Heat-Resistant Steel Castings
Welcome to Bhanu Special Castings Pvt. Ltd. – your trusted partner for high-performance heat-resistant steel castings in Vijayawada and across India. As a specialized high-temperature alloy foundry, we manufacture heat-resistant austenitic steels with chromium contents of 15–35% and nickel 8–37% (depending on grade), delivering excellent oxidation resistance, creep strength, and thermal cycling stability for furnace components, kiln systems, heat exchangers, reformer tubes, and petrochemical reactors operating in the 650–1100°C range.
Heat-resistant steel castings rely on high chromium (typically 15–35%) to form a protective chromium oxide scale that resists oxidation and carburization, while nickel (8–37%) stabilizes the austenitic structure for superior creep resistance and thermal shock performance. These alloys maintain useful mechanical properties at elevated temperatures—for example, grade HK (24–28% Cr, 18–22% Ni) provides good stress-rupture strength (typically 10–30 MPa range depending on time and load conditions) at 1000°C—making them essential for long-term service in industrial furnaces, ethylene crackers, cement kilns, and heat-treatment applications where carbon steel fails rapidly due to oxidation.
Our heat-resistant steel castings offer outstanding performance, including excellent oxidation resistance with protective scale formation, high creep strength at elevated temperatures, superior thermal shock resistance during cyclic heating/cooling, and good resistance to carburization and nitriding in aggressive atmospheres. Produced to ASTM A297 (grades HH, HK, HT, HL, HN, HP) and A351 (e.g., HF, HH) standards, these castings are ideal for furnace trays, pots, and conveyor rolls, kiln cars and roller supports, reformer tubes and cracker coils, retort baskets and fixtures, as well as radiant tubes and burner nozzles. Every casting undergoes advanced heat treatment and high-temperature testing to meet the stringent demands of the heat treatment, petrochemical, cement, and power generation industries.
Our Product Range
We manufacture high-temperature heat-resistant castings engineered for severe oxidation, thermal cycling, and creep resistance:
- Furnace Components Trays, pots, muffles, conveyor rolls, and pusher bars for continuous furnaces.
- Kiln Systems Kiln cars, roller supports, cooler plates, and burner nozzles.
- Heat Treatment Fixtures Retort baskets, jigs, load bars, and support rails for carburizing and annealing operations.
- Petrochemical Components Reformer tubes, cracker hangers, and catalyst support systems.
- Power Generation Components Boiler hangers, superheater supports, and soot blower parts.
- Radiant Tubes & Burners U-tubes, W-tubes, straight radiant tubes, and recuperator components.
- Glass Industry Components Furnace supports, feeder parts, and annealing lehr rolls.
- Custom High-Temperature Castings Application-specific designs engineered for your operating temperature and furnace atmosphere.
Weight Range: 0.5 kg to 4000 kg | Service Temperature: 650–1150°C
Industry Applications
Our heat-resistant steel castings serve critical high-temperature applications across:
- Heat Treatment Industry Carburizing, nitriding, and annealing furnaces operating between 850–1050°C.
- Petrochemical Processing Ethylene crackers, reformers, and pyrolysis furnaces operating up to 1150°C.
- Cement Manufacturing Rotary kilns, clinker coolers, and preheaters operating between 900–1450°C.
- Power Generation Coal-fired boilers, superheaters, and CFB boilers operating between 650–850°C.
- Steel Industry Reheating furnaces, annealing lines, and galvanizing baths operating up to 1200°C.
- Glass Manufacturing Melting furnaces, lehrs, and feeder systems operating up to 1500°C with refractory support.
- Aluminum & Non-Ferrous Processing Holding and homogenizing furnaces operating between 450–650°C.
- Waste Incineration Grate bars, ash handling systems, and flue gas components operating between 850–1050°C.
