For years, one question burned in the minds of fabricators: Can’t somebody create a stainless steel weld tint remover that simplifies the cleaning and restoration of stainless steel without damage to weld or base metal?
The welding of austenitic, mertensitic and ferriticstainless steel and the resultant damaged chromium oxide layer has long been a challenge for manufacturers. Aside from addressing aesthetics, the visible heat tint, removing this damaged layer (pickling) and restoring a healthy chromium oxide layer (passivating) is the only way to ensure the stainless steel part performs to its optimum potential. Chemical treatments have traditionally been based on using pickling and passivation products containing hydrofluoric (HF) or ammonium bifluoride (ABF) acids.
“With Praxair’s Elimitint P&P weld tint remover, fabricators benefit from pickling, neutralizing and stainless steel passivation in one product,” says Larry Cherne, Product Manager at Praxair. “It can be applied to the stainless steel surface by dipping, painting or spraying, requires only a water rinse for the fabricated piece when it’s done, it restores the corrosion resistance of the stainless steel.
Praxair’s Elimitint P&P weld tint remover does not contain hydrofluoric acid or ammonium bifluoride; instead, it employs low soluble salts. In the presence of chromium oxide, a select activator, the salts initiate the pickling process, which is in turn catalyzed by the increasing content of chromium III oxide that develops during the pickling process. In other words, the pickling is achieved using fluoride salts similar to the aluminum fluoride used in potable water treatment facilities. What’s more, Elimitint P&P weld tint remover can be left on stainless steel weldments as long as is needed – overnight or indefinitely – without fear of pitting, corrosion or thinning of the weld or base metal, which could result in premature failure in the field. Elimitint P&P weld tint remover also contains a small amount of nitric acid, which passivates the stainless steel concurrently with the pickling process.
Praxair is known for bringing innovative products to the market, including the ProStar “Smart” chemicals, which include the Elimitint P&P weld tint remover as well as the new DeBOND™ extreme paint and coatings remover, which provides blast- and grind-free paint removal, and the DeRUST™ FE rust remover, which only targets and removes iron oxides. These chemicals use “Smart” technology, enabling them to target specific problems such as chromium oxide, rust or iron oxide, or the bond between paint or coatings and their substrate. When these targeted items are depleted or broken down, ProStar “Smart” chemicals stop their action, which means they can be left on indefinitely without concerns for damage to substrates. Improve the productivity of your stainless steel fabricating process and eliminate the use of HF and ABF acids in your facility. Replace your chemical treatment products with a one-step solution – Elimitint P&P weld tint remover.
The ease and simplicity of application combined with the elimination of time constraints help fabricators structure the pickling and passivation process around fabricator needs, not the other way around.