ASME SA-479 347H Stainless Steel Bar - High Temperature Resistant,
20mm TPI Threads
ASME SA-479 347H stainless steel bar with precision 20mm TPI (threads per inch) redefines
high-temperature fastening in next-generation energy and aerospace
systems. Stabilized with niobium (Nb), this austenitic alloy
resists sensitization and creep deformation at temperatures up to
900°C, outperforming standard 304/316 grades in cyclic thermal
environments. The laser-cut 20mm TPI threads ensure leak-proof
integrity in pressurized hydrogen pipelines, molten salt reactors,
and hypersonic propulsion units. Engineered for ultra-low thermal
expansion and carbide precipitation control, it bridges the gap
between extreme heat resilience and mechanical reliability for
Industry 5.0 applications.
2. Technical Specifications
| Parameter | Details |
|---|
| Material | 347H Stainless Steel (UNS S34709) |
| Element Composition | Cr: 17–19%, Ni: 9–13%, Nb: 10×C% min, C: 0.04–0.10%, Mn: ≤2%, Fe:
Balance |
| Thread Specification | 20mm TPI (UNJC/UNJF standards), ±0.005mm pitch accuracy |
| Standard | ASME SA-479, ASTM A276, EN 10088-1, API 6ACRA |
| Thermal Properties | Continuous service: 900°C, Thermal expansion coefficient: 18.5
μm/m·°C (20–100°C) |
| Mechanical Performance | Tensile Strength: ≥690 MPa, Stress rupture limit: 100 MPa
(800°C/10k hrs) |
| Surface Innovation | Plasma electrolytic oxidation (PEO) coating optional for H₂S
resistance |
| Certifications | NACE MR0175 (Sour Service), TÜV SÜD H₂-Readiness, Nadcap AMS2750 |
| Eco-Innovation | 60% Post-Industrial Recycled Content, Low-Carbon Smelting (≤1.5t
CO₂/ton) |
3. Competitive Advantages
① Hydrogen-Embrittlement Immunity
Niobium stabilization eliminates sigma phase formation, ensuring
ductility in hydrogen-rich environments up to 700°C.
② Smart Thread Analytics
AI-optimized thread geometry reduces stress concentration by 40%,
validated via digital twin simulations.
③ Sulfur & Chloride Defense
Optional PEO nano-coating withstands sour gas (H₂S) and geothermal
brine corrosion for oil & gas extremes.
④ Zero Thermal Slack
Controlled grain boundary engineering prevents thread loosening
under 10,000+ thermal cycles.
⑤ Hypersonic-Ready
Low outgassing properties meet ESA/NASA standards for reusable
launch vehicle thrust chamber fasteners.
⑥ Circular Lifecycle
Designed for disassembly and remanufacturing, slashing
cradle-to-grave emissions by 70%.
4. Frontier Applications
- Gen-IV Nuclear Reactors: Control rod drive mechanism threads for sodium-cooled fast
reactors (SFRs).
- Hydrogen Liquefaction Plants: Cryogenic-compatible bolts for -253°C LH₂ storage tanks and
transfer lines.
- Venus Lander Systems: Pressure vessel fasteners enduring 460°C surface temperatures and
sulfuric acid clouds.
- Concentrated Solar Power (CSP): Receiver tube flange bolts for 1000°C+ solar flux in tower
systems.
- Plasma Torch Nozzles: Threaded assemblies for waste-to-energy plasma gasification at
8,000°C.
- Deep-Sea Hydrothermal Mining: Corrosion-proof fasteners for subsea rare-earth mineral
extraction robots.
- Methane Pyrolysis Reactors: High-temperature seals for turquoise hydrogen production modules.
- Space-Based Solar Arrays: Threaded struts for orbital solar farms with 300°C thermal
swings.
Why This Product?
The 347H threaded bar transcends traditional high-temperature
alloys by merging aerospace-grade precision with
decarbonization-ready metallurgy. From unlocking Earth’s most
hostile energy reserves to anchoring humanity’s interplanetary
ambitions, it’s engineered for environments where materials must
not just survive—they must evolve.
FAQ
Q: Why choose us?
A: Our company have been in steel business for more than ten years,
we are internationally experienced, professional, and we can
provide variety of steel products with high quality to our clients.
Q: Can provide OEM/ODM service?
A: Yes. Please feel free to contact us for more details discuss.
Q: How is your Payment Term?
A:One is 30% deposit by TT before production and 70% balance
against copy of B/L; the other is Irrevocable L/C 100% at sight.
Q: Can we visit your factory?
A: Warmly welcome. Once we have your schedule, we will arrange the
professional sales team to follow up your case.
Q: Can you provide sample?
A: Yes, for regular sizes sample is free but buyer need to pay
freight cost.
Q: How long is your delivery time?
A: Our daily inventory is more than 8000 tons, so for common
product size, just need 3 days from stocks; if the special size
from new production, delivery 15-20 days.
