What is a small diameter stainless steel seamless pipe

Small-diameter stainless steel seamless pipes generally refer to seamless steel pipes with an outer diameter less than or equal to 76mm. Usually applied to:
1. Seamless steel pipe for structure: GB8162-2008
2. Ground seam steel pipe for conveying fluid: GB8163-20083,
3. Seamless steel tubes for low and medium pressure boiler tube boilers: GB3087- Small seamless steel tubes 2008
4. High-pressure seamless pipes for boilers: GB5310-2008 (ST45.8-Ⅲ type)
5. High-pressure seamless steel pipes for chemical fertilizer equipment: GB6479-1999
6. Seamless steel pipe for geological drilling: YB235-70
7. Seamless steel pipe for oil drilling: YB528-65
8. Seamless steel pipe for petroleum cracking: GB9948-88
9. Special seamless pipe for oil drill collar: YB691-70
10. Seamless steel pipes for automobile half shafts: GB3088-1999
11. Seamless steel pipes for ships: GB5312-1999
12. Cold-drawn and cold-rolled precision seamless steel pipe: GB3639-1999 13. Various alloy pipes 16Mn, 27SiMn, 15CrMo, 35CrMo, 12CrMov, 20G, 40Cr, 12Cr1MoV, 15CrMo
In addition, there are GB/T17396-1998 (hot-rolled seamless steel pipes for hydraulic props), GB3093-1986 (high-pressure seamless steel pipes for diesel engines), GB/T3639-1983 (cold-drawn or cold-rolled precision seamless steel pipes), GB /T3094-1986 (cold-drawn seamless steel pipe with special-shaped steel pipe), GB/T8713-1988 (precision inner diameter seamless steel pipe for hydraulic and pneumatic cylinders), GB13296-1991 (stainless steel seamless steel pipe for boilers and heat exchangers), GB/T14975 -1994 (stainless steel seamless steel pipes for structural use), GB/T14976-1994 (stainless steel seamless steel pipes for fluid transportation) GB/T5035-1993 (seamless steel pipes for automobile axle shaft casings), API SPEC5CT-1999 (casing and oil pipes specifications), etc.