Results of metallography researches of connections from steel of 40Х, soldered a copper in соляных baths and in a vacuum, showed that phase composition and properties of connections little depended on the size of assembling gap if he is within the limits of 0,0.0,1 mm and on the character near to the равновесному state «iron-copper». Structure 40Х became after soldering – coarse-grained ferrite+pearlite, and after normalization a structure is ground down and is – ferrite+pearlite. Conducting of heat treatment (normalization, tempering and high vacation) is instrumental in smoothing of structure 40Х became in fineneedled sorbitic троостит with microhardness 3170-3540 Mpa. At the same time heat treatment is instrumental 40Х became in decarbonating, the depth of decarbonization layer makes 60.70 mkm.
phase composition, microstructure of the soldered stitch, properties of connections, depth of decarbonization layer, microhardness, diffusive area