Overview

Incoloy alloy pipes are tubular products manufactured from a family of nickel-iron-chromium superalloys, representing one of the most versatile and cost-effective material solutions for moderate-to-high temperature applications and corrosive environments. These pipes are produced through seamless (hot extrusion or cold drawing) or welded processes, serving as critical components for conveying aggressive chemicals, high-temperature gases, and corrosive fluids across chemical processing, petrochemical, power generation, and heat-treating industries .

Incoloy alloys are characterized by their nickel content typically ranging from 30-46% combined with chromium (19-23%) and significant iron content (typically >22%) , creating a unique balance of properties that bridges the performance gap between stainless steels and more expensive nickel-based superalloys. The alloy family encompasses several distinct grades optimized for specific service conditions :

• Incoloy 800/800H/800HT: Optimized for high-temperature creep resistance and oxidation resistance up to 1100°C (2000°F)

• Incoloy 825: Exceptional resistance to reducing and oxidizing acids, particularly sulfuric and phosphoric acids

• Incoloy 925: Age-hardenable grade offering high strength combined with excellent corrosion resistance for sour gas service

• Incoloy 330: Enhanced resistance to carburization and thermal shock in industrial heating applications

With a 50-year track record of proven performance, Incoloy alloys are specified when stainless steel performance is inadequate but premium nickel alloys would be over-specified . These pipes are used in ethylene furnace quench boilers, hydrocarbon cracking, super-heater and reheater tubing in power plants, industrial furnaces, heat exchangers, and chemical processing equipment .

Available in sizes ranging from 1/8" to 26" diameter and various schedules, Incoloy alloy pipes provide engineers with reliable fluid handling solutions that balance performance requirements with economic considerations .

Key Features

• Cost-Effective Performance Bridge: Incoloy pipes occupy the strategic middle ground between stainless steels and high-nickel superalloys. With nickel content of 30-46%, they offer significantly better performance than 300-series stainless steels in high-temperature and corrosive environments, while providing substantial cost savings compared to Inconel or Hastelloy grades .

• Multiple Grades for Varied Service Conditions: Incoloy pipes are available in several grades optimized for specific applications :

  • 800/800H/800HT Series: Superior creep and rupture strength at temperatures above 1100°F (600°C), with excellent resistance to oxidation, carburization, and sulfidation

  • 825: Exceptional resistance to both reducing and oxidizing acids, with additions of molybdenum and copper targeting sulfuric and phosphoric acid environments

  • 925: Age-hardenable grade offering high strength (125 ksi minimum yield) combined with NACE MR0175 compliance for sour gas service

  • 330: Enhanced silicon content providing superior resistance to carburization and thermal shock in industrial heating applications

• Superior High-Temperature Performance: Grades like Incoloy 800H and 800HT are specifically engineered for elevated temperature service, with controlled carbon content and grain size providing superior creep and rupture strength up to 1100°C (2000°F) . These alloys maintain structural integrity under extreme thermal cycling, with excellent resistance to oxidation, carburization, and nitriding atmospheres .

• Exceptional Corrosion Resistance in Diverse Media: Incoloy pipes offer outstanding resistance to a wide range of corrosive environments :

  • Incoloy 825: Excellent resistance to sulfuric acid, phosphoric acid, nitric acid, and reducing chemicals; immunity to chloride-ion stress-corrosion cracking

  • All 800 series: Good resistance to many acidic environments and aqueous corrosion at moderate temperatures

  • All grades: High nickel content provides protection against chloride-induced stress corrosion cracking

• NACE/API Compliance for Oil & Gas: Grades such as Incoloy 925 and 825 are available with NACE MR0175/ISO 15156 certification for sour service applications. Incoloy 925 offers age-hardenable properties with resistance to sulfide stress cracking and stress-corrosion cracking in H₂S-containing crude oil and natural gas environments .

• Excellent Fabricability: Incoloy alloys are readily machined using standard methods and can be welded by common techniques used on stainless steels . The alloys exhibit good cold forming characteristics and maintain excellent ductility during fabrication.

