将不同拉应力(0～120 MPa)作用下的P92钢在650 ℃空气中氧化不同时间(0～400 h), 得到了该钢的氧化动力学曲线并分析了其表面氧化层的形貌和物相组成。结果表明: 在不同拉应力作用下, 试样表面的氧化层主要由FeCr2O4、MnCr2O4、Cr2O3和Fe2O3组成; 氧化层厚度随氧化时间的延长而增加, 厚度增加速率随拉应力的增大而增加; 在氧化初期施加拉应力时试样的表面氧化层厚度小于未施加拉应力的, 当氧化时间延长到80 h以后则大于未施加拉应力的, 且随拉应力的增加继续增大; 氧化400 h时, 当拉应力不大于80 MPa时试样表面的氧化层致密, 当拉应力达到120 MPa后氧化层出现微裂纹。

P92 steel under different tensile stresses (0-120 MPa) was oxidized in air at 650 ℃ for different time (0-400 h), and then the oxidation kinetic curves of the steel were obtained. The morphology and phase composition of the oxidation layer on the steel surface were also analyzed. The results show that under different tensile stresses, the oxidation layers at the surface of samples mainly consisted of FeCr2O4, MnCr2O4, Cr2O3 and Fe2O3. The thickness of oxidation layer increased with the prolongation of oxidation time and the thickness increase rate increased with the increase of tensile stress. During the initial oxidation period, the oxidation layer thicknesses at the samples surface under different tensile stresses were lower than those without tensile stress while larger than those without tensile stress for the oxidation time over 80 h, and increased continuously with the increase of tensile stress. After oxidation for 400 h, the oxidation layer on the sample surface was dense with the tensile stress less than 80 MPa, and the cracks were observed while the tensile stress reached 120 MPa.