氮含量对022Cr25Ni7Mo3N双相不锈钢热加工行为的影响

通过热拉伸、热压缩试验研究了不同氮含量的022Cr25Ni7Mo3N双相不锈钢的热加工行为和软化机制。结果表明,试验钢高温抗拉强度随N含量增加而提高,该影响关系在较低变形温度区间尤为明显;在1100℃平面压缩达到稳态流变之后,试验钢的流变应力很快再次上升,出现二次硬化现象,N含量提高致使试验钢在更低的应变条件下更快地进入二次硬化阶段;试验钢高温变形过程中的应变主要传导到高温更软的铁素体相中,该相积蓄的较大应变能促进了铁素体的动态再结晶启动;022Cr25Ni7Mo3N双相不锈钢的软化机制主要是铁素体的动态回复和动态连续再结晶。

Effect of nitrogen content on hot working behavior of 022Cr25Ni7Mo3N duplex stainless steel

The hot working behavior and softening mechanism of 022 Cr25 Ni7 Mo3 N duplex stainless steel with different nitrogen content were studied by thermal tensile and thermal compression tests. The results show that the high temperature tensile strength of the tested steel increases with the increase of N content, especially obvious in the lower deformation temperature range. After the flow stress curve reaches steady-state rheology via plane strain compression test at 1100 ℃, the flow stress of the tested steel quickly increases again and the phenomenon of secondary hardening occurs, and the increase of N content leads the tested steel to enter the secondary hardening stage faster under the lower strain condition. The strain of the tested steel during high temperature deformation is mainly transmitted to the softer ferrite phase at high temperature, and the larger strain accumulated by the softer ferrite phase can promote the dynamic recrystallization of the ferrite. The softening mechanism of the 022 Cr25 Ni7 Mo3 N duplex stainless steel is mainly the dynamic recovery and the dynamic continuous crystallization of the ferrite.