Alloy W,Hastelloy W Wire,UNS N10004

Alloy W,Hastelloy W Wire,UNS N10004

Introduction to Alloy W (Hastelloy W Wire, UNS N10004) – Multiform Product Series

Alloy W, commercially branded as Hastelloy W and designated under UNS N10004, is a nickel-molybdenum-chromium superalloy renowned for its exceptional corrosion resistance—particularly in reducing environments like hydrochloric acid (HCl) solutions, a key advantage over many other nickel-based alloys. This alloy balances high molybdenum content (for hydrochloric acid resistance) with chromium (for oxidation stability) and controlled iron content (for mechanical workability), making it suitable for manufacturing into a diverse range of product forms. As specified, Alloy W is available in Bar (Round bar, Flat bar), Ribbon, Wire, Rods, Tube, Pipe, Foil, Plate, Sheet, Strip, and Forging Stock, catering to critical applications across chemical processing, 

pharmaceutical, and environmental industries where corrosion resistance and structural integrity are non-negotiable.

1. Chemical Composition (Typical, wt%)

The chemical composition of UNS N10004 adheres to strict industry standards such as ASTM B622 (for nickel-alloy bars), ASTM B619 (for nickel-alloy wire), and ASME SB622, ensuring consistent corrosion performance and processability across all product forms. The typical composition is as follows:

Element

Content Range (wt%)

Function

Nickel (Ni)

56.0 - 60.0

Serves as the alloy matrix, enhancing ductility and stabilizing the austenitic structure; improves compatibility with corrosive media.

Molybdenum (Mo)

24.0 - 26.0

The primary alloying element—provides exceptional resistance to reducing acids (e.g., HCl, sulfuric acid) by forming a protective oxide layer and inhibiting localized corrosion.

Chromium (Cr)

14.0 - 16.0

Enhances oxidation resistance (critical for high-temperature corrosive environments) and improves resistance to pitting in chloride-containing solutions.

Iron (Fe)

4.0 - 6.0

Improves hot workability (essential for manufacturing bars, plates, and tubes) without compromising corrosion resistance.

Cobalt (Co)

≤ 2.0

Controlled to minimize cost and avoid interference with the alloy’s corrosion-resistant phase structure.

Carbon (C)

≤ 0.05

Minimized to prevent carbide precipitation at grain boundaries, which can cause intergranular corrosion in harsh acids.

Manganese (Mn)

≤ 1.0

Aids in deoxidation during melting and improves cold workability for thin forms (e.g., foil, strip).

Silicon (Si)

≤ 0.8

Reduces oxide formation during hot processing and enhances fluidity of molten alloy for casting (used in forging stock production).

Phosphorus (P)

≤ 0.04

Limited to avoid brittleness, especially in welded joints of tubes and pipes.

Sulfur (S)

≤ 0.03

Minimized to prevent hot cracking during fabrication (critical for wire drawing and tube extrusion).

2. Physical Properties

Alloy W exhibits stable physical properties across a broad temperature range (-200°C to 650°C), ensuring consistent performance for both low-temperature storage equipment and moderate-high-temperature processing components. Key properties (uniform across all product forms) are:

Property

Value

Test Condition

Density

9.13 g/cm³

Room temperature (25°C)

Melting Point Range

1330 - 1390°C

-

Thermal Expansion Coefficient

12.8 × 10⁻⁶/°C

20 - 100°C; 15.9 × 10⁻⁶/°C (20 - 600°C)

Thermal Conductivity

10.8 W/(m·K)

100°C; 18.2 W/(m·K) (600°C)

Electrical Resistivity

1.38 × 10⁻⁶ Ω·m

Room temperature (25°C); 1.65 × 10⁻⁶ Ω·m (600°C)

Modulus of Elasticity

210 GPa

Room temperature (tensile); 175 GPa (600°C)

Poisson’s Ratio

0.31

Room temperature

Curie Temperature

≈ -100°C

Below this temperature, the alloy is weakly ferromagnetic (irrelevant for most application temperatures).

