Method and apparatus for the manufacture of welding electrodes
OwnerWerner A. Holmgreninventor
Life of this patent
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Abstract
In the method of manufacturing a continuous powder-filled tubular welding electrode, a strip of metal is initially shaped into an open channel and subsequently into a tube by abutting the edges of the strip. The edges are then welded to one another. The powder falls from a hopper into the tube which is fed downwards at the weld spot. The falling powder falls past the weld spot. The speed of the falling powder at the weld spot is higher than the speed of the tube, e.g., the speed of the falling powder is twice the speed of the tube. The powder which is subjected to the welding heat for a very short period of time fills the welded tube below the weld stop in step with the speed of the tube. Subsequently, a suitable reduction of the cross-sectional area of the powder-filled tube takes place.
Claims18
A method for the continuous manufacture of powder-filled tubular electrodes including the steps of:
- continuously feeding a metal strip at a predetermined speed;
- forming said metal strip into an open channel with edges extending longitudinally of the channel;
- forming a tube by abutting said edges;
- discharging a welding powder into the tube from a filling station;
- passing said tube through a welding station at which location the abutting edges are continuously welded to each other as the metal strip passes at said predetermined speed by heating said edges at a welding location;
- inserting said welding powder into the tube at some distance from said welding location;
- reducing the cross-sectional area of said welded and powder-filled tube to a desired dimension;
- the improvement comprising:
- feeding said metal strip downwards in the vicinity of said welding location at an angle to the horizontal plane which is greater than the limit sliding angle of said welding powder within said metal strip;
- causing said powder to fall into said tube such that said speed of said powder when passing said welding location on said metal strip is greater than said predetermined speed of said metal strip at said welding location;
- and
- introducing a shielding gas into said welded tube in an amount so that interspaces between said powder particles are substantially filled with said shielding gas.
An apparatus for continuous manufacture of a powder-filled tubular electrode including:
- first storing means for storing a metal strip;
- means for feeding said metal strip at a pre-determined speed from said first storing means, said feeding means being operatively associated with said first storing means;
- means for continuously forming said metal strip into an open channel with longitudinally extending edges and subsequently into a tube by abutting said longitudinal edges, said means for continuously forming said metal strip being operatively associated with said means for feeding said metal strip;
- a welding station for continuously welding said abutting edges to each other by heating said edges to welding temperature at the welding location thereby producing a welded tube, said welding station being operatively associated with said means for continuously forming said metal strip;
- second storing means for storing welding powder and being provided with a conduit for leading said welding powder to a nozzle means disposed for introduction of said welding powder, in operation, into said tube, said second storing means for storing said welding powder being operatively associated with said welding station;
- means for proportioning a desired amount of said welding powder per time unit, said means for proportioning being operatively associated with said second storing means;
- means for reducing the size of a cross-sectional area of said welded tube to a desired dimension, said means for reducing the size of said welded tube being operatively associated with said welding station;
- the improvement comprising:
- first guiding means being disposed to guide said metal strip in the vicinity of said welding station at an angle to the horizontal plane which is greater than the limit sliding angle of said welding powder, a falling path for said welding powder partly constituted by said metal strip formed into said open channel above said welding location on said metal strip substantially stationary with respect to said apparatus and said metal strip being formed into said welded tube below said welding location, said first guiding means being operatively associated with said welding station;
- and
- said falling path, in operation, extending between an upper level above said nozzle means and a lower level below said welding location, the distance between said upper level and said welding location being so great that said falling welding powder is accelerated at said welding location to a falling speed which is greater than the speed of said metal strip;
- and
- means for introducing a shielding gas into said welded tube, said means for introducing being operatively associated with said welding station, whereby interspaces between particles of said welding powder in said welded tube, during operation of said apparatus, are substantially filled with said shielding gas.
Dependencies are inferred from the claim text.