2014年7月4日星期五

CBN abrasive grit Meaning and effect of high temperature refractory

Meaning and effect of high temperature refractory                                                                                          Refractoriness is the material reaches a certain degree of softening temperature under high temperature, high temperature performance characterization of the material to resist.
Significance of refractoriness and different melting  brown fused aluminum oxide  points indicated. The crystalline melting point of the liquid to the solid phase at body temperature equilibrium. Refractoriness multiphase body reaches a certain degree of softening temperature. The vast majority of ordinary refractories, for both the multiphase heterogeneous materials, without necessarily melting point, it began to appear liquid to completely melt is a gradual process, in a fairly wide temperature range, solid-liquid phase coexistence. Gu Yu Characterization softening and melting characteristics of this material at high temperature can be measured in refractoriness.
Refractory material is not a specific absolute quantities, the material is measured under specified test conditions to achieve the particular degree of softening of the relative time specification. The test material made according to the method prescribed truncated triangular pyramid (referred to as test cone), and has a fixed bend down at a specific temperature, heating rate standard temperature truncated triangular cone (referred to as standard cone) of servers in a given heating rate and a certain heating under atmospheric conditions, in  Glass beads  order to test the degree of bending down cone with a standard cone bend down quite a contrast method for determining the degree of refractoriness. Under the sea bottom truncated cones, long 8mm, on the sea bottom 2mm, height 30mm. When measured, the cone angle may be in the liquid phase at elevated temperatures. With increasing temperature, increasing the amount of liquid, the liquid viscosity is reduced, the cone softened. When softened to a certain extent, the effect of its own weight cone gradually bend down. When tested with a standard taper cone while bending down until its apex in contact with the chassis, then this standard inverted cone curved determined temperature prevail, as the test cone refractoriness. Our general  steel fiber for concrete  standard cones and cone bent down to WZ temperature tenth bid. If the test standard taper cone and WZ171 No. bend down simultaneously, the refractoriness of the sample is 1710 ℃. Many other countries Seck cone (SK) as a standard cone, specific measurement method is slightly different.
[1] refractoriness refractory is an important technology assessment indicators. However, not as a product temperature limit. Polycrystalline refractory material composed of a single phase, which is generally lower than the melting point of the crystal refractoriness. However, some refractory material, such as when high viscosity liquid form, which can be higher than the melting point of refractoriness.

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