Kobe Steel Develops High-Performance Titanium Sheets for Plate Heat Exchangers

Kobe Steel, Ltd. has developed two commercially pure titanium sheets for use in plate heat exchangers. The company plans to start marketing precoated titanium sheet and high heat transfer titanium sheet from October. This is the first time that high-performance commercially pure titanium sheet has been successfully commercialized for use in plate heat exchangers.

Kobe Steel's high-performance titanium sheets not only increase the performance of plate heat exchangers, but also contribute to the environment and to resource savings. Kobe Steel will market the new sheet products to manufacturers of plate heat exchangers for use in ships and factories. As less titanium is used, makers can benefit from lower costs.

Heat exchangers are used in heating and cooling. Plate heat exchangers use multiple, thin metal plates to transfer the heat between two fluids with different temperatures, for example refrigeration fluid or seawater for cooling. Made of titanium, stainless steel or other corrosion-resistant metals, the plates provide a large surface area to facilitate heat transfer.

Total shipments in Japan of titanium mill products amounted to 15,610 metric tons in fiscal 2010, ended March 2011. Approximately 20% of this amount, or 3,140 metric tons, was used in plate heat exchangers. Plate heat exchangers are an important application for commercially pure titanium, a product in which Japan excels. About 75% of the sheet for plate heat exchangers is exported to overseas manufacturers.

Mainly using domestic titanium sponge, Japanese titanium producers make commercially pure titanium sheet of outstanding flatness and workability. Roughly 70% to 80% of the world's titanium sheet for plate heat exchangers is produced in Japan, according to Kobe Steel estimates. Kobe Steel anticipates that demand will continue to grow for titanium plate heat exchangers.

 

Precoated titanium sheet

Kobe Steel's organic precoated titanium sheet improves press formability of the sheet for use in plate heat exchangers. This enables heat exchanger makers to increase productivity.

Kobe Steel's titanium sheet, with an acrylic resin precoat, offers the same high formability during pressing operations as conventional lubricant-film coated sheet. However, as no lubricant film is used, the new material eliminates the cost of removing the film and the disposal of the used film.

Furthermore, in comparison to conventional lubricant-oil coated sheet, Kobe Steel's precoated titanium sheet can press-form 10% deeper, broadening the design of plate heat exchangers. The higher strength of the new precoated sheet contributes to stretch forming and increases the strength of the heat exchanger itself. As sheet thickness can be reduced by 10%, the amount of titanium used can also go down. This lowers the cost of the heat exchanger and is anticipated to increase the demand for titanium plate heat exchangers.

Alkaline degreasing is used to easily remove the coating after press-forming. The chemical composition of the precoat is also easy on the environment.

 

High heat transfer titanium sheet

Kobe Steel's high heat transfer titanium sheet has minute convex-shaped bumps on the surface, which increase heat conductivity. Using this new sheet increases the heat transfer rate by more than 10% in boiling heat transfer type heat exchangers. Performance can be increased without changing the equipment design.

Due to higher heat transfer, the number of titanium heat transfer plates can be reduced. At the same time, as the volume of fluid can be decreased, a smaller pump can be used to circulate the fluid. Thus, a smaller unit can be designed and manufactured at a lower cost.

 

About Kobe Steel

Kobe Steel, Ltd. is Japan's top producer of titanium mill products. Kobe Steel is a leading Japanese manufacturer with businesses covering iron and steel, welding, aluminum and copper, machinery, natural resources and engineering, environmental solutions, construction equipment, and other businesses. In fiscal 2010, ended March 2011, Kobe Steel had consolidated sales of 1.86 trillion yen (US$22.35 billion) and employees of 34,772. More information is available at: www.kobelco.com