Method for eliminating yield point elongation of hot galvanizing low-alloy high-strength steel

Abstract

The invention relates to a method for eliminating yield point elongation of hot galvanizing low-alloy high-strength steel. The method comprises the steps of 1, setting of working rolls of a withdrawaland straightening machine, 2, setting of the overlapping amount, 3, setting of the elongation rate, 4, setting of the tension value and 5, setting of the process speed. In the step 1, the diameter ofa first bending roll is set as phi 30mm*2, the diameter of a second bending roll is set as phi 36mm*2, the diameter of a first straightening roll is set as phi 50mm/phi 180mm, and the diameter of a second straightening roll is set as phi 70mm/phi 180mm; in the step 2, the overlapping amount of the first bending roll of is set as 7-10mm, the overlapping amount of the second bending roll is 9-13mm,the overlapping amount of the first straightening roll is 8-12mm, and the overlapping amount of the second straightening bending roll is 5-8mm; in the step 3, the elongation rate is set as 1.0-1.6%;in the step 4, the tension value is set to 150-200 KN; and in the step 5, the process speed is set to 80-150 m/min. By the withdrawal and straightening machine, a certain elongation rate and tension are given, so that a certain amount of strain is generated by the steel strip, and the purpose of eliminating the yield point elongation of a steel strip is achieved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for eliminating the yield platform of hot-dip galvanized low-alloy high-strength steel. Background technique [0002] In order to adapt to the development trend of weight reduction, consumption reduction, safety and environmental protection in the automobile industry, with the development of modern automobile manufacturing technology and the improvement of automobile use requirements, the requirements for automobile steel are getting higher and higher. Hot-dip galvanized low-alloy high-strength steel relies on good mechanical properties and surface conditions, and high strength can reduce the thickness of the steel strip to achieve lightweight. After galvanizing, the corrosion resistance of the zinc layer is good, which improves the service life. It is widely used in Automobile sheet processing technology field. [0003] Because the overaging period of th...

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Problems solved by technology

[0003] Because the overaging period of the hot-dip galvanizing production line is very short, dislocations cannot move from the inside to the surface in time, resulting in different degrees of yield platforms in hot-dip galvanized low-alloy high-strength steels after annealing and galvanizing. During processing and forming, slip lines are often generated, which reduces the stamping and forming ability, and the surface quality after processing is poor

For hot-dip galvanized low-alloy high-strength steel with a long yield platform, obvious hand-feeling defects similar to orange peel will appear on the surface after processing and forming, which cannot meet the surface quality requirements of the inner and outer panels of automobiles, and the stamping capacity will be greatly reduced, resulting in Increased stamping scrap rate

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