| abstract |
Low alloy steel for borehole oil pipes is proposed, which has high resistance to cracking under the action of stress in a sulfide-containing medium and is suitable for casing or laying in oil or gas wells. Specifically described is low alloy steel for borehole oil pipes, containing, wt.%: C 0.2-0.35, Si 0.05-0.5, Mn 0.05-1.0, P 0.025 or less, S 0, 01 or less, Al 0.005-0.10, Cr 0.1-1.0, Mo 0.5-1.0, Ti 0.002-0.05, V 0.05-0.3, B 0.0001- 0.005, N 0.01 or less, O (oxygen) 0.01 or less, Nb 0-0.1, Ca 0-0.01, Mg 0-0.01 and Zr 0-0.1, and having a half width (H) and a diffusion coefficient of hydrogen (D) (10cm / s) satisfying the following equation (1): 30H + D≤19.5. |