致,符合ASTM A335标准对P91和GB 5310—2008标准对10Cr9Mo1VNbN的要求。

Low temperature thermomechanical annealing of P91 large-sized seamless steel tube

Microstructure,grain size,non-metallic inclusion and mechanical properties of P91 large-sized hot-expanded steel tube with low temperature thermomechanical annealing were investigated It was compared with crude seamless steel tube and hot-expanded steel tube with normalizing+tempering.The results indicate that the microstructure of the hot-expanded steel tube with the low temperature thermomechanical annealing is tempered martensite,and the longitudinal and horizontal yield strength,tensile strength,elongation,brinell hardness reach approximately 565 MPa,740 MPa,25% ,220 HB and 540 MPa,730 MPa,24% ,218 HB respectively These mechanical properties of P91 hot-expanded steel tube decrease slightly,while the microstructure,grain size,non-metallic inclusion keep consistent before and after the low temperature thermomechanical annealing The test results fully meet the requirements of ASTM A335 to P91 and GB 5310-2008 to 10Cr9Mo1VNbN.