Diameter 2,200 mm

The manufacture of high-spec stainless steel components, including those that involve special materials and dimensions, is part of the day-to-day activity of Kuhn Special Steel. However the company is now breaking new ground for the Siemens Group, as it begins production of new, larger gas turbine components for Siemens Turbomachinery Sweden.

The specific items concerned are low-pressure blade housings; “highly sophisticated parts” in the respectful estimation of Tobias Stelzer, the man in charge of work preparation department.

Ever since 2003, Kuhn Special Steel has been making decanter components with external diameters of up to 1,200 mm. The past two years have also seen components of up to 1,600 mm in diameter form part of the firm’s day-to-day work on behalf of customers from various sectors. The range of finished-machined parts dimensions for supplying to Siemens, which went up to 1,800 mm in 2014, now stands at 2,200 mm. Our foundry is nevertheless already busy with the complex task of preparing for the production of even larger components.

One of the major time-intensive challenges created by orders of this type is the need for a customised, order-specific mould to allow the component concerned to be cast. This has also involved extensive modification of one of our large vertical casting machines, including – for example – new concrete walls and recessed structural steel elements. The corresponding control systems have also been upgraded as part of this modification to make them computerised and fully automatic, allowing operating parameters to be entered and read from a PC workstation. High-precision control systems are now likewise used to regulate the casting parameters.

The increase in component diameter from 1,800 mm to 2,200 mm has brought total mould-weight up to around ten metric tons, and we have had to install new lifting equipment to handle these moulds and finished parts. The extra driving force required to move the increased mass has been supplied – thanks to flexible reaction on the part of Kuhn Special Steel – with larger motors.

The actual casting process has also required adaptation. This has involved not only the firm’s foundry employees; it has also supposed a challenge for Kuhn’s R&D department. All those involved have been spurred on by the search for new solutions, and committed to fulfill their mission to perfection.

These efforts on the part of Kuhn Special Steel to modify and extend its foundry operation make the company more attractive to further customers, as the foundry is now able to make even larger centrifugal castings.

Photos: www.siemens.com/presse