... 1, GB8162-99 2, GB8163-99 3, GB3087-1999 4, GB5310-95 5, GB6479- 1 With seamless steel tube structure GB8162-992 The ... transmission fluid with stitched tube GB8163-993 boiler seamless steel tube GB3087-19994 With high pressure boiler, seamless tube GB5310 ... 199912 GB3639-199913 all kinds of alloy pipes 16Mn,27SiMn,15CrMo,35CrMo,12CrMov,20G,40Cr,12Cr1MoV,15CrMo. hot rolled seamless steel pipes/tubes