回火的英文：
(n) backfire
tempering 回火（钢铁专业词汇）

参考例句：

degree of hardness and elasticity of a tempered meta
（金属回火后的）硬度和弹性.

Backfire:an explosion of prematurely ignited fuel or of unburned exhaust gases in an internal-combustion engine.
回火:过早点燃的燃料的爆炸或内燃机中未燃的废气的爆炸。

fire-proof baffle
回火挡板

hardened and tempered
淬火与回火的

Steel is tempered by heating and then cooling it
钢是经过加热，然后冷却来回火。

Two times temper has little effect on the hardness.
二次回火后硬度变化不大。

three times temper will decrease the hardness.
三次回火后，硬度反而降低。

"Three. They are hardening, temper and anneal. "
三种。它们是淬火、回火和退火。

Degree of hardness and elasticity of a tempered metal
(金属回火后的)硬度和弹性.

backfire是什么意思：
v. 适得其反，事与愿违；放出逆火，发生回火
n. 逆火，回火

The car backfired.
车回火了。

The engine backfired noisily.
那发动机发生逆火引起爆鸣。

To explode in the manner of or make the sound of a backfire.
用逆火的方式爆裂或发出逆火的声音。

The President's tactics could backfire.
总统的策略可能会适得其反。

To start or use a backfire in extinguishing or controlling a forest fire.
在熄灭或控制森林大火蔓延中燃起或使用逆火。

tempering是什么意思：
n. 性情；脾气；心情；回火
v. 使缓和；调和；（使）回火

hardened and tempered
淬火与回火的

I was in a flaming temper.
我正怒气冲天。

She is a girl of sweet temper.
她是个性情温柔的姑娘。

He curbed his temper.
他稳住了情绪。

Temperance is the best physic
克制乃是最好的治疗