本发明属于耐热合金热加工技术领域,特别是涉及一种700℃超超临界火电机组用镍铁基合金的热加工工艺及应用,适用于镍铁基耐热合金的锅炉部件制造。该工艺包括锻造开坯和热挤压,其中:锻造开坯原料为经过均匀化退火的铸锭或电极棒,初锻温度为1150℃~1200℃,终锻温度在950℃以上,应变速率为0.01s-1~0.5s-1,工程应变在50%以下;热挤压的原料为开坯锻件,变形温度为1050℃~1200℃,应变速率为1.0s-1~10s-1,工程应变在70%以下。本发明根据热变形原料中晶粒组织的差异,选用不同的热变形参数,同时保证热变形组织的均匀性与热变形过程的低成本。经过锻造开坯和热挤压的合金未出现锻造裂纹、混晶等缺陷,组织均匀,再结晶比例高于95%,晶粒细小,动态再结晶平均晶粒尺寸不大于15微米。
The invention belongs to the technical field of hot working for the heat-resistant alloy, in particular to the hot working technology and application of a Ni-Fe based alloy for 700℃ ultra-supercritical power unit, and is suitable for the manufacture of boiler parts of Ni-Fe based heat-resistant alloy. The process includes forging and hot extrusion. The raw material of forging is homogenized annealed ingot or electrode rod, the initial forging temperature is 1150℃~1200℃, the final forging temperature is above 950℃, the strain rate is 0.01s-1~0.5s-1, and the engineering strain is below 50%. The raw material of hot extrusion is forging, the deformation temperature is 1050℃~1200℃, the strain rate is 1.0s-1~10s-1, and the engineering strain is below 70%. According to the difference of grain structure in the hot deformation materials, different hot deformation parameters are selected to ensure the homogeneity of the deformation microstructures and the low cost of the hot working process. The alloy after forging and hot extrusion has no defects, such as, forging crack and mixed grain, and the microstructure is uniform. The recrystallization proportion is higher than 95%, and the average grain size of dynamic recrystallization is no more than 15 μm.