U.S. Code of Federal Regulations

Regulations most recently checked for updates: Feb 01, 2023

§ 471.02 - General definitions.

In addition to the definitions set forth in 40 CFR part 401, the following definitions apply to this part:

(a) “Nonferrous metal” is any pure metal other than iron or any metal alloy for which a metal other than iron is its major constituent in percent by weight.

(b) “Forming” is a set of manufacturing operations in which metals and alloys are made into semifinished products by hot or cold working.

(c) “Alkaline cleaning” uses a solution (bath), usually detergent, to remove lard, oil, and other such compounds from a metal surface. Alkaline cleaning is usually followed by a water rinse. The rinse may consist of single or multiple stage rinsing. For the purposes of this part, an alkaline cleaning operation is defined as a bath followed by a rinse, regardless of the number of rinse stages. Each alkaline cleaning bath and rinse combination is entitled to a discharge allowance.

(d) “Atomization” is the process in which a stream of water or gas impinges upon a molten metal stream, breaking it into droplets which solidify as powder particles.

(e) “Burnishing” is a surface finishing process in which minute surface irregularities are displaced rather than removed.

(f) “Casting” is pouring molten metal into a mold to produce an object of desired shape.

(g) “Cladding” or “metal cladding” is the art of producing a composite metal containing two or more layers that have been metallurgically bonded together by roll bonding (co-rolling), solder application (or brazing), or explosion bonding.

(h) “Contact cooling water” is any wastewater which contacts the metal workpiece or the raw materials used in forming metals for the purpose of removing heat from the metal.

(i) “Continuous casting” is the production of sheet, rod, or other long shapes by solidifying the metal while it is being poured through an open-ended mold.

(j) “Degreasing” is the removal of oils and greases from the surface of the metal workpiece. This process can be accomplished with detergents as in alkaline cleaning or by the use of solvents.

(k) “Direct chill casting” is the pouring of molten nonferrous metal into a water-cooled mold. Contact cooling water is sprayed onto the metal as it is dropped into the mold, and the metal ingot falls into a water bath at the end of the casting process.

(l) “Drawing” is the process of pulling a metal through a die or succession of dies to reduce the metal's diameter or alter its cross-sectional shape.

(m) “Dye penetrant testing” is a nondestructive method for finding discontinuities that are open to the surface of the metal. A dye is applied to the surface of metal and the excess is rinsed off. Dye that penetrates surface discontinuities will not be rinsed away thus marking these discontinuities.

(n) “Emulsions” are stable dispersions of two immiscible liquids. In the Nonferrous Metals Forming and Metal Powders Point Source category, this is usually an oil and water mixture.

(o) “Electrocoating” is the electrodeposition of a metallic or nonmetallic coating onto the surface of a workpiece.

(p) “Extrusion” is the application of pressure to a billet of metal, forcing the metal to flow through a die orifice.

(q) “Forging” is deforming metal, usually hot, with compressive force into desired shapes, with or without dies. Where dies are used, the metal is forced to take the shape of the die.

(r) “Grinding” is the process of removing stock from a workpiece by the use of a tool consisting of abrasive grains held by a rigid or semi-rigid grinder. Grinding includes surface finishing, sanding, and slicing.

(s) “Heat treatment” is the application of heat of specified temperature and duration to change the physical properties of the metal.

(t) “Hot pressing” is forming a powder metallurgy compact at a temperature high enough to effect concurrent sintering.

(u) “Hydrotesting” is the testing of piping or tubing by filling with water and pressurizing to test for integrity.

(v) “Impregnation” is the process of filling pores of a formed powder part, usually with a liquid such as a lubricant, or mixing particles of a nonmetallic substance in a matrix of metal powder.

(w) “In-process control technology” is the conservation of chemicals and water throughout the production operations to reduce the amount of wastewater to be discharged.

(x) “Metal powder production” operations are mechanical process operations which convert metal to a finely divided form.

(y) “Milling” is the mechanical treatment of a nonferrous metal to produce powder, or to coat one component of a powder mixture with another.

(z) “Neat oil” is a pure oil with no or few impurities added. In nonferrous metals forming, its use is mostly as a lubricant.

(aa) “Powder forming” includes forming and compressing powder into a fully dense finished shape, and is usually done within closed dies.

(bb) “Precious metals” include gold, platinum, palladium, and silver and their alloys. Any alloy containing 30 or greater percent by weight of precious metals is considered a precious metal alloy.

(cc) “Product testing” includes operations such as dye penetrant testing, hydrotesting, and ultrasonic testing.

(dd) “Refractory metals” includes the metals of columbium, tantalum, molybdenum, rhenium, tungsten and vanadium and their alloys.

(ee) “Rolling” is the reduction in thickness or diameter of a workpiece by passing it between lubricated steel rollers.

(ff) “Roll bonding” is the process by which a permanent bond is created between two metals by rolling under high pressure in a bonding mill (co-rolling).

(gg) “Sawing” is cutting a workpiece with a band, blade, or circular disc having teeth.

(hh) “Shot casting” is the production of shot by pouring molten metal in finely divided streams to form spherical particles.

(ii) “Stationary casting” is the pouring of molten metal into molds and allowing the metal to cool.

(jj) “Surface treatment” is a chemical or electrochemical treatment applied to the surface of a metal. Such treatments include pickling, etching, conversion coating, phosphating, and chromating. Surface treatment baths are usually followed by a water rinse. The rinse may consist of single or multiple stage rinsing. For the purposes of this part, a surface treatment operation is defined as a bath followed by a rinse, regardless of the number of stages. Each surface treatment bath, rinse combination is entitled to discharge allowance.

(kk) “Swaging” is a process in which a solid point is formed at the end of a tube, rod, or bar by the repeated blows of one or more pairs of opposing dies.

(ll) “Tube reducing” is an operation which reduces the diameter and wall thickness of tubing with a mandrel and a pair of rolls with tapered grooves.

(mm) “Tumbling” or “barrel finishing” is an operation in which castings, forgings, or parts pressed from metal powder are rotated in a barrel with ceramic or metal slugs or abrasives to remove scale, fins, or burrs. It may be done dry or with an aqueous solution.

(nn) “Ultrasonic testing” is a nondestructive test which applies sound, at a frequency above about 20 HJz, to metal, which has been immersed in liquid (usually water) to locate inhomogeneities or structural discontinuities.

(oo) “Wet air pollution control scrubbers” are air pollution control devices used to remove particulates and fumes from air by entraining the pollutants in a water spray.

(pp) “Grab sample” is a single sample which is collected at a time and place most representative of total discharge.

(qq) “Composite sample” is a sample composed of no less than eight grab samples taken over the compositing period.

(rr) A “flow proportional composite sample” is composed of grab samples collected continuously or discretely in proportion to the total flow at time of collection or to the total flow since collection of the previous grab sample. The grab volume or frequency of grab collection may be varied in proportion to flow.

(ss) The term “control authority” is defined as the POTW if it has an approved pretreatment program; in the absence of such a program, the NPDES State if it has an approved pretreatment program or EPA if the State does not have an approved program.

(tt) “Continuous operations” means that the industrial user introduces regulated wastewaters to the POTW throughout the operating hours of the facility, except for infrequent shutdowns for maintenance, process changes, or other similar activities.

(uu) “Intermittent operations” means the industrial users does not have a continuous operation.

(vv) The term “off-kg (off-lb)” means the mass of metal or metal alloy removed from a forming operation at the end of a process cycle for transfer to a different machine or process.