How the grate material affects its durability

Grate material affects durability through high-temperature stability, wear resistance and corrosion resistance. Selection should weigh the sulphur and ash content of the fuel, the furnace temperature range and the operating environment.

High-temperature stability

A grate made of heat-resistant steel (such as ductile iron or alloy steel) or high-temperature steel works stably in the 700-900℃ range and clearly reduces creep and thermal fatigue. Nickel-chromium heat-resistant alloys resist extreme temperature swings and avoid fracture or deformation from uneven thermal expansion. Ceramic grates have excellent heat resistance, reaching above 1200℃, but weak thermal shock resistance, so they suit constant temperatures without severe changes.

Wear resistance and mechanical strength

Stainless steel (such as 316L) and high-strength alloy steel have high surface hardness (HRC≥50), which reduces wear from fuel particle friction and extends bar life. Structural measures such as stepped grate bars combined with wear-resistant material disperse local stress and lower the risk of fracture. High-temperature bonded refractories such as silicon carbide composites improve surface density and wear resistance for high-ash fuels.

Corrosion resistance

Sulphur and acid gases in the fuel, chloride ions and oxidising conditions all affect grate life. With chloride-bearing fuels such as biomass, austenitic stainless steel or ceramic resists chloride penetration and oxidation corrosion.

Material selection and maintenance

The table gives the applications and durability advantages of each material type.

Even with a suitable material, ash must be cleaned regularly, furnace temperature swings controlled and combustion parameters adjusted to the fuel so that corrosive gases are reduced and grate life extended.