Alloying hot galvanizing steel with tensile strength larger than or equal to 590 MPa and production method

Abstract

An alloyed hot-dip galvanized steel with a tensile strength ≥ 590MPa, the steel base composition and wt% are C: 0.080-0.095, Mn: 1.65-1.85%, Si: 0.010-0.015%, P≤0.01%, S ≤0.006%, Al: 0.02-0.03%, Ti: 0.06-0.08%. Production steps: hot rolling, cooling, crimping, pickling and cold rolling; continuous annealing; continuous hot-dip galvanizing; alloying; cooling with an air knife; post-processing. In the present invention, under the conditions of ensuring tensile strength ≥ 590Mpa, yield strength ≥ 340MPa, elongation ≥ 20%, and n ≥ 0.14, the structure of the alloyed coating is fine, uniform, and dense, and the pulverization level does not exceed 2. By adding the element Ti , not only can minimize the decomposition of martensite during the alloying process, but also reduce the alloying time from the current not less than 10s to 5-9s, thereby improving production efficiency.

Description

technical field [0001] The invention relates to a steel for automobiles and a production method, in particular to an alloyed hot-dip galvanized steel with a tensile strength ≥ 590 MPa and a production method. Background technique [0002] With the development of automobile lightweight technology, it has become an inevitable trend for automobile steel to develop towards high-strength steel. As one of the members, dual-phase steel has the advantages of combining low yield strength, high tensile strength and good plasticity, so it has become the first choice for automotive steel. Compared with ordinary cold-rolled steel, galvanized dual-phase steel also has excellent corrosion resistance, which ensures that the car has good corrosion resistance and perforation ability. It is currently mainly used for structural parts and reinforcements of cars. Duplex steels can also be used in automotive panels. The alloying process is to heat the steel plate in a holding furnace after galva...

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Problems solved by technology

[0008] The purpose of the present invention is to overcome the deficiencies in the prior art of severe powdering of the high-strength steel coating and the decline in the mechanical properties of the steel base after alloying, and provide a method that ensures tensile strength ≥ 590Mpa, yield strength ≥ 340MPa, and elongation ≥ 20 %, under the condition of n≥0.14, by adding the element Ti, the effect of purifying the grain boundary is achieved, and the alloying time is reduced to 5-9s, and the alloyed hot-dip galvanized steel with a tensile strength ≥590MPa and its production method

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