What is heat treatment? from jccasting's blog

In fact, nothing can be made without heat treatment, the process of heating and cooling metals under tight control to improve their properties, performance and durability.

Heat treatment softens the metal and improves formability. It hardens the part for strength. It can place a hard surface on a relatively soft part for added wear resistance. It forms a corrosion-resistant skin to protect components that would otherwise corrode. Also, it can harden brittle products.

Heat treating parts is critical to the operation of automobiles, aircraft, spacecraft, computers and a variety of heavy equipment. Saws, shafts, cutting tools, bearings, gears, shafts, fasteners, camshafts and crankshafts all rely on heat treating.

Basic knowledge of heat treatment

Although steel accounts for the vast majority of heat-treated materials, alloys of aluminum, copper, magnesium, nickel, and titanium can also be heat-treated.

The heat treatment process requires three basic steps:

heated to the specified temperature

Hold at that temperature for an appropriate time

Lower the temperature according to the prescribed method

Temperatures may range up to 2400°F and times at temperature may vary from a few seconds to as many as 60 hours or more.

Some materials cool slowly in the furnace, but others must be cooled or quenched quickly. Certain cryogenic processes require processing at -120°F or lower. Quenching media include water, brine, oil, polymer solutions, molten salts, molten metals and gases. Each has specific properties that make it ideal for certain applications. However, 90% of parts are quenched in water, oil, gas or polymers.

The value of heat treatment Heat treatment

Adding an estimated $15 billion in value to metal products annually by giving components the specific properties they need to operate successfully.

It is closely related to the manufacture of steel products: about 80% of heat-treated parts are made of steel. These include bars and tubes output from steel mills, and parts that have been cast, forged, welded, machined, rolled, stamped, drawn or extruded.

It is also a crucial step in the manufacture of non-ferrous metal products. For example, aluminum alloy automotive castings are heat-treated to increase hardness and strength; brass and bronze items are heat-treated to increase strength and prevent cracking; and titanium alloy structures are heat-treated to increase strength at high temperatures.