Quenching vs. Tempering — What's the Difference?
By Fiza Rafique & Urooj Arif — Updated on May 15, 2024
Quenching involves rapidly cooling metal to harden it, while tempering is a subsequent heat treatment that reduces brittleness and increases toughness by reheating and then cooling the metal at a controlled rate.
Difference Between Quenching and Tempering
Table of Contents
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Key Differences
Quenching is a heat treatment process where metal is heated to a high temperature and then rapidly cooled, usually in water, oil, or air, to increase hardness. This rapid cooling traps carbon atoms within the metal's crystal structure, resulting in a harder but more brittle material. Tempering, on the other hand, is performed after quenching to reduce the brittleness introduced by the rapid cooling. During tempering, the quenched metal is reheated to a lower temperature (below its critical point) and then cooled again, typically in air.
Quenching is crucial for achieving high strength and wear resistance, making it essential for tools and components that endure high stress and wear. Tempering addresses the brittleness issue by balancing hardness and toughness, making the metal more resilient and less prone to cracking. It is a critical step for items requiring a combination of strength and flexibility, such as springs, blades, and structural components.
While quenching and tempering are distinct processes, they are often used sequentially to achieve optimal mechanical properties in metalworking. The specific temperatures and durations for each process vary depending on the type of metal and the desired final properties.
Comparison Chart
Definition
Rapid cooling of heated metal
Reheating and controlled cooling of quenched metal
Purpose
Increase hardness
Reduce brittleness and increase toughness
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Process
Heating metal to high temperature, then rapid cooling
Reheating below critical point, then cooling
Resulting Properties
Hard but brittle
Tougher, more ductile with adequate hardness
Common Cooling Mediums
Water, oil, air
Air
Applications
Tools, wear-resistant components
Springs, blades, structural components
Sequential Use
Initial hardening stage
Post-quenching treatment for balance
Internal Stress Impact
Introduces internal stresses
Relieves internal stresses
Compare with Definitions
Quenching
A process increasing hardness and strength but causing brittleness.
The quenched gears were extremely hard but required tempering to avoid breaking.
Tempering
A process that balances hardness and toughness.
After quenching, the blade was tempered to prevent it from shattering under impact.
Quenching
Critical for wear-resistant components.
The manufacturing of high-stress industrial parts often involves quenching.
Tempering
Used to relieve internal stresses in metal.
Tempering ensures that the metal is less likely to crack during use.
Quenching
Rapidly cooling metal to harden it.
After heating the steel blade, the blacksmith quenched it in oil.
Tempering
Heating quenched metal to reduce brittleness.
The tempered steel had improved toughness and flexibility.
Quenching
Used in initial metalworking stages.
Quenching is essential for achieving the desired hardness in cutting tools.
Tempering
Involves reheating below critical temperature and cooling.
The blacksmith tempered the sword by reheating it to a precise temperature.
Quenching
Involves submerging heated metal in water, oil, or air.
Quenching in water can sometimes lead to cracks due to rapid cooling.
Tempering
Essential for components requiring both strength and resilience.
Tempered springs maintain their shape under repeated stress.
Quenching
In materials science, quenching is the rapid cooling of a workpiece in water, oil or air to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as phase transformations, from occurring.
Tempering
To modify by the addition of a moderating element; moderate
"temper its doctrinaire logic with a little practical wisdom" (Robert H. Jackson).
Quenching
To put out (a fire, for example); extinguish.
Tempering
To bring to a desired consistency, texture, hardness, or other physical condition by blending, admixing, or kneading
Temper clay.
Paints that had been tempered with oil.
Quenching
To suppress; squelch
The disapproval of my colleagues quenched my enthusiasm for the plan.
Tempering
To harden or strengthen (metal or glass) by application of heat or by heating and cooling.
Quenching
To slake; satisfy
Mineral water quenched our thirst.
Tempering
To strengthen through experience or hardship; toughen
Soldiers who had been tempered by combat.
Quenching
To cool (hot metal) by thrusting into water or other liquid.
Tempering
(Music) To adjust (the pitch of an instrument) to a temperament.
Quenching
(physics) The extinction of any of several physical properties.
Tempering
To be or become tempered.
Quenching
(metallurgy) The rapid cooling of a hot metal object, by placing it in a liquid, in order to harden it.
Tempering
A state of mind or emotion; disposition
An even temper.
Quenching
(astronomy) A process in which a galaxy loses cold gas, thus strongly suppressing star formation.
Tempering
Calmness of mind or emotions; composure
Lose one's temper.
Quenching
(botany) The dissipation of energy from light in excess of what can be used for photosynthesis.
Tempering
A tendency to become easily angry or irritable
A quick temper.
Quenching
Present participle of quench
Tempering
Anger; rage
A fit of temper.
Quenching
The act of extinguishing; causing to stop burning;
The extinction of the lights
Tempering
A characteristic general quality; tone
Heroes who exemplified the medieval temper.
The politicized temper of the 1930s.
Tempering
The condition of being tempered.
Tempering
The degree of hardness and elasticity of a metal, chiefly steel, achieved by tempering.
Tempering
A modifying substance or agent added to something else.
Tempering
(Archaic) A middle course between extremes; a mean.
Tempering
Present participle of temper
Tempering
The act by which something is tempered.
Tempering
The process of giving the requisite degree of hardness or softness to a substance, as iron and steel; especially, the process of giving to steel the degree of hardness required for various purposes, consisting usually in first plunging the article, when heated to redness, in cold water or other liquid, to give an excess of hardness, and then reheating it gradually until the hardness is reduced or drawn down to the degree required, as indicated by the color produced on a polished portion, or by the burning of oil.
Tempering
Hardening something by heat treatment
Tempering
Moderating by making more temperate
Common Curiosities
Why is tempering necessary after quenching?
Tempering is necessary to reduce the brittleness and improve the toughness of quenched metal.
What is quenching?
Quenching is a process of rapidly cooling heated metal to increase its hardness.
At what temperature is tempering done?
Tempering is done at temperatures below the metal's critical point, typically between 150°C and 700°C.
What is tempering?
Tempering is the process of reheating quenched metal to reduce brittleness and increase toughness.
Why is quenching important?
Quenching is important for achieving high hardness and strength in metals.
Can quenching cause metal to crack?
Yes, the rapid cooling in quenching can introduce internal stresses that may cause cracking.
What mediums are used for quenching?
Common mediums for quenching include water, oil, and air.
What is the main difference between quenching and tempering?
Quenching increases hardness but causes brittleness, while tempering reduces brittleness and increases toughness.
Is tempering done immediately after quenching?
Yes, tempering is usually done immediately after quenching to optimize the metal's properties.
Are quenching and tempering used together?
Yes, they are often used sequentially to achieve a balance of hardness and toughness.
What types of metals are commonly tempered?
Steels and other metals that have been quenched are commonly tempered.
What industries use quenching and tempering processes?
Automotive, aerospace, tool manufacturing, and construction industries commonly use these processes.
What happens if metal is not tempered after quenching?
If not tempered, quenched metal remains very hard but brittle, making it prone to cracking or breaking under stress.
What types of metals are commonly quenched?
Steels and other iron-based alloys are commonly quenched.
Can tempering be repeated?
Yes, tempering can be repeated to achieve desired mechanical properties.
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Written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
Co-written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
