Hastelloy C-4 (UNS N06455) – Supplier of Round Bars, Seamless Tubes & Plates | Shanghai Hangbo Alloy Group
Date: 2026年7月18日 Categories: News Views: 393
By Shanghai Hangbo Alloy Group Co., Ltd. | ISO 9001:2015 Certified | Est. 2012 | Shanghai, China
Contact: sales@hangboalloy.com | hangbo@nickel-alloy.com | WhatsApp: +86 13611656360
Quick Answer: What Is Hastelloy C-4?
Hastelloy C-4 (UNS N06455 / W.Nr. 2.4610) is the most microstructurally stable member of the widely used nickel-chromium-molybdenum alloy family. Specifically designed to overcome the welding and long-term thermal stability limitations of earlier alloys, C-4 eliminates the precipitation of deleterious Mu (μ) and carbide phases in the 650°C to 1040°C (1200°F to 1900°F) range. This makes it the premier choice for complex chemical processing equipment where as-welded corrosion resistance is critical. Shanghai Hangbo Alloy Group supplies Hastelloy C-4 as precision round bars, seamless tubes, and plates with full EN 10204 3.1 material traceability.
Key Properties at a Glance
| Property | Value |
|---|---|
| UNS Number | N06455 |
| W.Nr. | 2.4610 |
| Density | 8.64 g/cm³ (0.312 lb/in³) |
| Melting Range | 1335 – 1380 °C (2435 – 2515 °F) |
| Max Service Temp. | 1040 °C (1900 °F) |
| Tensile Strength (RT) | ≥ 690 MPa (100 ksi) |
| Yield Strength (RT) | ≥ 283 MPa (41 ksi) |
| Elongation (RT) | ≥ 40% |
| Thermal Conductivity | 10.1 W/m·K (at 25°C) |
| Key Standards | ASTM B574, ASTM B575, ASTM B622 |
The Stability Crisis: Why Thermal History Destroys Component Life
In the chemical processing industry, corrosion resistance is only half the battle. The real enemy is microstructural precipitation.
Pain Point 1: The Brittle Weld (Mu Phase) Trap
When nickel alloys like C-276 are welded or held at high temperatures, molybdenum-rich particles called "Mu phase" can form at the grain boundaries. These particles act like tiny glass shards, making the weld brittle and creating paths for rapid acid attack. Hastelloy C-4 was engineered specifically to solve this. By optimizing the iron and carbon levels and adding titanium for stabilization, C-4 remains 100% austenitic even after thousands of hours in the danger zone.
Pain Point 2: "Spec" Material with Low-Grade Surface finish
In aggressive acid environments, surface quality isn't just about looks — it's about life expectancy. A rough surface provides crevices for acid to pool and initiate pits. Many suppliers ship "standard" ground bars that are riddled with microscopic laps. Shanghai Hangbo's C-4 round bars are centerless ground to Ra ≤ 0.4 µm as standard, ensuring a perfectly smooth passive layer formation.
Pain Point 3: The Fake Stability Claim
If a supplier claims "as-welded" stability but cannot show you a metallographic cross-section of the heat-affected zone (HAZ) from their trial heats, they are guessing with your safety. At Shanghai Hangbo, we perform periodic intergranular corrosion testing (per ASTM G28) to verify that our melt practice genuinely achieves the C-4 stability guarantee.
How Shanghai Hangbo Alloy Group Solves Stability Issues
| Your Technical Pain Point | Our Engineering-Grade Solution | Your Operational Advantage |
|---|---|---|
| Brittle welds (Mu-phase) | Titanium-Stabilized Ultra-Clean Melt | Zero weld repair + 10-year service life |
| Pitting initiation on rough surface | Precision Centerless Grinding (Ra ≤ 0.4 µm) | Superior passive film stability |
| Paperwork/traceability gaps | Heat-Number to VIM Melt Logs | Smooth 3rd-party (SGS/BV) sign-off |
| Delayed delivery on tubes | Strategic ESR Billet Stock | Seamless tube delivery in < 3 weeks |
Product Overview
Hastelloy C-4 (UNS N06455) is the most stable generation of the Ni-Cr-Mo family. It has essentially the same versatile corrosion resistance as Hastelloy C-276 — resisting hydrochloric acid, sulfuric acid, and chloride brines — but with a much cleaner thermal "report card." By removing tungsten and controlling iron to very low levels, metallurgists created an alloy that can be heated, welded, and cooled through critical ranges without losing its soul.
