Glossary |
Boiler and boiler tube industry terms and their definitions.
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| Machinability | A measure of the relative ease with which steel may be machined. |
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| Machining | The deliberate removal of metal by one or more of several processes. |
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| Macroetch | "A testing procedure for locating and identifying porosity, pipes, bursts, unsoundness, inclusions, segregations, carburization, flow lines from hot working, etc. Surface of the test piece should be reasonably smooth or even polished. After applying a suitable etching solution, the structure developed by the action of the reagent may be observed without a microscope." |
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| Magnaflux Test | This test is conducted by suitably magnetizing the material and applying a prepared wet or dry magnetic power or fluid which adheres to it along lines of flux leakage. It shows the existence of surface and slightly subsurface non-uniformities. |
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| Malleability | The property that determines the ease of deforming a metal when the material is subjected to rolling or hammering. The more malleable metals can be hammered or rolled into thin sheet more easily than others. |
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| Mandrel | "(1) A device used to retain the cavity in hollow metal products during workout. (2) A metal bar around which other metal may be cast, bent, formed, or shaped." |
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| Maraging | A process of improving the mechanical strength of certain ferrous alloys. The name was derived from two hardening reactions: martensite and aging. The maraging strengthening mechanism is based on the age hardening (precipitation hardening) of extra-low carbon martensite. |
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| Martensite | A constituent in quenched steel formed without diffusion and only during rapid cooling below the martensitic start (Ms) temperature. Martensite is the hardest of the transformation products of austenite. |
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| McQuaid-Ehn Test | A special test for revealing the austenitic grain size of ferretic steels when the steel is heated to 1700F and carburized. There are eight standard McQuaid-Ehn grain sizes- sizes 5 to 8 are considered fine grain and sizes under 5 are considered coarse grain. |
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| Mechanical Properties | "Those properties of a material that reveal the elastic and in-elastic reaction when force is applied, or that involve the relationship between stress and strain for example, the modulus of elasticity hardness, tensile strength and fatigue limit. These properties have often been referred to as """"physical properties,"""" but the term """"mechanical properties"""" is correct." |
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| Mechanical Tubing | "Used for a variety of mechanical and structural purposes, as opposed to pressure tubing, which is used to contain or conduct fluids or gases under pressure. It may be hot finished or cold drawn. It is commonly manufactured to consumer specifications covering chemical analysis and mechanical properties." |
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| Metallography | "The science dealing with the constitution, and structure of metals and alloys as revealed by the unaided eye or by such tools as low powered magnification, optical microscope, electron microscope and diffraction or X-ray techniques." |
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| Metric System of Measurements | "In the metric system of measurements, the principal unit for length is the meter: the principal unit for volume, the liter: and the principal unit for weight, the gram. The following prefixes are used for sub-divisions and multiples: milli = 1/1000: centi = 1/100: deci = 1/10: deca 10: hecto = 100: kilo = 1000. In abbreviations, the sub-divisions are frequently used with a smaller letter and the multiples with a capital letter, although this practice is not universally followed everywhere the metric system is used. All the multiples and the sub-divisions are not used commercially. Those ordinarily used for length are kilometer, meter, centimeter, and millimeter: for area square meter, square centimeter, and square millimeter: for volume, cubic meters, cubic decimeter (liter), cubic centimeter, and cubic millimeter. The most commonly used weights are the kilogram and gram. The metric system was legalized in the United States by an Act of Congress in 1866." |
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| Micro-Etch | Micro-etching is used for the examination of a sample under a microscope. Etching solutions tend to reveal structural details because of preferential chemical attack on the polished surface. |
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| Microcleanliness | Refers to the extent or quality of nonmetallic inclusions observed by examination under a microscope. |
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| Minimum Wall | Any wall having tolerances specified all on the plus side. |
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| Modulus of Elasticity | The ratio of stress applied to a material and the resulting strain occurring at the stresses below the elastic limit. |
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