Weld cleaning | Tuesday, 28 May 2019

What is pickling and why is it dangerous?

Various treatment methods are employed on stainless steel to restore its corrosion resistance following operations such as cutting and welding.

One of the most common methods is chemical pickling, which mainly involves the use of a special mixture sometimes referred to as the pickling paste.

 Chemical pickling is, without a doubt, an effective weld cleaning method. However, it comes at a price – one you should never be willing to pay.

Namely, the pickling paste commonly contains two strong acidic solutions – nitric and hydrofluoric acids. They are both quite hazardous and can pose a serious threat to your health and safety.

When pickling is not carried out in the right way, it also represents a huge risk to the natural environment through air pollution and the destruction of greenery.

Chemical Pickling

Considerations for Human Health and the Environment

As established above, pickling paste is dangerous to both the human body and the environment.

But just how dangerous?

  • The hydrofluoric and nitric acids in the pickling solution are dangerously corrosive chemicals that have the ability to cause grave skin injuries, namely serious skin burns. In addition to that, if you breathe in the acidic vapor released from the pickling paste, you may suffer from breathing difficulties and a sore throat. These acidic vapors usually exude a pungent and irritating odor.
  • The hydrofluoric acid inside the pickling solution is in a diluted state. However, this does not prevent the acid from causing substantial damage. The diluted form of the acid is enough to turn the entire mixture poisonous. Poisoning can occur if you inhale a considerable amount of the vapor released by the material. When it comes into contact with the skin, serious burns will appear in patches on your skin.
  • As a matter of fact, hydrofluoric acid has the penetrating ability to pierce the skin and react with the calcium in the blood or the bone. If this happens, then you will be in need of emergency medical treatment. Washing the acid off with water will be of very little help. If such a situation ever arises, one has to apply a special ointment on the affected area. This is an HF ointment that contains calcium gluconate, a compound that binds the fluoride and helps in damage limitation.
  • The pickling process also produces heaps of waste in the form of rinsing water and exhausted pickling solutions. The waste comprises nitric acid, hydrofluoric acid, and heavy metal remnants. As a result, waste is considered hazardous.

Electrochemical Weld Cleaning - A Safe Alternative

Electrochemical weld cleaning is a relatively new weld cleaning method and is considered a much safer alternative to chemical pickling.

Its effectiveness derives from carefully developed weld cleaning fluids that, in combination with electricity, renew the protective layer of stainless steel and thereby prevent future corrosion.

Unlike chemical pickling, the electrochemical process is not associated with the aforementioned negative effects on human health and the environment.

Watch the video below to learn more about the differences between weld cleaning fluids and dangerous pickling acids.

When properly performed, electrolytic weld cleaning is also much faster than chemical pickling.

Tom, one of our experts, has compared the two methods and measured how much time they need to eliminate corrosion on TIG-welded stainless steel plates.

See the results of the test in the video below.

In addition to greater efficiency, electrochemical weld cleaning has not only eradicated the contamination but also (re)passivated the surface of the steel.

What Cougartron can do for you?

Cougartron equipment is built for fast and effective weld cleaning and surface passivation. But above all, they are engineered to provide a safer working environment for you and your team.

Cougartron weld cleaners are strong enough to eliminate all types of contamination from your stainless steel welds including rust, discoloration, weld burns, and cross-contamination.

Our product range includes machines designed to meet various production needs. Click here to see our full selection of weld cleaning machines.

Further reading:

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