Possible problems with the Electrical Resistance Welding

Possible problems with the Electrical Resistance Welding

In electrical resistance welding of tinplate containers, several problems can arise, including:

The removal of tin from the welded area that covers the steel, which can leave the area unprotected both internally and externally against chemical attacks, and may cause corrosion and attacks that compromise the tightness of the container.

The appearance of rust stains due to electrochemical corrosion, which may render the product unmarketable.

The formation of zones of different potential that cause corrosion, caused by various heterogeneities such as different concentrations of the electrolyte, different composition of the metal, differential aeration, galvanic couples and chemical compounds.

Ejections and projections of metal outside the weld, which represent exposed metal and a serious defect, especially for beverage containers.

The presence of oxygen during welding can cause oxidation, affecting the adhesion of the weld protection varnish.

Mechanical problems such as incorrect adjustment of the welding frequency, irregular wire profiling, poor condition of the idler pulleys, and poor alignment of the sheaves can result in a weak or defective weld.

Dust contamination in the surrounding area and in the rest of the container, which can affect the quality of the welding and the adhesion of the protective coating.

Poor grinding of the channel that guides the welding wire can cause a weak or marked weld, which can be damaged in the subsequent flanging, necking or closing processes.

These are some of the issues that can affect the quality and integrity of electric resistance welding on tinplate containers. It is important to take measures to prevent these problems and ensure the quality of the weld.