• Multiple Pipe Types Available: Incoloy pipes are offered in both seamless and welded configurations :

  • Seamless Pipes (ASTM B407): Manufactured from solid billet through hot extrusion or cold drawing, offering superior structural integrity and higher pressure ratings

  • Welded Pipes (ASTM B514, B515): Formed from flat strip and longitudinally welded, cost-effective and available in larger diameters

  • Heat Exchanger Tubes (ASTM B163): Specifically for condenser and heat exchanger applications

• Wide Range of Standards Compliance: Incoloy pipes meet numerous international standards including ASTM, ASME, BS, DIN, ISO, and VdTÜV, ensuring global acceptance and code compliance .

Specifications with Explanation

Incoloy Alloy Pipe Chemical Composition by Grade (Typical values, wt%)

Typical Mechanical Properties (Annealed Condition)

Physical Properties

Applicable Pipe Standards

Available Pipe Dimensions and Schedules

Common Schedule Availability

• Sch. 5S, 10S: Light wall for general process applications

• Sch. 40S: Standard wall for moderate pressure service

• Sch. 80S: Heavy wall for higher pressure applications

• Sch. 160, XXS: Extra heavy wall for severe service conditions

Surface Finishes Available

• Solution annealed and pickled (standard)

• Bright annealed

• Polished (180#, 240#, 320#, 400#, 600#)

• Mechanically polished

• Sand blasted

• Shot blasted

Pipe End Finishes

• Plain End (PE)

• Bevelled End (BE) for field welding preparation

Applications

Incoloy alloy pipes serve as critical fluid handling components across industries where high-temperature performance and corrosion resistance are required without the premium cost of higher-nickel alloys :

Petrochemical and Hydrocarbon Processing

• Ethylene Furnace Quench Boilers: Piping for high-temperature hydrocarbon cracking processes

• Hydrocarbon Cracking Units: Transfer lines for cracked gases at elevated temperatures

• Steam Superheaters and Reheaters: Power plant piping systems operating above 1100°F (600°C)

• Fired Heaters: Radiant and convection section piping

Chemical Processing Industry

• Sulfuric Acid Piping and Vessels: Incoloy 825 pipes handling H₂SO₄ at various concentrations

• Phosphoric Acid Evaporators: For fertilizer production and acid concentration

• Nitric Acid Condensers: Piping for nitric acid service where chloride SCC resistance is required

• Pickling Tanks and Equipment: Handling corrosive pickling acids

• Heat Exchangers: For aggressive chemical process streams

Oil and Gas Industry

• Sour Gas Well Piping: Incoloy 825 and 925 pipes for H₂S-containing environments (NACE MR0175 compliant)

• Down-hole Tubular Products: High-strength piping for subsurface gas well components

• Surface Gaswell Components: Valves, hangers, and landing nipples

• High-Strength Piping Systems: For critical oil and gas applications requiring both strength and corrosion resistance

Power Generation

• Super-heater and Re-heater Tubing: Power plant boiler components operating at elevated temperatures

• Nuclear Steam-Generator Tubing: For nuclear power plant applications

• Pressure Vessels: High-temperature pressure containment

Industrial Heating and Heat Treating

• Industrial Furnace Components: Radiant tubes, muffles, and retorts

• Heat-Treating Equipment: Baskets, trays, and fixtures for thermal processing

• Carburizing Equipment: Piping for carburizing atmospheres

• Heating-Element Sheathing: Protective tubes for electric heating elements

Pollution Control

• Flue Gas Desulfurization (FGD) Systems: Piping for sulfuric acid condensate environments

• Waste Incineration Equipment: High-temperature corrosive flue gas handling

• Pollution-Control Equipment: Scrubbers and ductwork for emissions control

Marine and Offshore

• Marine Exhaust Systems: Piping for shipboard engine exhaust

• Seawater Handling Systems: Components requiring chloride SCC resistance

• Propeller Shaft Housings: Protective piping for marine applications

Nuclear Industry

• Nuclear Fuel Reprocessing: Piping for radioactive waste streams and fuel recycling

