Content area
Full Text
In the 1930s, Friedrich Singer started using a zinc-phosphate coating as a lubricant for semi-finished products in coldforming processes. This practice - still common in industry - is increasingly under fire because the chemicals used must be disposed of properly and at considerable expense. Carl Bechem offers a zinc-phosphate-free lubricant coating for cold-forging applications that is less costly and more environmentally friendly than traditional products.
In the process of cold forming, lubricants are applied on the semi-finished products. This is done, without preheating, in single- or multi-stage processes after a wet chemical pre-treatment. In cold forming, tribological conditions are characterized by high relative speeds between the tooling and the workpiece, high surface pressure and enlarged surfaces. Temperatures of up to 500°C (932°F) will occur under these conditions, resulting in the need for lubricating systems to reduce direct-metal contact between tools and workpieces.
Reduced Chemical Disposal Costs
Massive cold forming became viable as an industrial process with the Singer technique, patented in Germany in 1934. By modern standards, however, this process has a number of disadvantages since the application of individual layers requires a high amount of energy and a high quantity of chemicals that must be properly disposed of after use. The system and its applications are subject to strict environmental regulations.
Environmental protection, global competition and the pressure to control costs require energy-saving and raw-material-efficient manufacturing processes. The use of zinc-phosphate coatings on semi-finished parts has to be reconsidered particularly because of its environmental implications. However, the replacement of zinc-phosphate layers is complicated due to demanding process requirements. Besides good separating properties between tool and semi-finished part, an alternative fluid has to guarantee consistent surface quality, high load-carrying capacity and good emergency-running properties.
Zinc Phosphate and Soap
At present, chemical zinc phosphating is still the industrial standard for cold forming. Zinc...