摘要:
A steel pipe for an air bag inflator which has a high strength of a tensile strength of 900 MPa or more, preferably 1000 MPa or more, together with high toughness, and exhibits good burst resistance wherein no cracks develop in a burst test at -40˚C or lower is produced by a method comprising providing a raw steel pipe containing, in mass %, 0.05 to 0.20 % of C, 0.1 to 1.0 % of Si, 0.025 % or lower of P, 0.010 % or lower of S, 0.05 to 1.45 % of Cr, 0.10 % or less of Al, 0.02 % or less of Ti, and one or both of Ti and Mn satisfying 0.4 ≤ Mn + 40 X Ti ≤ 1.2, rapidly cooling the raw steel pipe from a temperature of Ac1 transformation temperature or higher, tempering the resultant steel pipe at a temperature lower than Ac1 transformation temperature, subjecting the tempered steel pipe to a cold working wherein a reduction of area is 65 % or less, and then subjecting the worked steel pipe to a stress relief annealing at a temperature lower than Ac1 transformation temperature. The L/T ratio of X ray integral intensity ratios of {110} face measured in the cross section perpendicular to the axis direction (L) and the cross section perpendicular to the periphery direction (T) of the above steel pipe is 50 or lass.
摘要:
L'invention concerne un tube d'acier haute résistance destiné à un système de coussin de sécurité gonflable qui comprend une composition chimique en pourcentage en poids selon laquelle les éléments suivants sont compris entre les valeurs suivantes: C: entre 0,05 et 0,20 %, Si: entre 0,1et 1,0 %, P: 0,025 % ou moins, S: 0,010 % ou moins, Cr: entre 0,05 et 1,0 %, Al: 0,10 % ou moins, Ti et/ou Mn: une ou des quantités satisfaisant aux conditions (1) Ti = 0,02 % et (2) 0,4 = Mn + 40 X Ti = 1,2; et en complément: Fe. La composition d'acier de l'invention peut contenir en outre (i) un ou plusieurs des éléments suivants: Mo: entre 0,05 et 0,50 %, Ni: entre 0,05 et 1,5 %, V: entre 0,01 et 0,2 %; et B: entre 0,0003 et 0,005 %; (ii) un ou plusieurs des éléments suivants: Cu: entre 0,05 et 0,5 %; et Nb: entre 0,003 et 0,1 %; et/ou (iii) un ou plusieurs des éléments suivants: Ca: entre 0,0003 et 0,01 %, Mg: entre 0,0003 et 0,01 %; et REM: entre 0,0003 et 0,01 %. L'invention concerne également un procédé de production dudit tube en acier qui consiste: à former un tube d'acier comprenant ladite composition; à écrouir ledit tube de manière à lui donner une forme prédéterminée; à chauffer le tube obtenu à une température de transformation Ac1 ou à une temperature supérieure; à procéder au refroidissement, puis au revenu du tube à une température de transformation Ac1 ou à une temperature inférieure.
摘要:
Disclosed is a seamless steel pipe for line pipes which is suitable for flowlines or risers since it has high strength, excellent toughness and good corrosion resistance even when it is formed thick. This seamless steel pipe for line pipes has a chemical composition consisting of, in mass%, 0.02-0.08% of C, not more than 0.5% of Si, 1.5-3.0% of Mn, 0.001-0.10% of Al, more than 0.4% and not more than 1.2% of Mo, 0.002-0.015% of N, 0.0002-0.007% of Ca and one or two of REM in total, and the balance of Fe and impurities. In the impurities, P is not more than 0.05%, S is not more than 0.005%, and O is not more than 0.005%. The seamless steel pipe for line pipes satisfies the following formula: 0.8 = [Mn] × [Mo] = 2.6 (wherein [Mn] and [Mo] represent values equivalent to respective contents of Mn and Mo in mass%).
摘要:
A seamless steel pipe, characterized in that it contains, in mass %, 0.30 to 0.50 % of C, 0.5 % or less of Si, 0.3 to 2.0 % of Mn, 0.025 % or less of P, 0.005 % or less of S, 0.15 to 1.0 % of Cr, 0.001 to 0.05 % of Al, 0.005 to 0.05 % of Ti, 0.02 % or less of N, 0.0005 to 0.01 % of B, and 0.0050 % or less of O (oxygen), and Beff defined by the following formula (a) or (b) takes a value of 0.0001 or more, where Beff = B-10.8x(N-14xTi/47.9)/14 --- (a) when Neff = N-14xTi/47.9 >= 0, and Beff = B --- (b) when Neff = N-14xTi/47.9
摘要:
Disclosed is a seamless steel pipe for line pipes which has high strength and stable toughness while exhibiting good sulfide corrosion cracking resistance over a temperature range from low temperature to room temperature. The seamless steel pipe has a chemical composition consisting of, in mass%, 0.03-0.08% of C, 0.05-0.5% of Si, 1.0-3.0% of Mn, more than 0.4% and not more than 1.2% of Mo, 0.005-0.100% of Al, 0.001-0.005% of Ca and the balance of Fe and impurities including N, P, S, O and Cu. In the impurities, N is not more than 0.01%, P is not more than 0.05%, S is not more than 0.01%, O is not more than 0.01%, and Cu is not more than 0.1%. The seamless steel pipe has a microstructure composed of a bainite-martensite duplex structure.
摘要:
A high strength oil well seamless steel pipe excellent in sulfide stress cracking, which has a chemical composition that C: 0.1 to 0.20 %, Si: 0.05 to 1.0 %, Mn: 0.05 to 1.0 %, Cr: 0.05 to 1.5 %, Mo: 0.05 to 1.0 %, Al: 0.10 % or less, Ti: 0.002 to 0.05 %, B: 0.0003 to 0.005 %, with the proviso that the value of C(%) + (Mn(%)/6) + (Cr(%)/5) + (Mo(%)/3) is 0.43 or more, and the balance: Fe and inevitable impurities, with the proviso that in the impurities, P: 0.025% or less, S: 0.010 % or less, and N: 0.007 % or less. The above oil well seamless steel pipe may contain one or more of specific amounts of V and Nb and/or one or more of specific amounts of Ca, Mg and REM. The production of the oil well steel pipe does not need a further heat treatment step for grain refinement, and therefore the above oil well steel pipe can be produced by the employment of the inline pipe making-heat treatment process exhibiting high production efficiency, at a reduced cost.