Abstract: A method for manufacturing a weldable steel component having a chemical composition including, by weight: 0.40%?C?0.45%; 0.75%?Si?1.50%; 0.3%?Mn?3%; 0%?Ni?5%; 1.11%?Cr?4%; 0%?Cu?1%; 0.410%?Mo?1.5%; 0.410%?Mo+W/2?1.5%; 0.038%?Nb?0.3%; 0.0005%?B?0.010%; 0.006%?N?0.025%; Al?0.9%; Si+Al?2.0%, optionally at least one element selected among V, Nb, Ta, S and Ca, in contents less than 0.3%, and among Ti and Zr in contents not more than 0.5%, the rest being iron and impurities resulting from the preparation, the aluminium, boron, titanium and nitrogen contents, expressed in thousandths of %, of said composition further satisfying the following relationship: B??×K+0.5, (1) with K=Min (I*; J*), I*=Max (0; 1), and J*=Max (0; J), I=Min(N; N?0.29(Ti?5)), J=Min(N; 0.5(N?0.52 Al+?{square root over ((N?0.52 Al)2+283)})), and whereof the structure is bainitic, martensitic or martensitic/bainitic and additionally comprises 3 to 20% of residual austenite.

Abstract: The invention concerns steel building components whereof the chemical composition comprises, by weight: 0.40 %=C=0.50%, 0.50%=Si=1.50%, 0%=Mn=3%, 0%=Ni=5%, 0%=Cr=4%, 0%=Cu=1%, 0%=Mo+W/2=1.5%, 0.0005%=B=0.010%, N=0.025 %, Al?0.9%, Si+Al=2.0%, optionally at least one element selected among V, Nb, Ta, S and Ca, in contents less than 0.3%, and among Ti and Zr in contents not more than 0.5%, the rest being iron and impurities resulting from the preparation, the aluminium, boron, titanium and nitrogen contents, expressed in thousandths of %, of said composition further satisfying the following relationship: B=?×K+0.5, (1) with K=Min (1*; J*), I*=Max (0;1) and J*=Max(0;J), I=Min(N; N?0.29(Ti?5)), J=Min {N; 0.5 (N?0.52 Al+v(N?0.52 Al)2+283)}, and whereof the structure is bainitic, martensitic or martensitic/bainitic and additionally comprises 3 to 20% of residual austenite. The invention also concerns a method for making said components.

Abstract: Assembled submarine hull steel components, each steel component having a chemical composition consisting of, in weight percent: 0.030%?C<0.080% 0.040%?Si?0.13% 0.1%?Mn?1.4% 2%?Ni?4% Cr?0.3% 0.30%?Mo+W/2+3(V+Nb/2+Ta/4)?0.89% 0.15%?Mo?0.89% V+Nb/2+Ta/4?0.004% Nb?0.004% Cu?0.45% Al?0.1% Ti?0.04% N?0.0300% impurities resulting from the production operation, said impurities including B?0.0005%, P+S?0.015%, the balance being iron, the chemical composition complying with the condition: 410?540×C0.25+245[Mo+W/2+3(V+Nb/2+Ta/4)]0.30?460.

Abstract: Assembled submarine hull steel components, each steel component having a chemical composition consisting of, in weight percent: 0.030%?C<0.080% 0.040%?Si?0.13% 0.1%?Mn?1.4% 2%?Ni?4% Cr?0.3% 0.30%?Mo+W/2+3(V+Nb/2+Ta/4)?0.89% 0.15%?Mo?0.89% V+Nb/2+Ta/4?0.004% Nb?0.004% Cu?0.45% Al?0.1% Ti?0.04% N?0.0300% impurities resulting from the production operation, said impurities including B?0.0005%, P+S?0.015%, the balance being iron, the chemical composition complying with the condition: 410?540×C0.25+245[Mo+W/2+3(V+Nb/2+Ta/4)]0.30?460.

Abstract: The invention relates to a steel for the production of submarine hulls having the chemical composition: 0.030%?C<0.080% 0.040%?Si?0.48% 0.1%?Mn?1.4% 2%?Ni?4% Cr?0.3% 0.30%?Mo+W/2+3(V+Nb/2+Ta/4)?0.89% Mo?0.15% V+Nb/2+Ta/4?0.004% Nb?0.004% Cu?0.45% Al?0.1% Ti?0.04% N?0.0300% the balance being iron and impurities resulting from the production operation, boron being an impurity whose content is less than 0.0005%, and P+S?0.015%, the chemical composition complying with the condition: 410?540×C0.25+245[Mo+W/2+3(V+Nb/2+Ta/4)]0.30?460.

Abstract: The invention concerns mold or mold frame parts for plastic material injection molding made of quenched and tempered martensitic stainless steel consisting, in wt. %, of: 0.02%=C=0.09%, 0.025%=N=0.12% with 0.05%=C+N=0.17%; Si=0.34% Al=0.080% with Si+23 Al=0.20% and Si+0.6 Al=0.25%; and 0.00025=Al×N=0.0020 0; 0.55%=Mn=1.8%; 11.5%=Cr=16% optionally up to 0.48% of copper, up to 0.90% of the sum Mo+W/2, up to 0.90% of nickel, up to 0.090% of vanadium, up to 0.090% of niobium, up to 0.025% of titanium, optionally up to 0.25 of sulphur, the rest being iron and impurities derived from preparation, the composition further satisfying the condition: 6.5=F?(Cr+Mo)+2(Si+V+Nb)?27(C+N)?(Ni+Mn/2+Cu/3)=13.

Abstract: Method for assembling a rack portion (1) of a self-raising oil rig, which rack portion (1) is constituted by at least one rectangular plate (3) which comprises teeth (51) at the longitudinal lateral faces (5) thereof, and at least one reinforcement (8) which is in the form of a half-shell and which is welded to a main face (6) of the at least one rectangular plate, along the longitudinal edges (11) of the at least one reinforcement, according to which an internal chamfer and an external chamfer which are separated by a projection of thickness T are produced at each of the longitudinal edges (11) of the at least one reinforcement (8), the at least one reinforcement (8) is provided at a main face (6) of the rectangular plate (3), at least one welding pass is carried out at the internal portion of each of the longitudinal edges (11) of the at least one reinforcement in order to produce an internal weld bead having a connection radius R greater than or equal to 4 mm, and the chamfers are filled at the external po

Abstract: The invention relates to a steel for the production of submarine hulls, which is characterised in that the chemical composition thereof comprises, by weight percent: 0.03%?C<0.08%; 0.04%?Si?0.48%; 0.1%?Mn?1.4%; 2%?Ni?4%; Cr?0.3%; 0.3%?Mo+W/2+3(V+Nb/2+Ta/4)?0.89%; Mo?0.15%; V+Nb/2+Ta/4?0.004%; Nb?0.004%; Cu?0.45%; Al?0.1%; Ti?0.04%; N?0.03%; the remainder comprising iron and impurities resulting from production, boron being an impurity with a concentration of less than 0.0005% and P+S?0.015%, the chemical composition satisfying condition 410?540×C0.25+245[Mo+W/2+3(V+Nb/2+Ta/4)]0.30?460. The inventive steel has an essentially martensitic or lower bainitic structure comprising at least 90% martensite or lower bainite, at most 5% residual austenite, at most 5% ferrite. The steel has a yield strength of between 480 MPa and 620 Mpa and a Charpy toughness V, KCV at ?60° C. of more than 50 J.