Spanish company launches new Schuler press for forged production of railway wheels

Precise pre-forming leads to improved cycle times for entire railway wheel processThe new hydraulic pre-form forging press supplied by Schuler SMG is responsible for the first stage in the railway wheel production process. With a press force of 11,250 US tons, the pre-forming press compresses a 2,200 degrees Fahrenheit round block of steel into a cake.  In a second stage, it is forged into a pre-formed wheel. A wheel-rolling machine then continues to form the pre-formed product into a wheel. Finally, the wheel receives its final shape by punching the hub in a 2,800 US ton press.

Thanks to the new 11,250 ton press, the pre-form can be sized much more precisely and there is thus less rolling work required in the downstream wheel rolling machine. This significantly reduces the line¡¯s cycle time, says Mikel Mendoza, the project manager responsible for wheel production at CAF.

The process is capable of producing railway wheels with a maximum diameter of around five feet and weighing over one ton. The line is designed in such a way that a fully formed wheel leaves the line every 90 seconds, states Dr. Walter Osen, head of the forging business unit at Schuler SMG in Waghäusel. New die technology and automation further improve process and material efficienciesIn order to tap the full potential of the new pre-forming press, new dies were also developed in cooperation with Schuler Presses in Goeppingen, Germany. ¡°The aim is to reduce input weight by up to ten percent with the aid of the new dies, explains Dr. Walter Osen.

Automation reduces transport times from the oven to the press and to the wheel rolling machine. As a result, the furnace temperature can be lowered and energy savings can be made, says Mikel Mendoza. Fast integration and start-up achieved within 10 daysThe new Schuler pre-forming press was integrated into a completely redesigned production line within just ten days. Teams of suppliers had been given the previous three months to install the 11,250 ton press during ongoing production, and to equip the furnace, de-scaling line, press and wheel rolling machine with robot in order to link them into a fully automatic line with automatic ejector stations. The complete line was put into operation in record time.

Nearly all forms of railway wheels can be pre-formed using the Schuler forging press technology. The power and high press force of the machine become apparent from its impressive statistics: the main cylinder has a diameter of around ten feet. The respective hydraulic system contains 8,000 gallons of hydraulic oil to help the cylinder do its work. The whole system requires four megawatts of power. Lubrication and cooling ensure the process goes as smoothly as possible. Three robots cool the dies before, during and after the forming process and spray them with a water-graphite mixture.

In a second step, the 2800-ton press for the final pressing and punching of the wheel hubs will be replaced in summer 2009 by a new 5,600-ton flanging press supplied by Schuler SMG. This will close the last gap in CAF¡¯s fully automatic wheel production process.