Stress Rupture Strength

95 MPa

1000 hours at 500°C; 35 MPa (1000 hours at 600°C)

3. Production Process (Adapted for Multiform Products)

The manufacturing of Alloy W into its diverse product forms requires tailored process control to ensure dimensional accuracy, surface quality, and corrosion performance. Below is a unified production framework with form-specific optimizations:

3.1 Raw Material Melting & Casting (Foundation for All Forms)

Melting: High-purity raw materials (nickel, molybdenum, chromium, etc.) are melted via vacuum induction melting (VIM) followed by vacuum arc remelting (VAR). This dual process eliminates gaseous impurities (O₂ < 30 ppm, N₂ < 50 ppm) and chemical segregations—critical for preventing corrosion weak points in thin forms (e.g., foil, wire) and thick components (e.g., forging stock).

Casting: Molten alloy is cast into:

Ingots (500 - 2000 kg) for bars, rods, and forging stock.

Slabs (10 - 50 mm thick) for plates, sheets, and strips.

Blooms (100 - 300 mm diameter) for tubes and pipes.

All cast forms undergo homogenization annealing at 1150 - 1200°C for 6 - 8 hours to uniformize chemistry.

3.2 Form-Specific Hot & Cold Processing

3.2.1 Bars (Round/Flat), Rods, & Forging Stock

Hot Forging: Ingots are hot-forged at 1050 - 1150°C into round bars (diameter: 10 - 300 mm) or flat bars (thickness: 5 - 100 mm, width: 20 - 500 mm). Forging stock is shaped into near-net forms (e.g., valve bodies) via press forging.

Hot Rolling: For smaller rods (diameter: 5 - 20 mm), hot rolling at 1000 - 1100°C is used, followed by air cooling.

Cold Finishing (Optional): Precision bars undergo cold drawing (for round bars) or cold rolling (for flat bars) to achieve tight tolerances (±0.05 mm), then stress-relieved at 600 - 700°C.

3.2.2 Plates, Sheets, Strips, & Foil

Hot Rolling: Slabs are hot-rolled at 1000 - 1100°C into plates (thickness: 5 - 100 mm) or coils (for sheets/strips).

Cold Rolling: Sheets (thickness: 0.5 - 5 mm) and strips (thickness: 0.1 - 1 mm, width: 10 - 200 mm) are cold-rolled in multiple passes. Foil (thickness: 0.01 - 0.1 mm) requires ultra-fine cold rolling with intermediate annealing (950 - 1050°C, water-quenched) to maintain ductility.

Leveling: Plates and sheets undergo roller leveling to ensure flatness (≤0.1 mm/m).

3.2.3 Tubes & Pipes

Extrusion: Blooms are extruded at 1050 - 1100°C into seamless tube blanks (outer diameter: 20 - 200 mm, inner diameter: 10 - 180 mm).

Piercing & Rolling: Tube blanks are pierced into seamless tubes via the Mannesmann process, then cold-drawn (for precision pipes) to final dimensions (outer diameter: 6 - 150 mm, wall thickness: 0.5 - 20 mm).

Welded Tubes (Optional): For large-diameter pipes (outer diameter > 200 mm), strip is formed into a cylinder and welded via TIG welding, then post-weld annealed at 1000 - 1050°C to restore corrosion resistance.

3.2.4 Wire & Ribbon

Hot Rolling: Blooms are hot-rolled into wire rods (diameter: 5 - 15 mm) at 1000 - 1100°C.

Cold Drawing: Wire rods are cold-drawn through diamond dies into wire (diameter: 0.1 - 5 mm) with intermediate annealing (950 - 1050°C, 30 - 45 minutes). Ribbon (thickness: 0.05 - 0.5 mm, width: 1 - 50 mm) is produced via cold rolling of wire rods or flat drawing.

3.3 Uniform Heat Treatment

All Alloy W products undergo solution annealing at 1050 - 1100°C for 15 - 60 minutes (duration varies by thickness: 15 min for foil, 60 min for forging stock), followed by rapid water quenching. This process dissolves carbides and precipitates, producing a uniform austenitic microstructure—critical for maximizing corrosion resistance across all forms.

