carbide

 n chemistry, a carbide usually describes a compound composed of carbon and a metal. In metallurgy, carbiding or carburizing is the process for producing carbide coatings on a metal piece.

Lustre

Lustre (or luster) is a description of the way light interacts with the surface of a crystal, rock, or mineral. The word lustre traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance.

A range of terms are used to describe lustre. Many terms refer to materials having similar lustres, such as earthy, metallic, greasy, and silky. Similarly, the term vitreous (derived from the Latin for glass, vitrum) refers to a glassy lustre. A list of these terms is given below.

cross-thread

cross-thread:

To screw together two threaded pieces without aligning the threads correctly.

Galling

Galling usually refers to the adhesive wear and transfer of material between metallic surfaces in relative converging contact during sheet metal forming and other industrial operations.

In engineering science and in other technical aspects, the term galling is widespread. In recent years, there have been attempts to standardize or redefine the word in coordination with greater understanding of the involved frictional mechanisms. ASTM International has formulated and established a common definition for the technical aspect of the galling phenomenon in the ASTM G40 standard: "Galling is a form of surface damage arising between sliding solids, distinguished by microscopic, usually localized, roughening and creation of protrusions, (i.e. lumps, see figure 1), above the original surface".

Swaging

Swaging is a forging process in which the dimensions of an item are altered using a die or dies, into which the item is forced. Swaging is usually a cold working process; however, it is sometimes done as a hot working process.

The term swage can apply to the process of swaging (verb), or to a die or tool used for swaging (noun).

COR-TEN

Weathering steel, best-known under the trademark COR-TEN steel and sometimes written without the hyphen as "Corten steel", is a group of steel alloys which were developed to obviate the need for painting, and form a stable rust-like appearance if exposed to the weather for several years.

United States Steel Corporation (USS) holds the registered trademark on the name COR-TEN. Although USS sold its discrete plate business to International Steel Group (now Arcelor-Mittal) in 2003,^[2] it still sells COR-TEN branded material in strip-mill plate and sheet forms.

The original COR-TEN received the standard designation A 242 ("COR-TEN A") from the ASTM International standards group. Newer ASTM grades are A 588 ("COR-TEN B") and A 606 for thin sheet. All alloys are in common production and use.

Mu-metal

Mu-metal is a nickel-iron alloy (approximately 75% nickel, 15% iron, plus copper and molybdenum) that has very high magnetic permeability. The high permeability makes mu-metal very effective at screening static or low-frequency magnetic fields, which cannot be attenuated by other methods. The name came from the Greek letter mu (μ) which represents permeability. A number of different proprietary formulations of the alloy are sold under trade names such as Mumetal, MuMetal, and MuShield; this article will cover their common features.

Asperity

Asperity, defined as "unevenness of surface, roughness, ruggedness" (OED, from the Latin asper — "rough"), has implications in physics and in seismology. Smooth surfaces, even those polished to a mirror finish, are not truly smooth on an atomic scale. They are rough, with sharp, rough or rugged projections, termed "asperities".

Brinelling

Brinelling refers to a material surface failure caused by contact stress that exceeds the material limit. This failure is caused by just one application of a load great enough to exceed the material limit. The result is a permanent dent or "brinell" mark. It is a common cause of roller bearing failures, and loss of preload in bolted joints when a hardened washer is not used. Engineers can use the Brinell hardness of materials in their calculations to avoid this mode of failure. A rolling element bearing's static load rating is defined to avoid this failure type.

False brinelling is damage caused by fretting, with or without corrosion, that causes imprints that look similar to brinelling, but are caused by a different mechanism. Brinell damage is characterized by permanent material deformation (without loss of material) and occurs during one load event, whereas false brinelling is characterized by material wear or removal and occurs over an extended time from vibration and light loads.

Patina

Patina (pronounced /ˈpætənə/ or /pəˈtiːnə/) is a film on the surface of bronze or similar metals (produced by oxidation over a long period); a sheen on wooden furniture produced by age, wear, and polishing; or any such acquired change of a surface through age and exposure. On metal, patina is a coating of various chemical compounds such as oxides or carbonates formed on the surface during exposure to the elements (weathering). Patina also refers to accumulated changes in surface texture and colour that result from normal use of an object such as a coin or a piece of furniture over time.

Knurling

Knurling is a manufacturing process, typically conducted on a lathe, whereby a visually-attractive diamond-shaped (criss-cross) pattern is cut or rolled into metal. This pattern allows hands or fingers to get a better grip on the knurled object than would be provided by the originally-smooth metal surface. Occasionally, the knurled pattern is a series of straight ridges or a helix of "straight" ridges rather than the more-usual criss-cross pattern.

Roasting

Roasting is a metallurgical process involving gas-solids reactions at elevated temperatures. A common example is the process in which sulfide ores are converted to oxides, prior to smelting.

Dross

Dross is a mass of solid impurities floating on a molten metal bath. Dross (slang) has been used to describe persons of contemptible status. For example 'Human dross' is synonymous with 'Human scum'.

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