Continuous Cooling Transformation Diagrams of HT-60 High Strength Steels for Welding

• Published in: JOURNAL OF THE JAPAN WELDING SOCIETY Vol. 31; no. 2; pp. 111 - 120
• Main Authors: Bada, Toyoaki, Uta, Masahiro, Inagaki, Michio
• Format: Journal Article
• Language: Japanese
• Published: JAPAN WELDING SOCIETY 1962
• ISSN: 0021-4787; 1883-7204
• DOI: 10.2207/qjjws1943.31.111

1) Continuous cooling transformation diagrams are constructed for six kinds of HT-60 strength steels, (four normalized steels, two heat-treated steels) by using the new apparatuses which can automatically reproduce any weld thermal cycle (maximum heating temperature 1350°C). 2) The critical cooling time C'f derived from those CCT diagrams, i. e. the critical cooling time with regard to the first emergence of proeutictiod ferrite, is obtaind as follows, steel S6 : 1.8 sec, S5 : 2.9 sec, S1 : 3.2 sec, S3 : 4.2 sec, S2 : 0.8 sec, S4 : 7.4 sec. 3) It should be mentioned that the judgement of weldability with value of C'f is in good accord with the result of other weldability tests, i. e. the hardness test with taper specimen, the bead bend ductility test, the maximum hardness test in H.A.Z. and the synthetic H.A.Z. ductility test, The value of C'f is considered on important factor of weldability for ductility of weld heat affect zone and weld cracking susceptibility.