Mn is a weak carbide forming element. Its role in the refining process is to deoxidize and eliminate the effects of sulfur. It can also reduce the austenite transformation temperature of DNV DH32 ship steel plate, refine the ferrite grain, and improve DNV DH32 ship steel plate strength and toughness are beneficial.
At the same time, it can solid solution strengthen ferrite and increase the hardenability of DNV DH32 ship steel plate. Therefore, in the composition design, manganese should be controlled at the upper limit. Among the controlled rolled steels, the Mn content in the DNV DH32 ship steel plate is generally between 1.3% and 1.5%. Generally, low carbon and high manganese steel is used as the welded structural steel.
The larger the Mn/C ratio (up to 215), the DNV DH32 ship steel plate, the better the low temperature toughness of the board. But when the Mg content exceeds about 1.5%, the DNV DH32 ship plate will harden and the ductility will deteriorate.
