Low Alloy Steel

TThe properties of low alloy steel and carbon steel are mainly different as follows

1. The hardenability is higher than that of carbon steel. Generally, the maximum quenching diameter of carbon steel water quenching is only 10mm-20mm.

2. The strength and yield strength are higher than those of carbon steel. Such as ordinary carbon steel Q235 steel σ S is 235MPa, while low alloy structural steel 16Mn σ S is more than 360MPa. 40 steel σ s / σ B is only 0.43, far lower than alloy steel.In practice, a small amount of niobium or vanadium or titanium is often added to improve the strength of steel. These elements can be economically strengthened by precipitation hardening. Other alloy elements added for various purposes can also achieve the purpose of strengthening. Sometimes low alloy plate is used to replace ordinary carbon plate without changing the section size. Its only purpose is to obtain higher strength and more durable structure without increasing weight.

3. Tempering stability is higher than that of carbon steel. Due to the poor tempering stability, when carbon steel is quenched and tempered, lower tempering temperature is required to ensure higher strength, so the toughness of steel is low; In order to ensure better toughness, the strength is low when high tempering temperature is used, so the comprehensive mechanical property level of carbon steel is not high.

4. Low alloy steel can meet the requirements of special properties. Carbon steel is often poor in oxidation resistance, corrosion resistance, heat resistance, low temperature resistance, wear resistance and special electromagnetic properties, and can not meet the needs of special use performance.