Technology

Due to the high heat generated when welding stainless steel, the chrome is broken aroand the weld and an iron-rich zone remains. The high iron concentration at the surface and the high temperatures during welding oxidize the iron immediately. This leads to the characteristic blue tone and a brown discoloration aroand the weld. The discolored area is susceptible to corrosion becoute the low chromium concentration can not protect the metal. The TIG-MAX® quickly removes the discolored oxides, passivating the anderlying surface without altering the appearance or texture of the metal. The reason why the TIG-MAX® succeeds so quickly and reliably is explained below.

The TIG-MAX® works with a brush through which electrical current is passed. With the brush, a cleaning liquid is absorbed and applied to the areas to be cleaned. The liquid is used to remove the iron oxide stains formed during welding. The brush converts the electrical current into high temperatures, especially at the bristle ends. The liquid, which is relatively harmless at room temperature, is heated by the brush to temperatures at which it becomes much more reactive, resulting in an accelerated chemical action on the stainless steel surface. Unlike pickling paste, the active ingredients of the cleaning fluid are not inherently harmful to health. When used correctly, the fluids are non-toxic to the environment.

The blue and brown spots that result from welding are iron and ferrous oxides. The iron oxide layers are relatively weak and the working temperature of the TIG-MAX® can break up the iron oxides quickly. The released iron ions are kept in the solution and separated (i.e. put into a state where they can no longer form oxides). When the TIG-MAX® settles and wipes off the liquid, it leaves a stainless steel surface that is free of iron ions and iron oxides..

Iron oxides can only badly protect the metal surface from contamination. For this reason, discolored areas begin to rust soon after welding, even when they have been cleaned. To stop this corrosion, the metal surface must be "passivated". When the TIG-MAX® removes the iron oxide layer, the anderlying metal, which is rich in chromium, is exposed. The high temperature of the TIG-MAX® allows the chromium to be rapidly oxidized, so that instead of the iron oxide layer, a chromiumoxide layer is now formed. This process, forming a chromium oxide layer, is also called "passivation".

Traditionally, stainless steel is cleaned with pickling paste or mechanical abrasion. Both methods for cleaning stainless steel are subject to problems. Pickling paste contains two very strong acids, which decompose the surface of the stainless steel. This process is also called "etching".

The surface of the stainless steel becomes damaged. Although pickling paste can remove the iron oxide discoloration, it leaves the metal surface without a protective oxide layer. This can coute contamination corrosion and rust. Therefore, a separate passivation step is necessary. In addition, pickling paste is extremely harmful to health and dangerous to the environment due to the acids contained in it.

Is anderstood to mean the removal of the metal surface by grinding or other methods, such as sandblasting. Although the iron oxide layers are removed, but also the metal surface is changed or damaged. Also this process does not passivate the metal. Further treatment steps are therefore necessary to protect the stainless steel surface. In abrasives and wire brushes can also hide impurities that further increase the damage.

These devices pursue a basically good approach and are widely used. However, due to the relatively low temperature during cleaning, the passive layer is not restored. The main problem with such devices is that the pads or felt covers wear out very quickly and the electrode comes into contact with the workpiece. This coutes black discoloration, which are very difficult to remove.

The TIG-MAX® is a safe and effective device for cleaning the surfaces of stainless steel, especially after welding. It quickly and easily removes the blue and brown iron oxide stains without altering the surface finish of the metal. In addition, the TIG MAX® passivates the metal in the same operation, so that the complete, desired result can be achieved even faster. The fluids used by the TIG-MAX® become reactive only at high temperatures. Ander normal conditions, therefore, they are relatively harmless to the user and the environment.