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研究了新型螺栓用20Cr Ni4Mo钢的高温持久性能,在高温持久试验机上测定了该种螺栓用钢在350~450℃不同应力条件下的高温持久强度。用国际上普遍采用的等温线法、时间-温度参数法对试验数据进行拟合,得到了回归方程,并进行了外推估算。比对各种方法的拟合以及外推情况结果表明,拉森-密勒(L-M)参数法拟合及外推效果最好,因此,L-M参数法最适合于本文研究材料持久性能的预测。用L-M参数法外推20Cr Ni4Mo钢在工况温度为230℃、持久105h时的强度极限σ230105=186.21 MPa,表明该螺栓用钢在此工况温度下应具有较好的持久性能。
The long-term durability of 20Cr Ni4Mo steel for the new type of bolts was studied. The high temperature strength of the steel for bolts was tested on the high temperature lasting machine under different stress conditions of 350-450 ℃. With the internationally accepted isotherm method, the time - temperature parameter method to fit the experimental data, the regression equation was obtained, and extrapolated estimates. The results of fitting and extrapolating the results of various methods show that L-M parameter method is the best fit and extrapolation method for L-M parameter method. Therefore, L-M parameter method is the most suitable for the prediction of the material’s long-term performance. The L-M parameter extrapolation of 20Cr Ni4Mo steel at the working temperature of 230 ℃, 105h persistence of the ultimate strength σ230105 = 186.21 MPa, indicating that the bolt steel at this operating temperature should have good long-lasting performance.