Page 22 - MetalForming June 2013

New Stamping Lubricants
Meet New Challenges
The desire of automotive OEMs and their suppliers to protect high-strength and coated-steel stamped parts from corrosion has many switching to neat oils and emulsions. Still using water- based lubes? Follow the tips offered here to forestall corrosion.
Beginning in the 1970s, synthetic stamping lubricants became viable options to petroleum- based products throughout North America. These water-based lubricants provided improvements to post- process operations such as welding, reduced costs associated with parts washing and housekeeping, and were environmentally friendly. Their popu- larity increased in 1989 when the Auto- Steel Partnership approved, for the first time, use of a synthetic lubricant (Fuchs’ Eco Draw HVE 1) by automo- tive OEMs.
As use of synthetics increased, sup- pliers continued to enhance lubricity, anticorrosion properties and residue characteristics of synthetic lubricants. Along the way, many stampers stan- dardized on synthetic lubricants. While direct savings may or may not have always been realized in the pressroom, improvement to weld quality, increased weld-tip life, reduced housekeeping and disposal costs and improved safe-
Paul Bosler is product manager, draw- ing and stamping lubricants, Fuchs Lubricants Co.: pbosler@fuchs.com; www.fuchs.com.
ty typically amounted to substantial overall savings.
In recent years, stampers, particu- larly those serving the automotive industry, have begun to face new chal- lenges related to the increased use of high-strength and advanced high- strength steels (HSS and AHSS), as well as coated steels and aluminum alloys. Stamping these materials can push the capability limits of some lubricants. And, European and Asian automotive OEMs often restrict or discourage the use of water-based lubricants when stamping their components.
Meet the Enemy— Friction and Heat
The work-hardening and spring- back characteristics of high-strength steels can require stampers to boost press tonnage and increase ram dwell time. The resulting increase in friction and associated heat can break down stamping lubricants, deplete their boundary protection and render them ineffective. In these situations, stam- pers opt for lubricants with extreme- pressure (EP) additives such as chlo- rine, sulfur and phosphorous. Activated by heat, these additives react with
BY PAUL BOSLER
20 MetalForming/June 2013
www.metalformingmagazine.com
Water-based stamping lubricants can lead to galvanic corrosion when stamping zinc-coated steels.
metal to form metal- lic “salts” with low shear strength. These salts provide an additional yet temporary coating to protect the tools and workpiece.
The most robust levels of chlorine and sulfur can be contained in paraf- fin, olefin or fats. However, these car- riers are oil-soluble and do not mix well