What are Buttweld fittings?
Buttweld fittings are pipe fittings used to connect, change direction, branch, or reduce the pipe size in a permanent, welded connection. These fittings are welded to the pipe by butt welding, ensuring a strong, leak-proof joint that enhances durability and pressure resistance.
Types of Buttweld Fittings
| Fitting Type | Function |
| Elbows (90° & 45°) | Changes the direction of flow in a pipeline |
| Tees (Equal & Reducing) | Splits or combines flow in a pipeline |
| Reducers (Concentric & Eccentric) | Reduces pipe size while maintaining flow |
| Caps | Closes the end of a pipe |
| Stub Ends | Used with lap joint flanges for easy disassembly |
| Crosses | Connects four pipes at 90-degree angles |
Incoloy Buttweld Fittings: Overview
Incoloy buttweld fittings are pipe fittings made from Incoloy alloys, designed for high-temperature, high-corrosion, and high-pressure environments. These fittings are welded to pipes, ensuring a strong, leak-proof, and durable connection in critical industrial applications.
What is Incoloy?
Incoloy is a nickel-iron-chromium alloy with excellent corrosion resistance, oxidation resistance, and high-temperature strength. It is commonly used in chemical, marine, power, and aerospace industries.
Common Grades of Incoloy Buttweld Fittings
| Incoloy Grade | Features |
| Incoloy 800 | High-temperature strength, oxidation resistance |
| Incoloy 800H/800HT | Improved creep and stress rupture strength |
| Incoloy 825 | Excellent corrosion resistance, acid-resistant |
| Incoloy 925 | High strength, offshore and marine applications |
Chemical Composition of Grade Incoloy Butt weld Fittings
| Grade | C | Mn | Si | S | Cu | Fe | Ni | Cr | Al | Ti |
| 800 | 0.10 max | 1.50 max | 1.00 max | 0.015 max | 0.75 max | 39.50 min | 30.00 – 35.00 | 19.00 – 23.00 | 0.15 – 0.60 | 0.15 – 0.60 |
| 800H | 0.05 – 0.10 | 1.50 max | 1.00 max | 0.015 max | 0.75 max | 39.50 min | 30.00 – 35.00 | 19.00 – 23.00 | 0.15 – 0.60 | 0.15 – 0.60 |
| 800HT | 0.06 – 0.10 | 1.50 max | 1.00 max | 0.015 max | 0.75 max | 39.50 min | 30.00 – 35.00 | 19.00 – 23.00 | 0.15 – 0.60ᴬ | 0.15 – 0.60ᴬ |
| 825 | 0.05 max | 1.00 max | 0.5 max | 0.03 max | 1.50 – 3.00 | 22.00 min | 38.00 – 46.00 | 19.50 – 23.50 | 0.02 max | 0.06 – 1.20 |
Mechanical Properties of Incoloy Butt weld Pipe Fittings
| Element | Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
| 800 / 800H / 800HT | 7.94 g/cm3 | 1385 °C (2525 °F) | Psi – 75,000 , MPa – 520 | Psi – 30,000 , MPa – 205 | 30 % |
| 825 | 8.14 g/cm3 | 1400 °C (2550 °F) | Psi – 80,000 , MPa – 550 | Psi – 32,000 , MPa – 220 | 30 % |
Incoloy Buttweld Fittings Equivalent Grades
| STANDARD | WERKSTOFF NR. | UNS | JIS | BS | GOST | AFNOR | EN | OR |
| Incoloy 800 | 1.4876 | N08800 | NCF 800 | NA 15 | ЭИ670 | Z8NC32-21 | X10NiCrAlTi32-20 | XH32T |
| Incoloy 800H | 1.4958 / 1.4876 | N08810 | NCF 800H | NA 15(H) | ЭИ670 | Z8NC33-21 | X5NiCrAlTi31-20 | XH32T |
| Incoloy 800HT | 1.4859 / 1.4876 | N08811 | NCF 800HT | NA 15(HT) | ЭИ670 | – | X8NiCrAlTi32-21 | XH32T |
| Incoloy 825 | 2.4858 | N08825 | NCF 825 | NA 16 | ЭП703 | NFE30C20DUM | NiCr21Mo | XH38BT |
Types of Incoloy Buttweld Fittings
Elbows (90° & 45°) – Changes pipeline direction.
Tees (Equal & Reducing) – Splits or merges fluid flow.
Reducers (Concentric & Eccentric) – Reduces pipe size.
Caps – Closes pipeline ends.
Stub Ends – Works with lap joint flanges.
Crosses – Connects four pipelines.
Step-by-Step Manufacturing Process of Incoloy Buttweld Fittings
Incoloy buttweld fittings are manufactured using precision engineering and high-quality Incoloy alloys to ensure durability, strength, and corrosion resistance. The process involves seamless or welded pipe formation, cutting, shaping, heat treatment, machining, and quality testing.
1. Raw Material Selection
Material: High-quality Incoloy alloys (800, 800H, 825, 925, etc.) in the form of seamless pipes, welded pipes, or plates.
Standard Compliance: The material must meet ASTM B366, ASTM B564, and ASME SB366 specifications.
2. Cutting & Preparation
The pipes or plates are cut to the required lengths based on the fitting design.
Plasma cutting, saw cutting, or water jet cutting is used for precision.
3. Welding (For Welded Buttweld Fittings)
If using welded pipe, TIG/MIG welding is performed.
Automatic welding processes ensure precision and uniformity.
Welded fittings undergo post-weld heat treatment (PWHT) to restore mechanical properties.
