求翻译：淬火的目的之一就是提高钢的硬度。如果零件需要淬火，必须选用优质碳素结构钢，化学成分不稳定是没有办法确定热处理工艺的。自然是不能保证完全达到强度要求。是什么意思？

One of the aims is to improve quenching the hardness of steel. If parts need hardening, must use high-quality carbon structural steel, chemical composition of instability is no way to determine the heat treatment process. Nature is not guaranteed to reach the strength requirements.

One of the aims of the hardening of steel is to raise the hardness. If Parts need to be quenched, it must be selected quality carbon steel, chemical composition is not stable, there is no way to determine if the heat treatment process. Naturally, there can be no assurance that reached its full stren

One of quenching goals is enhances the steel degree of hardness.If the components need to quench, must select the high quality carbon structural steel, the chemical composition is unstable does not have the means determination heat treatment craft.Cannot guarantee naturally meets the intensity requi

Quenching one purpose is to increase the hardness of steel. If parts need to quench, must be high quality carbon structural steel, unstable is no way to determine the chemical constituents of heat treatment process. Naturally cannot guarantee that reach full strength requirements.

One of the aims is to improve quenching the hardness of steel. If parts need hardening, must use high-quality carbon structural steel, chemical composition of instability is no way to determine the heat treatment process. Nature is not guaranteed to reach the strength requirements.