Ads by Google
As the company who manufactures the first drill collar in CHINA, SFMC has been manufacturing drill collars for more than 30 years. All SFMC API 7-1 Spiral drill collar s are made of AISI 4145H or AISI 4145H Modified alloy steel in accordance with API Specification 7-1,API Recommended Practice 7G and API Q1 Latest Edition. The bores are trepanned from one direction with no mismatch. All drill collars are of Q&T full length by SFMC's own unique Power Frequency Induction Heating Treatment machine designed by SFMC, so as to ensure the Charpy "V" notch minimum impact strength of 40 ft/lb at 70°F and to guarantee the hardness from 285 to 341 BHN below the surface.
OD of drill collar (in) | Tensile strength (Mpa) | Yield strength(Mpa) | Elongation (L=4D)% | Impact AKV (J) | Brinell Hardness (HB) |
3-1/8~6-3/4 | ≥965 | ≥758 | ≥13 | ≥54 | ≥285 |
7~10 | ≥930 | ≥689 | ≥13 | ≥54 | ≥285 |
SFMC drill collars’ lengths are from 10 to 31 feet and outside diameter are form 3-1/8”~10”. SFMC also manufactures special Drill Collars with Spiral, Slip and Elevator recess, hardbanding. The square drill collar is available.
API 7-1 Spiral drill collars