Pickling: An Overview of This Metal Treatment Process

Have you heard of the metal treatment process of pickling? When most people hear the word "pickle," they immediately think of the edible vinegar pickle of its namesake. However, pickling also refers to a metal treatment process performed by a manufacturing company.By reading this article,you will learn about pickling and how pickling can improve the physical properties of treated metal.

What is pickling?

Pickling is a metal treatment process that removes impurities from the metal surface.It's called "pickling" because it involves the use of an acidic solution called a pickling solution.The exact composition of the pickling solution depends on the type of metal being used.For mild steel,the pickling solution usually consists of hydrochloric or sulfuric acid.On the other hand, for high carbon steels,the pickling solution usually contains additional acids such as phosphoric and/or nitric.

Benefits of Pickling 

It is not uncommon for newly produced metal to have a layer of impurities on its surface.For example,hot rolled steel forms an oxide layer as it is processed.The presence of this oxide prevents the steel from obtaining a smooth and clean surface.Although there are various methods of removing oxides from steel, fabrication companies often prefer pickling because of its simplicity.When pickling, the acidic pickling solution eats away the oxide layer without harming or otherwise disturbing the underlying steel.Even if a piece of metal has no oxide on its surface,it may contain some impurities.It is not uncommon for newly produced metals to contain trace amounts of inorganic compounds such as metals.Depending on the intended application of the metal, these impurities may affect its properties.However,due to the acidity of the pickling solution, pickling can remove most impurities.

Basic steps of pickling

Pickling is performed by immersing the metal in a pickling solution.After machining a piece of metal, a manufacturing company dips it into an acid solution.The pickling solution then attacks any oxides or other impurities left on the metal surface.There are other methods of descaling and cleaning metal besides pickling.A smooth clean surface is an alternative treatment that offers similar benefits.With a smooth and clean surface,the metal is exposed to an abrasive compound that physically removes surface defects and impurities.There is also abrasive blasting,which involves blasting metal with a pressurized stream of abrasive solution to create a clean smooth surface.