4. Heat Treatment (Annealing & Normalizing)
The fittings undergo annealing (1050-1150°C) followed by rapid cooling to:
✔ Enhance corrosion resistance
✔ Improve ductility and strength
✔ Remove internal stresses
5. Inspection & Quality Testing
All Incoloy buttweld fittings undergo strict quality checks to ensure reliability:
✅ Dimensional Inspection – Ensures compliance with ASME B16.9, B16.28, MSS-SP-43.
✅ Visual & Surface Inspection – Checks for defects, cracks, and porosity.
✅ Mechanical Testing – Hardness, tensile, and impact testing.
✅ Non-Destructive Testing (NDT) – Ultrasonic Testing (UT), Radiographic Testing (RT).
✅ Corrosion Resistance Testing – ASTM A262 (Intergranular Corrosion Test).
✅ Hydrostatic & Pneumatic Testing – Pressure and leak resistance test.
6. Marking & Packaging
Marking includes size, material grade (Incoloy 800, 825, etc.), ASTM standard, heat number, and manufacturer details.
Protective packaging ensures safe transportation and prevents surface damage.
Final Product:
✔ High-strength, corrosion-resistant Incoloy buttweld fittings suitable for oil & gas, petrochemicals, power plants, and marine applications.
What is the difference between socket weld and Butt weld fittings?
Socket weld and buttweld fittings are both used in piping systems to connect pipes, but they have distinct welding methods, applications, and pressure ratings.
| Feature | Socket Weld Fittings | Butt weld Fittings |
| Connection Type | Pipe fits into a socket and is welded around the joint | Pipes are joined end-to-end and welded along the seam |
| Welding Method | Fillet weld (external) | Butt weld (full penetration) |
| Strength & Integrity | Strong, but less than buttweld | Stronger, high-pressure resistance |
| Pipe Size Range | Up to 4 inches (DN 100) | ½ inch to 48 inches (DN 1200+) |
| Thickness | Generally thicker for high pressure | Standard pipe thickness |
| Pressure Rating | Higher (Class 3000, 6000, 9000) | Suitable for high-pressure and high-temperature applications |
| Leakage Risk | Slightly higher due to external fillet weld | Minimal risk (full penetration weld) |
| Flow Restriction | Slight bore restriction at joint | Smooth bore (no obstruction, less turbulence) |
| Installation Complexity | Easier to install, requires less welding skill | More difficult, requires skilled welding |
| Cost | Higher initial cost, but easier to install | Lower cost per unit, but higher installation cost |
Typical Applications
Socket Weld Fittings
✅ Used in high-pressure, small-diameter piping systems in:
Oil & gas pipelines
Steam & hydraulic lines
Chemical processing plants
Butt weld Fittings
✅ Used in large-diameter, high-temperature, high-pressure applications like:
Power plants (boilers, heat exchangers)
Petrochemical & refinery piping
Water treatment plants
Standards for Socket Weld & Buttweld Fittings
| Standard | Socket Weld | Buttweld |
| ASME B16.11 | ✔ | ❌ |
| ASME B16.9 | ❌ | ✔ |
| ASME B31.3 | ✔ | ✔ |
| MSS SP-97 | ✔ (SW Olet) | ✔ |
Welded Pipe Fittings
✅ Used in general industrial applications like:
Water distribution, HVAC, and plumbing
Structural and construction projects
Food, dairy, and pharmaceutical industries
Low-to-moderate pressure pipelines
Advantages of Incoloy Buttweld Fittings
✔ High-Temperature Strength – Performs well in extreme heat (>1100°F/593°C).
✔ Corrosion Resistance – Resists oxidation, carburization, and acid attacks.
✔ Acid & Chemical Resistance – Suitable for sulfuric, phosphoric, and nitric acids.
✔ Durability – Long lifespan in harsh industrial environments.
✔ Weldability – Easily welded using standard techniques.
Applications of Incoloy Buttweld Fittings
Petrochemical & Refinery Pipelines
Marine & Offshore Oil and Gas Industry
Heat Exchangers & Boilers
Power Plants (Nuclear, Thermal, Renewable Energy)
Aerospace & Jet Engine Components
Chemical Processing Plants
You can get an offer for products in below material forms:
-Pipe and Tube (EN 10216-5, ASTM A213, ASTM A249, A312, A790,)
-Forged Fitting and Flange (ASTM A182 , ASTM A105,ASTM B564 )
-Butt Weld Fittings (ASTM A234, ASTM A403,ASTM A815)
-Round bar , Billet (ASTM A276, ASTM A479)
– Plate, Sheet, Strip(ASTM A240, EN 10028-7, A480)
-Bolting, Nuts（ASTM A193, A194, A320）
Incoloy Buttweld Fittings Exported Countries
We Export Incoloy Buttweld Fittings to Saudi Arabia, United Arab Emirates, Qatar, Bahrain, Oman, Kuwait, Turkey, Egypt, Yemen , Syria, Jordan, Cyprus, Singapore, Malaysia, Indonesia, Thailand, Vietnam, South Korea, Japan, Sri Lanka, Maldives, Bangladesh, Cambodia, Argentina, Bolivia, Brazil, Venezuela, Colombia, Ecuador, Guyana, Paraguay, Uruguay, United States Of America, Canada, Mexico, Panama, Jamaica, Bahamas, Denmark, Norway, Germany, France,Italy, United Kingdom, Spain, Belgium, Greece, Czech Republic, Portugal, Hungary, Albania, Austria, Finland, Ireland, Croatia, Malta, Nigeria, Algeria, Angola, South Africa, Libya, Egypt, Sudan, Europe, Africa, Asia, North America, South America, Middle East.etc