Quenched and tempered, the standard through-hardening route for alloy steels such as 4130, 4140 and 4340: austenitize, quench to martensite, then temper to the hardness range on the drawing. Bar and plate are also sold in the Q&T condition, often around 28 to 32 HRC for 4140 prehard, ready to machine and use with no further treatment.
Print calls Q&T to 28 to 32 HRC, so buy 4140 prehard and skip the heat treat entirely.
Also heard as
- QT
- quench and temper
- quenched and tempered
- hardened and tempered
- H&T
Related terms
Through hardening
Hardening a steel part so martensite forms across the whole section, not just at the surface.
Tempering
Reheating hardened steel below its lower critical temperature to trade some hardness for toughness.
Quench
To cool hot metal rapidly in a liquid or gas so that it hardens, or the act of doing so.
Hardenability
A steel's ability to form martensite to a given depth, set by its chemistry and grain size, not its hardness.