Shata Machinery has been deeply engaged in the customized production and processing of castings for nearly 20 years.
The company possesses the expertise to address common in-service issues of boiler air caps-such as cracking, wear, and ablation-along with production defects including sand holes, air holes, and dimensional inaccuracies.
Shata Machinery custom-manufactures boiler air caps tailored to specific requirements.
Backed by a professional technical team, the company helps minimize process defects, installation difficulties caused by dimensional deviations, and hidden costs arising from frequent replacements.
About Boiler Air Caps
A boiler air cap is a high-temperature resistant casting accessory designed exclusively for boilers, typically available in mushroom, bell, or cylindrical shapes.
It serves as an essential component for fluidized bed boilers and biomass boilers, manufactured entirely from cast metal.
The core functions of a boiler air cap are twofold: first, to distribute air volume evenly, ensuring full combustion of fuel within the furnace chamber; second, to prevent ash and slag from falling into the furnace and avoid blockages in the boiler air duct.
This functional requirement makes high temperature resistance and wear resistance essential characteristics of boiler air caps.
General Parameters of Boiler Air Caps
| Parameter Item | Common Specification / Range |
|---|---|
| Product Name | Boiler Air Cap |
| Outer Diameter | φ50–φ150mm; common sizes: φ80, φ100, φ120mm (customizable per drawing) |
| Overall Height | 100–300mm (customizable per drawing) |
| Ventilation Hole Diameter | φ3–φ8mm (customizable per drawing) |
| Structure Type | Mushroom, Bell, Straight Cylinder, Inverted Taper; customizable upon request |
| Casting Process | Resin Sand Casting, Silica Sol Investment Casting, Lost Foam Casting |
| Common Materials | Heat-resistant Cast Steel ZG35Cr24Ni7SiN (24/7 High-Nickel Heat-resistant Cast Steel), ZG40Cr25Ni20Si2 (2520 Heat-resistant Cast Steel), Cr25Ni20 (2520 Stainless Steel), ZG8Cr26Ni4Mn3NRe (High-Chromium Rare Earth Heat-resistant Steel) |
| Applicable Boilers | Circulating Fluidized Bed Boiler, Biomass Boiler, Coal-fired Fluidized Bed Furnace, Industrial Power Station Boiler |
| Temperature Resistance | Regular: 800–1100℃; High-temperature Resistance: above 1200℃ |
| Product Features | High Temperature Resistance, Wear Resistance, Slag Leakage Prevention, Blockage Prevention, Uniform Air Distribution |
Comparison of Casting Processes for Boiler Air Caps
| Comparison Dimension | Resin Sand Casting | Lost Foam Casting | Silica Sol Investment Casting |
|---|---|---|---|
| Precision & Surface | Medium; better than ordinary sand casting, slightly inferior to investment casting and lost foam casting; slight sand texture on surface, requires post-processing | Medium-high; no parting line, no flash or burrs, surface precision far better than resin sand casting | Highest precision and smoothest surface among the three processes, small dimensional deviation |
| Product Structure | Suitable for large-sized, simple-structured, conventional boiler air caps | Excels in integrated forming of complex structures and special-shaped flow passages; can produce special shapes difficult for ordinary sand casting | Suitable for ultra-complex special-shaped and high-precision small air caps; few structural forming limitations, not suitable for large castings |
| Batch Adaptation | Suitable for small-batch production; long cycle for medium-large batches | Preferred for medium-large mass production; high mold cost allocation for small-batch orders | Suitable for small-medium batches and high-end customization; not suitable for oversized parts or low-cost high-volume orders |
| Internal Quality | Mature process, controllable casting defects, meets conventional high-temperature service requirements | No parting defects, uniform internal structure, low incidence of air holes and slag inclusions | Dense and porosity-free castings with excellent high-temperature and corrosion resistance |
| Cost & Production Cycle | Wood or aluminum molds with low cost and fast mold opening; lowest basic production cost, small overall investment, suitable for budget-limited conventional orders | Higher upfront cost than resin sand casting, stable mass production cycle; cost-effective for large-batch production, high cost for small batches | High wax mold cost and long mold opening cycle; highest overall cost among the three, suitable for high-end and high-requirement castings |
Recommended Heat-resistant Cast Steel for Different Working Conditions
For ordinary circulating fluidized bed boilers, conventional biomass boilers, coal-fired industrial boilers, and medium furnace temperature conditions with high operating intensity, ZG35Cr24Ni7SiN (24/7 High-Nickel Heat-resistant Cast Steel) is recommended.
The addition of nitrogen enhances its high-temperature strength, corrosion resistance, and thermal fatigue resistance.
For large power station fluidized bed boilers with ultra-high furnace temperatures, high-load continuous operation, heavy ash accumulation, and severe erosion and wear, ZG40Cr25Ni20Si2 (2520 Heat-resistant Cast Steel) is the recommended material.
It offers a stable structure and reliable performance in high-temperature environments.
For power plant boilers, circulating fluidized bed (CFB) boilers and other high-temperature applications, as well as boilers exposed to mildly corrosive flue gas, high temperature with moderate erosion, and humid or easily oxidizing environments, Cr25Ni20 (310S/2520 Stainless Steel) is the preferred material.
This material provides superior surface corrosion resistance, oxidation resistance, and high-temperature tolerance.
For boilers burning inferior coal or high-ash fuel, fluidized beds with heavy dust and severe particle erosion, and conditions prone to slagging and intense abrasion, ZG8Cr26Ni4Mn3NRe (High-Chromium Rare Earth Heat-resistant Steel) is recommended.
Its high chromium composition delivers outstanding wear resistance, slag resistance, and resistance to high-temperature coking.
why choose us
For purchasing inquiries, please contact Shata Machinery directly.
Simply provide product requirements, specifications, or engineering drawings. The technical team at Shata Machinery will evaluate the requirements promptly and deliver an accurate customized quotation.
In the early stages of cooperation, Shata Machinery provides finished samples for confirmation or adjustment by the client, followed by mass production in accordance with the approved standard samples.
Shata Machinery offers one-stop professional services to ensure on-time delivery.
Backed by extensive production experience, the company manufactures boiler air caps with enhanced structural stability and superior quality.
Shata Machinery sincerely looks forward to establishing friendly cooperation for mutual development and shared success.
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