Definition
Drill Pipe Grade — Drill pipe grade is the API classification of a drill pipe tube's steel by its minimum yield strength — E-75, X-95, G-105 and S-135 being the common grades — which sets how much tension and torque the pipe can safely carry.
Also known as: drill pipe grades, pipe grade, E-75, X-95, G-105, S-135
How grades are defined
Drill pipe grade designates the steel used in the pipe body under API Spec 5DP. Each grade corresponds to a minimum yield strength in thousands of psi: E-75 (75,000 psi), X-95 (95,000 psi), G-105 (105,000 psi) and S-135 (135,000 psi). Higher grades carry more tensile and torsional load for the same wall thickness, which matters as wells get deeper and hook loads rise.
The letter is a heritage designation and the number is the yield strength; together they define the allowable pull, collapse and burst ratings when combined with the pipe’s outside diameter and nominal weight.
Selecting a grade
- Depth and hook load — deeper wells and higher mud weights push operators toward G-105 and S-135.
- Environment — in sour (H2S) service, grade selection must respect NACE MR0175 / DS-1 limits, since higher-strength steels are more susceptible to sulfide stress cracking.
- Fatigue — grade does not by itself prevent fatigue; connection design and dogleg severity matter as much as body strength.
Matching grade to your well
Choosing the right grade balances load capacity, weight and cost. We stock drill pipe across common grades and can advise on the best fit for your depth and mud program — share your specs to confirm.