The difference between steel pipe material 16Mn and Q345

Q345 steel is the oldest 14MnNb, 12MnV, 16MnRE, 16Mn, 18Nb, and other steel alternative, rather than just replace a 16Mn steel. In the chemical composition, 16Mn and Q345 are also different. More importantly, the thickness of the two kinds of steel by the yield strength of the thickness of the packet size there is a big difference, which will lead to some thickness of the material allowable stress changes. Therefore, it is not appropriate to simply apply the permissible stress of 16Mn steel to the Q345 steel, but the allowable stress should be re-determined according to the new steel thickness packet size.

Q345 steel composition of the main elements and 16Mn steel is basically the same, the difference is increased Ti, Nb, V trace alloy elements. A small amount of Ti, V, Nb alloy elements can refine the grain, improve the toughness of steel, steel comprehensive mechanical properties have been greatly improved. It is precisely because of this, the thickness of the plate can be done more. Therefore, Q345 steel comprehensive mechanical properties should be better than 16Mn steel, in particular, its low temperature performance is 16Mn steel does not have, Q345 steel allowable stress slightly higher than 16Mn steel.

Abstract from Tianjin Xinyue Steel Group