International Scientific-Technical and Production Journal December 2009 # 12 English translation of the monthly «Avtomaticheskaya Svarka» (Automatic Welding) journal published in Russian since 1948 Founders: E.O. Paton Electric Welding Institute of the NAS of Ukraine Publisher: International Association «Welding» International Association «Welding» Editor-in-Chief B.E.Paton CONTENTS Editorial board: Yu.S.Borisov V.F.Khorunov SCIENTIFIC AND TECHNICAL A.Ya.Ishchenko I.V.Krivtsun B.V.Khitrovskaya L.M.Lobanov Makhnenko V.I., Poznyakov V.D., Velikoivanenko E.A., V.I.Kirian A.A.Mazur S.I.Kuchuk-Yatsenko Makhnenko O.V., Rozynka G.F. and Pivtorak N.I. Risk of cold Yu.N.Lankin I.K.Pokhodnya cracking in welding of structural high-strength steels ............................ 2 V.N.Lipodaev V.D.Poznyakov V.I.Makhnenko K.A.Yushchenko Gorban V.F., Kharchenko G.K., Falchenko Yu.V. and O.K.Nazarenko A.T.Zelnichenko I.A.Ryabtsev Petrushinets L.V. Investigation of joints of titanium aluminide with titanium alloy VT8 produced by diffusion welding ........................... 7 Sabokar V.K., Akhonin S.V., Petrichenko I.K. and Yasinsky A.V. Pressure welding of titanium aluminide to other titanium alloys ............ 10 International editorial council: N.P.Alyoshin (Russia) U.Diltey (Germany) INDUSTRIAL Guan Qiao (China) D. von Hofe (Germany) Welding and Cutting 2009. Essen, Germany, 14--19 V.I.Lysak (Russia) September 2009 ................................................................................. 13 N.I.Nikiforov (Russia) B.E.Paton (Ukraine) Shelyagin V.D., Khaskin V.Yu., Mashin V.S., Pashulya M.P., Ya.Pilarczyk (Poland) P.Seyffarth (Germany) Bernatsky A.V. and Siora A.V. Features of laser-MIG welding G.A.Turichin (Russia) of high-strength aluminium alloys ........................................................ 21 Zhang Yanmin (China) A.S.Zubchenko (Russia) Zelenin V.I., Kavunenko P.M., Tisenkov V.V., Teplyuk V.M., Poleshchuk M.A., Lebed V.D., Lipisy V.I., Bondarev S.V., Promotion group: V.N.Lipodaev, V.I.Lokteva Gavrilov S.A., Olgard N.T. and Cheburov S.A. Application of A.T.Zelnichenko (exec. director) plasma-arc metallisation for restoration of wheel pairs ......................... 28 Translators: A.A.Fomin, O.S.Kurochko, Tsaryuk A.K., Ivanenko V.D., Volkov V.V., Mazur S.I., I.N.Kutianova, T.K.Vasilenko PE «Melnik A.M.» Trojnyak A.A., Vavilov A.V., Kantor A.G. and Volichenko N.P. Editor Repair welding of turbine case parts from heat-resistant steels N.A.Dmitrieva Electron galley: without subsequent heat treatment ..................................................... 32 I.S.Batasheva, T.Yu.Snegiryova BRIEF INFORMATION Address: Lankin Yu.N. and Sushy L.F. Electrical conductivity of slag E.O. 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International Scientific and Technical Conference «Problems This publication and each of the articles of Welding, Related Processes and Technologies» ............................... 46 contained herein are protected by copyright. Permission to reproduce material contained in International Conference «High Mat Tech» ........................................... 48 this journal must be obtained in writing from the Publisher. Index of articles for TPWJ’2009, Nos. 1--12 ......................................... 49 Copies of individual articles may be obtained from the Publisher. List of authors ..................................................................................... 53 © PWI, International Association «Welding», 2009 RISK OF COLD CRACKING IN WELDING OF STRUCTURAL HIGH-STRENGTH STEELS V.I. MAKHNENKO, V.D. POZNYAKOV, E.A. VELIKOIVANENKO, O.V. MAKHNENKO, G.F. ROZYNKA and N.I. PIVTORAK E.O. Paton Electric Welding Institute, NASU, Kiev, Ukraine Mathematical model of the risk of cold cracking in welding of structural high-strength steels is considered. The model is based on distributed data on the state of microstructure, content of diffusible hydrogen and stressed state in elementary volumes within the welded joint zone. It is shown that the model makes it possible to more precisely evaluate the local conditions of cold cracking on the basis of the above parameters. Keywords: arc welding, low-alloy high-strength steels, the zones with high tensile stresses have a purely bain- brittle fracture, cold cracks, diffusible hydrogen, microstruc- ture, stressed state, probability model itic microstructure and low level of diffusible hydro- gen, i.e. they are not potential centers of cold cracks. It is a known fact that the presence of quench struc- In other words, the proper, physically substantiated tures, diffusible hydrogen and tensile stresses [1] are criteria that