Galvannealed sheet steel and process for production thereof

A technology of hot-dip galvanized steel sheet and manufacturing method, applied in hot-dip galvanizing process, metal material coating process, coating and other directions, can solve the problems of non-disclosure, uneven trace components, difficult countermeasures, etc., and achieve coating properties Excellent, good looking results

Active Publication Date: 2008-04-16
NIPPON STEEL CORP
View PDF12 Cites 13 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Many of these unevennesses are caused by the unevenness of the oxide film of the plated original plate, the unevenness of trace components, etc. in many cases, but basically the cause is difficult to identify, and the fundamental countermeasure

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Galvannealed sheet steel and process for production thereof
  • Galvannealed sheet steel and process for production thereof
  • Galvannealed sheet steel and process for production thereof

Examples

Experimental program
Comparison scheme
Effect test

Example

[0054] (Examples 1-13 and Comparative Examples 1-11)

[0055] Table 1 shows the composition of the annealed very low carbon steel sheet used in the test. After pre-treatment according to the conditions shown in Table 2, electroplating was carried out in the plating bath shown in Table 3 (bath temperature 60°C, current density 30A / dm 2 ) Pre-plating Ni.

[0056] Then, at 3%H 2 +N 2 In the atmosphere, heat to 450°C at a heating rate of 50°C / s, immediately immerse in a hot-dip galvanizing bath kept at 450°C, hold for 3 seconds and then wipe to adjust the weight per unit surface area of ​​the coating. Just after wiping The alloying is carried out at the specified heating rate, temperature, and soaking time. Regarding cooling, after performing slow cooling at 2°C / sec for 10 seconds, rapid cooling was performed at 20°C / sec. Then, temper rolling with a reduction ratio of 0.5% was performed.

[0057] The samples were produced under the various conditions shown in Table 4 (Ni pre-depositio...

Example

[0085] (Examples 14-22 and Comparative Examples 12 and 13)

[0086] Table 7 shows the composition of the annealed very low carbon steel sheet used in the test. After pretreatment under the conditions shown in Table 2, electroplating was carried out in the plating bath shown in Table 3 (bath temperature 60°C, current density 30A / dm 2 ) Pre-plating Ni.

[0087] Then, at 4%H 2 +N 2 Heated to 455°C at a temperature increase rate of 50°C / sec in the atmosphere, immediately immersed in a hot-dip galvanizing bath at 450°C for 2.5 seconds, then wiped to adjust the weight of the coating per unit surface area, just after wiping The temperature was raised at 50°C / sec, and after being maintained for 4 seconds, it was rapidly cooled at 50°C / sec. Then, temper rolling with a reduction ratio of 0.5% was performed.

Example

[0105](Examples 19-25 and Comparative Examples 15-17)

[0106] Using the cold-rolled and annealed original plates shown in Table 1, after the pretreatment shown in Table 2, they were electroplated in the plating bath shown in Table 3 (bath temperature 60°C, current density 30A / dm 2 ) Pre-plating Ni. Then, at 3% H 2 +N 2 In the atmosphere, heat to 460°C at a temperature increase rate of 50°C / sec. Immediately immerse in a hot-dip galvanizing bath kept at 455°C for 3 seconds and wipe to adjust the weight per unit surface area of ​​the coating. The weight per unit surface area of ​​the coating is 60g / m 2 . Then heat alloying treatment is carried out under prescribed conditions. The cooling after heating is performed by slow cooling of 2° C. / sec for 10 seconds, and then rapid cooling is performed at 20° C. / sec. Then, temper rolling with a reduction ratio of 0.5% was performed. In addition, the sample used for observing the interface alloy layer was immersed in a hot-dip galvanizing bat...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention aims at providing galvannealed sheet steel excellent in corrosion resistance, workability, coatability and appearance and a process for the production thereof. The invention relates to a process for the production of galvannealed sheet steel which comprises subjecting an ultra low carbon steel sheet to surface cleaning and preplating with nickel, heating the resulting sheet rapidly either in the absence of oxygen or in a reducing atmosphere to a sheet temperature of 430 to 500 DEG C at a temperature rise rate of 30 DEG C/sec or above, plating the sheet in a plating bath of molten Zn, wiping the resulting sheet, heating the sheet rapidly to 470 to 600 DEG C at a temperature rise rate of 30 DEG C/sec or above, and then cooling the sheet either without soaking or after soaking for less than 15 seconds. The galvannealed steel sheet produced by the process is composed of an ultra low carbon steel sheet and a galvannealed layer formed on at least one side of the sheet which layer comprises by mass Fe: 8 to 13 %, Ni: 0.05 to 1.0%, and Al: 0.15 to 1.5% with the balance being Zn and unavoidable impurities, and has an Al/Ni ratio of 0.5 to 5.0, the mean thickness of G layer present on the interface of basis steel being 1 m or below and the dispersion of the thickness falling within +- 0.3 m.

Description

technical field [0001] The present invention relates to an alloyed hot-dip galvanized steel sheet which is excellent in corrosion resistance, workability, and paintability and uses an ultra-low carbon steel sheet as the original sheet and a manufacturing method thereof. In addition, the present invention also relates to a method for producing a hot-dip galvanized steel sheet with an extremely good appearance. Background technique [0002] Conventionally, galvannealed steel sheets have been known as steel sheets for automobiles and constructions excellent in coating film adhesion and corrosion resistance after coating. In recent years, since deep drawability is required for automotive applications, alloyed hot-dip galvanized steel sheets made of ultra-low carbon steel sheets have been widely used. In this case, the corrosion resistance in the bare state and the corrosion resistance of the scratched part of the coating cannot necessarily be said to be sufficient. In addition...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): C23C2/02C23C2/06C23C2/28
Inventor 石塚清和西村一实菊池郁夫宫坂明博
Owner NIPPON STEEL CORP
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap