... boiler seamless steel tube GB3087-19994 With high pressure boiler, seamless tube GB5310-955 Fertilizer equipment with high pressure, seamless steel tube GB6479-19996 Geological drilling with seamless steel tube YB235 ... 16Mn,27SiMn,15CrMo,35CrMo,12CrMov,20G,40Cr,12Cr1MoV,15CrMo. hot rolled seamless steel pipes/tubes