Nitriding is a heat treatment process that enhances the surface hardness of metals, particularly steel. It involves introducing nitrogen into the surface layer of the metal, which forms hard nitrides. This process improves wear resistance, fatigue strength, and corrosion resistance, making it ideal for components like gears and crankshafts. The nitriding process typically occurs at lower temperatures compared to other heat treatments, usually between 500°C and 600°C. This allows the core of the metal to remain soft and ductile while the surface becomes hard. Nitriding can be performed using various methods, including gas nitriding, plasma nitriding, and salt bath nitriding.