Testing indicators of mullite firebricks

What is the temperature of a regular flame?  The external flame that generally belongs to the highest temperature of the flame is only around 500 ℃, but of course, the flame temperature will also vary depending on the combustion material. So what is the maximum refractory temperature range for mullite refractory bricks? According to its testing standards, the refractory temperature of mullite refractory bricks should be around 1200 ℃ -1700 ℃! What is this concept? The temperature for ironmaking is generally around 1300-1500 ℃, and mullite refractory bricks can theoretically withstand the test of molten iron for a certain period of time.

The fire resistance performance of mullite refractory bricks is truly genuine. The ultra-high temperature resistance makes mullite refractory bricks the preferred material for high-temperature furnace construction. The national standard for testing mullite refractory bricks, GB/T 35845-2018 "Mullite based thermal insulation refractory bricks", was officially implemented on January 1, 2019. For the various testing indicators specified in the new standard, you are definitely not very familiar with them. Below, the editor will provide a detailed introduction for you.

Firstly, the license plate identification of mullite refractory bricks is mainly divided into seven levels, namely MG-23, MG-25, MG-26, MG-27, MG-28, MG-30, and MG-32. The corresponding experimental temperatures with a heating line change rate not exceeding 2% are 1230 ℃, 1350 ℃, 1400 ℃, 1450 ℃, 1510 ℃, 1620 ℃, and 1730 ℃.

Secondly, the physical and chemical testing indicators of mullite refractory bricks mainly include alumina content, iron oxide content, bulk density, room temperature compressive strength, permanent linear change rate during heating, thermal conductivity, 0.05MPa load softening temperature, and anti stripping performance. It should be pointed out that the high-temperature creep performance and density of mullite refractory bricks are the key to measuring their quality performance, and their corresponding detection indicators are the heating permanent linear change rate and volume density.

Then, the appearance and allowable deviation detection indicators of mullite refractory bricks mainly include shape and size, allowable deviation in size, twist deviation, length of missing corners, length of missing edges, diameter of karst caves, crack length, and relative edge difference. It is worth noting that for some specific types of mullite refractory bricks, the allowable crack length can be determined by mutual agreement between supply and demand.