In terms of performance, compared with carbon steel, the advantages of low-alloy steel are mainly reflected in the following aspects:
1、Hardenability of low alloy steel is higher than that of carbon steel. Under normal circumstances, the maximum quenching diameter of carbon steel water quenching is only 10mm-20mm.
2、The strength and yield strength of low alloy steel are higher than that of carbon steel. For example, the σs of ordinary carbon steel Q235 steel is 235MPa, and 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、The tempering stability of low alloy steel is higher than that of carbon steel. Due to the poor tempering stability, when the carbon steel is quenched and tempered, in order to ensure higher strength, a lower tempering temperature is required, so the toughness of the steel is low; in order to ensure better toughness, high tempering is used，the strength is low at temperature, so the comprehensive mechanical properties of carbon steel are not high.
Low alloy steel can meet the requirements of special performance. Carbon steel is often inferior in terms of oxidation resistance, corrosion resistance, heat resistance, low temperature resistance, abrasion resistance, and special electromagnetic properties, and cannot meet the needs of special performance.
