VACUUM DIFFUSION WELDING METHOD FOR MULTI-LAYERED ITEMS MADE FROM HETEROGENEOUS STAINLESS STEELS Russian patent published in 2010 - IPC B23K20/14 

FIELD: metallurgy.

SUBSTANCE: invention can be used for welding of multi-layered items consisting of martensitic steels of 12X13 type and having magnetic properties, and austenitic steels of X18H10T type, which are not susceptible to magnetisation, namely for welding of housings of magnetic conductors of step motors. In order to decrease the creep value of layers from martensitic steel, diffusion welding is carried out in two steps: First, welded surfaces are heated to the temperature of not more than 700°C; after that they are compressed with force of more than 2 kgf/mm² and kept in such state for not less than 15 minutes. At the second step compression force is decreased to the value of less than 0.1 kgf/mm², and heating temperature of welded surfaces is increased up to 1050-1100°C, and they are kept at this temperature for not less than 15 minutes. In order to accelerate diffusion processes, welded surfaces of workpieces from martensitic steels are covered before welding with galvanic nickel layer with thickness of not less than 1.5 mcm.

EFFECT: method provides obtaining of welded joints equal in strength at manufacture of multi-layered items and at maintaining the axial size of each layer.

2 cl, 1 dwg