连铸坯代替锻坯生产13Cr厚壁钢管的研究

Research on 13Cr Thick-walled Steel Tube Produced by Continuous Casting Billets Instead of Forging Billets

分别使用连铸坯和锻坯通过热挤压生产φ219 mm×30 mm的13Cr厚壁无缝钢管,然后进行980℃×130 min淬火并720℃×200 min回火,对坯料组织、钢管组织、晶粒度、力学性能和δ铁素体进行了对比。结果表明:连铸坯显微组织疏松,柱状晶粗大,锻坯显微组织致密,等轴晶细小;经过84.5%的热挤压变形后,连铸坯钢管平均晶粒度是6.5~7.5级,锻坯钢管平均晶粒度是7.0~8.0级,组织均匀致密;连铸坯钢管和锻坯钢管的力学性能相当,采用连铸坯代替锻坯热挤压成形13Cr钢厚壁管在技术上具有可行性。

The 13Cr thick-walled seamless steel tubes ofφ219 mm×30 mm were hot-extruded by continuous casting billet and forging billet respectively.Then quenching of 980℃×130 min and tempering of 720℃×200 min were carried out.The billet microstructure,steel tube microstructure,grain size,mechanical properties andδferrite were compared.The results show that the microstructure of continuous casting billet is loose,the columnar crystal is thick;the microstructure of forging billet is compact and the equiaxed crystal is fine.After 84.5%hot extrusion deformation,the average grain size of continuous casting billet steel pipe is 6.5-7.5 level,the average grain size of forged billet steel pipe is 7.0-8.0 level,and the microstructure is uniform and compact.The mechanical properties of continuous casting steel tube and forging steel tube are equivalent.It is technically feasible to use continuous casting billet instead of forging billet for hot extrusion forming 13 Cr steel thick wall pipe.