Seamless steel pipe for high-pressure oil pipe of automobile engine and manufacturing method of seamless steel pipe

Abstract

The invention discloses a seamless steel pipe for a high-pressure oil pipe of an automobile engine and a manufacturing method of the seamless steel pipe. The seamless steel pipe is prepared from the components in percentage by mass: 0.09-0.17% of C, 0.08-0.5% of Si, 1.2-1.8% of Mn, 0.02-0.06% of Al, 0.02-0.10% of Nb, 0.02-0.08% of V, 0.05-0.4% of Ni, 0.03-0.15% of Cu, less than or equal to 0.015%of S, less than or equal to 0.025% of P, less than 0.002% of O, less than 0.008% of N, larger than or equal to 2 of Al / N, larger than 0.08 and less than 0.15 of V+Nb and the balance of Fe and other inevitable impurities. The seamless steel pipe for the high-pressure oil pipe of the automobile engine has high strength, good plasticity and toughness, and high resistance to cold heading cracking; thetensile strength is larger than 700MPa, the yield strength is larger than 580MPa, elongation is larger than 20%, no blasting occurs under a 500MPa water pressure test; and cracking cannot occur underthe deformation condition that cold heading deformation is larger than 50%.

Description

technical field [0001] The invention relates to steel pipe manufacturing technology, in particular to a seamless steel pipe for high-pressure oil pipes of automobile engines and a manufacturing method thereof. Background technique [0002] With the continuous increase of car sales and car ownership in our country, the pollution of cars to the environment has intensified. In order to control the smog, the country enforces that truck emissions must meet the National 4 standard, which requires the high-pressure oil pipe used in the engine to be able to bear the pressure of 180-200MPa , put forward higher performance and quality requirements for steel pipes. [0003] Oil pipes for engines work under the condition of high-voltage pulses, and the working temperature is about 200°C. It is required that the steel pipes have good pulse fatigue resistance and aging resistance under the working temperature. At the same time, operations such as piercing and cold bending are required in...

AI Technical Summary

Problems solved by technology

[0005] Chinese Patent Publication No. CN107747035A discloses "Steel for High-pressure Oil Pipes, High-Pressure Oil Pipes and Its Preparation Method". Alloy elements with high cost such as Mo and B are added, and at the same time, 4<(B×Mo) / (C×Mn)×104<12 has strict requirements on the element ratio of Mo, B, C and Mn , the difficulty of steelmaking has greatly increased, and the requirements for the cold heading performance of steel pipes during the processing of high-pressure oil pipes have not been considered

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