EXHAUSTIVE METALLURGICAL ANALYSIS AND SPECIFICATION OF INCOLOY 800 FASTENERS
Incoloy 800 (standardized as UNS N08800) is a highly engineered nickel-iron-chromium alloy designed specifically to provide excellent structural strength and superior resistance to oxidation and carburization in extreme high-temperature environments. The alloy's defining metallurgical characteristic is its ability to maintain a stable austenitic crystal structure even after prolonged, continuous exposure to elevated temperatures.
Furthermore, the significant nickel content (30-35%) renders Incoloy 800 highly resistant to chloride stress-corrosion cracking and embrittlement from the precipitation of sigma phase. Because of its outstanding thermal stability and resistance to aqueous corrosion, Incoloy 800 fasteners are the standard engineering choice for critical infrastructure in petrochemical processing, power generation, and specialized thermal heat-treatment facilities.
■ Product Overview
| Material Designation | Incoloy Alloy 800 |
|---|---|
| UNS Number | N08800 |
| Microstructural Phase | Austenite with gamma prime |
| Density | 7.94 g/cm³ |
| Melting Point Range | 1357 °C - 1385 °C |
| Primary Base Element | Iron (Fe) |
| Key Alloying Elements | Nickel (30-35%), Chromium (19-23%) |
| Primary Strengthening | Solid Solution / Cold Working |
■ Proprietary Datasheet Download
Incoloy 800 / UNS N08800 — Complete Technical Datasheet
Access exact high-temperature creep-rupture yield curves, thermal expansion models, and hot-forging tolerances.
⬇ DOWNLOAD DATASHEET■ Chemical Composition
The remarkable high-temperature phase stability of Incoloy 800 is derived from its precise baseline matrix of iron, nickel, and chromium. Additionally, strict metallurgical control over aluminum and titanium additions ensures the alloy maintains consistent structural integrity and resists embrittlement over long service periods.
| Element | Minimum (%) | Maximum (%) |
|---|---|---|
| Iron (Fe) | 39.50 | Balance |
| Nickel (Ni) | 30.00 | 35.00 |
| Chromium (Cr) | 19.00 | 23.00 |
| Carbon (C) | - | 0.10 |
| Manganese (Mn) | - | 1.50 |
| Silicon (Si) | - | 1.00 |
| Copper (Cu) | - | 0.75 |
| Aluminum (Al) | 0.15 | 0.60 |
| Titanium (Ti) | 0.15 | 0.60 |
| Sulfur (S) | - | 0.015 |
■ Mechanical Properties
Incoloy 800 exhibits excellent mechanical properties at both room temperature and elevated temperatures. The alloy cannot be hardened through standard thermal precipitation treatments; its strength is increased primarily through cold working.
| Mechanical Parameter | Metric Value (Min) | Imperial Equivalent (Min) |
|---|---|---|
| Ultimate Tensile Strength | 520 MPa | 75,000 psi |
| 0.2% Offset Yield Strength | 205 MPa | 30,000 psi |
| Elongation at Break | 30% | 30% |
| Hardness (Brinell) | 150 HB | 150 HB |
■ International Equivalent Grades
| Standard System | Grade Designation |
|---|---|
| USA (UNS) | N08800 |
| Europe / Germany | 1.4876 / X10NiCrAlTi32-20 |
| Japan (JIS) | NCF 800 |
| United Kingdom (BS) | NA 15 |
| France (AFNOR) | Z8NC32-21 |
| Russia (GOST) | ЭИ670 / XH32T |
■ Applications & Industries
- Chemical Processing: Fabrication of petrochemical furnace cracker tubes, pigtails, and process headers; high resistance to nitric acid.
- Power Generation: Critical components in nuclear and conventional power plants requiring phase stability and resistance to high-temperature aqueous corrosion.
- Industrial Thermal Processing: Radiant tubes, furnace components, and protective sheathing for electrical resistance heating elements.
- Pharmaceutical & Pulp: Highly corrosive environments where standard stainless steels succumb to chloride stress-corrosion cracking.
■ Complete Range of Incoloy 800 Fasteners
| Bolts & Studs | Nuts & Screws | Washers & Anchors |
|---|---|---|
| Hex Bolts / Heavy Hex Bolts | Standard Hex / Square Nuts | Plain Washers |
| Foundation / U-Bolts | Lock Nuts / Wing Nuts | Spring Washers |
| Fully Threaded Studs | Socket Head Cap Screws | Sleeve Anchor Bolts |
| J-Bolts / T-Head Bolts | Pan Head / Set Screws | Pin Type Anchors |
■ Standards & Specifications
| Raw Material Specification | ASTM B408 / ASME SB408 (Rod and Bar) |
|---|---|
| Dimensional Standards | ANSI, ASME, ISO, DIN, JIS |
| Inch Thread Profiles | ASME B1.1 Class 2A/3A & 2B/3B (UNC, UNF) |
| Metric Thread Profiles | Metric Coarse (BSW/BSF) and Fine Threads |
■ Mill Test Certificates (EN 10204 Type 3.1)
All Incoloy 800 fasteners are supplied with an integrated MTC acting as the component's metallurgical DNA, providing:
- Exact verification of the heat number for 100% batch traceability.
- Certified chemical spectrography (Nickel, Chromium, Aluminum, Titanium levels).
- Actual destructive mechanical testing results (tensile and yield limits).
- PMI (Positive Material Identification) verification.
■ Why Source Incoloy 800 from Ananka
- Global Certifications: ISO 9001, 14001, 45001, and PED 2014/68/EU certified hardware.
- Advanced Manufacturing: Capability for custom fasteners ranging from M2 up to M160.
- Uncompromising Quality: In-house Tensile, Hardness, IGC, and PMI testing.
- Vast Export Network: Supplying critical infrastructure across more than 40 countries.
■ Frequently Asked Questions
Q1: What is the difference between Incoloy 800, 800H, and 800HT?
Primarily carbon content and control of Al+Ti. Incoloy 800H (0.05-0.10% C) improves high-temperature creep. Incoloy 800HT further restricts carbon and mandates 0.85-1.20% combined Al+Ti for maximum stress-rupture strength at extreme temperatures.
Q2: Does Incoloy 800 resist chloride stress-corrosion cracking?
Yes. Due to its substantial nickel content (30-35%), it is highly resistant to chloride-ion SCC, a rapid failure mechanism for standard austenitic stainless steels in heated brine or chemical environments.
Q3: What is the operating temperature range for Incoloy 800 fasteners?
It is successfully deployed from cryogenic lows up to 1500°F (816°C). For applications exceeding these temperatures, 800H or 800HT variants are typically required.
Q4: Can Incoloy 800 fasteners be hardened by heat treatment?
No. It is a solid-solution alloy and cannot be precipitation-hardened. Strength increases are achieved strictly through cold working (strain hardening).
Q5: Why is Incoloy 800 preferred over stainless steel in petrochemical furnaces?
Standard stainless steels suffer sensitization or sigma-phase embrittlement at high temperatures. Incoloy 800 features a stable austenitic structure that resists these phase changes, ensuring structural survival where stainless steels would fail.