• Steam Generator Tubing: For nuclear power plants

Other Applications

• Pharmaceutical Processing: High-purity piping for drug manufacturing

• Food Processing Equipment: For acidic food products and cleaning solutions

• Tank Trucks: Transport vessels for corrosive chemicals

• Expansion Bellows: Flexible piping components for thermal expansion

Comparison: Grade Selection Guide

Buying Guide

Selecting the appropriate Incoloy alloy pipe requires careful evaluation of service conditions, mechanical requirements, fabrication considerations, and economic factors:

1. Define Service Environment:

   • Temperature Range: Maximum operating temperature and thermal cycling conditions

     • Up to 1100°F (600°C): All grades suitable

     • Above 1100°F: 800H/800HT required for creep resistance

     • Above 1800°F (982°C): Consider higher-nickel alloys

   • Corrosive Media: Identify specific chemicals, concentrations, and whether oxidizing or reducing conditions prevail

     • Reducing acids (H₂SO₄, H₃PO₄): Incoloy 825 with Mo and Cu additions

     • Sour gas (H₂S): 825 or 925 with NACE certification

     • High-temperature oxidation: 800H/HT, 330

   • Pressure Requirements: Operating pressure and design margin

2. Select Pipe Type Based on Service Criticality :

   • Seamless Pipe (ASTM B407) : For high-pressure systems, critical applications, and where weld seam concerns must be eliminated

   • Welded Pipe (ASTM B514) : For moderate-pressure applications, larger diameters, and cost-sensitive projects

   • Heat Exchanger Tube (ASTM B163) : For condenser and heat exchanger applications requiring precise dimensions

3. Determine Pipe Dimensions:

   • Nominal Pipe Size (NPS) : 1/8" through 26" available

   • Schedule: Sch. 5 through Sch. 160 based on pressure requirements

   • Length: Standard 6m or 12m, custom lengths available

   • Tolerances: Specify required dimensional tolerances per ASTM standards

4. Verify Specifications and Standards :

   • Confirm applicable ASTM/ASME standards:

     • Seamless pipe: ASTM B407 / ASME SB-407

     • Welded pipe: ASTM B514 / ASME SB-514

     • Heat exchanger tube: ASTM B163 / ASME SB-163

     • 825 pipe: ASTM B423 / ASME SB-423

   • For pressure applications, ensure ASME B31.3 or B31.1 code compliance

   • For sour service, verify NACE MR0175/ISO 15156 compliance

5. Consider Fabrication Requirements :

   • Welding: Can be welded by common techniques used on stainless steels; matching filler metals recommended

   • Hot Working: 870-1180°C range, finishing at 870-980°C

   • Cold Forming: Excellent cold forming characteristics; exhibits good ductility

   • Heat Treatment: For 825, stabilise annealed at 940°C; for 925, age-hardening heat treatment required for maximum strength

   • Post-Weld Treatment: May require annealing for maximum corrosion resistance in severe service

6. Request Documentation :

   • Mill Test Certificates (MTC) per EN 10204 3.1/3.2 with:

     • Heat number and full chemical composition

     • Complete mechanical property test results

     • Hydrostatic test certification

     • Heat treatment records

   • NACE/ISO certification for sour service grades

   • Third-party inspection reports for critical applications

7. Consider Total Cost of Ownership:

   • Initial Material Cost: Incoloy offers significant savings over higher-nickel alloys

   • Installation Cost: Factor in welding, testing, and inspection

   • Maintenance Cost: Reduced compared to less corrosion-resistant materials

   • Service Life: Extended life in corrosive/high-temperature environments justifies premium over stainless steel

   • Downtime Avoidance: Critical for continuous process operations

8. Plan for Lead Times :

   • Ready Stock: 7 days for standard sizes and common grades

   • Mill Orders: 40 days for non-standard dimensions, specialty grades, or special certification requirements

   • Express Service: Expedited processing may be available for urgent requirements (premium pricing)

FAQ

Q1: What is the difference between Incoloy 800, 800H, and 800HT pipes?

