What is the effect of the elements in A709 GR50 steel plate on the alloy?

A709 GR50 steel plate is a high strength low alloy steel, widely used in engineering structures, such as construction steel structure, construction machinery, mining and mountainous machinery, heavy truck, bridge, pressure vessels, especially for construction and construction machinery parts requiring good weldability and endurance.

Influence of elements in A709 GR50 steel plate on alloy: alloy elements have the most obvious strengthening effect on steel under quenching and tempering condition, because it makes full use of all four strengthening mechanisms.
Martensite is formed when quenching, and carbide is produced when tempering, which forms the intense second phase strengthening. Together, the endurance is greatly improved. Therefore, obtaining martensite and tempering it is the most economical and most useful inductive strengthening method of steel.

The alloying element in A709 GR50 steel plate can increase the hardenability of the steel to ensure that martensite can be easily obtained during quenching. The second is to increase the tempering stability of steel, so that the martensite adhere to a higher temperature, so that the quenched steel in the tempering of the carbide is more subtle, uniform and stable. Thus, alloy steels have higher strength than carbon steels under the same conditions.