What is difference between carbon steel and alloy steel plate?

The performance of carbon steel mainly has the following deficiencies:
(1) Low hardenability Generally, the maximum hardenable diameter of carbon steel water quenching is only 10mm-20mm.

(2) The strength and yield are relatively low. 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) Poor tempering stability. Due to the poor tempering stability, a lower tempering temperature should be used in order to ensure higher strength when carbon steel is quenched and tempered, so that the toughness of the steel is low; in order to ensure better Toughness, the strength is low when using high tempering temperature, so the comprehensive mechanical performance level of carbon steel is not high.

(4) Cannot meet the requirements of special performance. Carbon steel is often poor in terms of oxidation resistance, corrosion resistance, heat resistance, low temperature resistance, abrasion resistance, and special electromagnetic properties, and cannot meet the requirements of special performance.