Hayes Lemmerz is one of the world’s leading suppliers of automobile wheel rims. At its Spanish production site in Manresa, the company has switched to the TecTalis nanoceramic process from Henkel, a relatively new coating technology designed to be an inexpensive and an environmentally friendly alternative to conventional zinc-phosphating.
Henkel’s nanotechnology-based conversion coating system has been in use at Hayes Lemmerz’s Manresa production site near Barcelona, Spain, for one year now. Approximately 7,500 million steel wheels for cars and vans can be manufactured at the site every year.
“Focusing on our customers’ needs, one of our corporate goals is to manufacture as cheaply as possible without having to make any concessions on quality,” said Juan Canteli, production manager at the Manresa site.
In the past, Hayes Lemmerz had applied the zinc-phosphating process in order to protect the steel wheels from corrosion and to optimize adhesion of the subsequently applied organic coating. Due to its excellent quality, this surface treatment has long been accepted as state-of-the art in the metals industry.
Under practical production conditions, however, it comes with two serious disadvantages: high energy costs, and the fact that the waste phosphate sludges produced contain heavy metals, exerting a further negative effect on production cost and handicapping environmental performance.
With the switch to the new conversion coating process from Henkel in August 2008, the influence of these factors has been reduced. “Overall, this has brought us bottom-line savings in the pretreatment process of approximately 20%, without any trade-off with respect to the usual coating quality,” said Canteli.
With the TecTalis process, a ceramic conversion coating is applied to the metal either by spraying or immersion. The resultant layer is up to 100 times thinner and more finely structured than the crystalline stratum formed by the zinc-phosphating process. In addition, this technology can be introduced in existing production lines without costly upgrading work.
Working with client staff, a team from Henkel first performed a series of laboratory tests to ensure compliance with all the relevant specifications. An initial training course for the employees of the rim manufacturer also facilitated the final process changeover.
“The changeover to this new nanoceramic conversion coating technology has made a big difference to our process costs,” said Canteli. As well as entailing fewer operations, the new coating technique can be performed at room temperature, in contrast to the zinc-phosphating process. Previously, the phosphate bath first had to be heated to 50° C with continuous compensation of the subsequent heat losses then ensuing.
The results of this new application are also helping to improve the company’s environmental footprint. The pretreatment process is free of toxic heavy metals, which previously had to be disposed of at a costly expense. The formation of phosphate sludges and the clogging of nozzles by deposits were also problems in the past. “The maintenance requirement for bath upkeep is tending toward zero,” said Centeli. “And as a result of the reduction in toxic substances, we have also found that our consumption of caustic soda for treating the water has decreased by 50%.”
Henkel also supplied a monitoring and control system for keeping the pretreatment process at Hayes Lemmerz in Spain operating at optimum efficiency. Since the initial commissioning phase, the Lineguard ProcessControl 200 system has been supplying a constant chemical feed rate combined with minimum consumption aligned to the process specifications.
“The system is integrated within the production flow and equipped with appropriate measurement modules and metering pumps designed to meet the specific requirements of the pretreatment plant,” said Philip Huys, head of surface treatment at Henkel. The Lineguard ProcessControl 200 system ensures that the treated components are provided with the surface quality necessary for the downstream processes, therefore making an important contribution right at the beginning of the production line to the overall efficiency of the manufacturing operation.
