Regarding the refractoriness of refractory materials and refractory fibers, the following is a compilation based on information sources such as Baidu Baike:

Refractory materials
Refractory materials refer to inorganic non-metallic materials or products with a fire resistance greater than 1500 ℃ (note: there are also claims that it is greater than 1580 ℃, but the definition of the International Organization for Standardization shall prevail here). These materials can maintain their physical and chemical properties at high temperatures and are not easily melted, softened, or deformed, making them widely used in various high-temperature industrial fields such as metallurgy, chemical engineering, building materials, glass, etc.

The refractoriness is the basis for determining whether it can be used as a refractory material, and it characterizes the resistance performance of the material under high temperature. However, refractoriness is not the upper limit of the operating temperature of refractory materials, because when refractory materials reach refractoriness, a considerable proportion of liquid phase is already generated, and their mechanical strength and corrosion resistance will significantly decrease.

Refractory fiber
Refractory fiber is a general term for fibrous insulation materials with a fire resistance greater than 1500 ℃. It has the characteristics of general fibers, such as softness, high strength, and also has high temperature resistance, corrosion resistance, and oxidation resistance. These characteristics make refractory fibers an efficient insulation material, widely used in the insulation of various high-temperature equipment.

The refractoriness of refractory fibers is also influenced by factors such as their chemical composition, dispersion, proportion of liquid phase, and viscosity of the liquid phase. Due to differences in raw materials and preparation processes, the refractoriness of different refractory fiber products may also vary.

summary
Refractory materials refer to inorganic non-metallic materials with a fire resistance greater than 1500 ℃, widely used in high-temperature industrial fields.
Refractory fiber is a fibrous insulation material with a fire resistance greater than 1500 ℃, which has the properties of softness, high strength, high temperature resistance, corrosion resistance, and oxidation resistance.
The refractoriness and melting point are different, and they characterize the softening and melting characteristics of materials at high temperatures.
The refractoriness of refractory materials and refractory fibers are influenced by various factors, including chemical composition, dispersion, liquid phase ratio, and liquid phase viscosity.
Therefore, when selecting and using refractory materials and refractory fibers, it is necessary to choose suitable materials and products based on specific working conditions and requirements.