Non-standard flanges are non-metallic materials with a refractory degree of not less than 1587℃. It should be adopted according to the product design requirements, and should conform to the current relevant national material standards. Non-standard flanges are affected by physical and mechanical movement in the high temperature environment, which may cause damage phenomena such as melting, softening, cracking and wear of refractory materials.
There are strict requirements for non-standard flange materials in the following aspects:
(1) the temperature of stainless steel and molten parts is high, there will be no change and molten parts at the working temperature;
(2) can withstand the stress caused by high temperature operation, no loss of structural strength, no deformation, no fracture;
(3) the volume is stable at high temperature, not due to expansion and contraction of the masonry deformation or crack;
(4) the non-standard flange is not broken and peeling off when the temperature changes or the heat is uneven;
(5) should have a certain ability to resist chemical erosion;
(6) It should have enough strength and wear resistance to withstand the scour and impact of high temperature and high speed flame, smoke and slag;

Large diameter flanges should have good working performance, can meet the requirements of pipe fittings connection quality, and comply with the relevant product protection, safety protection laws and regulations and technical specifications. Connect volume density. The ratio of the nozzle of non-standard flange products to its total volume, true density refers to the opening of various pore volumes excluding other pipe tail parts. The connection tightness is closed with one end of the nozzle, and the other end is connected with the outside world. The ability of gas to pass through the nozzle in safety is at room temperature and under a certain pressure, usually measured by the permeability coefficient.
The raw materials of non-standard flange large diameter flange are refractory materials, high temperature resistant materials, good sealing performance and some ordinary steel materials and heat-resistant metals. Reasonable selection of materials plays a very important role in ensuring the quality of large-diameter flange products, safe and economic operation and improving its service life.