Method for eliminating micro-cracks on surface of galvanized sheet

A micro-crack and galvanized sheet technology, applied in the field of steel rolling, can solve problems such as poor galvanization of galvanized substrates, affecting the surface quality and strength of galvanized sheets, formability, and restricting the application of DP steel, so as to avoid the formation of banded structures , increase the cost of alloy and equipment, and avoid the effect of micro-crack defects

Active Publication Date: 2021-06-01
SHOUGANG JINGTANG IRON & STEEL CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, surface micro-cracks will be introduced in the production process of galvanized substrates, which will cause poor galvanization of galvanized substrates, affect the surface quality, strength and formability of galvanized sheets, and restrict the application of DP steel

Method used

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  • Method for eliminating micro-cracks on surface of galvanized sheet
  • Method for eliminating micro-cracks on surface of galvanized sheet
  • Method for eliminating micro-cracks on surface of galvanized sheet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] Embodiment 1 provides a kind of method for eliminating microcracks on the surface of galvanized sheet, specifically as follows:

[0060] (1) Obtain a slab with a size of 237mm, its temperature is 400°C, its grade is DP780, its chemical composition is shown in Table 1, and the rest is Fe and unavoidable impurities.

[0061] (2) Heat the slabs in step (1) into a heating furnace for heating, the distance between adjacent slabs is 1800mm, the outlet temperature of the second stage of heating is 1210°C, the time of the soaking section is 25min, and the furnace temperature is 1260°C ℃, the time in the furnace is 160min.

[0062] (3) The slab heated in step (2) is subjected to rough rolling and descaling, rough rolling, finish rolling and descaling, finish rolling, ultra-fast cooling and coiling to obtain a hot-rolled steel strip with a thickness of 2.8mm. Among them, the rough rolling start temperature is 1270°C, and the rough rolling end temperature is 1100°C; in the finish...

Embodiment 2

[0065] Embodiment 2 provides a kind of method for eliminating microcracks on the surface of galvanized sheet, specifically as follows:

[0066] (1) Obtain a slab with a size of 237mm, its temperature is 420°C, its grade is DP780, its chemical composition is shown in Table 1, and the rest is Fe and unavoidable impurities.

[0067] (2) Heat the slabs in step (1) into a heating furnace for heating, the distance between adjacent slabs is 1750mm, the outlet temperature of the second stage of heating is 1215°C, the time of soaking section is 28min, and the furnace temperature is 1265°C ℃, the time in the furnace is 155min.

[0068] (3) The slab heated in step (2) is subjected to rough rolling and descaling, rough rolling, finish rolling and descaling, finish rolling, ultra-fast cooling and coiling to obtain a hot-rolled steel strip with a thickness of 2.5mm. Among them, the rough rolling start temperature is 1265°C, and the rough rolling end temperature is 1110°C; in the finish rol...

Embodiment 3

[0071] Embodiment 3 provides a kind of method for eliminating microcracks on the surface of galvanized sheet, specifically as follows:

[0072] (1) Obtain a slab with a size of 237mm, its temperature is 390°C, its grade is DP780, its chemical composition is shown in Table 1, and the rest is Fe and unavoidable impurities.

[0073] (2) Heat the slabs in step (1) into a heating furnace for heating, the distance between adjacent slabs is 1850mm, the outlet temperature of the second stage of heating is 1225°C, the time of the soaking section is 20min, and the furnace temperature is 1255°C ℃, the time in the furnace is 150min.

[0074] (3) The slab heated in step (2) is subjected to rough rolling and descaling, rough rolling, finish rolling and descaling, finish rolling, ultra-fast cooling and coiling to obtain a hot-rolled steel strip with a thickness of 2.4mm. Among them, the rough rolling start temperature is 1280°C, and the rough rolling end temperature is 1105°C; in the finish...

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Abstract

The invention provides a method for eliminating micro-cracks on the surface of a galvanized sheet. The method comprises the following steps that a plate blank is obtained; after the plate blank is heated to the temperature of 1250-1270 DEG C, rough rolling and finish rolling are carried out, meanwhile, the finish rolling starting temperature is controlled to be 1100-120 DEG C, and finish rolling strip steel is obtained; the finish rolling strip steel is subjected to laminar cooling and coiling, and hot rolling strip steel is obtained; the laminar cooling ending temperature ranges from 630 DEG C to 670 DEG C; the hot-rolled strip steel is subjected to cold rolling, and cold-rolled strip steel is obtained; and the cold-rolled strip steel is galvanized, and a galvanized sheet with good surface quality is obtained. The galvanized sheet produced through the method has no microcracks; and in addition, the method does not increase alloy and equipment cost, only process and equipment parameters are adjusted, and the method is simple, high in applicability and remarkable in effect.

Description

technical field [0001] The invention belongs to the technical field of steel rolling, and in particular relates to a method for eliminating microcracks on the surface of a galvanized sheet. Background technique [0002] Galvanized sheet has good surface properties and corrosion resistance due to its zinc coating. For example, high-strength steel substrates (AHSS), especially dual-phase (DP) steel substrates, can be widely used in the automotive industry after galvanizing due to their excellent shock resistance, excellent formability and high specific strength. Dual-phase steel consists of a soft phase of ferrite matrix and a hard strengthening phase of martensitic phase, so dual-phase steel has unique mechanical properties, such as continuous yield, low yield strength ratio, high initial work hardening rate, good ductility, It can be widely used in the production of automobile structural parts, safety parts and reinforcement parts such as A / B / C pillars and other parts. [...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B1/38B21B45/02B21B45/08C22C38/02C22C38/06C22C38/32C22C38/38
CPCB21B1/38B21B45/0203B21B45/08C22C38/02C22C38/002C22C38/06C22C38/38C22C38/001C22C38/32B21B2001/386
Inventor 李润昌周纪名张环宇齐达李国昀李钊胡开艳张亮亮
Owner SHOUGANG JINGTANG IRON & STEEL CO LTD
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