• Microstructure characterization in the weld metals of HQ130 + QJ63 high strength steels

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      https://www.ias.ac.in/article/fulltext/boms/026/03/0295-0299

    • Keywords

       

      Microstructure characterization; high strength steel; weld metals.

    • Abstract

       

      Microstructural characterization of the weld metals of HQ130 + QJ63 high strength steels, welded under 80% Ar + 20% CO2 gas shielded metal arc welding and different weld heat inputs, was carried out by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The relative contents of acicular ferrite (AF) and pro-eutectic ferrites (PF) in the weld metals were evaluated by means of XQF-2000 micro-image analyser. The experimental results indicate that there is acicular ferrite in the grain and some pro-eutectic ferrite on the boundary of original austenite grains when the weld heat input is small (𝐸 = 9.6 kJ/cm), but the main microstructure is ferrite side plate (FSP) when the heat input is larger (𝐸 = 22.3 kJ/cm). So the weld heat input should be strictly controlled in the range 10 ∼ 20 kJ/cm and then the content of pro-eutectic ferrite is limited to $\lt$ 25%. Thus weld metals of HQ130 + QJ63 high strength steels with high toughness and excellent resistance to cracking can be ensured.

    • Author Affiliations

       

      Wang Juan1 Li Yajiang1

      1. Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University, Jinan 250061, P.R. China
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