Fractography and Porosity Analysis of Cr and Cr-Mo PM Steels

Archives of Metallurgy and Materials

卷:61

Lichańska E.¹  Sułowski M.¹  Radziszewska A.¹  Kulecki P.¹ 

[1] AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, Al. Mickiewicza 30, 30-059 Kraków, Poland;

关键词: sintered steels;    alloying elements;    porosity;    fractography;    mechanical properties;   

DOI  :  10.1515/amm-2016-0263

来源: DOAJ

【 摘 要 】

The aim of the study was to evaluate the effect of processing variables on the porosity and fractography of Cr and Cr-Mo PM steels. The measurements were performed on sintered steels made from commercial Höganäs pre-alloyed powders: Astaloy CrA, Astaloy CrL and Astaloy CrM with two different carbon concentrations (0.2% and 0.6%) added in the form of ultra fine graphite powder grade C-UF. Following mixing in Turbula mixer for 30 minutes, green compacts were single-action pressed at 660 MPa according to PN-EN ISO 2740 standard. Sintering was carried out in a laboratory horizontal tube furnace at 1120°C and 1250°C for 60 minutes, in an atmosphere containing 5%H2 and 95%N2. After sintering, the samples were tempered at 200°C for 60 minutes in air. For porosity evaluation computer software was employed. Hitachi S-3500M SEM equipped with EDS (made by Noran) was employed for fracture analysis. The steel based on Astaloy CrM pre-alloyed powder is characterized by fine pores and good mechanical properties. When sintered at 1250°C, it had area of pores approx. 7.12 μm2, ultimate tensile strength (UTS) about 679 MPa and elongation about 4%. The steels were characterized by ductile/cleavage and ductile fractures.

【 授权许可】

Unknown