Effect of post weld heat treatment on the wear resistance of hardfacing martensitic steel

AGUSTÍN GUALCO, HERNÁN G. SVOBODA, ESTELA S. SURIAN, LUIS A. DE VEDIA

SOLDAGEM E INSPEçãO

Asociacao Brasileira da Soldagem

Lugar: San Pablo; Año: 2008 vol. 13 p. 236 - 243

0104-9224

The effect of different post weld heat treatments on microstructure and wear resistance of martensitic deposits was studied. The deposit was welded using a metal-cored tubular wire, in the flat welding position, on 375x75x19 mm SAE 1010 plate, using 97,5 % Ar – 2,5 % CO2 shielding gas mixture and with an average heat input of 2,8 kJ/mm. The samples were heat treated at temperatures between 500 to 680ºC for two hours. Chemical composition, Vickers microhardness and wear properties with AMSLER tests in a sliding condition, were determined. In the as welded condition the microstructure was principally composed by martensite and retained austenite. Significant variations in wear resistance and hardness were measured for different tempering temperatures. For the different heat treated conditions, it was observed decomposition of retained austenite to martensite and carbide precipitation associated to the tempering of martensite. A secondary hardness effect was detected with maximum hardness of 710 HV for 550ºC heat treatment temperature. For this condition the best performance in wear test was obtained. Wear rates for the different conditions were obtained and mathematical expressions were developed. For each case wear mechanisms were analyzed.