During metalworking and equipment fabrication, various heat treatment techniques can be used to alter the physical and mechanical properties of materials. These techniques are used in combination to achieve desired metal characteristics.
Hardening – As its name indicates, hardening is performed to improve the hardness of a metal, resulting in a tougher and more durable product. The metal is heated above its critical transformation temperature and then it is cooled quickly via quenching. Hardening is often followed by tempering of the metal to alleviate internal stresses. In case hardening of steels, carbon is introduced to harden the outer layer of material, leaving a soft and ductile core, which improves wear resistance. The Hardening and tampering also exposes to series of corrosion mechanisms.
Quenching – Quenching involves cooling a metal at a rapid rate. Its impact on metal properties varies from alloy to alloy. Ferrous alloys, for instance, will harden when quenched, whereas non-ferrous alloys will tend to become softer. Most often, however, liquids like water or oil are used. Due to the rapid rate of cooling, quenching builds up stresses in the material which must be relieved by tempering. It leads to corrosion.
Annealing Corrosion Passivation / Treatment Chemicals
It involves heating a material above its recrystallization temperature, maintaining a suitable temperature for a suitable amount of time, and then cooling.
Stress Relieving Corrosion Passivation / Treatment Chemicals
Stress Relieving is the treatment of a metal or alloy by heating to a predetermined temperature below its lower transformation temperature followed by cooling in air. The primary purpose is to relieve stresses that have been absorbed by the metal from processes such as forming, straightening, machining or rolling.
Drawing Corrosion Passivation / Treatment Chemicals
Wire drawing is a metalworking process used to reduce the cross-section of a wire by pulling the wire through a single, or series of, drawing die(s). Wet drawing, Dry drawing, Metal coating, Ultrasonic vibration, Roller die Drawing
Milling Corrosion Passivation / Treatment Chemicals
The milling process removes material by performing many separate, small cuts. This is accomplished by using a cutter with many teeth, spinning the cutter at high speed, or advancing the material through the cutter