VDM Metals opens a new bright annealing line

VDM Metals has put a new bright annealing line into operation. It is expected to increase output by 30% to 40%. Strips can now be offered in widths from 350mm to 830mm and thicknesses from 0.40mm to 4mm. The coil weight has now been increased to 10 tonnes.


© VDM Metals


© VDM Metals


Werdohl/Germany (VDM Metals) – The new plant at the Werdohl site will set new standards in terms of height, efficiency and performance. “Annealing is a central process step for us. By recrystallizing the microstructure, material properties can be specifically adjusted,” says Niclas Muller, CEO of the company. The total investment amounted to 21 million euros. The new hall with its striking furnace tower is 73m long, 14m wide and up to 50m high. Behind the blue façade, the annealing furnace and two loop storage tanks were accommodated. They ensure that the strip can be annealed in the furnace without interruption, while the coils are changed at the inlet or outlet of the plant. Up to four coils can be simultaneously located in the plant. Further plant components – such as degreasing, cleaning and coiling systems – are located in the extension of the new hall.

Tower furnaces are state of the art in stainless steel production. The special features in Werdohl are on the one hand the high annealing temperatures and on the other a double muffle concept. There are no supporting rollers in the annealing unit. The lower muffle covers the temperature range from 1,150°C to 1,170°C. The lower muffle is equipped with a double muffle. This is standard in the stainless steel area. The upper muffle is operated at up to 1,230°C. “This is 80 degrees more than in conventional furnaces. This represents a quantum leap – both for the muffle material and furnace construction used and for the associated product processing options,” explains Muller. The annealing muffles are heated with natural gas, and hydrogen is used as a protective gas in the annealing chamber itself to prevent oxidation of the strips. The material to be annealed passes through the furnace after a cleaning and degreasing process. The protective gas keeps the material bright. This is why the term bright annealing system is also used.

Incidentally, the muffles are made of a material developed by VDM Metals itself: “VDM Alloy 602 CA”. The strips annealed here from corrosion- and heat-resistant materials are used in the electrical industry, the chemical and petrochemical industry and the automotive industry. The VDM Metals Group develops and manufactures nickel, cobalt and zirconium alloys as well as high-alloy special stainless steels. For 85 years the company has been supplying sheets, strips, rods, wires, welding consumables and powders.


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