Refractories Introduction (1/2)
Properties of refractories are important and meaningful to , on the one hand , quality control of not only raw materials but also manufacturing factors , and on the other hand , to the assessment of performances of end products. The main functions of properties testing are summarized as follows:
1.Quality control,by manufacture of user
2.Evaluation of new material before in-plant trails
3.Post-mortem examination on refractories that have performed markedly better or worse than normal
4.Feedback to researcher and developer
In this teaching material ,we will introduce common properties and their tests of refractories ,categorized in five groups, ie. chemical and mineralogical composition , structural property,mechanical property,thermal property and service property.
Firstly,it is necessary to know what a refractory is. In early textbooks,refractory was defined as inorganic nonmetallic materials with refractoriness higher than 1580℃.However ,with the development of refractory industry and standardization, there comes a more scientific definition by ASTM C 71-01 , in which refractory is referred to those nonmetallic materials having specific chemical and physical properties that make them applicable for structures,or as components of systems, that are exposed to working environments above 1000F°（538°C). The major constituents of refractories are high melting point oxides , non-oxides, carbons and in some cases also some suitable metals.