Refractoriness under load

Thermomechanical properties, e.g. softening under load, creep in compression, refractoriness under load and thermal shock resistance. 

The refractory bricks in common use are composed of mixtures of silica (SiOi) and alumina (AI2O3). The quality of the bricks is largely determined by the relative amounts of these materials and the firing temperature. Mixtures of silica and alumina form a eutectic (94.5% Si02, 1545°C), and for a high refractoriness under load... 

The refractoriness-under-load method described above has a number of drawbacks which should be taken into account ... 

Strength It is the resistance of the refractory against load shear stresses etc. In refractoriness, under load is important as some refractories fail at a lower temperature when subjected to load. 

ASTM C-832 Measuring the thermal expansion and creep of refractories under load... 

ISO 1893 2005 Refractory products - determination of refractoriness under load - differential method with rising temperature... 

Refractoriness-under-Load. The ability of a material to withstand specified conditions of load, temperature and time. Details of variations in this test will be found in the following national standards Britain-B.S. 1902 USA-ASTM-C16 Germany-DIN 51064 France-AFNOR B49-105. B.S. 1902 specifies a dilatometer method (Pt. 4.8)... 

DIN EN 993-8. Methods of testing dense shaped refractory products - Part 8 Determination of refractoriness-under-load. 

Ceramics are widely used as insulators, primarily in various kinds of furnaces. The class of ceramics used for this purpose is called the refractories. Apart from heat resistance, these refractories should also possess a thermo-mechanical property called refractoriness under load (RUL). This chapter focuses on the various thermal and thermo-mechanical properties of ceramics. 

The most important property of silica bricks is its very high refractoriness under load (RUL). This is due to interlocking tridymite needles. These bricks... 

Figure 2 Collection of test pieces made of unshaped refractories. Description from left to right (Top) Two bricks for measuring thermal conductivity (230 x 114 x 76 mm) Shape A according to EN cup for slag tests (100 x 100 x 100 mm, hole 50 mm in diameter and depth). (Middle) Test piece for measuring abrasion resistance according to ASTM C 704 (114 x 114 x 40 mm) test piece according to special specifications for petrochemical industry (230 x 50 x 50 mm) drilled 50 mm cylinders out of a shape B (one with 12.5 mm hole for determination of Refractoriness Under Load or Creep Under Compression). (Bottom) Shape B according to EN 3 cubes for petrochemical specifications (50 x 50 x 50 mm) Shape C according to EN.

The individual descriptions and properties are to some extent very differentiated. Consequently, this code system is quite expUcit. This is also proven by the fact that digits 11 and 12 indicate the refractoriness under load classification temperature by way of a hot test and the permanent linear change after prefiring. 

Refractoriness under load is the ability of a material to withstand specific conditions of load, temperature, and time (1). This is dependent on the softening point and the amount of glass or melt phase within the refractory system. 

Measurement methods vary. Both horizontal and vertical measuring techniques exist, and test piece sizes vary between 114 mm long x 38 mm x 38 mm in the ASTM standard test (3), which combines thermal expansion with a refractoriness under load test, down to small rectangular prisms of 55 mm x 10 mm x... 

Refractoriness under load Thermal shock resistance... 

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