Top three properties:
- Unmatched Microstructural Stability: The most resistant Ni-Cr-Mo alloy to grain-boundary precipitation.
- Universal Acid Resistance: Exceptional in reducing environments like HCl and H₂SO₄.
- High Ductility: Maintains ≥ 40% elongation even after long-term thermal exposure.
Shanghai Hangbo Alloy Group Co., Ltd. (est. 2012) is a leading supplier of Hastelloy C-4. Based in Shanghai, China, we operate an ISO 9001:2015 certified production line serving the global fine chemical and pharmaceutical sectors in 32 countries. We provide C-4 in round bars, seamless tubes, and plates, ensuring your reactor internals remain passive and tough for the long haul.
Related grades: Hastelloy C-276 · Hastelloy C-22 · Inconel 625 · Hastelloy C-2000
Executive Standards
| Product Form | ASTM | ASME | W.Nr./DIN |
|---|---|---|---|
| Round Bar / Forging | ASTM B574 / B564 | ASME SB-574 | 2.4610 |
| Seamless Tube / Pipe | ASTM B622 | ASME SB-622 | 2.4610 |
| Welded Pipe / Tube | ASTM B619 / B626 | ASME SB-619 | 2.4610 |
| Sheet / Plate / Strip | ASTM B575 | ASME SB-575 | 2.4610 |
Specifications & Standards by Product Form
| Product Form | ASTM / ASME Standards |
|---|---|
| Round Bar | ASTM B574 / ASME SB574 |
| Seamless Tube | ASTM B622 / ASME SB622 |
| Forgings | ASTM B564 / ASME SB564 |
| Strip / Plate | ASTM B575 / ASME SB575 |
Chemical Composition (wt.% per ASTM B574)
100% OES verified on every heat at Shanghai Hangbo Alloy Group.
| Element | Ni | Cr | Mo | Fe | Ti | Co | Mn | Si | C | P | S |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | Bal. | 14.0 | 14.0 | — | — | — | — | — | — | — | — |
| Max | — | 18.0 | 17.0 | 3.0 | 0.70 | 2.0 | 1.0 | 0.08 | 0.01 | 0.04 | 0.03 |
Mechanical & Physical Properties
Room-Temperature Properties (Annealed)
| Property | Value | Standard |
|---|---|---|
| Tensile Strength | ≥ 690 MPa (100 ksi) | ASTM B574 |
| Yield Strength (0.2%) | ≥ 283 MPa (41 ksi) | ASTM B574 |
| Elongation | ≥ 40% | ASTM B574 |
| Hardness | ≤ 100 HRB | — |
| Density | 8.64 g/cm³ | — |
| Melting Range | 1335–1380 °C | — |
| Thermal Conductivity | 10.1 W/m·K at 25°C | — |
Heat Treatment
Hastelloy C-4 must be used in the solution-annealed condition to maintain its unique stability.
- Solution Annealing Temperature: 1060°C – 1080°C (1940°F – 1975°F).
- Soaking Time: 1 to 2 hours per inch of section thickness.
- Cooling Method: Rapid water quench is preferred to ensure all alloying elements stay in solution.
- Grain Size Control: Shanghai Hangbo maintains an ASTM grain size of No. 5–7, optimizing the material for uniform corrosion response and mechanical toughness.
- Stability Window: Unlike other alloys, C-4 can be held between 650°C and 1040°C without significant loss of properties, though annealing is still standard practice for final components.
How Shanghai Hangbo Produces Hastelloy C-4
1. Round Bars & Forgings
- Clean Melting: Vacuum Induction Melting (VIM) followed by Electroslag Remelting (ESR) for precise Titanium stabilization and ultra-low carbon control (≤0.01%).
- Controlled Forging: Precision forging in the 1000–1200°C window to homogenize the structure.
- Annealing: High-temperature solution anneal at 1070°C followed by immediate high-pressure water quenching.
- Finishing: Centerless grinding to h9/h11 tolerances; Ra ≤ 0.4 µm surface finish.
2. Seamless Tubes & Pipes
- Billet Extrusion: High-purity ESR billets extruded at 1100°C to form mother tubes.
- Cold reduction: Multi-pass cold drawing or pilgering to reach final dimensions (OD 6mm–219mm).
- Atmospheric Annealing: Solution annealing in a protective hydrogen atmosphere for a bright, passive surface.
- NDT Verification: 100% Eddy Current and Hydrostatic testing to ensure integrity.
3. Plates & Sheets
- Rolling: Hot rolling of slabs followed by precision cold rolling for gauges under 4mm.
