C

CONDITIONING: A process of allowing textile materials (yarns, fabrics) to reach hygroscopic equilibrium with the surrounding atmosphere. Materials may be conditioned in a standard atmosphere (65%RH,27oC) for testing purposes.

COUNT: 1. A numerical designation of yarn size indicating the relationship of length to weight. 2 The number of warp yarns (ends) and filling yarns (picks) per inch in a woven fabric, or the number of wales and courses per inch in a knit fabric. For example, a fabric count of 68 x 52 indicates 68 ends per inch in the warp and 52 picks per inch in the filling.

CROCKING - The rubbing-off of dye from a fabric. Crocking can be the result of lack of penetration of the dyeing agent, the use of incorrect dyes or dyeing procedures, or the lack of proper washing procedures and finishing treatments after the dyeing process.

CARBURIZING - Adding carbon to the surface of steel by heating the metal below its melting point in contact with carbonaceous solids, liquids, or gases.

CASE HARDENING - A heat treatment or a combination of heat treatments of surface hardening involving a change in the composition of the outer layer of an iron-base alloy in which the surface is made substantially harder by inward diffusion of a gas or liquid followed by appropriate thermal treatment. Typical hardening processes are carburizing, cyaniding, carbo-nitriding and nitriding.

CYANIDING - Surface hardening by carbon and nitrogen absorption of a steel article or a portion of it by heating at a suitable temperature in contact with cyanide salt, followed by quenching.

Carbon has a major effect on steel properties. Carbon is the primary hardening element in steel. Hardness and tensile strength increases as carbon content increases up to about 0.85% C as shown in the figure above. Ductility and weldability decrease with increasing carbon.

Copper in significant amounts is detrimental to hot-working steels. Copper negatively affects forge welding, but does not seriously affect arc or oxyacetylene welding. Copper can be detrimental to surface quality. Copper is beneficial to atmospheric corrosion resistance when present in amounts exceeding 0.20%. Weathering steels are sold having greater than 0.20% Copper.

Chromium is commonly added to steel to increase corrosion resistance and oxidation resistance, to increase hardenability, or to improve high-temperature strength. As a hardening element, Chromium is frequently used with a toughening element such as nickel to produce superior mechanical properties. At higher temperatures, chromium contributes increased strength. Chromium is a strong carbide former. Complex chromium-iron carbides go into solution in austenite slowly; therefore, sufficient heating time must be allowed for prior to quenching.

Cycle Annealing: An annealing process employing a predetermined and closely controlled time–temperature cycle to produce specific properties or microstructure.

Carbon Potential: A measure of the ability of an environment containing active carbon to alter or maintain, under prescribed conditions, the carbon content of the steel exposed to it. In any particular environment, the carbon level attained will depend on such factors as temperature, time, and steel composition.

Carbon Restoration: Replacing the carbon lost in the surface layer from previous processing by carburizing this layer to substantially the original carbon level.

Carbonitriding: A case-hardening process in which a suitable ferrous material is heated above the lower transformation temperature in a gaseous atmosphere of such composition as to cause simultaneous absorption of carbon and nitrogen by the surface and, by diffusion, create a concentration gradient. The process is completed by cooling at a rate that produces the desired properties in the work piece.

Carburizing: A process in which carbon is introduced into a solid iron-base alloy by heating above the transformation temperature range while in contact with a carbonaceous material that may be a solid, liquid, or gas. Carburizing is frequently followed by quenching to produce a hardened case.

Cold Treatment: Exposing to suitable subzero temperatures for the purpose of obtaining desired conditions or properties, such as dimensional or microstructural stability. When the treatment involves the transformation of retained austenite, it is usually followed by a tempering treatment.

Conditioning Heat Treatment: A preliminary heat treatment used to prepare a material for a desired reaction to a subsequent heat treatment.

Controlled Cooling: A term used to describe a process by which a steel object is cooled from an elevated temperature, usually from the final hot-forming operation in a predetermined manner of cooling to avoid hardening, cracking, or internal damage.

Compressive Strength This test method covers determination of compressive strength of cylindrical concrete specimens such as molded cylinders and drilled cores.

Cutting Cores - Cores drilled from concrete for length or compressive strength or splitting tensile strength determinations and beams sawed from concrete for flexural strength determinations.
 

D

DENIER: A system of measuring the weight of a continuous filament fiber. The lower the number, the finer the fiber; the higher the number, the heavier the fiber. Numerically, a denier is the equivalent to the weight in grams of 9,000 meters of continuous filament fiber.

DYES: Substances that add color to textiles. They are incorporated into the fiber by chemical reaction, absorption, or dispersion. Dyes differ in their resistance to sunlight, perspiration, washing, and other agents; their affinity for different fibers; their reaction to cleaning agents and methods; and their solubility and method of application. Various classes and types are listed below.

Developed Dyes: Dyes that are formed by the use of a developer. The substrate is first dyed in a neutral solution with a dye base, usually colorless. The dye is then diazotized with sodium nitrate and an acid and afterwards treated with a solution of B-naphthol, or a similar substance, which is the developer. Direct dyes are developed to produce a different shade or to improve washfastness or lightfastness.

Direct Dyes: A class of dyestuffs that are applied directly to the substrate in a neutral or alkaline bath. They produce full shades on cotton and linen without mordanting and can also be applied to rayon, silk, and wool. Direct dyes give bright shades but exhibit poor washfastness. Various aftertreatments are used to improve the washfastness of direct dyes, and such dyes are referred to as “aftertreated direct colors.”

Disperse Dyes: A class of slightly water-soluble dyes originally introduced for dyeing acetate and usually applied from fine aqueous suspensions. Disperse dyes are widely used for dyeing most of the manufactured fibers.

Diagonal (45ｰ) Flame Test: In this test for flame resistance, a specimen is mounted at a 45ｰ angle and exposed to an open flame for a specific time.

DECARBURIZATION - When steel is subjected to high temperatures, such as are used in hot rolling, forging, and heat treating in a media containing air, oxygen, or hydrogen there is a loss of carbon at the surface which is known as decarburization. This resultant loss of carbon or chemistry change at the surface of the steel part reduces the strength of the part by reducing the size of the section and produces a softer surface hardness than the core of the part.

Decarburization: The loss of carbon from the surface of an iron-base alloy as the result of heating in a medium that reacts with the carbon.

Drawing: Drawing, or drawing the temper, is synonymous with Tempering, which is preferable.

Direct Quenching: Quenching carburized parts directly from the carburizing operation.

Double Tempering: A treatment in which quench hardened steel is given two complete tempering cycles at substantially the same temperature for the purpose of ensuring completion of the tempering reaction and promoting stability of the resulting microstructure.

Duplex stainless steels: are a mixture of bcc ferrite and fcc austenite crystal structures. The percentage each phase is a dependent on the composition and heat treatment. Most Duplex stainless steels are intended to contain around equal amounts of ferrite and austenite phases in the annealed condition. The primary alloying elements are chromium and nickel. Duplex stainless steels generally have similar corrosion resistance to austenitic alloys except they typically have better stress corrosion cracking resistance. Duplex stainless steels also generally have greater tensile and yield strengths, but poorer toughness than austenitic stainless steels.

Dealloying: is another form of corrosion that affects zinc containing copper alloys. During dezincification of brass, selective removal of zinc results in gradual replacement of sound brass by weak, porous copper. Unless stopped the metal is weakened and liquids or gases may be capable of leaking through the porous structure.