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原文
Valve cast steel hardness In spite of the welding zone NDT inspection and approval, but the time for machining, welding area should then check the hardness, which is the result of the inspection process to eliminate stress. If the tempering temperature is not enough, or lack of time, will cause the deposited metal welding area, high strength, ductility is poor, when the welding area will be machining very hard, easily lead to tool crack. Base metal and weld metal properties are inconsistent, but also easily lead to local stress concentration, the transition occurs at the junction of the obvious signs of welding. Therefore, the welding area needs to identify with and testing the hardness value. Gently polished with a hand-held grinding machine welding zone, using portable Brinell hardness tester hammering three points, the welding zone hardness and hardness of steel casting their values. If the two regions of similar hardness values??, then the oxygen - acetylene tempering essential for the success. If the welding zone is greater than the hardness hardness of steel castings for more than 20, the proposed rework until close to the base material hardness. Pressure cast steel after heat treatment the hardness of the general design for the 160 ~ 200HB, the hardness is too low or too high are not conducive to machining operations. Welding zone hardness is too high, so the plastic will fall, reducing the load of the safety valve body.
原文来自http://www.strainer.org.cn

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译文：
补焊区虽经无损探伤检查合格,但如需机加工时,应该再检查一下补焊区的硬度,这也是对消除应力处理效果的检查。如果回火温度不够,或时间不足,会引起补焊区域的熔敷金属强度高,塑性差,机加工时焊区域会很硬,容易导致刀具崩裂。母材和熔敷金属性能不一致,还容易造成局部应力集中,出现补焊过渡交界的明显痕迹。因此,补焊区域需要用硬度值来鉴定和检测。用手提砂轮机轻轻磨平补焊区域,采用便携式布氏硬度计锤击三个点,将补焊区硬度值与铸钢件本身硬度值进行比较。如果二个区域的硬度值相近,则说明氧-乙炔回火基本成功。如果补焊区硬度值大于铸钢件硬度20以上,建议返工,直至硬度与母材接近。承压铸钢件经热处理后的硬度一般设计为160～200HB,硬度太低或太高都不利于机加工作业。补焊区硬度太高,会使其塑性下降,降低阀门壳体承载的安全性能。

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