quantitatively connect, on the level of conditions that induce cold (hydrogen) cracks in weld- the distributed parameters, the necessary conditions ing of structural steels. As to the quantitative char- for cold cracking to occur in welding heating of struc- acteristics of the specified conditions, at present it is tural steels under consideration, are required. possible just to approximately evaluate critical values An approach for development of such criteria, of the corresponding characteristics, allowing for lo- based on the following factors, is given below: cality of cold cracking processes, presence of a signifi- · probability assessment of the risk of cold cracking cant gradient of changes of these characteristics in a is performed in a specified area of a welded joint zone of welding heating, their strong mutual effect (certain region of the fusion zone or HAZ); and other factors, by limiting their extreme demon- · initiation and propagation of cold cracks take strations with almost no account for their mutual ef- place by the brittle fracture mechanism, i.e. deter- fects. Meanwhile, development of the methods (ex- mined by correspondent normal stresses sjj(x, y, z) perimental and calculation) for determination of dis- at a point with coordinates x, y, z, acting in an area tributed parameters of the above characteristics in with normal j and corresponding characteristic of re- welding of different joints on structural steels, as well sistance of a material, Aj(x, y, z), to brittle fracture as the trends to optimization of the techniques to pre- formation. vent cold cracks require development of more precise Àj is a function of microstructural state and content criteria of the risk of their formation. of diffusion hydrogen for a given steel. It can be shown that many recent approaches [1] The probability of brittle fracture in specific volu- based on such integral characteristics as carbon me V, in compliance with the Weibull theory, is de- equivalent in the HAZ [1], content of hydrogen in termined by dependence filler metal, degree of restraint and thicknesses being h é æ ö ù welded, used as the quantitative conditions for micro- ê çsjj -- Aj÷ ú P (V) = 1 -- exp ê-- ç ÷ dV/V ú, (s > A ). (1) structure, diffusible hydrogen and effective stresses j ò ç ÷ 0 jj j ê è Bj ø ú are of a very general character. They are far from ë V û providing an ambiguous determination of the quanti- In (1), integration is carried out only with respect tative characteristics of the conditions causing cold to elementary volumes dV, where sjj > Aj, and Aj, h cracking at certain parameters of welding heating. It 1/h and BjV0 are the Weibull distribution__ parameters. has been proved in recent decades, due to the devel- As a rule, h = 4.0, and A and B = B V1/h are deter- opment of the «Sysweld» and other types of computer j j j 0 mined experimentally. systems, which help to obtain the calculation infor- __ mation on the distributed characteristics in the weld The values of Bj depend on the size of the volume and HAZ metals regarding the cold cracking condi- V along the section with normal j (Figure 1). If tions, that zones of potential cold cracks do not always stresses sjj and material resistance Aj in length lj of have the most extreme combinations of volumes of this volume change but slightly, then a change of quench microstructures, content of diffusible hydro- dV = ljdF can be made in integral of expression (1), gen and level of tensile stresses. Often the zones with where F is the cross-section area of volume V. a maximum volume of martensite and content of dif- Accordingly, the following will be obtained in- fusible hydrogen are within the compressive zones, or stead of (1): © V.I. MAKHNENKO, V.D. POZNYAKOV, E.A. VELIKOIVANENKO, O.V. MAKHNENKO, G.F. ROZYNKA and N.I. PIVTORAK, 2009 2 12/2009 Figure 1. Schematic of cold cracking in fusion zone (FZ) and Figure 2. Schematic of root weld with longitudinal (1) and trans- heat-affected zone (HAZ): 1 ---- longitudinal crack with normal y; verse (2, 3) cracks in welding sample (4) d thick and 2L wide, 2---- transverse crack with normal x; 3 ---- underbead crack with fixed with side fillet welds to plate (5) dp > > d thick normal z (longitudinal) Application of the described approach for descrip- h é æ ö ù tion of cold cracking conditions in welding of the butt ê çsjj -- Aj ÷ ú (2) Pj = 1 -- exp ê--ò ç -- ÷ dFú. weld root pass in a typical welding sample of steel ê çB /l1/h÷ ú ë F è j j ø û 14KhG2SAFD with thickness d = 18 mm thick is shown below (Figure 2). The CCT diagram is also From which given below (Figure 3). Arc welding with ANP-10 æ ö1/h electrodes was used for that.