Heat-resistant steel castings contain 15-35% chromium forming protective Cr2O3 scale (oxidation barrier) and 8-20% nickel stabilizing austenite structure for high-temperature strength. Common grades: HH (25Cr-12Ni, 1000°C max), HK (25Cr-20Ni, 1100°C max), HT (15Cr-35Ni, 1150°C max), HP (25Cr-35Ni, petrochemical service). These alloys maintain creep strength at elevated temperatures where carbon steel loses 90% of room-temperature strength—enabling continuous operation in furnaces, kilns, reformers, and heat exchangers that form the backbone of heat treatment, petrochemical, and cement industries.
Manufacturing Process & Key Properties
Our heat-resistant foundry employs controlled Cr-Ni alloy addition with solution annealing to produce austenitic castings with optimal oxidation resistance and creep strength.
Alloy Melting & Casting
Precise Cr (15-35%), Ni (8-35%) control, electric induction/AOD refining, controlled atmosphere to prevent oxidation losses.
Solution Treatment
1000-1150°C solution annealing, rapid quench to retain austenite, stress relief at 650-750°C for dimensional stability.
High-Temp Testing
Oxidation testing (1000°C, 100h), creep-rupture testing, hot hardness, dimensional stability verification after thermal cycling.
| Grade | Composition (Cr-Ni) | Max Temp | Key Features | Applications |
|---|---|---|---|---|
| HH (310) | 25% Cr, 12% Ni | 1000°C | Good oxidation, economical | Heat treatment fixtures, kiln cars |
| HK | 25% Cr, 20% Ni | 1100°C | Superior creep, best balance | Furnace trays, conveyor rolls |
| HT (330) | 15% Cr, 35% Ni | 1150°C | Maximum creep strength | Petrochemical tubes, reformers |
| HP | 25% Cr, 35% Ni | 1100°C | Carburization resistant | Ethylene crackers, pyrolysis |
- Outstanding Oxidation Resistance: Chromium oxide scale <0.5mm /year at 1000°C; 10-15 year service life vs. months for carbon steel.
- Excellent Creep Strength: Maintains 10-15 MPa strength at 1000°C enabling load-bearing furnace components; carbon steel has <2 MPa.
- Superior Thermal Cycling: Austenite structure resists thermal fatigue; handles 500+ heat-cool cycles without cracking (heat treatment furnaces).
- Carburization/Nitriding Resistance: HP grade resists carbon/nitrogen pickup in petrochemical atmospheres preventing embrittlement.
Quality Assurance & Customization
We provide fully customized heat-resistant steel castings with grade selection (HH to HP), solution treatment optimization, and geometry design for your specific temperature/atmosphere. Every casting undergoes Cr/Ni verification, high-temperature oxidation testing, creep testing, and dimensional inspection per ASTM A297, A351 standards. Complete test certificates with oxidation data and thermal cycling results provided.
High-Temp Specialists
30+ years manufacturing furnace components; 1000+ heat treatment furnaces use our HK trays with 10-15 year life.
Oxidation Testing Lab
In-house 1000°C oxidation furnace, creep-rupture testing, metallographic lab verifying austenite microstructure.
Application Engineering
Grade selection for your temperature/atmosphere, fixture design, thermal expansion calculations, field support.
Grades and Applications of Heat-Resistant Steel Castings
Our Heat-Resistant Steel castings are manufactured in multiple grades to cater to various high-temperature industrial needs: ASTM A297 HH, ASTM A297 HK, ASTM A297 HT, ASTM A297 CA15, ASTM A297 CA40, ASTM A297 CB30, Inconel, Hastelloy.
