44Si2CrV钢弹簧的室温蠕变

试验结果得出,44Si2CrV钢弹簧经淬火+中温回火处理并除掉表面脱碳层后,在室温下所受应力超过临界蠕变应力值时即发生蠕变;钢的抗拉(或剪切)强度越高,临界蠕变应力越高。44Si2CrV钢900℃淬火,500℃回火,临界蠕变应力 τ_cc =700 MPa;900℃淬火,380℃回火, τ_cc =800 MPa。蠕变开始时的塑性变形速率较大,之后急剧减小,在一定应力下保持一定时间后蠕变停止。经长时间压缩,蠕变变形已经停止的弹簧,于200℃保温2 h后空冷,弹簧的自由高度伸长,并且在原来的应力下加载,弹簧蠕变又重新开始。

Creep of Spring of Steel 44Si2CrV at Room Temperature

Test results showed that the creeps of spring of steel 44Si2CrV quenched + medium tempering and removed decarburized layer happened at room temperature as stress was higher than critical creep stress value, and the higher tensile or shear strength, the higher critical creep stress. The critical creep stress τ_cc of steel 44Si2CrV quenched at 900 P and tempered at 500°C was 700 MPa, τ_cc  quenched at 900°C and tempered at 380 °C was 800 MPa. The plastic deformation speed was higher at creep beginning, then decreased abruptly. The creep stopped at certain stress for definite time. After loading for a long time and creep of spring stopped, as the spring was heated at 200 °C for 2 h air cooled, the free height of spring increased, and the creep of spring restarted again when it is loaded with original stress.