Gao Pei,Huang Guijun.Constitutive Model and Hot Processing Map of Ni-Cr-Fe Heat-resistant Alloy for Advanced Ultra-Supercritical Boilers[J].Special Steel,2025,46(04):128-134.
Gao Pei,Huang Guijun.Constitutive Model and Hot Processing Map of Ni-Cr-Fe Heat-resistant Alloy for Advanced Ultra-Supercritical Boilers[J].Special Steel,2025,46(04):128-134. DOI: 10.20057/j.1003-8620.2025-00111.
Constitutive Model and Hot Processing Map of Ni-Cr-Fe Heat-resistant Alloy for Advanced Ultra-Supercritical Boilers
利用Gleeble-3500热模拟试验机对先进超超临界锅炉用Ni-Cr-Fe耐热合金进行变形温度950~1 250 ℃、应变速率0.01~10 s
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,应变量为0.7的热压缩变形试验。基于Arrhenius双曲正弦模型,创新性地将应变量因素引入,构建了适用于耐热合金的改进型本构模型,并采用相关系数R及绝对误差δ两个指标,对模型预测流变应力的准确性进行评估;同时,通过构建该耐热合金的热加工图及微观组织分析,系统评估并确定该合金的热加工工艺参数最优区间。结果表明,耦合应变量的改进型本构模型的材料常数与应变量的最佳拟合阶数为6阶,相关系数R为0.988 89,绝对误差δ为5.905 %,该模型对耐热合金的流变应力具有较好的预测能力;热变形所需的激活能Q值为389 kJ/mol,结合微观组织确定Ni-Cr-Fe耐热合金最佳热加工工艺为1 150~1 200 ℃、0.1~1 s
-1
。
Abstract
Thermal compression deformation experiments on Ni-Cr-Fe heat-resistant alloy for advanced ultra-supercritical boilers were conducted using a Gleeble-3500 thermal simulator testing machine over a temperature range of 950 ℃–1 250 ℃, strain rates of 0.01 s⁻¹-10 s⁻¹, and a strain of 0.7. Based on the Arrhenius hyperbolic sine model, strain factor is innovatively introduced to construct an improved constitutive model suitable for heat-resistant alloys, and two indexes, correlation coefficient R and absolute error δ, are used to evaluate the accuracy of the model's prediction of rheological stress; At the same time, by constructing the hot processing map of the heat-resistant alloy and the microstructure analysis, the optimal range of hot working process parameters of the alloy is systematically evaluated and determined. The results showed that the optimal fitting order of the material constants and strain of the improved constitutive model with coupled strain was 6, the correlation coefficient R was 0.988 89, and the absolute error δ was 5.905%. The model had good predictive ability for the rheological stress of heat-resistant alloy; The activation energy Q for hot deformation was calculated as 389 kJ/mol. Based on microstructural analysis, the optimal hot working process for the Ni-Cr-Fe heat-resistant alloy was identified as 1 150 ℃-1 200 ℃ and 0.1 s⁻¹-1 s⁻¹.
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