What are Mullite Refractory Bricks?

What is the temperature of an ordinary flame? Generally speaking, the highest temperature flame is around 500℃. Of course, the flame temperature of different burning materials will also vary. What is the maximum temperature range of mullite refractories? According to test standards, the refractory temperature of mullite refractory bricks should be around 1200℃-1700℃! What is this concept? The iron-making temperature is generally around 1300-1500°C, and mullite refractory bricks can withstand the test of molten iron for a certain period.

Therefore, the fire-resistant properties of mullite refractory bricks are real. The ultra-high temperature performance of mullite refractory bricks makes it the first choice for high-temperature furnace construction. However, on January 19, 2018, the national standard “mullite” officially implemented the testing of “refractory bricks” (GB845). Of course, we are unfamiliar with the various testing indicators specified in the new standards. Below, Henan refractory brick manufacturer Xinhongji Refractory will introduce them to you in detail.

First, the mullite refractory brick license plate logo is divided into 7 levels, mg-23, mg-25, mg-26, mg-27, mg-28, mg-30, and mg-32. When the change rate of the heating line is less than 2%, the corresponding test temperatures are 1230°C, 1350°C, 1400°C, 1450°C, 1510°C, 1620°C, and 1730°C.

Secondly, the physical and chemical test indicators of mullite refractory bricks mainly include alumina content, iron oxide content, bulk density, normal temperature compressive strength, heating permanent linear change rate, thermal conductivity, 0.05Mpa load softening temperature, anti-flaking performance, and other indicators. It is pointed out that measuring the linear density and density of mullite refractory materials is the key to measuring its fire resistance.

Then, the inspection indicators for the appearance and allowable deviation of mullite refractory bricks mainly include shape size, size allowable deviation, twist deviation, corner length, side length, hole diameter, crack length, and relative edge deviation. For some special types of mullite refractory bricks, the allowable crack length can be determined according to the supply and demand agreement.