| 2007 №09 (01) | 2007 №09 (03) |
The Paton Welding Journal, 2007, #9, 6-10 pages
Phase and structural transformations in welding and arc treatment of 30KhGSA steel joints
V.M. Kulik, V.G. Vasiliev, G.M. Grigorenko, M.M. Savitsky, L.K. Doroshenko
E.O. Paton Electric Welding Institute of the NASU. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine.Abstract
Considered are structural changes in weld metal of 30KhGS type on high-strength steel joints occurring in welding and arc treatment. Under these conditions austenite transformation of hardened metal of the joint occurs at temperatures close to A1 and A3 of steel in as-delivered state. Subsequent cooling provides recovery of the hardening structure. Short-time heating in the intercritical temperature range causes formation of a substantial amount of temper ferrite and reduction of the amount of martensite formed during subsequent cooling at the expense of increase of the ferrite and bainite components. This leads to the highest decrease in hardness and increase in impact toughness of the metal. This improvement of properties and increase in crack resistance of the welded joints takes place after short-time heating to tempering temperatures.
Keywords: arc welding, high-strength steel, heat-affected zone, arc treatment, heating, cooling, dylatometry, differential thermal analysis, hardness, impact toughness, delayed cracking
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