A: The primary differences lie in carbon content and titanium/aluminum levels, which affect high-temperature properties :

• Incoloy 800: Basic grade with carbon ≤0.10%, suitable for applications up to 1100°F

• Incoloy 800H: Controlled carbon (0.05-0.10%) and larger grain size to provide superior creep and rupture strength above 1100°F

• Incoloy 800HT: Additional controls on aluminum and titanium (Al+Ti 0.85-1.20%) with similar carbon range, offering the highest creep resistance of the three

All three share similar corrosion resistance, but 800H and 800HT are preferred for applications requiring long-term structural stability under stress at elevated temperatures above 600°C . Today, most suppliers carry dual-certified 800H/HT alloy combining the properties of both forms .

Q2: What is the difference between Incoloy 825 and Incoloy 925 pipes?

A: The primary difference lies in strengthening mechanism and resultant properties :

• Incoloy 825: Solid-solution strengthened alloy with additions of molybdenum and copper. It offers exceptional resistance to reducing and oxidizing acids, particularly sulfuric and phosphoric acids. It cannot be heat treated for higher strength (annealed condition only).

• Incoloy 925: Age-hardenable alloy containing aluminum and titanium that form strengthening precipitates during controlled aging. This allows 925 to achieve significantly higher strength—yield strength of 125 ksi minimum versus 32-35 ksi for annealed 825—while maintaining good corrosion resistance. 925 is specifically designed for sour gas service with NACE MR0175 compliance .

Q3: What is the maximum service temperature for Incoloy 800H/HT pipes?

A: Incoloy 800H and 800HT maintain useful mechanical properties for continuous service up to approximately 1100°C (2000°F) , with excellent oxidation resistance throughout this range . For applications requiring creep resistance, they perform well up to 815°C (1500°F). These alloys are designed for high-temperature structural applications and will not become embrittled even after long periods of usage in the 1200-1600°F range where many stainless steels become brittle .

Q4: Can Incoloy 825 pipes replace stainless steel in acid service?

A: Yes, and this is often the logical upgrade path . Incoloy 825 offers:

• Far better corrosion resistance than 316L and 904L stainless steels in sulfuric and phosphoric acid environments

• Immunity to chloride stress corrosion cracking due to nickel content >40%

• Excellent resistance to pitting and crevice corrosion from molybdenum additions

• Stabilization against intergranular corrosion from titanium addition

It is particularly effective in the 10-40% sulfuric acid concentration range at moderate temperatures and is widely used for chemical processing, acid production, and pickling equipment .

Q5: What NACE standards apply to Incoloy pipes for oil and gas?

A: For oil and gas sour service (environments containing hydrogen sulfide), Incoloy pipes must comply with NACE MR0175/ISO 15156 :

• Incoloy 825: Widely used in sour service applications with appropriate heat treatment

• Incoloy 925: Specifically designed for sour service with resistance to sulfide stress cracking and stress-corrosion cracking in H₂S-containing crude oil and natural gas

• Incoloy 800H/HT: Listed in NACE MR0175 for oil and gas service

This standard defines material requirements for resistance to sulfide stress cracking (SSC) and stress corrosion cracking (SCC) in H₂S-containing environments.

Delivery, Certification & Service

Quality Certification

• Material Traceability: Complete heat traceability from melt to finished pipe with unique identification markings per applicable standards

• Mill Test Certificates (MTC) : EN 10204 3.1/3.2 compliant certificates provided with every shipment including :

  • Heat number and full chemical composition analysis per applicable specifications

  • Complete mechanical property test results (tensile, yield, elongation)

  • Hydrostatic test certification

  • Heat treatment records (solution annealing temperatures, times)

  • Dimensional inspection reports

  • Non-destructive testing reports when specified

• Third-Party Inspection: Available through Lloyds, DNV, Bureau Veritas, ABS, SGS, TÜV, or customer-nominated agencies

• Special Testing Available :

  • Positive Material Identification (PMI)

  • Ultrasonic inspection (Flaw detection, wall thickness verification)

