What is Pickling of Stainless Steel?
Since humans first began using iron for infrastructure and technology, they have encountered several issues, such as rusting, gradually weakening the metal, and lowering its durability and valley for money. However, the tables have turned since stainless steel, and its corrosion resistance properties have come into play. Like steel itself, stainless steel is an alloy. An alloy is always made up of various components. In non-corrosive stainless steel, chrome is one of the most commonly used alloying elements. Nickel, molybdenum, and other metals are also sometimes employed for specific purposes. When chromium is added to stainless steel, a passive layer is formed that aids in the steel’s use, which is mostly due to its capacity to operate in moist settings without rusting. Whether it is used in the making of surgical and dental equipment in medical technology, the construction of aircraft, the manufacturing of kitchen appliances, utensils, and cutlery in the food and catering industry, or the manufacture of road tankers and shipping containers in the automotive and transportation industries, stainless steel is used everywhere.
How the process takes place
Despite the fact that humans have produced steel for hundreds of years, stainless steel is relatively new. It can provide the same material qualities as steel while exhibiting the corrosion resistance of alloys like aluminum but at a lower cost. A stainless-steel item can be created in one of two ways: Hammered, flattened, and welded bits of raw steel may be used to create a product. Another option is to use molten steel that has been poured into a mold that replicates the final design. The kind of product and its applications determine which process of producing stainless steel is the most efficient. The process of making stainless steel includes melting steel scrap, solid casting, heat treating, cleaning, and polishing. Passivation and pickling are two crucial procedures that must be completed after manufacture for finishing.
Passivation Vs Pickling
Metals are safeguarded from rust and pitting via pickling and passivation chemical processes. Despite the fact that both processes entail applying acids to metal surfaces, they are different. Steel loses corrosion resistance when it is heated by welding to a point where a heat tint is apparent because the coating just below has lost chromium. Applying an acidic solution to steel to remove heat-affected areas and the underneath chromium-reduced layer is known as the pickling of stainless steel. Usually, it leaves behind a gray, dull appearance. Stain steel pickling means preparing the surface for passivation by removing the heat-affected layer.
Also Read : How to prevent rusting of Iron
On the other hand, Passivation does not involve the removal of any metal. Instead, an oxidizing acid is used to disintegrate carbon steel, eliminate sulfide inclusions, and clean the stainless steel’s surface of iron as well as other surface impurities. The acid also aids in producing the passive film rich in chromium and provides the corrosion resistance property. Passivation does not alter the look of the metal when carried out properly.
The majority of stainless-steel manufacturing firms, including Shalco Industries, employ pickling paste since it is such an important stage. Pickling paste is a clear liquid that comprises a mixture of nitric and hydrofluoric acids. They can be applied by brush or spray-on processes and are typically utilized to post-weld clean stainless steel. Industry experts have the option to purchase it online from stainless steel pickling paste suppliers. Due to their extensive industrial use, they typically fall within a reasonable price range. The average stainless steel pickling paste price is between 280 and 500 Rupees in India for 1 Kg. The majority of businesses rely on stainless steel; hence pickling and passivation paste for stainless steel is extremely common.