03Cr25Ni6Mo3Cu2N双相不锈钢脆断和腐蚀缺陷分析及工艺改进

Analysis and Process Improvement of Brittleness and Corrosion Defects of 03Cr25Ni6Mo3Cu2N Duplex Stainless Steel

本文通过03Cr25Ni6Mo3Cu2N双相不锈钢的化学成分分析、显微组织观察、力学性能和耐蚀性能试验,对材料脆断和腐蚀等性能缺陷及其产生原因进行了分析,并针对原因提出了工艺改进措施。结果表明,存在脆断和腐蚀等性能缺陷的钢棒和滤网片的金相组织异常,钢中存在较多的σ相直接导致了钢棒矫直脆断、加工性能恶化、耐蚀性能降低。钢棒热锻后在σ相析出温区缓慢冷却和长时停留,以及后续热处理时固溶不充分,是钢中存在大量σ相的主要原因。针对问题原因改进工艺,一方面钢棒在热锻后进行快速冷却,避免在σ相析出的敏感温区缓冷和长时停留,另一方面在热处理时对钢棒进行充分固溶,减少或消除σ相,03Cr25Ni6Mo3Cu2N双相不锈钢固有的优良性能得以发挥,钢棒加工性能得到明显改善,钢棒制造的离心机芯滤网不再发生表面腐蚀问题,材料使用寿命得到明显提高,工艺改进措施取得了良好效果。

By means of chemical composition analysis,microstructure observation,mechanical properties test and corrosion resistance test of 03Cr25Ni6Mo3Cu2N duplex stainless steel,the performance defects such as brittle fracture and corrosion and their causes are analyzed,the process improvement measures are put forward.The results show that the microstructure of the bar and the filter screen is abnormal,and the moreσphase in the steel directly leads to the bar straightening brittle fracture,the worse workability and the lower corrosion resistance.The main reasons for the existence of a large number ofσphases in steel are the slow cooling and long-term retention ofσphase precipitated in the temperature range after hot forging,and insufficient solid solution during subsequent heat treatment.In view of these,on the one hand,the steel bar is cooled quickly after hot forging to avoid the slow cooling and long stay in the temperature range ofσphase precipitation.On the other hand,the steel bar is dissolved fully during heat treatment,to reduce or eliminateσphase.Then the inherent excellent properties of 03Cr25Ni6Mo3Cu2N duplex stainless steel can be brought into play,the workability of the steel bar can be improved,and the surface corrosion of the filter net of centrifuge core made of steel bar can no longer occur,the service life of the material has been improved,and the improvement measures of the process have achieved good results.