  • Radiographic examination of weld seams (for welded pipe)

  • Mechanical testing at elevated or cryogenic temperatures

  • Microstructural evaluation (grain size, precipitate distribution)

  • Intergranular corrosion testing

  • Ferrite determination (for weld metal)

  • NACE MR0175/ISO 15156 compliance verification for sour service

  • Hardness testing

Available Pipe Forms and Dimensions

Common Schedule Availability

Surface Finishes Available

• Solution Annealed and Pickled: Standard finish for most pipe applications—oxide-free surface with matte appearance

• Bright Annealed: Smooth, bright finish for clean applications

• Polished: Various grit finishes (180#, 240#, 320#, 400#, 600#) for sanitary or aesthetic requirements

• Mechanically Polished: Uniform finish for specific applications

• Sand Blasted: Textured finish for coating preparation

• Shot Blasted: For enhanced surface properties

Pipe End Finishes

• Plain End (PE) : Standard for most pipe shipments

• Bevelled End (BE) : For field welding preparation

Packaging and Protection

• Bundling: Thick woven plastic bags to bundle finished pipes together in batches

• Wooden Crates: Export-grade wooden boxes for high-value or precision pipes (for pipes vulnerable to dirt, scratches, or rough handling)

• Individual Wrapping: Protective paper or plastic for polished surfaces

• End Protection: Plastic caps for all pipe ends to prevent debris ingress and bevel damage

• Custom Marking: Stenciling, tagging, or stamping per customer specifications

• Export Packing: Seaworthy packaging with waterproof lining and fumigation certification as required

Value-Added Services Available

• Custom length cutting

• Bending

• Polishing

• Shot blasting

• Drilling/punching

• Oil degreasing

After-Sales Technical Support

• Material Selection Assistance: Expert guidance on grade selection for specific applications based on service conditions

• Welding Support: Procedure recommendations, parameter optimization, and filler metal selection

• Fabrication Guidance: Recommendations for bending, forming, and installation

• Heat Treatment Guidance: For solution annealing, aging, or stress relieving requirements

• Failure Analysis: Investigation and analysis of in-service material performance issues

• Field Service: On-site technical support for critical applications and large projects

• Installation Support: Assistance with proper handling and installation procedures

Delivery Commitment

• Ready Stock: 7 days for standard sizes and common grades

• Mill Orders: 40 days for non-standard dimensions, specialty grades, or special certification requirements

• Express Service: Expedited processing may be available for urgent requirements (premium pricing)

• Just-in-Time (JIT) Delivery: Coordinated delivery schedules to support project timelines

• Global Logistics: International shipping with full export documentation, customs clearance support

Trade Terms and Logistics

• Trade Terms: EXW, FOB, CFR, CIF

• Loading Ports: Ningbo, Wenzhou, Shanghai (or other major ports as arranged)

• Minimum Order: Typically 500 kg for mill orders (subject to negotiation)

Quality Assurance

All Incoloy alloy pipes are manufactured in accordance with strict quality management systems, certified to ISO 9001:2015 and applicable industry standards. Production facilities maintain:

• Advanced Melting Capabilities: Precise control of alloy chemistry and impurity levels

• Specialized Tube Manufacturing: State-of-the-art seamless pipe extrusion and cold drawing facilities

• Precision Welding: Automated welding systems with real-time quality monitoring

• Comprehensive Testing: In-house laboratories with full mechanical, chemical, metallurgical, and non-destructive testing capabilities

• Traceability Systems: Computerized tracking from melt to finished product

Industry-Specific Certifications Available

• Chemical Processing: ASME B31.3 process piping compliance

• Pressure Equipment: PED (Pressure Equipment Directive), ASME Section VIII, ASME B31.1/B31.3

• Oil & Gas: NACE MR0175/ISO 15156 compliance, API specifications

• Nuclear: NQA-1, 10CFR50 Appendix B, ASME Section III

• Aerospace: AS9100, AMS specifications where applicable

• International Standards: ASTM, ASME, BS, DIN, ISO, VdTÜV, SEW