Common Heat-Resistant Cast Iron Materials for Grate Bars

Heat-Resistant Cast Iron (Mid-Range Mainstream, Most Commonly Used in Industrial Chain Grates)

National standard system: silicon-series, chromium-series, and aluminum-series heat-resistant cast iron (GB/T 9437), divided into three sub-series.

1. Medium-Silicon Heat-Resistant Cast Iron RTSi5 (RQTSi5)

• Temperature resistance: 750–900°C
• Performance: Silicon element improves oxidation resistance and high-temperature growth resistance; excellent casting properties, moderate price; relatively high brittleness, prone to cracking under rapid temperature changes;
• Applicable: Small and medium-sized coal-fired chain grates, reciprocating grates, biomass atmospheric boilers (moderate temperature conditions)

2. Chromium-Series Heat-Resistant Cast Iron RTCr2, RTCr16

• RTCr2: Temperature resistance 800°C, general-purpose basic heat-resistant cast iron;
• RTCr16: High-chromium heat-resistant cast iron, temperature resistance 950°C, significantly improved oxidation resistance and sulfur corrosion resistance;
• Advantages: toughness superior to silicon cast iron, better resistance to flue gas sulfur corrosion; Disadvantage: cost higher than silicon cast iron;
• Applicable: Industrial steam coal-fired boilers, high-sulfur coal combustion, medium-load chain grate bars (the most widely used material in domestic industrial boilers)

3. High-Aluminum Heat-Resistant Cast Iron

• Temperature resistance up to 1000°C, moderate cost, but highest brittleness and worst thermal shock resistance;
• Only used for fixed grates with stable temperatures and no frequent startup/shutdown; now being gradually phased out.

Overall Summary of Heat-Resistant Cast Iron

✅ Cost-effective first choice for small and medium-sized industrial coal/biomass boilers; ❌ Not suitable for: waste incineration, high-temperature furnaces, frequently started/stopped boilers, high-chlorine corrosion flue gas environments.