Call Today: (972) 934-0493

Definitions O-Q

O.D.: Short notation for outside diameter, meaning the outside surface or diameter of the pipe.

Oxalic Etchant: A general-purpose electrolytic etching process, using about a 10% Oxalic acid solution, 6-8 volts DC for 30 seconds or less and with a stainless steel cathode.

Oxygen: A chemical element with the symbol O. Chemically combines with acetylene and results in very high torch nozzle temperatures.

Oxygen Concentration Cell: An electrolytic cell created by a differential in oxygen availability at one area to another more accessible area.

Overload: Application of a load, beyond the yield strength of the metal, so that permanent stretching or deformation and/or fracture result.

Oxalic Acid: An electric etch (6Vdc, 1 inch spacing for 15-30 seconds) to reveal grain boundary carbides.

Pearlite: A layered or laminated structure of ferrite and iron carbide, which looks like stripes on a zebra. The white/gray background is ferrite and the dark jagged stripes are iron carbide.

Pelican Hook: A rotatable hook, which can be opened to insert or remove loading line or object. The pelican hook is closed by an oval link that is slipped over the beak.

Perk Tube or Riser Tube: A percolator tube that is centered in the boiler of an ammonia absorption refrigerator. The percolator tube provides a path through which the heated water/ammonia mixture is transmitted out of the refrigerator boiler into the refrigerator cooling section.

Permanent Deformation: When an object or test specimen is loaded or a load is applied, that load will cause a small stretch to occur in the metal. When the load causing a slight bend or stretch is removed, the component returns to its original shape/form. In this process, the metal has been subjected to elastic deformation. When the load exceeds the elastic limit and that load is removed, a permanent bend or deformation will occur. The metal is then said to have become plastic, i.e., has experienced permanent deformation.

PEX: Crosslink polyvinyl chloride (PVC) piping.

Pin (Pin End): Threaded end of the joint of pipe, which is screwed or threaded into the coupling. In that, way the joints of drill pipe are connected to produce a drill string.

Pitting Corrosion: An extremely localized chemical attack that results in deep holes or pits, which penetrate locally into or through the metal or metal structure.

Other corrosion failures:

Corrosion Failure Analysis

Water Pipe Leak

Plastic Deformation: In metal, when the load causing a slight bend or stretch is removed, the component returns to its original shape/form. At that point, the metal has been subjected to elastic deformation. When the load exceeds the elastic limit and that load is then removed, a permanent bend or deformation will persist. The metal is said to have become plastic, i.e., has experienced permanent deformation.

Plumbing Manifold: An assemblage of piping, brass fittings, crimp clamps and apertures for hot and cold water that feed flexible PEX supply lines to individual fixtures.

Porosity: Non-occupied voided space within what should be a sold metal structure. Some porosity is present in most castings. However, large amounts of porosity caused by gas bubbles, lack of sufficient liquid or metal to fill the joint or mold can act as a stress riser and be a precursor to failure.

Porous Mass: A volume of material, which is designed and fabricated to contain a very high level of porosity.

Primer: Small encapsulated percussion cap which, when struck by the firing pin, ignites the cartridge powder.

Primer Sealant: Coating to seal joint between primer and cartridge.

Progressive Stepwise Fracture: Progressive stepwise fracture is differentiated from fatigue fracture in that the stress cycles in progressive stepwise fracture are not periodic, as is usually the case in metal fatigue. In stepwise fracture, the crack will progress whenever a local stress of sufficient magnitude is experienced. If during that use the application of the applied stress exceeds the threshold stress level necessary to make the crack grow, the crack will extend. The spacing between steps will present a macroscopic fracture surface very similar to metal fatigue. Progressive stepwise fracture will often present dimple rupture fracture topography.

Psi: An acronym for pounds per square inch. It is a term, which gives the strength of, or stress or pressure put onto an object or test specimen. It represents pounds of force or load applied to one square inch of material.

Pulling Out Of Hole (POOH): A term of art describing the act of removing the drill string from the wellbore. Pulling out of hole is the opposite of assembling a drill string. Each joint is successively removed from the top of the drill string while the remainder of the drill string is held in the slips to prevent it from falling down the wellbore.

Quasi-Cleavage: A fracture pattern that is less defined than dimple rupture and cleavage. The quasi-cleavage fracture surface has various amounts of transgranular cleavage but with evidence of plastic deformation.

Quench: Quick withdrawal of heat by rapid cooling with water, oil or forced air.

Contact Us

J.E.I. Metallurgical, Inc.

5514 Harbor Town
Dallas, Texas 75287

Phone: (972) 934-0493
Fax: (469) 737-3938
Email: r.c.jerner@metallurgist.com

Location Map

Follow Me On