A kind of low-cost weathering steel for 340mpa grade cold-rolled automobile and its making method

Abstract

The invention relates to the technical field of water cooling cycle, in particular to a low-cost weathering steel for a 340MPa grade cold-rolled automobile and a manufacturing method thereof. The chemical composition and weight percentage content of the weathering steel are: C: ≤ 0.10, Si: 0.10-0.45, Mn: 0.30-0.60, P: 0.06-0.13, S ≤ 0.015, Als: 0.010-0.040, Cu: 0.2-0.4 , Ni: 0.1 to 0.2, Ca: 0.001 to 0.003, and the remainder is Fe and inevitable impurities. The invention greatly reduces the manufacturing cost; the measures such as controlling the hot rolling time in the furnace, the high pressure water pressure for phosphorus removal, the rough rolling temperature, etc. are mainly adopted, so as to reduce the occurrence probability and degree of Cu brittleness and iron oxide scale, and improve the surface quality of the steel plate; The hot-rolled coiling temperature and cold-rolled flat elongation process are designed according to the thickness of the finished product to ensure the uniformity and stability of the mechanical properties of the steel plate with different thickness of the finished product.

Description

technical field [0001] The invention relates to the technical field of water cooling cycle, in particular to a low-cost weathering steel for a 340MPa grade cold-rolled automobile and a manufacturing method thereof. Background technique [0002] According to statistics, 1 / 6 of the world's annual steel production is lost due to corrosion, and my country's annual direct economic loss due to steel corrosion exceeds 10 billion yuan. [0003] Weathering steel is atmospheric corrosion-resistant steel. A small amount of alloying elements are added to the steel to form a dense layer of about 50-100 μm thick between the rust layer and the substrate. Spinel-type oxide film, due to the existence of this dense oxide film, prevents oxygen and water in the atmosphere from infiltrating into the steel matrix, slows down the deep development of corrosion into the steel material, and greatly improves the atmospheric corrosion resistance of the steel material. ability. The atmospheric corrosi...

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Problems solved by technology

[0010] The purpose of the present invention is to provide a low-cost weathering steel for 340MPa grade cold-rolled automobiles and its manufacturing method, so as to solve the problems of many additions and high cost of existing weathering steel alloys

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