Surface-treated zinc based metal plated steel plate and method for production thereof

• US 20050221108A1
• Filed: 06/27/2003
• Published: 10/06/2005
• Est. Priority Date: 06/28/2002
• Status: Abandoned Application

• Current Assignee: JFE Steel Corporation (JFE Holdings Incorporated)
• Original Assignee: JFE Steel Corporation (JFE Holdings Incorporated)
• Inventors: Shimizu, Tomoyuki, Kyouno, Kazuaki, Higai, Kazuhiko
• Application Number:
  US10/515,944
• Publication Number:
  US 20050221108A1
• Time in Patent Office: Days
• US Class Current: 428/626
• CPC Class Codes: B05D 7/51 One specific pretreatment, e.g. phosphatation, chromatation, in combination with one specific coating pretreatment of metallic substrates C23C; pretreatment before coating in general B05D3/00
• CPC Class Codes: C09D 5/08 Anti-corrosive paints
• CPC Class Codes: C23C 22/07 containing phosphates
• CPC Class Codes: Y10T 428/12569 Synthetic resin
• CPC Class Codes: Y10T 428/12799 Next to Fe-base component [e.g., galvanized]

Abstract

The application provides a surface-treated zinc series plated steel sheet containing a steel sheet having on a surface thereof a zinc series plated layer, and on the plated layer, a surface-treated film containing a reaction product of a metallic salt with the plated metal, and a resin in a mass proportion of from 1 to 50% by mass with respect to the metallic salt, wherein the surface-treated film has a layer mainly containing the reaction product having a thickness of from 0.02 to 3 μm, and the layer mainly containing the reaction product contains 20% by volume or more of the resin contained in the surface-treated film, and a process for producing the same. According to the invention, such a chromium free surface-treated zinc series plated steel sheet is obtained that is excellent in corrosion resistance of flat part, corrosion resistance after forming, electroconductivity and formability, as equivalent to a general-purpose chromate-treated zinc series plated steel sheet. According to the process of the invention, neither chromium nor chromium compound is used, and no special wastewater treatment is necessary in a coating process of a surface treating solution and upon using the surface-treated steel sheet thus obtained.

Claims

1. A surface-treated zinc series plated steel sheet containing a steel sheet having on a surface thereof a zinc series plated layer, and on the plated layer, a surface-treated film containing a reaction product of a metallic salt with the plated metal, and a resin in a mass proportion of from 1 to 50% by mass with respect to the metallic salt, wherein the surface-treated film has a layer mainly containing the reaction product having a thickness of from 0.02 to 3 μ

m, and the layer mainly containing the reaction product contains 20% by volume or more of the resin contained in the surface-treated film.

2. A surface-treated zinc series plated steel sheet as described in claim 1, wherein the surface-treated film further contains a lubricating agent.

3. A surface-treated zinc series plated steel sheet as described in claim 1 or 2, wherein the metallic salt is at least one kind selected from the group consisting of a phosphate, a nitrate, a carbonate, a sulfate, an acetate and a hydroxide of at least one metal selected from the group consisting of Al, Mn, Mg, V and Zn.

4. A process for producing a surface-treated zinc series plated steel sheet containing a step of treating a zinc series plated steel sheet with a treating solution containing a metallic salt and a resin in a mass proportion of from 1 to 50% by mass with respect to the metallic salt, and having a pH of from 1 to 4 and a free acidity of 3 to 20 in terms of 0. 1N sodium hydroxide, so as to adhere a solid matter of from 0.05 to 3.0 g/m² in terms of an amount of the metallic salt.

5. A process for producing a surface-treated zinc series plated steel sheet as claimed in claim 4, wherein the resin contains a lubricating agent.

6. A process for producing a surface-treated zinc series plated steel sheet as claimed in claim 4, wherein the metallic salt is at least one kind selected from the group consisting of a phosphate, a nitrate, a carbonate, a sulfate, an acetate and a hydroxide of at least one metal selected from the group consisting of Al, Mn, Mg, V and Zn.

7. A process for producing a surface-treated zinc series plated steel sheet as claimed in one of claims 4 to 6, wherein the process comprises a step of coating the treating solution on a surface of the zinc series plated steel sheet, and a step of drying the coating by heating.