Results of investigations on development of high-efficient electrode and filler materials for welding and surfacing of copper and alloys on its base are considered. It is shown that increased requirements to quality of welded joints and deposited metal can be satisfied, primarily due to development of reliable welding consumables: electrode and filler wires, fluxes (fused and activating flux-pastes), as well as special coated electrodes. Arc welding and surfacing processes improved on their base provide the required level of thermophysical properties of welded joints, high strength and tightness of welds, reliable service durability in friction assemblies and corrosion media, etc. Effectiveness of new welding consumables is confirmed by their practical application in manufacture of welded crucible moulds of electrometallurgical furnaces, welding busbars, electrode holders, enlargement of hot-rolled coils for their further rolling, making various bimetal items by surfacing, etc. 10 Ref., 5 Tables. K e y w o r d s : arc welding and surfacing, copper and its alloys, electrode and filler wires, fluxes, coated electrodes, welded joints, thermophysical properties, quality

The paper gives the results of investigation of the influence of various kinds of alkali-silicate binder on adaptability to fabrication and welding properties of coated electrodes for tin bronze welding and surfacing. Both standard (sodium, potassium and mixed) and test lithium-containing liquid glasses were used during investigations. A procedure developed at PWI was used to determine plastic properties of electrode coating mixture and to assess the strength and hygroscopicity of electrode coatings. Studies of welding-technological and sanitary-hygienic properties of test electrodes were also performed. This resulted in selection of optimum kind of liquid glass, the most suitable for manufacture of coated electrodes for tin bronze welding and surfacing. 8 Ref., 4 Tables, 5 Figures.

P u b l i s h e d M o n t h l y Si n c e 2 0 0 0 English translation of the monthly « Avtomaticheskaya Svarka» ( Automatic Welding) j ournal published in Russian since 1948 ED I TOR I A L B OA R D Ed i t o r -i n -Ch i e f B . E. P a t o n Su b s c r i p t i o n s , issues per year, air postage and packaging included. B ack issues available.

It was shown that one of the efficient methods for producing bimetal product steel + high-tin bronze is submerged electric arc surfacing applying flux-cored wires. Analyzed were the causes for formation of different defects, which are possible in surfacing of bronze on steel. Considered were technological and metallurgical measures of eliminating porosity both on the deposited metal as well as along the fusion line of bronze with steel. To provide a minimum penetration of steel and reduction of iron content in bronze the process is performed using «split» electrode (two-electrode surfacing) at the optimum modes. The special attention is paid to study of causes for formation of intercrystalline penetrations of bronze into steel and their influence on quality of bimetal joint. The threshold value of energy input is determined at which the tendency to decrease the formation of intercrystalline penetrations is observed. 10 Ref., 2 Tables, 4 Figures. K e y w o r d s : high-tin bronze, submerged arc surfacing, bimetal joint, intercrystalline penetrations * Counterbody-steel St.45 (annealing-hardening) of HB 200-210.

Tin bronzes find wide application in machine-building, metallurgy and other branches of industry. They are used for manufacture of parts operating under conditions of increased wear resistance by casting method. Welding and surfacing processes are used for production, as well as elimination of pouring spoilage and repair of parts from tin bronzes. This review gives an analysis of existing developments in area of current technological processes of welding and surfacing of tin bronzes, as well as new electrode and filler materials for these purposes. The main difficulties were considered appearing during application of welding processes, namely high porosity susceptibility (copper alloys are more susceptible), formation of solidification cracks in welds and HAZ, tin liquation, that results in structure inhomogeneity, as well as high susceptibility to hot crack formation in deposited bronze metal or steel during bronze on steel surfacing. Described are the methods of welding and surfacing of cast tin bronzes, among which argon-arc welding, submerged-arc welding and manual coated-electrode arc welding are the most widespread. It is shown that wires and strips from wrought alloys used as electrode and filler materials do not provide the necessary chemical composition of the deposited metal. Development of special flux-cored wires and coated electrodes, providing optimized metal alloying and receiving of necessary properties, is preferable. For example, welding consumables, chemical composition and properties of which would correspond to the base metal, are necessary for welding and surfacing of cast tin bronzes (BrO10F1, BrO5Ts5S5). A conclusion was made based on performed analysis about necessity of development of new consumables (coated electrodes, flux-cored wires) for welding and surfacing of bronzes of critical designation. 40 Ref., 4 Tables. 1 Figure. K e y w o r d s : tin bronzes, electrode materials, methods of welding and surfacing, metallurgical peculiarities