The Paton Welding Journal, 2015, №07



2015 №07 (09)

DOI of Article 10.15407/tpwj2015.07.01

2015 №07 (02)

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The Paton Welding Journal, 2015, #7, 3-9 pages
 

Vacuum diffusion welding of stainless steel through porous nickel interlayers

A.I. Ustinov, Yu.V. Falchenko, T.V. Melnichenko, L.V. Petrushinets, K.V. Lyapina And A.E. Shishkin

E.O. Paton Electric Welding Institute, NASU. 11 Bozhenko Str., 03680, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
 
Abstract
Features of formation of permanent joints by diffusion welding through an intermediate interlayer based on porous nickel, produced by vapour phase vacuum deposition (EB PVD) were studied in the case of stainless steel Kh18N10T. It is shown that application of vacuum porous nickel condensates promotes lowering of temperature-force parameters of diffusion welding (welding temperature of 800 °C + cyclic load with 20 MPa amplitude). Such an influence of the interlayer on the conditions of producing the welded joints is associated with superplastic behaviour of porous nickel and its non-equilibrium structure (small grain size and presence of vacancy type defects). It is established that pore healing in the interlayer is observed and diffusion processes between the interlayer and stainless steel are activated during diffusion welding. This results in formation of a defectfree zone of the joint based on nickel, alloyed with iron and chromium with strength properties only slightly different from those of base metal. 18 Ref., 6 Figures.
 
Keywords: diffusion welding, stainless steel, intermediate layer, porous nickel interlayer, temperature-force parameter, foil deformation behaviour
 
 
Received:                23.03.15
Published:               13.10.15
 
 
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