Effect of Si and Al on microstructure-property-relationship of Q&P-steels during galvannealing. Issue 2 (22nd January 2021)

• Record Type: Journal Article
• Authors: Wallner, M.; Schneider, R.; Steineder, K.; Sommitsch, C.
• Is Part Of: Materials science and technology. Volume 37:Issue 2(2021)
• Page Start: 182
• Page End: 189
• Publication Date: 2021-01-22
• Subjects: Quenching & partitioning -- galvannealing -- retained austenite -- austenite decomposition -- carbide precipitation -- thermal stability -- martensite tempering -- mechanical properties; Materials science -- Periodicals; Microstructure -- Periodicals; Metallurgy -- Periodicals; 620.1105
• DOI: 10.1080/02670836.2021.1882754
• Languages: English
• ISSNs: 0267-0836

Abstract

Abstract : The influence of a thermal-treatment simulating a galvannealing-process (GA) on the microstructure of a 0.2C–4Mn–1.5Si and 0.2C–4Mn–1.5Al (in wt-%) medium-Mn-Q&P-steel was investigated in detail using dilatometry. After Q&P-process, the retained austenite (RA) fraction is higher and mechanical properties are superior for the Si-concept. Owing to galvannealing, strength decreases substantial for both concepts. For the Si-concept however, RA starts to decompose into pearlite upon galvannealing temperatures of 520°C, leading to a significant decrease in elongation. For the Al-concept, the RA-fraction remains constant up to 560°C, which even results in increased elongations values compared to the galvannealed Si concept. This contribution shows that Al as an alloy-element in Q&P-steel is more suitable for RA stabilisation at higher temperature than Si.