PAINT FAILURE, STEEL SURFACE QUALITY AND ACCELERATED CORROSION TESTING

Carbonaceous deposits on steel adversely affect the salt spray performance of painted steel, with a strong correlation between the amount of surface carbon and the time to salt spray failure. The carbonaceous residues, formed during the steelmaking process, interfere with the deposition of an effective zinc phosphate conversion coating. The poor performance of a painted steel with high surface carbon is attributable to excessive porosity in the phosphate coating. Cathodic electrocoats containing alkaline resistant resins have shown a relative insensitivity to cathodic undercutting in salt spray tests. A rapid corrosion test for painted steel has been developed which incorporates conditions encountered in service but as yet not used in currently accepted corrosion tests for painted steel. The addition of freeze/dry cycles, with surface dust contamination and the use of a higher test temperature in a salt immersion/humidity test produces substantially earlier failures than with the conventional salt spray test.

• Supplemental Notes:
  • Presented at the SAE Congress and Exposition, Detroit, 27 February-3 March 1978.
• Corporate Authors:

  Society of Automotive Engineers (SAE)

  400 Commonwealth Drive
  Warrendale, PA  United States  15096
• Authors:
  • Hospadaruk, V
  • Huff, J
  • Zurilla, R W
  • Greenwood, H T
• Publication Date: 1978-3

Media Info

• Features: References;
• Pagination: 12 p.

Subject/Index Terms

• TRT Terms: Automobiles; Carbon; Corrosion; Corrosion protection; Corrosion tests; Dust; Electroplating; Electrostatics; Freezing; Humidity; Materials tests; Paint; Phosphates; Porosity; Protective coatings; Resins; Salt fog tests; Steel; Temperature; Thaw; Vehicular materials; Zinc
• Uncontrolled Terms: Freeze thaw cycles
• Old TRIS Terms: Automobile materials
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00178842
• Record Type: Publication
• Source Agency: Engineering Index
• Report/Paper Numbers: SAE 780186 Preprint, HS-025 333U
• Files: HSL, TRIS
• Created Date: Sep 27 1985 12:00AM