What are the disadvantages of carbon steel?

(1) Low hardenability. Under normal circumstances, the maximum quenching diameter of carbon steel water quenching is only 10mm-20mm. (2) Strength and yield are relatively low. For example, the σs of ordinary carbon steel Q235 steel is 235MPa, while the σs of low alloy structural steel 16Mn is more than 360MPa. The σs/σb of 40 steel is only 0.43, which is much lower than that of alloy steel. (3) Tempering stability is poor. Due to the poor tempering stability, when carbon steel is quenched and tempered, in order to ensure higher strength, a lower tempering temperature needs to be used, so that the toughness of the steel is low; in order to ensure better toughness, a high tempering temperature is used The strength is low at high temperatures, so the comprehensive mechanical properties of carbon steel are not high.

(4) Unable to meet special performance requirements. Carbon steel is often poor in oxidation resistance, corrosion resistance, heat resistance, low temperature resistance, wear resistance and special electromagnetic properties, and cannot meet the needs of special performance.