10CrNiMo结构钢低周疲劳过程中的应变滞后特性

Strain Hysteresis Characteristic in the Course of Low Cycle Fatigue for 10CrNiMo Structural Steel

在6级轴向逐级增加的系列恒应变幅(0.3%~1.0%)控制下,室温空气中,采用光滑圆形横截面试样,研究了10CrNiMo结构钢在低周疲劳作用下的应力-总应变及应力-塑性应变的滞后回线特性。结果表明:在小应变幅(0.3%~0.4%)控制下,虽然弹性应变占绝对优势,但塑性应变并不为零,且逐级增长;而在大应变幅(0.6%~1.0%)控制下,塑性应变增长较快,并逐渐占主导地位。无论应变幅大小,只须几个循环,材料便进入稳定状态,而初始循环与失稳循环却表现出不稳定的特征。

Characteristics of hysteresis loops of stress- strain （total） and stress- strain （plastic） under low cycle fatigue action for 10CrNiMo structural steel were studied by taking smooth rounded cross-section specimens, in air and at room temperature, under the control of six series of different axial strain amplitudes ranging from 0. 3% to 1.0%. The results manifested that al- though elastic strain is entirely dominant, plastic strain is not zero and increases gradually, under the control of the small strain amplitudes from 0. 3% to 0.4% ; plastic strain increases fast and plays a leading role gradually, under the control of the big strain amplitudes from 0. 6% to 1.0% ; the test material will get into a stable state acted only by several cycles despite of the strain amplitudes , and the first cycle and the last one indicate unsteady features.