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Volume 18 - Friction, Lubrication, and Wear Technology Part 23

Tham khảo tài liệu 'volume 18 - friction, lubrication, and wear technology part 23', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 1 1 ni Fig. 11 Examples of laser-clad microstructures. a Tribaloy T-800 alloy on ASTM A 387 steel. b Haynes Stellite alloy No. 1 on AISI 4815 steel. Source Ref 33 The Fe-Cr-Mn-C cladding of Mazumder and Singh Ref 41 had a microstructural consisting of M7C3 and M6C type carbides in a ferritic matrix a solid solubility extension of chromium in ferrite by 50 and a microhardness of 550 HV. The molybdenum-clad coating on gray iron of Belmondo and Castagna Ref 42 consisted of molybdenum dendrites surrounded by a Cr-Ni matrix containing Cr2C3 which had a microhardness of 900 HV. Wear Behavior of Laser-Clad Layers. Mazumder and Singh Ref 41 found that the Fe-Cr-Mn-C cladding on AISI 1016 steel resulted in tribological properties that were superior to Stellite 6. The width of the wear scar was reduced from 3.5 mm 0.14 in. in the base alloy to about 0.6 mm 0.02 in. in the laser cladding. Under the same test conditions Stellite 6 a common hardfacing alloy developed a wear scar which of 1.4 mm 0.06 in. . Abbas et al. Ref 43 laser clad a mild steel with Stellite 6 Alloy 4815 and their composites with SiC by using pneumatic powder delivery. Wear tests conducted by grinding the samples against a revolving alumina disk showed that the composite clad samples had the best abrasive wear resistance Fig. 12 . Fig. 12 Abrasive wear behavior of mild steel laser clad with Stellite 6 Stellite 6 SiC and Alloy 4815 SiC. Source Ref 43 Belmondo and Castagna Ref 42 performed wear tests on the Mo-Cr2C3 clad cast iron samples using a reciprocating motion testing machine. When compared with plasma-sprayed coatings of similar composition the performance of laserclad coatings was far superior under all testing conditions especially at the highest pressures. With a load of 25 MPa 3.6 ksi and slider roughness of 0.3 . - m 12 in. the wear loss in the laser sample was 0.4 mg 1.4 X 10-5 oz compared to 1.3 mg 4.6 X 10-5 oz in the plasma-sprayed sample. In addition the plasma-sprayed coating developed .