What is the 09MnNiDR steel application?

09MnNiDR material is Manganese-Nickel alloy steel for low temperature service. Due to its low carbon content, it belongs to low-alloy structural steels and Mn and Ni are its main alloys. Mn element in 09MnNiDR steel mainly enhances the strength of steel by solid solution strengthening, while Ni can improve the low temperature toughness of ferrite and has the effect of significantly reducing the temperature of cold and crisp transitions. Its carbon equivalent is less than or equal to 0.44, hardenability tends to be small, and cold cracks are not easily formed. The letter D in 09MnNiDR steel means that it is for low temperature service. The letter R is for boiler and pressure vessel using.The low temperature impacting test shall be done for 09MnNiDR alloy steel, the impacting energy value should above 34 J.

09MnNiDR steel welding

The weld has good plasticity and toughness, and usually does not require preheating. When the 09MnNiDR steel plate thickness exceeds a certain thickness, the rigidity of the joint is restricted, or the carbon equivalent is high, preheating should be considered. However, the preheating temperature should not be too high, otherwise the grains in the HAZ will grow up and oxides will precipitate at the grain boundary. Therefore, the welding line energy and interlayer temperature should be controlled during welding, and stress-relief heat treatment should be performed after welding.