Key applications include:
- Railway Industry: Brake shoes, coupler parts
- Construction: Excavator teeth, foundation supports
- Electrical Industry: Transformer housings, switchgear frames
- Agriculture: Plough blades, harvester parts
- Shipbuilding: Deck fittings, anchor components
- Medical Equipment: X-ray table bases, sterilization racks
- Heavy Machinery: Gear housings, pressure vessels
- Textile Industry: Dyeing machine parts, rollers
| Grade | Properties | Common Applications |
|---|---|---|
| ASTM A297 HH / HK / HT | High-temperature strength, excellent oxidation and creep resistance | Furnace trays, kilns, heat treatment fixtures, boiler parts |
| ASTM A297 CA15 / CA40 / CB30 | Good hardness at elevated temperature, moderate creep resistance, oxidation-resistant | Valves, burners, industrial high-temp components, jigs and baskets |
| Inconel / Hastelloy | Exceptional high-temp strength, superior oxidation and thermal fatigue resistance | Aerospace components, chemical processing equipment, high-temp furnace liners |
Key Properties & Benefits of Heat-Resistant Steel Castings
Heat-resistant steel castings, primarily austenitic Fe-Cr-Ni alloys per ASTM A297 (e.g., grades HK, HT, HP), maintain structural integrity, resist oxidation/scaling, and exhibit excellent creep resistance at elevated temperatures (typically up to 1050–1150°C depending on grade and atmosphere), thanks to high chromium (20–35%) and nickel (8–37%) contents that form stable protective oxide layers.
- Excellent High-Temperature Strength: Retains useful tensile and creep strength at 800–1100°C; ideal for load-bearing furnace trays, kiln rollers, radiant tubes, and boiler components under prolonged thermal exposure.
- Superior Oxidation & Scaling Resistance: High chromium (typically 20–35%) forms a stable, adherent Cr₂O₃ protective layer; minimizes metal loss in oxidizing atmospheres common in kilns, heat treatment furnaces, and ethylene crackers.
- Outstanding Creep & Rupture Resistance: Resists time-dependent deformation under sustained stress at high temperatures; essential for long-service life in reformer tubes, cracker coils, and heat exchanger parts.
- Good Thermal Fatigue & Shock Resistance: Withstands repeated heating/cooling cycles without cracking; well-suited for heat treatment fixtures, jigs, retort baskets, and cement kiln supports.
- Resistance to Carburization & Other High-Temp Corrosion: Higher-nickel grades (e.g., HT, HP) provide excellent protection against carburization, sulfidation, and nitriding in petrochemical, cement, and power generation environments.
- Extended Service Life & Reduced Downtime: Significantly outperforms carbon or low-alloy steels in high-temperature service; delivers cost-effective, reliable performance with service lives often exceeding 10 years in continuous-operation furnaces and kilns.
These properties ensure heat-resistant steel castings deliver dependable, long-term performance in demanding high-temperature, oxidative, carburizing, and thermally cyclic industrial environments.
Typical Composition & Properties (ASTM A297 & Superalloy Grades)
| Element / Property | Typical Range / Value | Notes (Service Temp & Key Grades) |
|---|---|---|
| Chromium (Cr) | 20–30% | Forms protective oxide; 25–28% in HK/HT, 28–32% in some HH |
| Nickel (Ni) | 8–40%+ | Stabilizes austenite; 8–12% in HH, 33–37% in HK/HT, 50–70% in Inconel/Hastelloy |
| Carbon (C) | 0.2–0.75% | Higher for strength; low in superalloys for weldability |
| Silicon (Si) | 0.5–2.5% | Improves oxidation resistance (higher in HK/HT) |
| Max Service Temperature | 870–1150°C+ | HH: ~870–980°C; HK/HT: ~1050–1150°C; Inconel/Hastelloy: 1100–1200°C+ |
| Creep Strength (e.g., 1000 h rupture) | 10–100 MPa at 900–1050°C | Higher in HK/HT/Inconel; critical for long-term load |
| Oxidation Resistance | Excellent | Low scaling rate at high temps due to Cr/Ni |
| Tensile Strength at RT | 450–750 MPa | Retains 50–70% at 900°C in austenitic grades |
Values typical for ASTM A297 austenitic grades (HH/HK/HT) and superalloys (Inconel/Hastelloy); actual performance depends on heat treatment and environment. Custom alloys available for specific temperature/corrosion needs.
Common Questions
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