High strength anti-collision pipe for automobile and method of manufacturing the same

Abstract

The invention relates to a high-strength anti-collision tube used for a car and a manufacturing method thereof, wherein a. the high-strength anti-collision tube comprises the chemical compositions according to percentages by weights of 0.15-0.25 percent of C, 0. 8-1.5 percent of Mn, 0.2-0.5 percent of Si, 0.01-0.04 percent of Ti, 0.001-0.004 percent of B, 0.05-0.15 percent of V, more than 0.008 percent and less than or equal to 0.015 percent of N, and the rest of Fe and unavoidable impurities; b. the manufacturing method comprises the following steps: the chemical compositions are smelted and cast into a steel ingot; c. a steel tube is made by a process of punching plus cold rolling or cold drawing; d. the heat treatment of the processes of normalizing, high-frequency induction hardening and annealing is carried out for the steel tube, wherein the normalizing temperature is 800-900 DEG C, and the normalizing heat-insulation time is 10-40 minutes; the high-frequency induction hardening and heating time is 2-4 seconds, and the hardening and heating temperature is 900-950 DEG C; the annealing temperature is 150-250 DEG C, and the heat insulation time is 0.5-4 hours. The invention can produce the car anti-collision tube with the maximum wall thickness of 2.5mm, not only ensures that the high-frequency induction heating is even, but also fully restricts grains to grow and has the advantages of even superfine crystal organizations, ultrahigh strength, good tenacity, and the like.

Description

technical field [0001] The invention relates to a high-strength small-diameter thin-walled steel pipe, in particular to a high-strength anti-collision pipe for automobiles and a manufacturing method thereof. Background technique [0002] In order to increase the rigidity of the car door, most cars are equipped with anti-collision tubes in the door. Crash tubes made of high-strength steel form the first barrier against crashes, transferring side or front impact loads evenly to the main body members. [0003] In recent years, as the requirements for automobile safety performance have become higher and higher, the requirements for high-strength anti-collision tubes for automobiles have continued to increase, mainly for the development of high-performance and high-strength materials, while ensuring welding performance. [0004] Since steel with ultra-fine grains can improve the strength and toughness of steel at the same time, currently the steel pipe with ultra-fine grain stru...

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Problems solved by technology

[0009] Increasing the thickness of the steel pipe can further improve the impact performance of the automobile anti-collision pipe. The existing automobile anti-collision pipe mainly adds a small amount of B, Ti and selectively adds an appropriate amount of Cr, Ni, and Mo. During the high-frequency quenching process, these elements Due to the small number and large size of the precipitates with C and N, the grain growth rate cannot be fully suppressed, especially for steel pipes with a wall thickness greater than 2mm, because the grain growth rate cannot be sufficiently suppressed, it cannot obtain uniform internal and external structures. Ultra-fine grains with an average grain equivalent diameter of less than 6 μm, so that it is impossible to achieve ultra-high strength and good toughness

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