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Heat Treated Steel Processes and Definitions


Below is a heat-treating glossary with definitions and explanations for many commonly used terms for metal heat-treating and metal finishing processes. Click each word to learn more about that process.

Heat Treating

The process of applying extreme temperatures to strengthen the metal; heat treating can be broadly defined as the process of heating metal, holding for some period of time, and then cooling the metal at various rates to achieve the desired mechanical properties. A wide range of properties can be obtained from metal of the same chemical content using different heat treatments. CMC Impact Metals heat treating operations are primarily focused around grades of carbon and low alloy steels.

 

Annealing

The process of heating metal and allowing it to cool slowly in order to remove internal irregularities and toughen the metal; the purpose of annealing is to produce a soft, pliable material suitable for machining, drawing, or other cold-working processes. The annealing process involves heating the material to about 1500 deg F, then cooling very slowly until the material reaches 1250 to 1300 deg F, and finally completing the cooling process in ambient air. Varying the speed of the initial cooling cycle results in different internal granular structures in the steel that are tailored to the intended subsequent processing.

 

Normalizing

A type of annealing done to ferrous alloys to make them less brittle; this process is performed to make the internal granular structure of the steel more uniform. It involves heating the steel to 1600 to 1750 deg F, holding until the material temperature is fully uniform and then cooling in air. This treatment will often improve the impact resistance and ductility properties of the material with little or no decrease in strength. Often material is quenched and tempered after a normalizing cycle. The normalizing will often improve a steel's response to quenching and tempering.

 

Quench and Temper

A process that involves heating the metal and cooling it rapidly; this process is used to harden and strengthen steel. Strength and hardness can be increased by over 50% with the quench-and-temper process with no loss of, and sometimes even increased, ductility and impact toughness. It can also be used to create steels of very high hardness (400 Brinell Hardness and above) that are used in abrasion resistant and armor plate applications. The typical cycle for quenching and tempering involves heating the steel to 1550 to 1700 deg F until fully uniform, and then rapidly cooling in water or other quenchants. The steel is typically tempered at 800 to 1200 deg F depending on the desired final properties. The higher the temperature, the lower the resulting hardness of the steel.

 

Straightening

The ability to correctly size the metal to the appropriate measurements for construction; steel often has to be mechanically straightened after Q&T due to the distortion that takes place during the hardening process. Rounds, structural shapes and flat bar products are straightened using hydraulic presses or machine straightening. If required by the specifications or customer, stress relieving may be performed.

 

Shot Blasting

The process of propelling a stream of abrasive material against the metal, usually to smooth a rough surface; shot blasting utilizes small beads of steel accelerated by a wheel turning at over 3000 rpm to remove oxidation and scale from the steel surface. This provides a smooth clean surface for final finishing.

 

Powder Coating

A type of coating applied to metal, in the form of dry powder; if your product requires a final finish that is clean and durable, we can provide a shop-applied powdercoated surface. The powder coating process starts by applying a statically adhering powder to all surfaces; the coating is then cured in an oven to produce a very hard, durable surface. The primary advantage of powder coatings is that they are applied dry without noxious solvents and are much more environmentally friendly than traditional coatings.

 

Precision Cutting

Cutting metal to exact lengths and widths using small scale measuring; CMC Impact Metals has the capability to provide custom parts, cut to your precise size requirements with the latest plasma and laser cutting technology to make final assembly at your facility quicker and more efficient.

 

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