Creusot Loire Industrie

Pierre Bocquet

Philippe Bourges

Philippe Mabelly

Process for manufacturing a pressure vessel intended to work under pressure between &minus;40&deg; C. and 200&deg; C. in the presence of H,S under conditions defined by the NACE MR 0175-97 standard, in which: components of the vessel are manufactured from a steel of chemical composition: 0.03%&lE;C&lE;0.15%; 0%&lE;Si&lE;0.5%; 0.4%&lE;Mn&lE;2.5%; 0.5%&lE;Ni&lE;3%; 0%&lE;Cr&lE;1%; 0%&lE;Mo&lE;0.5%; 0%&lE;Al&lE;0.070%; 0%&lE;Ti&lE;0.04%; 0%&lE;B&lE;0.004%; 0%&lE;V&lE;0.02%; 0%&lE;Nb&lE;0.05%; Cu&lE;1%; S&lE;0.015%; P&lE;0.03%; the balance being iron and impurities resulting from the smelting operation; CET&equals;C&plus;(Mn&plus;Mo)/10&plus;(Cr&plus;Cu)/20&plus;Ni/40<0.35; 800/500 cct<10 s; the components being quenched and tempered; the structure is martensitic or martensitic-bainitic with less than 10% ferrite; the temper temperature is <680&deg; C. Optionally, a stress-relieving operation is carried out at a temperature &gE;595&deg; C. The components are welded under conditions such that the cooling time tc between 800&deg; C. and 500&deg; C. of the HAZ is >5 seconds and a postweld heat treatment is carried out between 595&deg; C. and 680&deg; C., the steel being such that R,&gE;550 MPa, R,&gE;450 MPa, A %&gE;17%, K,&gE;40 J at &minus;40&deg; C. and the hardness at any point on the surface of the vessel is &lE;248 HV. Vessel obtained and steel.

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Buxy, France

Pierre Bocquet