The difference between Q345 and 16Mn
Q345 is defined by the yield strength of the material, and 16Mn is defined by the chemical composition of the material.
The starting point for both is not the same. Q345 is ordinary carbon steel, Q said yield point. 16 MN is a steel containing 0.16% carbon and containing manganese (0.7% -1.0%). Q345 is carbon steel, the yield strength is 345MPA, the steel plastic good. 16MN is a low carbon alloy steel, high strength, but its poor plasticity.
1. According to the same characteristics can be welded low alloy high strength structural steel.
2. According to the quality level classification: Q345 is ordinary low quality alloy steel, 16Mn is high quality low alloy steel.
Q345 is GB / T1591-94 low alloy high strength structural steel. JB4726-2000 Carbon steel low alloy steel forgings for pressure vessels. Look at the standard should understand that the use of two different steel.
In comparison, 16Mn phosphorothioate content requirements more stringent quality requirements more stringent. 16MN and Q345 general purpose is the same, but for containers and boilers can only use 16MN, because the Q345 is not listed in the GB150, to be used if the procedure is very troublesome According to the characteristics of the same welding low alloy high strength Structural steel.
Classified by quality grade: Q345 is ordinary low quality alloy steel, 16Mn is high quality low alloy steel. Q345 refers to the total yield strength of 345MPa, and 16Mn is only one of them.
q345 steel is the old brand 14mnnb, 12mnv, 16mnre, 16mn, 18nb, and other alternative steel, instead of just a 16mn steel. In the chemical composition, 16mn and q345 are not the same. More importantly, there is a large difference in the size of the grouping of the two steels depending on the yield strength, which will inevitably cause a change in the allowable stress of materials of a certain thickness. Therefore, simply applying the allowable stress of 16mn steel to q345 steel is not appropriate. Instead, permissible stress should be re-determined according to the new grouping of steel thickness.
The proportion of q345 steel and 16mn steel is basically the same, the difference is the increase of ti, nb, v trace alloy elements. A small amount of ti, v, nb alloy elements can refine the grain, improve the toughness of the steel, the overall mechanical properties of the steel has been greatly improved. Precisely because of this, the thickness of the plate can be done larger. Therefore, q345 steel mechanical properties should be superior to 16mn steel, especially its low temperature performance is 16mn steel does not have, q345 steel allowable stress slightly higher than 16mn steel.
