Phosphorus and Boron Segregation at Prior Austenite Grain Boundaries in Low-alloyed Steel

• Published in: ISIJ International Vol. 42; no. 6; pp. 676 - 678
• Main Authors: Suzuki, S., Tanino, M., Waseda, Y.
• Format: Journal Article
• Language: English
• Published: Tokyo The Iron and Steel Institute of Japan 01.01.2002; Iron and Steel Institute of Japan
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Metals. Metallurgy; Physics; Solid solution hardening, precipitation hardening, and dispersion hardening; aging; Solid solution, precipitation, and dispersion hardening; aging; Treatment of materials and its effects on microstructure and properties; Grain boundaries; Boron; Reviews; Segregation; Austenite; Phosphorus; Low alloy steels; Steels; Temper brittleness; Microstructure; Heat treatments
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.42.676

Grain boundary segregation of metalloid impurity elements such as phosphorus and antimony is known to induce temper embrittlement of low-alloyed steels. Fracture in temper embrittlement takes place mainly along prior austenite grain boundaries, which are formed in austenite at high temperatures and remain in the martensite or ferrite/pearlite microstructure after phase transformation. Numerous studies on segregation at prior austenite grain boundaries have been performed, and these results suggest that metalloid impurity elements are segregated at prior austenite grain boundaries in low-alloyed steels. In order to reveal grain boundary segregation of impurity elements, segregation at grain boundaries in ferritic iron and steel has also been characterized. Grain boundary segregation of phosphorus and boron are focused in this work. The microstructure in the center part of samples in which austenite was decomposed was observed by a conventional optical microscope. Vickers hardness was also measured to evaluate mechanical properties of the samples.