P

pH: Value indicating the acidity or alkalinity of a material. It is the negative logarithm of the effective hydrogen ion concentration. A pH of 7.0 is neutral; less than 7.0 is acidic; and more than 7.0 is basic.

PRECONDITIONING: Bringing a sample or specimen of textile material to a relatively low moisture content (approximate equilibrium in an atmosphere between 5 and 25% relative humidity) prior to conditioning in a controlled atmosphere of higher humidity for testing. (While preconditioning is frequently translated as predrying, specimens should not be brought to the overdry state.)

PICK: A filling yarn that runs crosswise between selveges in woven goods. The pick intersects with the warp (or lengthwise yarn) to form a woven.

PICK COUNTER – 1. A mechanical device that counts the picks as they are inserted during weaving. 2. A mechanical device equipped with a magnifying glass used for counting picks (and/or ends) in finished fabrics.

Preheating: Heating to an appropriate temperature immediately prior to austenitizing when hardening high-hardenability constructional steels, many of the tool steels, and heavy sections.

Phosphorus increases strength and hardness and decreases ductility and notch impact toughness of steel. The adverse effects on ductility and toughness are greater in quenched and tempered higher-carbon steels. Phosphorous levels are normally controlled to low levels. Higher phosphorus is specified in low-carbon free-machining steels to improve machinability.

PEARLITE - Another microscopic structure of steel which is produced by slow cooling or air cooling low to medium carbon and low alloy steels from the austenitic state.

Q

QUENCHING AND TEMPERING - In this operation the procedure consists of heating the material to the proper austenitizing temperature, holding at that temperature for a sufficient time to effect the desired change in crystalline structure, and quenching in a suitable medium - water, oil or air depending on the chemical composition. After quenching, the material is reheated to a predetermined temperature below the critical range and then cooled under suitable temperatures (tempering).

R

RAVELING: The process of undoing or separating the weave or knit of a fabric.

ROCKWELL HARDNESS - A hardness test performed on a Rockwell hardness testing machine. Hardness is determined by a dial reading which indicates the depth of penetration of a steel ball for softer steels and a diamond cone for heat treated and harder steels when a load is applied.

S

SELVAGE – The narrow edge of woven fabric that runs parallel to the warp. It is made with stronger yarns in a tighter construction than the body of the fabric to prevent raveling.

SHRINKAGE: Widthwise or lengthwise contraction of a fiber, yarn, or fabric, usually after wetting a redrying or on exposure to elevated temperature.

Soil Clean Up
Polluted soil can form a risk to the health of the user, to those living in the area and to the environment; however the risks that are connected with it are often underestimated. It is therefore always of the greatest importance to accurately determine the cleanup urgency for the relevant soil before actually starting the cleanup process.

Soil Survey
With the increasing demand for land in urban areas, old industrial land is often used for new commercial development. SPECTRO can carry out various tests to determine the quality of the land (soil and ground water) and as a result, potential health risks, material and financial loss can be significantly minimized. SPECTRO has the qualified personnel, a fully equipped drilling vehicle, efficient sampling and computer programs which make it possible to report results quickly. Every report drawn up for a soil study is tested against the applicable legal standards and our report will include a risk evaluation prognosis of soil pollution spread, together with a detailed plan of approach.

Stainless Steels
Stainless Steels are iron-base alloys containing Chromium. Stainless steels usually contain less than 30% Cr and more than 50% Fe. They attain their stainless characteristics because of the formation of an invisible and adherent chromium-rich oxide surface film. This oxide establishes on the surface and heals itself in the presence of oxygen. Some other alloying elements added to enhance specific characteristics include nickel, molybdenum, copper, titanium, aluminum, silicon, niobium, and nitrogen. Carbon is usually present in amounts ranging from less than 0.03% to over 1.0% in certain martensitic grades. Corrosion resistance and mechanical properties are commonly the principal factors in selecting a grade of stainless steel for a given application.
Stainless steels are commonly divided into five groups:
    > Martensitic stainless steels
    > Ferritic stainless steels
    > Austenitic stainless steels
    > Duplex (ferritic-austenitic) stainless steels
    > Precipitation-hardening stainless steels.

