Friction Stir Processing of Cast Iron Using Cermet Tool

• Published in: Advanced Materials Research Vol. 1088; pp. 124 - 129
• Main Authors: Hosokawa, Hiroyuki, Mizutani, Yoshiki
• Format: Journal Article
• Language: English
• Published: Zurich Trans Tech Publications Ltd 10.02.2015
• Subjects: Cast iron; Cemented carbides; Cermets; Cobalt; Friction stir processing; Oxides; Pearlite; Tungsten carbide; Friction Stir Processing; High-Temperature Oxidation Resistance; Surface Hardening; Cermet; Abrasion Resistance
• ISBN: 3038354023; 9783038354024
• ISSN: 1022-6680; 1662-8985; 1662-8985
• DOI: 10.4028/www.scientific.net/AMR.1088.124

With the aim of developing a durable tool for friction stir processing (FSP) of cast iron, the durability of a Ti (C,N)-Ni cermet tool has been investigated and compared with that of a WC-Co cemented carbide tool. Results of exposure tests in air revealed that the WC-Co cemented carbide sample oxidized rapidly above 973 K, whereas the cermet material showed little oxidization even after holding at a temperature of 1103 K. When these tools were used for the FSP of cast iron surfaces, it was found that an oxide layer of over 100 μm was generated on the lateral faces of the WC-Co cemented carbide tool after it was used to work a length of 400 mm. In contrast, a thin oxide layer of only 5 μm was generated after the cermet tool worked a length of 2400 mm. Cross sections of the iron casts (FC250) subject to FSP using these tools showed that in a bowl-shaped region approximately 1.5 mm deep the initial pearlite structures changed to martensite structures. The martensite structures in this region had a Vickers hardness of 600 to 800 HV, while that of the initial pearlite structure was about 280 HV.