Product Introduction
The ZG35Cr24Ni7SiN heat-resistant steel boiler pad block is a precision-cast high-temperature load-bearing support component, specially designed for industrial boilers, heat treatment furnaces, and various thermal processing equipment. This nitrogen-strengthened austenitic heat-resistant cast steel pad block maintains excellent dimensional stability and load-carrying capacity at continuous operating temperatures of 1100°C (with peak tolerance up to 1200°C).
As a critical furnace structural component, the ZG35Cr24Ni7SiN boiler pad block serves as a heat-resistant support foundation, protecting the furnace bottom structure, evenly distributing heavy workpiece loads, and maintaining precise alignment under extreme thermal cycling conditions. Unlike ordinary carbon steel pads, which rapidly oxidize, soften, and undergo dimensional creep at high temperatures, this advanced heat-resistant steel pad block retains its mechanical integrity and structural precision through thousands of thermal cycles.
It is melted in an electric arc or induction furnace, followed by precision casting and solution heat treatment, which optimizes microstructural uniformity and eliminates residual casting stresses.
The ZG35Cr24Ni7SiN boiler pad block is particularly suitable for boiler and furnace applications due to its unique metallurgical composition: a high-chromium, nickel, silicon, and nitrogen alloy system that provides a rare combination of oxidation resistance, thermal fatigue resistance, high-temperature strength, and creep resistance under temperature conditions where most commercial steel grades fail within months.
Chemical Composition & Material Design
The high-temperature performance of the ZG35Cr24Ni7SiN heat-resistant steel boiler pad block is achieved through a precisely balanced multi-alloy system:
| Element | Weight % | Functional Role |
| C | 0.30–0.40% | Forms austenitic matrix and enhances base strength; controlled to avoid compromising corrosion resistance |
| Cr | 23.0–25.5% | Forms dense, self-healing Cr₂O₃ oxide scale; primary barrier against oxidation and sulfidation |
| Ni | 7.00–8.50% | Stabilizes austenitic structure; prevents phase transformation during heating/cooling; enhances toughness |
| Si | 1.30–2.00% | Improves castability; accelerates oxide layer self-repair; raises oxidation resistance ceiling temperature |
| Mn | 0.80–1.50% | Solid-solution strengthens matrix; binds sulfur to prevent thermal embrittlement |
| N | 0.20–0.28% | Solid-solution strengthens austenite; forms fine Cr₂N carbonitride precipitates that pin grain boundaries; partially substitutes for nickel, reducing alloy cost while maintaining high-temperature performance |
| S | ≤ 0.03% | Closely controlled to eliminate hot cracking and thermal embrittlement |
| P | ≤ 0.04% | Strictly limited to prevent grain boundary embrittlement |
Key Features
Outstanding high-temperature oxidation resistance
ZG35Cr24Ni7SiN heat-resistant steel forms a stable Cr₂O₃ scale, effectively preventing scaling up to 1100°C.
High thermal fatigue and creep strength
Austenitic structure with nitrogen addition maintains structural stability and load-bearing ability under prolonged boiler service.
Excellent resistance to carburization and sulfidation
Ideal for coal-fired, biomass, and gas-fired boiler pad block applications where corrosive gases are present.
Precision-cast to near-net shape
Minimizes machining, preserves surface integrity, and ensures consistent dimensional accuracy for easy installation as a boiler support pad or wear pad.
Good weldability and repair capability
Allows post-service overlay or repair if needed, extending the total life of the pad block and adjacent furnace components.
Fully traceable quality
Every ZG35Cr24Ni7SiN boiler pad block is supplied with a material test certificate (MTC) showing actual chemical composition and mechanical properties.
Customization Capabilities
We offer comprehensive customization services for ZG35Cr24Ni7SiN boiler pad blocks:
- Dimensions: Custom sizes and shapes per customer drawings and specifications
- Load Capacity: Tailored to specific workpiece weight and application requirements
- Surface Treatment: Shot blasting, grinding, or other finishes as specified
- Structural Design: Custom rib configurations, reinforcement features, lifting holes, and positioning grooves
- Marking: Customer-specified identification markings, heat numbers, and certification tracking
Product Showcase
Company Advantages
When you source ZG35Cr24Ni7SiN heat-resistant steel boiler pad blocks from us, you gain a manufacturing partner dedicated to quality, precision, and international trade excellence.
Extensive Experience in Heat-Resistant Steel Casting
We cast high-temperature alloy castings and have over 20 years of foundry experience, covering grades such as ZG35Cr24Ni7SiN, ZG40Cr25Ni12Si2, ZG40Cr28Ni16, and other ASTM/ACI grades. Our boiler pad blocks and industrial furnace pad blocks have been supplied to boiler manufacturers and plant operators across Europe, North America, Southeast Asia, and the Middle East.
OEM/ODM Capability
Provide your 2D or 3D drawings, and our technical team will review the casting design, recommend draft angles, shrinkage allowances, and machining strategies to deliver boiler pad blocks with precise dimensions, reliable installation, and superior performance. We can also reverse-engineer from existing samples.
Custom Heat Treatment Process
Our solution annealing furnaces with precise temperature control ensure that your ZG35Cr24Ni7SiN pad blocks achieve the correct austenitic microstructure and outstanding high-temperature performance.
Short Lead Times and Flexible Logistics
Standardized production scheduling and export packaging (seaworthy wooden crates) ensure that boiler pad blocks, heat-resistant steel grate castings, and other industrial furnace wear pads are delivered to you on time via sea, air, or express.
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