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Your search for "s" found 30 matching terms. Click here to search again.

Term	Definition
S	Chemical symbol for Sulphur.
Salt Bath	A method of heating steel using a bath of molten salts. Salt baths give uniform heating and prevent oxidation, they are used for hardening, tempering or quenching. The type of salt used depends on the temperature range required. For hardening, sodium cyanide, sodium carbonate and sodium chloride are in common use.
Sb	Chemical symbol for Antimony.
Scale	The oxidised surface of steel produced during hot working, as in rolling, and by exposure to air or steam at elevated temperature.
Scarfing	Also termed deseaming. It is a process for burning out defective areas on the surface of ingots or semi-finished products such as billets so that the product is suitable for subsequent rolling or forging.
Scrap	It forms the basic raw material for making steel by the electric arc process. Steel offers ecological advantages as it can be recycled enabling the discarded car of today to appear as part of a new model tomorrow. Scrap is sorted and graded before use and the necessary elements are added during the steel making process to achieve the desired specifications.
Se	Chemical symbol for Selenium. Seams A surface defect caused during the steel making process. Seams are generally formed from blow holes in the ingot, non metallic inclusions, or stresses arising during the solidification stage. They appear as longitudinal discontinuities in the bar.
Secondary Hardness	An increase in hardness which sometimes occurs when hardened steel is re-heated. It can be caused by the transformation of retained austenite to martensite or by the precipitation of alloy carbides.
Segregation	A term applied to the concentration and partial separation of one or more elements from solution during solidification of liquid steel in an ingot mould. Sulphur and phosphorus tend to segregate to a greater extent than other elements which can have a particular adverse effect on machinability in high sulphur free- cutting steels. Modern steel making and continuous casting have largely overcome this problem.
Selenium	An element that closely resembles sulphur in its properties. The main use in steel is as a freecutting additive but due to high cost its use is limited to stainless steel. One of the benefits being the ability to obtain a very good surface finish on machined components.
SG Iron	An abbreviation for Spheroidal Graphite Cast Iron. As the name implies, graphite is present in spheroidal form instead of flakes and compared with Grey Cast Iron it has higher mechanical strength, ductility and increased shock resistance.
Shearing Test	The test applied to metal to determine the stress required to fracture it across its section.
Sherardizing	A process developed in Britain in 1904 by Sherard Cowper-Coles. It is a method of producing a protective zinc coating on iron and steel products.
Shore Scleroscope	An instrument that measures the hardness of a sample in arbitrary terms of elasticity. A diamond tipped hammer is allowed to fall freely down a graduated glass tube on to the sample under test. The hardness is measured by the height of the rebound. In another form the rebounding hammer actuates the pointer of a scale so that the height of the rebound is recorded.
Spinning	The formation of sheet metal blanks into hollow circular shapes. This is carried out on a lathe with forming tools which service to press and shape the metal. Annealing may be needed during and/or after the operation to remove the effects of work hardening.
Spot Welding	A process for joining steel sheets. The two parts are held between electrodes and the heat generated at the interface between the sheets causes local welding when pressure is applied.
Spring Steel	The steels used for spring making depend on the application and type of spring. They range from plain carbon grades in the range 0.5% to 1.00% C. to Chromium, Chromium-Vanadium, Nickel-Chromium-Molybdenum, Silico- Manganese and Silicon-Manganese-Chromium-Molybdenum types. Full details can be found in BS5770.
Stabilisation	A term applied to a number of processes: a) A type of heat treatment to relieve internal stresses: b) The retarding or prevention of a particular reaction by the addition of a stabilising element; c) A thermal and/or mechanical treatment given to magnetic material in order to increase the permanency of its magnetic properties or condition.
Stainless Steel	Can be defined as a group of corrosion resisting steels containing a minimum 10% chromium and in which varying amounts of nickel, molybdenum, titanium, niobium as well as other elements may be present. An Englishman, Harry Brearley, is generally acknowledged to be the pioneer who developed stainless steels for commercial use.
Steel	Generally defined as a metallic product whose principal element is iron and where the carbon content is not more than 2%. (The presence of large quantities of carbide forming elements may modify the upper limit of the carbon content.)
Strain Ageing	The gradual changes in physical and mechanical properties, in particular hardness and tensile strength, which takes place following cold rolling or deformation. At atmospheric temperatures, this may take place over a number of weeks but can be accelerated by heating.
Strain Hardening	The loss of ductility and gain in hardness resulting from strain ageing.
Stress Relieving	A heat treatment including heating and soaking at a suitable temperature (e.g. 600-650oC) followed by cooling at an appropriate rate in order to reduce internal stresses without substantially modifying the steel's structure. This treatment may be used to relieve stresses induced by machining, quenching, welding or cold working.
Stress Strain Curve	A graph in which stress (load divided by the original cross sectional area of the test piece) is plotted against strain (the extension divided by the length over which it is measured).
Sub-Critical Annealing	Heating to, and holding at, some point below the critical temperature. Subsequent cooling may be in air. This form of heat treatment has a variety of uses depending on the temperature and specification of the steel, its purpose is often to soften the material.
Sub-zero Treatment	A low temperature treatment carried out after quenching on hardened steel to transform the retained austenite into martensite. It involves immersing the component in a bath of solid carbon dioxide at a temperature of minus 70-80oC.
Sulphur	Generally regarded as an impurity in steel as it can have detrimental effects on strength, ductility and weldability as well as producing hot and cold shortness. Its content in most steels is limited to a maximum of 0.050%. Sulphur is beneficial to machining and is added to freecutting steels in amounts up to 0.35% with the manganese content increased to overcome any detrimental effects.
Surface Hardening	A method of hardening the surface of steel to increase its wear resistance. Depending on the analysis of the steel, the following treatments can be employed: Case-hardening, Nitriding, induction hardening, Flame hardening.
Swaging	A method of forming or reducing steel or other metals to a desired shape by a series of blows rapidly applied by dies or hammers. The process is applied to wires, rods and tubes and can be used for a variety of pointing, tapering, sizing and reducing operations.
Swarf	The particles of metal arising from machining or grinding operations, much of it finds its way to the steel maker for remelting.

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