超高强度不锈钢作为一种兼具优异力学、工艺与耐腐蚀性能的不锈钢，常用来制造航空、航天和海洋等领 域的关键零部件。 但是，由于目前对该类合金热加工工艺研究不够充分，导致缺乏科学设计该类合金热加工工艺的依 据， 难以对其进行合理有效加工。 本研究以具有优良综合性能和广阔应用前景的USS122G超高强度不锈钢为研究对 象，利用Gleeble-3500 热模拟实验机对该合金在变形量为 60%(应变约为 0.9)、变形温度为 930~1130℃、应变速率为 10-2~101 s-1 的热压缩变形行为进行系统研究，建立了 Arrhenius 型本构模型并对其进行修正，获得了基于Murty失稳准 则的热加工图。结果表明，随着变形温度的升高(或应变速率的降低)，合金流变应力逐渐减小；构建的Arrhenius型 本构方程能够对该合金在应变为0.9时的流变应力进行较好预测。 利用基于Murty失稳准则建立的热加工图所 得到的合理加工工艺为：温度930~975 ℃时应变速率0.01~0.28 s-1，温度 975~1 050 ℃时应变速率 0.10~0.28 s-1 和 温度1050~1130℃时应变速率0.01~0.81s-1。

Ultra-high strength stainless steel possesses excellent mechanical properties, processing performance and corrosion resistance, and can usually be used to manufacture key devices in the aerospace, aviation and marine fields. However, there is still a lack of documentation for the reasonable design of hot processing maps of ultra-high strength stainless steel since research on hot processing technology for alloys is insufficient and valid technology for processing ultra-high strength stainless steel is lacked. In this work, USS122G ultrahigh-strength stainless steel, which has excellent performance and application potential, was chosen as the subjective alloy. The isothermal compression deformation behavior of the alloy was studied via a Gleeble-3500 thermal simulation experimental machine. The corresponding deformation (strain), deformation temperature and strain rate are approximately 60% (0.9), 930~1 130 ℃ and 10-2~101 s-1, respectively. On this basis, an Arrhenius-type constitutive model of the alloy was established and modified. Furthermore, a hot working diagram based on the Murty instability criterion was obtained. The results show that the flow stress of the alloy decreases with increasing deformation temperature (or decreasing strain rate). The flow stress of the alloy with a strain of 0.9 can be well predicted by the present Arrhenius-type constitutive equation. Moreover, the suitable strain rates for the alloy are 0.01~0.28 s-1, 0.1~0.28 s-1 and 0.01~0.81 s-1 for temperatures of 930~975 ℃, 975~ 1 050 ℃ and 1 050~1 130 ℃, respectively, according to the present hot working diagram.