Snap Temper: A precautionary interim stress-relieving treatment applied to high hardenability steels immediately after quenching to prevent cracking because of delay in tempering them at the prescribed higher temperature.

Soaking: Prolonged heating of a metal at a selected temperature.

Stabilizing Treatment: A treatment applied to stabilize the dimensions of a workpiece or the structure of a material such as 1) before finishing to final dimensions, heating a workpiece to or somewhat beyond its operating temperature and then cooling to room temperature a sufficient number of times to ensure stability of dimensions in service; 2 ) transforming retained austenite in those materials that retain substantial amounts when quench hardened (see cold treatment); and 3) heating a solution-treated austenitic stainless steel that contains controlled amounts of titanium or niobium plus tantalum to a temperature below the solution heat-treating temperature to cause precipitation of finely divided, uniformly distributed carbides of those elements, thereby substantially reducing the amount of carbon available for the formation of chromium carbides in the grain boundaries on subsequent exposure to temperatures in the sensitizing range.

Selective Quenching: Quenching only certain portions of a workpiece.

Slack Quenching: The incomplete hardening of steel due to quenching from the austenitizing temperature at a rate slower than the critical cooling rate for the particular steel, resulting in the formation of one or more transformation products in addition to martensite.

Spray Quenching: Quenching in a spray of liquid.

Sulfur decreases ductility and notch impact toughness especially in the transverse direction. Weldability decreases with increasing sulfur content. Sulfur is found primarily in the form of sulfide inclusions. Sulfur levels are normally controlled to low levels. The only exception is free-machining steels, where sulfur is added to improve machinability.

Silicon is one of the principal deoxidizers used in steelmaking. Silicon is less effective than manganese in increasing as-rolled strength and hardness. In low-carbon steels, silicon is generally detrimental to surface quality.

SCLEROSCOPE OR SHORE HARDNESS - A hardness test performed on a Shore Scleroscope Hardness Tester. The hardness is determined by the rebound of a diamond pointed hammer (or tup) when it strikes the surface of a specimen. The hammer is enclosed in a glass tube and the height of the rebound is read either against a graduated scale inscribed on the tube, or on a dial, depending on the model used. This type of hardness testing is generally used on large parts which cannot be tested by either using a Rockwell or Brinell machine.

SUB-CRITICAL ANNEALING - Also Stress Relief Annealing. A heat treating operation used to relieve or dissipate stresses in weldaments, heavily machined parts, castings and forgings. The parts are heated to 1150” F., uniformly heated through, and are either air cooled from temperature or slow cooled from temperature depending on the type of part and subsequent finishing or heat treating operations.


 

T

TEAR STRENGTH: The force required to begin or to continue a tear in a fabric under specified conditions.

TEX: 1. A unit for expressing linear density, equal to the weight in grams of 1 kilometer of yarn, filament, fiber, or other textile strand. 2. The system of yarn numbering based on the use of tex units.

THREAD COUNT: 1. The number of ends and picks per inch in a woven cloth. 2. The number of wales and courses per inch in a knit fabric.

Temper Brittleness: Brittleness that results when certain steels are held within, or are cooled slowly through, a certain range of temperatures below the transformation range. The brittleness is revealed by notched-bar impact tests at or below room temperature.

Transformation Ranges or Transformation Temperature Ranges : Those ranges of temperature within which austenite forms during heating and transforms during cooling. The two ranges are distinct, sometimes overlapping but never coinciding. The limiting temperatures of the ranges depend on the composition of the alloy and on the rate of change of temperature, particularly during cooling.

Transformation Temperature: The temperature at which a change in phase occurs. The term is sometimes used to denote the limiting temperature of a transformation range.

Time Quenching: Interrupted quenching in which the duration of holding in the quenching medium is controlled.

Titanium is used to retard grain growth and thus improve toughness. Titanium is also used to achieve improvements in inclusion characteristics. Titanium causes sulfide inclusions to be globular rather than elongated thus improving toughness and ductility in transverse bending.

TEMPERING - Also termed drawing. Reheating hardened, usually quenched, steel to some temperature below the lower critical temperature followed by any desired rate of cooling after the steel has been thoroughly soaked at temperature. Usual tempering temperatures are 300” to 1100” F.