the relative size of individual, microscropic crystals of steel
A term relating to the size of grains. (See above)
The average size of the crystals or grains in a metal as measured against an accepted standard.
The average diameter of grains, usually determined microscopically, on an etched plane surface of the metal as described in ASTM Standard Method E112.
Refers to the size of individual mineral crystals or particles within a rock or sediment deposit.
Size of the particles or crystals that constitute a rock or sediment; hence fine, medium, or coarse-grained.
The term normally applies to the austenitic grain size as determined in carbon and alloy steels by the McQuaid-Ehn test. ASTM E 112 defines methods for rating grain size. When specifying grain size it should be clearly stated when austenitic grain size is required and when ferrite particle size is required.
(4) the size range of fragments or crystals in consolidated materials. A description of the textural coarseness of a rock.
The second element in standard grinding wheel marking system or, in a more general meaning, the average size of abrasive grains used to make a wheel, coated abrasive or other product. Traditional sizing is based on mesh sizes where a number indicates openings per inch of screening mesh. However, a number of other measurement systems are also common such as measurements for very small grit size in units of millionth of a meter, or micron. Special sizing systems established by ANSI, CAMI, FEPA and others are used for coated abrasives where the average size of elongated abrasives is difficult to determine. Contact AES for size conversion tables.
A measure of the average (or median) size of a partricular mineral in a rock. Often measured by the linear intercept method, although modern image analysis is replacing this. Units can either be area, volume, or diameter length.
The number of fundamental entities, or members, in a grain. For example, if a grid is spatially decomposed into subgrids, then the grain size is the number of grid points in a subgrid.
Grain size is normally quantified by a numbering system. Coarse 1-5 and Fine 5-8. The number is derived from the formula N=2^(n-1) where n is the number of grains per square inch at a magnification of 100 diameters. Grain size has an important effect on physical properties. It is generally considered that fine grain steels have a better combination of strength and toughness, whereas coarse grain steel have better machinability.
The average diameter of grains in the metal under consideration, or alternatively, the number of grains per unit area. Grain size is a significant issue since an increase in grain size is accompanied by lower ductility and impact resistance. The addition of certain metals to steel affects grain size. Vanadium and aluminum tend to give steel a fine grain when added. The ASTM has set up a grain size standard for steels.
