Products and solutions, 2009-06-17, 04:38 PM
New order from the energy industry: Italian steel forge Societá delle Fucine produces turbine and generator shafts for modern power plants
Turbine and generator shafts for power plants are made in one piece by the so-called open-die forging process. Societá delle Fucine, an Italian subsidiary of stainless steel producer ThyssenKrupp Acciai Speciali Terni, is among the global leaders in this area. Under an order from Siemens Energy, the forge has now produced shafts for a combined-cycle power plant in Belgium which is scheduled to come on stream in 2011. Recently, an ingot weighing 500 metric tons - the biggest in Europe - was produced over a 15-hour period at the melt shop in Terni. It was then forged by Societá delle Fucine. The finished part is for a Russian rolling mill and will weigh some 230 tons.
Among other things, the Italian steel forge produces shafts and rotor shafts up to 20 meters in length, mainly for use in power plants. Unlike drop forging, in which the material is squeezed into a die of given shape, in open die forging operations the workpiece is forged between two flat dies, allowing the steel to flow at the sides. Enormous forces are involved: at a speed of just 50 millimeters per minute, 12,600 tons of press force descend toward the red-hot workpiece, a 200-ton plus ingot heated to a temperature of 1,200 degrees Celsius. A giant manipulator - a computer-controlled “pair of tongs” - has positioned the colossal workpiece beneath the hydraulic press with millimeter precision. With a power of six megawatts, four hydraulic pumps drive 4,500 liters of water per minute through the press cylinders at a pressure of 510 bar to produce the enormous press force. With its help, Societá delle Fucine transforms the red-hot ingots into huge forgings - the largest in Europe, matched only by products from Japan. As the parts cool during this process, they are repeatedly reheated to the required temperature in forging furnaces and processed in several steps.
ThyssenKrupp Acciai Terni recently implemented a variety of measures to further strengthen its forging operation. Thanks to the construction of the 250-ton capacity manipulator and an innovative VOD (Vacuum Oxygen Decarburization) plant in the melt shop to produce special high-strength steel grades, Societá delle Fucine not only achieved enormous improvements in efficiency and quality but also extended its product portfolio into highly profitable segments. In the process, the employees demonstrated their enterprising and pragmatic approach to work. In cooperation with the manufacturer, the team headed by the production manager Ambro Carpinelli made the individual components of the manipulator in the plant themselves. “This reduced procurement costs and also saved a lot of time,” says Carpinelli. “Because we built over 90 percent of the manipulator ourselves, we will save further costs in the future on maintenance and repair work.”
Societá delle Fucine is now one of the leading players in the global forging market. The future of the company and its 220 employees continues to lie in the energy industry. The forging operation is ideally positioned in this sector, even though gaining access to the power plant construction market is extremely difficult because the demands placed on components are immense. For example, new generators for power plants have to deliver 1,600 megawatts of electricity. For this they require a high-strength forged core of exceptional quality and unusual dimensions. Apart from one other competitor in Japan, Societá delle Fucine is the only supplier in the world that can meet these requirements.
More than 50 percent of its core business is in the manufacture of generators and low-pressure shafts for the energy sector. Large shafts for rolling mills and custom-forged containers for the petrochemical and nuclear energy sectors are now also among the company’s products, which it supplies to customers throughout the world: Italian forgings are shipped not only to other countries in Europe but also to Asia, the Middle East and America. “We even deliver our products to Japan,” reports Massimo Calderini, Managing Director of Societá delle Fucine. “The 500-ton ingot highlights the outstanding importance of forging capacity in Terni,” says Calderini. And customers, too, are aware of its importance. “Societá delle Fucine has a unique position among forging suppliers - especially as regards the size of the forgings,” says Carsten Hellweg, forging buyer at Siemens AG. “Our steam turbines and generators are used in power plants throughout the world and have to meet the highest quality standards. In terms of both fulfilling contractual requirements and delivery performance, Societá delle Fucine has proved itself a reliable partner. That’s also the reason why we have concluded long-term supply agreements with the company.”