증명서
API, Ce, SASO, PVOC, SONCAP, GS, ISO9001
Material
K55 or J55,L80,N80,P110
Standards
API 5CT and API 5B
Surface treatment
painted
Marks
as per the API standard
Usage
water/oil/gas well drilling
Inspection
BV, SGS, or buyer representatives
Certificate
COC, CO, SASO, FORM E/A, CIQ, etc