FolaSal®-coated steel sheet for refrigerators
02.08.2017 | Salzgitter Flachstahl GmbH
Many know Liebherr as one of the world’s leading manufacturers of construction machines and cranes. But many more people probably know Liebherr as a company with a long tradition of manufacturing quality refrigerators and freezers. The era of Liebherr cooling device production began in Ochsenhausen, Germany in 1954. At that time, less than ten percent of the German households had a refrigerator, but the demand increased as the economy grew. Meanwhile, around 4,500 appliances leave the Ochsenhausen factory each day. Naturally, other manufacturing sites were added and now three additional locations are producing Liebherr cooling devices. Appliances for private households now also come from Radinovo (Bulgaria), devices for industry, trade and laboratories from Lienz (Austria), and refrigerators and freezers for commercial applications from Kluang (Malaysia).
A supply relationship of many years connects the companies Liebherr and Salzgitter. Liebherr uses the steel from Salzgitter to manufacture refrigerator doors and sidewalls. Initially, the Ochsenhausen plant received cold-rolled sheet coils for many years, but in 2012 Salzgitter Flachstahl GmbH and Salzgitter Mannesmann Stahlservice GmbH were jointly able to qualify as suppliers of pre-painted, pre-cut parts (FolaSal®) to the Radinovo plant. The FolaSal® coating is applied and burned in in Salzgitter in a continuous strip coating procedure. Placing the final coat on the material for such applications presents a special challenge, because a large portion of the material ultimately becomes a visible part and consequently is more or less always visible to the refrigerator owner. In this light, it is clear that the coating process in Salzgitter must ensure a faultless surface while also complying with narrow tolerances for color, gloss and surface structure. It goes without saying that the paint is designed to withstand all the manufacturing steps at Liebherr unscathed and to stand up to the later contact with diverse foods and household chemicals without staining.
In order to satisfy all of these requirements reliably and durably, the material is produced on the strip coating and upstream lines at Salzgitter Flachstahl GmbH and in the subsequent panel formation at Salzgitter Mannesmann Stahlservice GmbH in special campaigns with special quality specifications. Furthermore, a complex in-process coating inspection takes place during the painting to ensure such features as the coating thickness, gloss, color, paint hardness, paint adhesion and formability characteristics. Random samples from each coating campaign also undergo long-term testing at Salzgitter Mannesmann Forschung GmbH.
These comprehensive quality assurance measures are very important. But the most important prerequisite to ensure that the final product fulfills all expectations is and remains close coordination and cooperation between Liebherr as customer and Salzgitter as supplier, as well as among all the people involved in the manufacturing process.