Not only have we ever stricter requirements for bevel gears and other important elements of mechanical power transmission but also especially in the last 10 years higher expectations regarding steel as the raw material for them. Gear designers and steel manufacturers have joined forces to optimize the manufacturing processes
Dr. Hippenstiel, Managing Director Production and Technology of one of Europe’s leading manufacturers of specialty steels BGH Edelstahlwerke GmbH underlines that as steel plays a prominent role in further enhancing the quality of bevel gears, besides the properties of steel the development work entails its processability: “Due to their geometry, bevel gears are highly demanding components. The tooth area extends over almost the entire cross section. Therefore, not only should a very good steel purity be ensured, but also the most homogeneous possible distribution of the alloy elements and the microstructure. This results in isotropic technological properties.”
BGH has been the trusted steel supplier for ATA Gears for decades. Both the technical and the commercial experts are highly integrated into the continuous cooperation to improve and further develop case hardening steels.
The two companies have developed their joint action in many ways. As Dr. Hippenstiel describes it: “As part of the cooperation, the optimization of case-hardening steels beyond DIN requirements has been an important target. A separate manufacturing instruction for the gear steels has been created jointly, and this was then implemented by BGH in their production. ATA Gears therefore gets a special steel, which brings further advantages in their following processes. In addition to the chemistry, testing of the steel is determined and coordinated throughout the whole process.” By virtue of its long and profound experience, BGH is a valued partner both in heat treatment issues and due to the advice it can give on materials science. Dr. Hippenstiel describes the interdependencies as they concern bevel gears: “Most steels, including case-hardened steels, are standardized, and their chemical composition and some essential technological properties are specified. The gearbox manufacturers then select an appropriate steel grade based on the component size. Steel with low alloy content is sufficient for small gears, steel with added chrome, nickel and molybdenum is absolutely essential for large bevel gears. But the steel selection according to general standard is not sufficient, the standard specifies lower and upper analysis in a band, but for complex applications the upper analysis are needed. BGH therefore produces special analysis variants for customers’ use, and these are later refined into a premium product with perfect further processing and heat treatment by BGH customer´s, including ATA.”
ATA Gears’ Sales Director Tami Komssi underlines that for ATA’s Gear Doctors it is not enough to know that something works, but also why its works. “For us, the key is to understand how gear design and geometry, selected material grade and determined carburizing data work together – not only at the engineer’s desk, but in real manufacturing conditions, too,” Tami Komssi declares.
Dr. Hippenstiel, Managing Director Production and Technology, BGH Edelstahlwerke GmbH
Sustainability is clearly a major issue in steel manufacture, too, and BGH has a proud tradition of sustainable production dating back to 1466. Dr. Hippenstiel describes the production process: “Secondary raw materials are used for steel production at BGH, and great importance is attached to the internal recycling of residual materials. The process development has set itself the goal of saving energy. For example, a heat treatment line for bar steel was recently developed, which only inductively reheats the forged bar steel for austenitizing on the surface. This means that CO2 emissions can be reduced by 70% compared to austenitizing in gas-fired furnaces.”
Dr. Hippenstiel firmly believes in the future of steel: “Steel is a wonderful sustainable material with a long history and a great future. There is no mobility, no security, no lifestyle and leisure, and no energy without steel.”
BGH is determined to stay at the forefront and continue as the best partner for companies using steel as an important raw material for their own products. Dr.Hippenstiel sums up the future mission of BGH: “BGH must further differentiate itself technologically from its competitors and further advance the topics of product and customer orientation. Resource efficiency also plays a major role in the future, if only to remain attractive to our successful customers in the changed market environment.”
At ATA Gears, we could not agree more.