Incoloy 800H Tube Fittings

What Are Incoloy 800H Tube Fittings?

Incoloy 800H Tube Fittings are precision components used to connect, branch, redirect, terminate or transition tubing in high-temperature instrumentation and process systems.

They are selected for applications where the tubing system can experience prolonged elevated-temperature exposure and where creep, stress-rupture performance, oxidation resistance and metallurgical stability are important.

Typical applications include:
High-temperature process instrumentation
Heat exchangers
Reformer systems
Petrochemical equipment
Process heaters
Furnace equipment
Heat-treatment systems
Chemical-processing equipment
Power-generation equipment
High-temperature tubing systems

Incoloy 800H should be selected based on the actual design temperature, stress, product form, material condition, atmosphere and applicable design code.

Incoloy 800H Tube Fittings Specifications

Parameter Specification
Material Incoloy 800H
Alloy Alloy 800H
UNS N08810
Werkstoff No. 1.4958
Alloy Family Nickel-Iron-Chromium
Nickel 30.0–35.0%
Chromium 19.0–23.0%
Iron 39.5% Min
Carbon 0.05–0.10%
Aluminium 0.15–0.60%
Titanium 0.15–0.60%
Aluminium + Titanium 0.30–1.20%
Wrought Fittings ASTM B366 / ASME SB366
Forged Components ASTM B564 / ASME SB564, where applicable
Seamless Pipe & Tube ASTM B407 / ASME SB407
Butt-Weld Dimensions ASME B16.9, where applicable
Forged SW / Threaded Dimensions ASME B16.11, where applicable
Connection Types Compression, Double Ferrule, Threaded, Tube-to-Tube
Thread Options NPT, BSP, BSPT, BSPP and Metric, as specified
Size Inch and metric configurations
Material Condition Solution Annealed / specification-dependent
Grain Requirement ASTM No. 5 or coarser for applicable 800H requirements
Certification MTC / EN 10204 documentation where required

ASTM B407 covers seamless nickel-iron-chromium alloy pipe and tube and includes UNS N08810. ASTM identifies N08810 as an alloy normally used above 1100°F (593°C) where creep and rupture resistance are required, with controlled grain size.

Chemical Composition of Incoloy 800H

Typical chemical requirements for Incoloy 800H / UNS N08810 include:

Element Composition
Nickel 30.0–35.0%
Chromium 19.0–23.0%
Iron 39.5% Min
Carbon 0.05–0.10%
Manganese 1.50% Max
Silicon 1.00% Max
Copper 0.75% Max
Aluminium 0.15–0.60%
Titanium 0.15–0.60%
Aluminium + Titanium 0.30–1.20%
Sulfur 0.015% Max

The controlled carbon content and grain structure distinguish 800H from standard Alloy 800. Special Metals identifies 800H with carbon of 0.05–0.10% and an ASTM grain size of No. 5 or coarser.

Mechanical Properties of Incoloy 800H

Representative minimum room-temperature mechanical requirements for solution-annealed Alloy 800H include:

Property Minimum Value
Tensile Strength 450 MPa / 65 ksi
Yield Strength, 0.2% Offset 170 MPa / 25 ksi
Elongation 30%
Grain Size ASTM No. 5 or coarser

The actual certified properties depend on product form, dimensions, heat treatment and applicable material specification. The material test certificate should be used for the supplied heat.

Why Choose Incoloy 800H Tube Fittings?

Incoloy 800H is selected primarily when elevated-temperature creep and stress-rupture performance are important.

Key Advantages
High nickel content
High chromium content
Good oxidation resistance
Good carburization resistance
Good resistance to high-temperature corrosion
Controlled carbon content
Controlled coarse-grain structure
Improved creep resistance compared with standard Alloy 800 in applicable service
Good stress-rupture performance
Good mechanical strength
Useful resistance to thermal cycling
Suitable for high-temperature process equipment

The grade should not be selected solely on the basis of a nominal temperature number. Actual design suitability depends on stress, time at temperature, product form, atmosphere and applicable code requirements.

Manufacturing Process of Incoloy 800H Tube Fittings

1. Material Selection
Certified UNS N08810 material is selected according to the applicable specification.
2. Cutting
Approved starting material is cut to the required component dimensions.
3. Forming or Forging
The required fitting geometry is produced through the appropriate manufacturing process.
4. Solution Annealing
The material is heat treated according to the applicable product specification and required metallurgical condition.
5. Grain-Size Control
For 800H applications where controlled grain size is required, the manufacturing and heat-treatment process is controlled to meet the applicable grain-size requirement.
6. CNC Machining
Precision machining produces:
Tube bores
Ferrule seats
Threads
Internal passages
Connection ends
External profiles
7. Finishing
Components undergo:
Deburring
Cleaning
Surface finishing
Thread inspection
Dimensional finishing
8. Final Inspection
Finished fittings are inspected against the drawing, material specification and customer requirements.

Applications of Incoloy 800H Tube Fittings

Petrochemical Industry
Potential applications include:
Reforming systems
Process heaters
Furnace equipment
High-temperature process instrumentation
Heat exchangers
Hydrocarbon processing

Chemical Processing Industry
Potential applications include:
High-temperature process systems
Heat-transfer equipment
Process-control systems
Chemical-processing equipment
Furnace systems

Power Generation
Potential applications include:
Heat exchangers
Reheaters
High-temperature process equipment
Furnace systems
Process instrumentation

Furnace and Heat-Treatment Equipment
Incoloy 800H can be considered for suitable:
Furnace tubing
Heat-treatment equipment
Heating systems
Process heaters
High-temperature components

Oil & Gas Industry
Potential applications include:
Process instrumentation
Reforming equipment
High-temperature process lines
Heat exchangers
Furnace systems
Petrochemical processing

Industrial Process Equipment
Potential applications include:
Reactors
Heat exchangers
Process heaters
Process skids
High-temperature instrumentation