The invention relates to a non-quenched-tempered ocean
engineering structure
pipe with steel grade of more than 360MPa. The non-quenched-tempered ocean
engineering structure
pipe comprises the following component elements in percentage by weight: 0.02-0.12% of C, 0.17-0.35% of Si, 1.20-2.10% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, less than or equal to 0.30% of Cu, 0.05-0.30% of Ni, less than or equal to 0.30% of Cr, less than or equal to 0.30% of Mo, 0.005-0.060% of Al, 0.03-0.12% of Nb, 0.005-0.030% of Ti, less than or equal to 0.40% of CE, 0.21% of Pcm, and the balance of Fe. The non-quenched-tempered ocean
engineering structure
pipe is scientific and reasonable in design, and adopts a low-carbon high-
niobium steel design and a thermo-mechanically rolled non-
quenching-
tempering technology, and the non-quenched-tempered ocean engineering structure pipe with the steel grade of more than 360MPa is realized through transforming a rolling
production line. Starting from the metallurgical design conception, offline
quenching and
tempering processing is not required, the production of the seamless steel pipe can be achieved only through thermo-mechanical rolling, the procedure cost of per
ton can be reduced greatly, more importantly, the capacity can be greatly released, and the market competitiveness of domestic enterprises can be effectively improved.