... 4-1/2"~20" Steel grade: J55, K55, N80, L80 Thread Type: LTC, STC, BC Quality Control: ISO9001Product Descriptionoil pipeCasing is a ... "~20"Steel grade: J55, K55, N80, L80, P110, Q125Thread Type: LTC, STC, BCProduction Standard: API SPEC 5L\API SPEC 5B ... of the production:*Size and surface inspection*Non-destructive test*Thread inspection*Hydrostatic test*Drifting test*Physical and chemical analysis* ...