SU71419A1 - The method of automatic welding under a layer of flux - Google Patents

Description

Electric arc welding of high-strength steels often gives poor results — cracks in the cladding and in the heat-affected zone. Preheating and subsequent slow cooling of the welded areas significantly reduces and even eliminates the formation of cracks.

For preheating the base metal and subsequent slow cooling, as well as to reduce shrinkage stresses in the weld during automatic electric welding under the granular flux of the proposed method, the flux poured into the groove of the weld is preheated to red heat.

Flux preheating improves arc stability and completely removes moisture from the flux, eliminating one of the reasons for the formation of pores and cracks in the weld. At the same time, the fusibility increases and the viscosity of the slag decreases and thus the refining and finally the alloying

the effect of flux on the weld metal.

When heated, the flux uses its heat content;

a) for preheating the base metal locally;

b) to slow down the cooling of the weld metal and improve the conditions for the emission of gases from it;

c) to reduce the hardness of the heat affected zone;

d) to reduce structural stresses in the weld.

The use of preheated flux is as follows.

A layer (not less than 40 mm thick) of the granulated flux heated to 500-800 ° C is pre-poured on the welded area, and then welded. At the end of welding, the flux is retained on the weld and removed after cooling to a temperature below 80 ° C.

The flux can be heated in a furnace of one type or another, in crucibles or on the bottom of the furnace, or electrically heated in lined

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