tempering range

The rate of water added by micro-damping is usually controlled within the range of 0.3%~ 0.5%, and the tempering time is usually controlled in 25~ 40 min.

微量着水量一般控制在0.3%～0.5%，润麦时间25～40min。

When rising tempering temperature to the range of 300~ 375 ℃, impact toughness of the steel is decreased to the lowest.

回火温度升至330～375℃时，冲击韧性降至最低；

After tempering within the range 450~ 550 ℃, impact toughness dropped, and transition temperature increased. This tempering embrittlement mainly depends on M_7C_3 precipitation.

450～550℃回火，冲击韧性下降，转变温度升高，该回火脆性主要取决于M7C3沉淀。

In addition, the temperature range of elastic abnormality will extend along with the increase in tempering time.

同时，随着回火时间增加，弹性反常的温度范围加宽。

Result shows that a good combination of strength and toughness can be gained after quenching at 840 ℃ and tempering in the range of 180~ 220 ℃;

结果表明，65MnV钢经840℃淬火、180～220℃回火可获得高的强韧性；