The sulfur content of steel as a determining factor in cutting processes.
Biermann, D.1, a; Weinert, K.1, b; Felderhoff, F.1, c; Heilmann, M.1, d
- 1)
- Institut für Spanende Fertigung, Technische Universität Dortmund, Baroper Str. 301, 44227 Dortmund
a) biermann@isf.de; b) weinert@isf.de; c) felderhoff@isf.de; d) heilmann@isf.de
Kurzfassung
Besides the alloying elements, undesired impurities are responsible for workpiece quality and the machining characteristics of steel grades to a considerable degree. Concerning material properties, sulfur is such an undesired impurity, because of its influence on the physical and, in particular, the mechanical properties of steel grades. High sulfur content reduces fatigue strength and fracture toughness. Nevertheless, the machining characteristics are affected positively by high sulfur content. Tool wear is reduced and chip breaking is more favorable. Manganese sulfides in the microstructure lead to a lubricating effect in the machining process. Since the highest mechanical requirements must be met, the sulfur content of high-grade structural steels, such as case-hardening steels or heat-treated steels, must be reduced. High-grade structural steels with minimal sulfur content have acquired great importance in the automotive industry, in particular for engine parts and gear components like diesel injection pumps and gear shafts. In the context of this research, the machining of high-grade structural steels with high and minimal sulfur content is analyzed. The differences and similarities resulting from the different sulfur content are consequently compared in detail. The manufacturing processes turning and deep hole drilling with twist drills and single-lip drills are examined. The results show the influence of the sulfur content of stee grades on machining processes. Based on this knowledge of the machining process, the machining of steels with minimal sulfur content was optimized by adapting tool design, tool coating and cutting material, because the sulfur content of steels is only one determining factor in the complex system 'cutting process'.
Schlüsselwörter
Edelbaustahl, Schwefelgehalt, Drehen, Tiefbohren, Einlippenbohrer, Wendelbohrer, Spanbildung
Veröffentlichung
In: SCT, International Conference on Steels in Cars and Trucks, 2008, S. 212-219