How to distinguish the 16Mn seamless steel pipe from 45 # steel.

How to distinguish the 16Mn seamless steel pipe from 45 # steel.
45 # steel is widely used in machinery manufacturing with good mechanical properties of this steel. But this is a medium carbon steel, hardened performance is not good, 45 steel can be hardened to HRC42 ~ 46. So if you need a surface hardness, and also hope to play 45 # steel superior mechanical properties, it often does carburizing on the surface of 45 # steel, so you can get the required surface hardness.
16Mn seamless steel pipe is a pressure vessel dedicated board with a yield strength of 340MPa grade, and it has a good mechanical properties and process performance. Phosphorus, sulfur content is slightly lower than the S & P 16Mn steel, in addition to the tensile strength and elongation requirements are higher than ordinary steel, the 16Mn also sought assurances toughness. It is currently China's most widely used and the largest amount ofpressure window special steel. Special steel 16Mn seamless steel pipe for the bridge as "16Mnq", a special steel for automobile frames "16MnL", a special steel pressure vessel is "16MnR".
Such steel is to rely on the adjustment of carbonaceous (C) amount to improve the mechanical properties of the steel, and therefore, according to the level of the carbon content, such steels can be divided into:
Mild steel - carbon content is generally less than 0.25% , such as10# steel and 20# steel;
Medium carbon steel - carbon content is generally between 0.25 to 0.60%, such as 35# steel and 45# steel;
High carbon steel - carbon content is generally greater than 0.60%. Such steel is generally not used in the manufacture of steel pipe.