Steel for submarine hulls with improved weldability

A process of producing a submarine hull, comprising

• (a) providing steel components, said steel components having thicknesses of between 15 mm and 150 mm,
• said steel components having a chemical composition consisting of, in weight percent:
• 0.030%≦C≦0.080%
• 0.040%≦Si≦0.19%
• 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%
• W≦1.48%
• 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)]0.030≦460
• the steel components having a structure comprising:
• at least 90% of martensite,
• a maximum of 5% of residual austenite, and
• a maximum of 5% of ferrite,
• the steel components having an elastic limit of between 480 MPa and 620 MPa
• (b) assembling and welding said steel components together to manufacture said submarine hull,
• wherein the steel components are welded by arc welding using a coated electrode welding process or by arc welding using a solid wire MIG welding process,
• wherein the welding is started without preheating, including when the welding is carried out when ambient temperature is less than 0° C., and the welding of said steel components comprises using filler metal.