16Mn seamless pressure pipes and GB8162 standard

Why 16Mn seamless pressure pipes should not be in accordance with GB8162 standard?
The 16Mn seamless steel pipe standard includes GB8162, GB8163, GB6479 and GB9948. For example, 16Mn9948 one kind of 16Mn seamless steel pipe.
GB8162 and GB8163 seamless steel pipe differences:
GB8162 "structural seamless steel pipe", this standard applies to the general structure of the mechanical structure; GB8163 "transmission fluid with seamless steel pipe" This standard applies to transport fluids generally seamless steel pipe, the main difference is that the GB8163 steel should be carried out hydraulic test or ultrasonic, eddy current and magnetic flux leakage inspection one by one, so for the standard selection of pressure line pipe, GB8162 standard should not be used.
16mn seamless and 16MnR, 19Mng are merged into Q345R. Q345R is ordinary low-alloy steel, and common used boiler and pressure vessel, delivery status: hot rolled or normalizing, is a low-alloy steel, containing low Mn content. Performance is similar with 20G (412-540), and the tensile strength (450-655) slightly stronger, elongation of 19-21%, poorer than 20G of greater than 24 percent. Q345R process is in reference to standard GB713-2008.