Seamless steel pipe for ship and preparing method of seamless steel pipe

Abstract

The invention relates to the technical field of seamless steel pipes, in particular to a seamless steel pipe for a ship and a preparing method of the seamless steel pipe. Chemical components of the seamless steel pipe comprise, by weight percentage, 0.12% to 0.2% of C, 0.18% to 0.32% of Si, 1.18% to 1.8% of Mn, 0.2% to 0.4% of Mo, 11.6% to 12.2% of Cr, 0.2% to 0.3% of Ti, 0.45% to 0.58% of V, 0.32% to 0.48% of Re, 0.02% to 0.05% of Al, 0.0008% to 0.018% of B, 0.008% to 0.01% of N, not larger than 0.02% of P, not larger than 0.02% of S, not larger than 0.003% of O and the balance Fe and inevitable impurities. The sum of mass percentages of all components is 100; the steel pipe tensile strength of the seamless steel pipe is larger than or equal to 900 Mpa, the steel pipe elongation is larger than or equal to 10%, the inner and outer surface roughness is smaller than or equal to 0.4 micrometer, and the requirements of the steel pipe special for the ship on strength, toughness and surface quality are met; and the experiment shows that compared with a conventional seamless steel pipe, the seamless steel pipe for the ship has the beneficial effects that the production efficiency is improved, and the production cost is reduced.

Description

technical field [0001] The invention relates to the technical field of seamless steel pipes, in particular to a seamless steel pipe for ships and a preparation method thereof. Background technique [0002] At present, there are five steel grades of carbon steel and carbon-manganese steel seamless steel pipes for ships: 320, 360, 410, 460, and 490. Among them, the pressure pipes are divided into I, II, and III grades, which have relatively high strength and plasticity at high temperatures. high demands. [0003] Seamless steel pipes have a hollow cross-section and are widely used as pipes for transporting fluids, such as pipes for transporting oil, natural gas, gas, water, and certain solid materials. Compared with solid steel such as round steel, the steel pipe is lighter in weight when the bending and torsional strength is the same. It is an economical cross-section steel and is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe...

AI Technical Summary

Problems solved by technology

For seamless steel pipes for ships, when manufacturers manufacture parts, most of them use seamless steel pipes to increase the process of outer circular cutting (grinding) and inner hole grinding so that the base metal can meet the requirements of precision and roughness before proceeding to the next step. Processing, the outer surface roughness of the produced steel pipe is greater than 0.4μm, and the grinding process is required to achieve high-quality base metal steel pipe, the procedure is complicated, the production cost is increased, and the production efficiency is reduced

At the same time, the cracking of seamless steel pipes has always been a concern of the steel pipe industry. Cracks in the production process of steel pipes will not only cause waste of raw materials, but may also cause delays in the production schedule due to reduced production efficiency; Cracks may cause huge property losses or even casualties. In addition, due to the complexity of the production process parameters of seamless steel pipes, when cracks occur in steel pipes, it is often impossible to find out the cause of the cracks in time.

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