__________ is not a heat treatment process.

ANS:B - Pakerising

It seems you meant "Parkerizing," which is a surface treatment process rather than a heat treatment process. Here's an explanation: Parkerizing, also known as phosphating, is a surface treatment process used to coat steel surfaces with a layer of phosphate. The purpose of Parkerizing is to improve corrosion resistance, enhance paint adhesion, and provide a base for further surface finishing such as painting or oiling. The Parkerizing process typically involves the following steps:

1. Cleaning: The steel surface is thoroughly cleaned to remove any dirt, oil, grease, or other contaminants. This step is crucial to ensure proper adhesion of the phosphate coating.
2. Surface Activation: The cleaned steel surface is then treated with an acidic solution or chemical etchant to remove any oxide layers and activate the surface for phosphate deposition.
3. Phosphating: The activated steel surface is immersed in a phosphate solution containing phosphoric acid and other additives such as zinc or manganese salts. The phosphate solution chemically reacts with the metal surface to form a layer of insoluble phosphate crystals. This layer provides corrosion protection and improves paint adhesion.
4. Rinsing: After phosphating, the steel surface is rinsed with water to remove excess phosphate solution and neutralize any remaining acidic residues.
5. Drying: The phosphated steel surface is dried to remove moisture and prepare it for further processing, such as painting or oiling.

Parkerizing is commonly used in various industries, including automotive, firearms, machinery, and aerospace, to provide a durable and corrosion-resistant surface finish. It is especially favored in applications where a matte or non-reflective finish is desired, such as military equipment or firearm components.