tempering furnace(The electric arc furnace fume extraction system is being upgraded and five tempering furnaces being rebuilt in Lauderdale Steel. 劳德代尔钢公司的一座电弧炉排烟系统正在升级改造，五座回火炉正在改建。)
overtemper(Straight carbon tool steels are still used occasionally in machining, but fast rates of machining cause such a tool to heat so much that it overtempers itself and softens. 虽然普通碳素工具钢在机加工中仍偶有使用，但车削速度过快会引起这种钢的刀具过热，以致产生过回火而软化。)
