Why can’t low carbon steel be quenched?

‌‌The reason why low carbon steel cannot be hardened is because its carbon content is low and it cannot produce a hardening effect after quenching. ‌‌

Low carbon steel, that is, carbon steel with a carbon content of less than 0.25%, due to its low carbon content, cannot incorporate enough carbon elements into the iron molecular structure during quenching to produce a hardening effect. Quenching is a heat treatment process that changes the structural structure of steel by heating the steel to a certain temperature and then cooling it quickly, thereby improving its hardness and strength. However, for low carbon steel, due to its low carbon content, even after quenching treatment, it is not possible to incorporate enough carbon elements into the iron molecular structure to produce a significant hardening effect. Therefore, low carbon steel usually cannot achieve the expected hardening effect after quenching. Instead, rapid cooling during the quenching process may cause large internal stress inside the steel, thus affecting the performance and service life of the steel.

Additionally, mild steel is less hardenable, which means that even if you try to quench the entire steel, it will be difficult to achieve a uniform hardening effect. Hardenability refers to the ability of steel to obtain a uniform hardened layer during the quenching process. The poor hardenability of low carbon steel means that the hardening effect on the surface and inside is inconsistent, which further limits the possibility of increasing the hardness of low carbon steel through quenching. .

To sum up, the main reasons why low carbon steel cannot be quenched include its low carbon content and poor hardenability. This makes it impossible for low carbon steel to achieve the expected hardening effect after quenching, and may instead cause damage to the steel. Performance is adversely affected.