- To increase hardenability
- To produce a finer grain size
- To help control part distortion
- To improve tensile strength without appreciably lowering ductility
- To avoid quench cracking
- To gain toughness
- To achieve better wear resistance
- To improve hot hardness
- To achieve better corrosion resistance
The role manganese plays in deoxidation of steel and modification of sulfides presents it is a major alloying element. It has complex interactions with carbon and is used to control inclusions. Manganese is beneficial to surface quality in all carbon ranges with the exception of rimmed steels (< 0.15%C) and is particularly beneficial in high-sulfur steels. Manganese contributes to strength and hardness, but to a lesser degree than carbon. The increase depends on the carbon content – higher-carbon steels being affected more by manganese. Higher manganese in steels lowers ductility and weldability (but to a lesser extent than carbon). Manganese also increases the rate of carbon penetration during carburizing.
Next time, we will look at some of the 50 ways manganese affects steel.