Forming Prepainted Steel Products Coated with Solid Lubricant Films -An Alternative to Post-Painting

The concept of forming prepainted steel products directly, as an alternative to post-painting formed parts, is economically very attractive. Significant paint burnishing, scoring, and flaking may occur when prepainted steel is subjected to conventional stamping plant forming operations. Results obtained on laboratory friction and forming test equipment show that prepainted steel products coated with solid lubricant films display improved lubricity and formability and exhibit anti-burnishing, -scoring, and -flaking tendencies. These test results successfully predicted field performance of prepainted sheet steel products coated with a solid lubricant: formability was improved and surface damage reduced under actual press line stamping conditions. These improvements have been attributed to a solid lubricious material separating the tool-paint interface.