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.

Quenching - Rapid cooling of hardening; normally achieved by immersion of the object to be hardened in water, oil, or solutions of salt or organic compounds in water.

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.

Quality - Refers to the suitability and integrity of the steel for the purpose or purposes for which it is intended

Quarter Buckle - See Buckle, Quarter.

Quarter Hard (No. 3 Temper) - (A) In low carbon cold-rolled strip steel, a medium soft temper produced by a limited amount of cold rolling after annealing. (B) In brass mill terminology. Quarter hard is one B and S number hard or 10.95% reduction. (C) In stainless steel terminology tempers are based on minimum tensile, or yield strength. For Chromium-Nickel grades Quarter Hard Temper is 125,000 T. S., 75,000 Y.S. min.

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.

Quartz - "A form of silica occurring in hexagonal crystals which are commonly colorless and transparent, but sometimes also yellow, brown, purple, green, etc. It is the most common of all solid minerals. See also Silica "

Quartzite - A compact granular rock composed of quartz. It is a metamorphosed sandstone, and siliceous cement is often so blended with the quartz grains as to give the rock a nearly homogeneous texture. Primary materiel in silica brick.

Quench Crack - A crack resulting from thermal stress induced during rapid cooling or quenching, or from stresses induced by delayed transformations some time after the article has been fully quenched.

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.

Quench Severity - The quench severity is characterized by the H value and relates to the rate of temperature change during quenching.

Quench Tank - 1) Tank of water used to quickly cool the strip before it reaches the delivery end of the line. 2) The water bath which is used to cool the steel strip after it has been annealed on CA line or reflowed on the Tin plater.

Quencher Water - Water that keeps boiler duct work cool.

Quenching - (1) In the heat treating of metals, the step of cooling metals rapidly in order to obtain desired properties; most commonly accomplished by immersing the metal in oil or water. In the case of most copper base alloys, quenching has no effect other than to hasten cooling. (2) Rapid cooling

Quick Return - A mechanism on some machine tools that provide rapid movement of the ram or table on the return or onointing stroke of the machine.

Quench Aging - Aging that occurs after quenching following solution heat treatment.

Quench Hardening - Hardening by austenitizing and then cooling at a rate such that a substantial amount of austenite is transformed to martensite.

Quench Hardening - Hardening a ferrous alloy by austenitizing and then cooling rapidly enough so that some or all of the austenite transforms to martensite. The austenitizing temperature for hypoeutectoid steels is usually above Ac3 and for hypereutectoid steels usually between Ac1 and Ac (cm).

Quench Hardening (Steel) - 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 - Rapid cooling.

Quenching - In the heat treating of metals, the step of cooling metals rapidly in order to obtain desired properties; most commonly accomplished by immersing the metal in oil or water. In the case of most copper base alloys, quenching has no effect other than to hasten cooling.