... ,;3. Steel grade: J55 N80 L80 K55,,,, P110;4. Standard: API Spec 5 CT.5. My company can make for steel ... oil industry. My company is in strict accordance with the API standard drill pipe, casing lightpipes hose body heat pipe and ... threaded processing technology, threaded parameters is 20% higher than API standard requirements, advanced inspection testing equipment can undertake magnetic flux leakage ...