EVALUATION OF FAILURE MECHANISMS OF CERAMICS AND COATED CARBIDES USED FOR MACHINING STAINLESS STEELS

Author: Dearnley P. A.   Thompson V.  

Publisher: Maney Publishing

ISSN: 1743-2944

Source: Surface Engineering, Vol.2, Iss.3, 1986-01, pp. : 191-202

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Abstract

It is generally agreed by the manufacturing sector that stainless steels are among the. most difficult materials to machine, since they severely limit tool life. In the present study the failure mechanisms of ceramic and coated carbide cutting tool materials used for turning austenitic and martensitic stainless steels were investigated. In several cases the life of coated carbides was prematurely curtailed by tearing and/or fracture of the coating, which lead to localized spalling. However, in situations where the coatings were evenly worn TiN–Ti(C, N) appeared to be the best coating, while Al2O3 was the worst. At a cutting speed of 350 m min −1, coated carbide life was limited by rapid wear and plastic deformation of the cutting edge. Under these conditions Al2O3 based ceramic tools offered the most potential, often lasting 5-10 times longer than coated carbides.