Low alloy steel for oil well pipes excellent in sulfide stress cracking resistance

Abstract From the Canadian patent

Subject, To provide a low alloy steel for oil well pipes excellent in sulfide stress cracking resistance, which are suitable for a casing or tubing for oil wells or gas , wells. Means for Solution, A low alloy steel for oil well pipes excellent in sulfide stress cracking resistance containing, by mass %, C: 0.2 to 0.35% Si: 0.05 to 0.5%, Mn: 0.05 , to , 1.0% P: 0.025% or less, S: 0.01% or less, Al: 0.005 to 0.10% Cr: 0.1 to , 1.0%, Mo: , 0.5 to 1.0%, Ti: 0.002 to 0.05% V: 0.05 to 0.3%, B: 0.0001 to 0.005%, N: 0.01% or , less, 0 (oxygen): 0.01% or less Nb: 0 to 0.1%, Ca: 0 to 0.01%, Mg: 0 to 0.01% and , Zr: 0 to 0.1%, in which a half-value width H and a hydrogen diffusion coefficient , …