356x6, all 6mm.
According to GB2080 1-2006 or ASME B3 1.3, the negative deviation of thickness is 12.5%, the corrosion allowance is 2.0 mm, and the allowable stress at 400 degrees is 86MPa.
For seamless pipes, the maximum allowable working pressure is 1.58MPa, that is, 15.8 kg pressure.
For welded pipes, the maximum allowable working pressure is: 1.26MPa, that is, 12.6 kg, in which the weld shall be qualified by local X-ray photography.
It is recommended to use 15CrMo material, because GB/T2080 1 stipulates that the maximum temperature of 20 steel can only be 350 degrees.
356x5, that is, 5 mm, according to GB2080 1-2006 or ASME B3 1.3, with negative thickness deviation 12.5%, corrosion allowance of 2.0 mm and allowable stress of 400 degrees 105MPa, then
For seamless pipes, the maximum allowable working pressure is 1.4MPa, that is, 14.kg pressure.
For welded pipes, the maximum allowable working pressure is: 1. 12MPa, that is, 1 1.2 kg, in which local X-ray photography is required for the weld.