Process for coating a workpiece of steel with an anti-corrosive agent

• US 5,575,865 A
• Filed: 03/24/1995
• Issued: 11/19/1996
• Est. Priority Date: 04/10/1991
• Status: Expired due to Fees

• Current Assignee: Eibach Oberflächentechnik GmbH, ITW Befestigungssysteme GmbH (Illinois Tool Works Inc.), Rudolf Reinecke
• Original Assignee: Eibach Oberflächentechnik GmbH, ITW Befestigungssysteme GmbH (Illinois Tool Works Inc.), Rudolf Reinecke
• Inventors: Isenberg, Rainer, Hoffmann, Wolfgang, Herr, Hans W., Reinecke, Rudolf
• Primary Examiner(s): Silverberg, Sam
• Application Number:
  US08/409,918
• Time in Patent Office: 606 Days
• Field of Search: 427/406, 427/409, 427/408, 148/265, 428/623
• US Class Current: 148/265
• CPC Class Codes: B05D 2202/10 based on Fe
• CPC Class Codes: B05D 2350/20 Chromatation
• CPC Class Codes: B05D 2350/65 metal layer
• CPC Class Codes: B05D 5/086 having an anchoring layer
• CPC Class Codes: B05D 7/16 using synthetic lacquers or varnishes
• CPC Class Codes: C23C 28/00 Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
• CPC Class Codes: C23C 28/32 including at least one pure metallic layer
• CPC Class Codes: C23C 28/3225 with at least one zinc-based layer
• CPC Class Codes: C23C 28/345 with at least one oxide layer
• CPC Class Codes: F16B 33/06 Surface treatment of parts furnished with screw-thread, e.g. for preventing seizure or fretting corrosion preventing means F16B33/008; settable coatings for locking threaded members F16B39/225; deformable coatings for locking threaded members F16B39/34

Abstract

A process for coating a workpiece of steel with an anti-corrosive agent, comprising the steps of providing the surface of the workpiece with a chemo-mechanical layer, and chromatizing the chemo-mechanical layer, and characterized by the steps of providing the chromated layer with a further layer containing metallic components and organic binding agents, and curing the further layer by a heat treatment.

Claims

1. A process for coating a workpiece of steel with an anti-corrosive agent, comprising the steps of:

providing the surface of said workpiece with a chemo-mechanical layer which includes a galvanized component selected from the group of zinc, tin, aluminum, and cadmium;

chromatizing said chemo-mechanical layer;

providing said chromated layer with a further layer containing predominantly metallic components, resinous organic binding agents, and a solvent;

curing said further layer by means of a heat treatment comprising heating of said further layer upon said coated workpiece to a temperature level of approximately 200°

C. for approximately 15-20 minutes so as to cause volatilization of said solvent and cross-linking of said resin components whereby said cured further layer forms an inorganic layer substantially comprising metallic components and resinous binders; and

providing said cured further layer with an organic top layer.

2. The process according to claim 1, wherein:

said organic top layer contains a lubricant.

3. The process according to claim 1, wherein the chromated layer contains a chrome yellow.

4. The process according to claim 1, wherein:

said chromated layer is applied as an extremely thin layer which is nevertheless resistant against wiping.

5. The process according to claim 1, wherein the chromatizing step is performed by using a chromate compound dissolved in an aqueous suspension.

6. The process according to claim 1, wherein the further layer contains zinc, about 85%, and aluminum, about 2 to 3%, or similar metals.

7. The process according to claim 1, wherein the further layer contains a solvent, about 10%, and a binding agent, about 5%.

8. The process according to claim 1, wherein the organic top layer contains an organic binding agent, a solvent, about 45 to 50%, and pigments.

9. The process according to claim 1, wherein the process is applied to means of construction comprising fasteners.

11. The process as set forth in claim 1, wherein:

said chemo-mechanical layer contains a lubricant.

12. The process as set forth in claim 3, wherein:

said chemo-mechanical layer also contains a lubricant.

13. The process as set forth in claim 3, wherein:

said lubricant comprises PTFE particles.

14. The process as set forth in claim 11, wherein:

said lubricant comprises PTFE particles.

15. The process as set forth in claim 12, wherein:

said lubricant comprises PTFE particles.

16. The process as set forth in claim 1, wherein:

said organic top layer comprises an organic binding agent and a solvent.

17. The process as set forth in claim 13, wherein:

said chemo-mechanical layer contains a lubricant.

19. The process as set forth in claim 17, wherein:

said organic top layer contains a lubricant.

20. The process as set forth in claim 17, wherein:

said lubricant comprises PTFE particles.

22. The process as set forth in claim 19, wherein:

said lubricant comprises PTFE particles.

24. The process as set forth in claim 22, wherein:

said further layer comprises approximately 85% zinc and approximately 2-3% aluminum.

25. The process as set forth in claim 22, wherein:

said further layer comprises approximately 10% solvent and approximately 5% binding agents.

26. The process as set forth in claim 22, wherein:

said chemo-mechanical layer comprises a lubricant.

27. The process as set forth in claim 25, wherein:

said lubricant comprises PTFE particles.

28. The process as set forth in claim 13, wherein:

said further layer comprises approximately 85% zinc and approximately 2-3% aluminum.

10. A process for coating a workpiece of steel with an anti-corrosive agent, comprising the steps of:

providing the surface of said workpiece with a chemo-mechaical layer which includes a galvanized component selected from the group of zinc, tin, aluminum, and cadmium;

chromatizing said chemo-mechanical layer;

providing said chromated layer with an adhering agent based upon water-soluble organic resins;

providing said chromated layer, with said adhering agent, with a further layer containing predominantly metallic components, resinous organic binding agents, and a solvent;

curing said further layer by means of a heat treatment comprising heating of said further layer upon said coated workpiece to a temperature level of approximately 200°

C. for approximately 15-20 minutes so as to cause volatilization of said solvent and cross-linking of said resin components whereby said cured further layer forms an inorganic layer substantially comprising metallic components and resinous binders; and

providing said cured further layer with an organic top layer.

18. The process as set forth in claim 10, wherein:

said organic top layer contains a lubricant.

21. The process as set forth in claim 18, wherein:

said lubricant comprises PTFE particles.

23. A process for coating a workpiece of steel with an anti-corrosive agent, comprising the steps of:

providing the surface of said workpiece with a chemo-mechaical layer which includes a galvanized component selected from the group of zinc, tin, aluminum, and cadmimum;

chromatizing said chemo-mechanical layer;

providing said chromated layer with an adhering agent based upon water-soluble organic resins;

providing said chromated layer, with said adhering agent, with a further layer comprising predominantly metallic components, resinous organic binding agents, and a solvent; and

curing said further layer by means of a heat treatment comprising heating of said further layer upon said coated workpiece to a temperature level of approximately 200°

C. for approximately 15-20 minutes so as to cause volatilization of said solvent and cross-linking of said resin components whereby said cured further layer forms an inorganic layer substantially comprising metallic components and resinous binders.