1Cr21Ni5Ti双相不锈钢不同温度时效脆化倾向研究

Embrittlement Tendency of 1Cr21Ni5Ti Duplex Stainless Steel Aged at Different Temperatures

对1Cr21Ni5Ti双相不锈钢在400~600℃之间进行时效处理,测试其冲击韧性和力学性能,结合断口形貌和金相组织观察,研究1Cr21Ni5Ti双相不锈钢不同温度时效脆化规律,提出抑制缓解脆化的工艺措施。结果表明:1Cr21Ni5Ti双相不锈钢在550℃时效的脆化倾向较小,脆化倾向最敏感的时效温度区间为450~500℃,在此区间时效时,铁素体脆化而发生解理或准解理断裂;同时,高的Ti/C比值增大450~500℃之间的脆化倾向,但高的Ti/C提高奥氏体的稳定性,显著降低600℃时效脆化倾向。在上述基础上,研究证明增加锻造比使奥氏体相产生足够变形并使其均匀分布,能有效阻止铁素体脆性裂纹的扩展,可以较大程度地降低脆化倾向。

Through the aging treatment of 1Cr21Ni5Ti duplex stainless steel at 400~600℃,the impact toughness and mechanical properties of 1Cr21Ni5Ti duplex stainless steel were tested.Combined with the observation of fracture morphology and metallographic structure,the aging embrittlement law of 1Cr21Ni5Ti duplex stainless steel at different temperatures was studied,and the measures to inhibit and alleviate embrittlement were put forward on the basis of the above research.The results indicate that the embrittlement tendency of 1Cr21Ni5Ti duplex stainless steel caused by aging at 550℃is comparatively small,and the steel is more susceptible to embrittlement after aging at 450~500℃,which is attributed to the cleavage or quasi-cleavage fracture of ferrite phase due to its embrittlement.Meanwhile,higher Ti/C ratio increases the aging embrittlement tendency at 450~500℃.However,high Ti/C ratio can stabilize austenite phase,which can significantly reduce the aging embrittlement tendency at 600℃.It is also shown that increasing forging ratio can make austenite phase have sufficient deformation and make it uniformly distributed,which can effectively prevent the growth of brittle crack of ferrite phase and largely reduce the embrittlement tendency.