Q-BOP
Modified Basic Oxygen Furnace in which the oxygen and other gases are blown in from the bottom, rather than from the top. While the Q-BOP stirs the metal bath more vigorously, allowing for faster processing, the design produces essentially the same steel grades as the top-blowing basic oxygen furnace. Today's state-of-the-art furnace design combines the previous technologies: 60% of the oxygen is blown from above, with the rest blown through the bottom of the vessel.

Qualification Trials
The testing required for a new process adopted to make certain grades of steel with exacting end uses. In order for the process to become qualified, the steel made by the process must be tested.

Quarter Hard Temper
Cold Rolled steel produced to a Rockwell hardness range of 60 to 75 on the B scale. Product of this temper is intended for limited bending and cold forming and can be bent 90 degrees in the rolling direction and 180 degrees across the rolling direction over its own thickness.

Quench Aging
Quench aging is a type of artificial or accelerated aging which causes a change in the properties of steel that occurs gradually with time at moderately elevated temperatures after a hot working heat treatment. It is a consequence of the precipitation of carbon, nitrogen or both, from supersaturated solid solution in ferrite. The consequences of quench aging are increased hardness, increased yield and tensile strength, decreased elongation and reduction of area in tension test, increased temperature of transition from ductile to brittle fracture in a notch-impact test, an increase in coercive force and a decrease in magnetic permeability.

Quench Annealing
Annealing an austenitic ferrous alloy by solution heat treatment followed by rapid quenching.

Quench Hardening
A process of hardening a ferrous alloy of suitable composition by heating within or above the transformation range and cooling at a rate sufficient to increase the hardness substantially. The process usually involves the formation of martensite.

Quenching
Cooling very rapidly from a high temperature by immersing in water or some other liquid.

Quenching and Tempering
This treatment is given in addition to annealing in order to develop the optimum mechanical properties and in place of annealing when the amount of machining or cutting to be done is not great. It consists of first heating the steel above the critical range, and then cooling it rapidly by immersing it in a liquid cooling medium such as oil or water. This is followed by heating the steel to an intermediate temperature, very seldom higher than 650oC and usually somewhat lower.

Quenching Crack
Cracks formed as a result of thermal stresses produced by rapid cooling from a high temperature.

Quench Tank
Tank of water used to quickly cool the strip before it reaches the delivery end of the line.

Quencher Water
Water that keeps boiler duct work cool.