3.4 Surface Finishing & Quality Inspection

Surface Treatment:

Bars/rods: Grinding or polishing (Ra ≤ 0.8 μm) for precision applications.

Plates/sheets: Pickling (nitric-hydrofluoric acid) to remove oxide scales; passivation (chromate treatment) for enhanced corrosion resistance.

Tubes/pipes: Internal honing (for high-purity fluid transport) and external polishing.

Wire/foil: Electrochemical cleaning to ensure surface smoothness (Ra ≤ 0.2 μm) for wire bonding or thin-film applications.

Quality Control:

Chemical analysis: X-ray fluorescence (XRF) and optical emission spectroscopy (OES) to verify composition.

Mechanical testing: Tensile strength (≥690 MPa at room temperature), elongation (≥30%), and hardness (≤220 HB).

Non-destructive testing: Ultrasonic testing (for bars/tubes) to detect internal defects; eddy current testing (for wire/foil) for surface flaws; pressure testing (for pipes/tubes) at 1.5× design pressure.

4. Product Applications (By Form & Industry)

Alloy W’s diverse product forms and superior corrosion resistance make it a staple in industries handling aggressive chemicals. Below are key applications organized by product form:

4.1 Bars (Round/Flat), Rods, & Forging Stock

Chemical Processing:

Round bars: Machined into pump shafts, valve stems, and agitator shafts for hydrochloric acid (HCl) storage tanks and reactors.

Flat bars: Fabricated into heat exchanger support brackets and reactor internals (resist HCl and sulfuric acid mixtures).

Forging stock: Forged into large valves, flanges, and pressure vessel nozzles for petrochemical cracking units.

Pharmaceutical: Machined into tablet press components (resist organic acid cleaning agents).

4.2 Plates, Sheets, & Strips

Chemical Industry:

Plates: Constructed into HCl evaporator bodies and sulfuric acid absorption towers.

Sheets: Formed into tank liners for phosphoric acid production (resist dilute to concentrated acid).

Strips: Welded into flexible connectors for chemical transfer hoses (withstand thermal cycling).

Environmental Engineering: Sheets used as scrubber internals in flue gas desulfurization (FGD) systems (resist SO₂ and acidic wastewater).

4.3 Tubes & Pipes

Chemical Transport:

Seamless tubes: Used for transporting concentrated HCl (up to 37% concentration) and chlorine gas (Cl₂) at 100 - 200°C.

Welded pipes: Installed in industrial water treatment systems (resist chlorinated water corrosion).

Pharmaceutical: Sanitary tubes for transporting sterile drugs and solvents (complies with FDA 21 CFR Part 177).

4.4 Wire, Ribbon, & Foil

Electronics:

Wire (0.1 - 0.5 mm diameter): Used as lead wires for sensors in corrosive environments (e.g., HCl gas detectors) and as bonding wires in high-temperature electronics.

Ribbon: Fabricated into heating elements for small-scale acid digestion equipment (operate at 300 - 400°C).

Aerospace: Foil (0.02 - 0.1 mm thick) used as thermal barrier coatings in engine fuel lines (resist jet fuel impurities).

Medical Devices: Fine wire (0.05 - 0.1 mm) for surgical instruments (resist bodily fluid corrosion).

Conclusion

Alloy W (Hastelloy W Wire, UNS N10004) stands out as a versatile, corrosion-resistant superalloy, offering an extensive product portfolio—from heavy forging stock to ultra-thin foil—to meet diverse industrial needs. Its exceptional performance in hydrochloric acid and other aggressive media, combined with strict manufacturing controls, makes it a reliable choice for chemical processing, pharmaceutical, and environmental applications. For custom requirements—such as ultra-precision wire (down to 0.01 mm diameter), large-diameter pipes (up to 1000 mm), or specialty surface finishes—tailored production processes are available to align with specific application demands.

Packing of Standard Packing: 

Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 894 gallon liquid totes Special package is available on request.