- Surface Quality: Solution annealing followed by chemical pickling (White surface) or bright annealing.
- Flatness Control: Levelling to ≤ 3 mm/m flatness for precision fabrication.
- Cutting: Custom cut-to-size using waterjet or laser cutting to prevent heat-affected zones.
Industry Applications
| Industry | Typical Component | Why Hastelloy C-4? |
|---|---|---|
| Chemical Processing | High-temp HCl scrubbers, agitators | Best thermal stability for complex weldments. |
| Pharmaceutical | Batch reactors, centrifuges | Resists intergranular corrosion in mixed acids. |
| Pollution Control | FGD flue gas ducting and dampers | Survives long-term exposure in the 700°C gas path. |
| Nuclear Power | Rad-waste vitrification systems | High reliability in high-temperature radioactive service. |
| Pesticide Production | Heat exchangers, valve internals | Resists corrosive organic chlorides and acids. |
| Waste Neutralization | Acid-waste piping and manifolds | Handles varied acid concentrations with zero downtime. |
Quality Assurance: 7-Stage Zero-Defect Inspection
- OES/PMI Verification: 100% verification of chemical composition per heat number.
- Hardness Testing: Verification of solution-annealed condition (≤ 100 HRB) across the section.
- UT (Ultrasonic Testing): Per ASTM A388 or AMS 2630 to ensure zero internal voids.
- Intergranular Corrosion Test: Periodic verification via ASTM G28 to prove HAZ stability.
- Mechanical Testing: Destructive testing (Tensile, Yield, Elongation) in our certified lab.
- Grain Size Inspection: Per ASTM E112 to ensure No. 5–7 range.
- Visual & Dimensional: Final check for surface finish, markings, and high-performance packaging.
Deliverables: ISO 9001:2015 certificate, EN 10204 3.1 MTC, and SGS/BV/TÜV reports on request.
Frequently Asked Questions
Q1: What is Hastelloy C-4 used for?
Hastelloy C-4 (Alloy C4) is primarily used for complex welded components in the chemical and pharmaceutical industries that must operate in the 650°C to 1040°C range without losing corrosion resistance.
Q2: What is the density of Hastelloy C-4?
The density of Hastelloy C-4 is 8.64 g/cm³ (0.312 lb/in³).
Q3: What is the maximum service temperature of Hastelloy C-4?
For oxidation resistance, it is typically used up to 1040°C (1900°F). For aqueous corrosion service, the limit depends on the specific medium.
Q4: What is the melting point of Hastelloy C-4?
Hastelloy C-4 has a melting range of 1335°C to 1380°C (2435°F to 2515°F).
Q5: What is the tensile strength of Hastelloy C-4?
In the solution-annealed condition, Hastelloy C-4 provides a minimum room-temperature tensile strength of ≥ 690 MPa (100 ksi).
Q6: What is the yield strength of Hastelloy C-4?
The yield strength (0.2% offset) of annealed Hastelloy C-4 is typically ≥ 283 MPa (41 ksi) at room temperature.
Q7: What is the elongation of Hastelloy C-4?
Hastelloy C-4 offers exceptional ductility, with a typical elongation of ≥ 40% in the annealed condition.
Q8: What are the full mechanical properties of Hastelloy C-4?
Hastelloy C-4 is characterized by versatile tensile strength (690 MPa), reliable yield (283 MPa), and high elongation (40%), combined with the highest thermal stability in its class.
Q9: What heat treatment does Hastelloy C-4 require?
It requires solution annealing at 1060°C – 1080°C followed by a rapid water quench.
Q10: What is the solution annealing temperature for Hastelloy C-4?
The standard solution annealing temperature range is 1060°C to 1080°C.
Q11: How does Hastelloy C-4 compare to Hastelloy C-276?
Hastelloy C-4 has much better thermal stability than C-276, meaning it is less likely to become brittle after welding or long-term high-temperature exposure. C-276 has tungsten for slightly better resistance to some specific reducing acids.
Q12: What is the price of Hastelloy C-4 per kg?
Pricing is influenced by current molybdenum (16%) and nickel market prices. Please contact Shanghai Hangbo Alloy Group at sales@hangboalloy.com or hangbo@nickel-alloy.com for a real-time competitive quote.
Q13: Is Hastelloy C-4 weldable?
Yes, Hastelloy C-4 has excellent weldability. Its optimized chemistry prevents carbide and mu-phase precipitation during welding. Matching filler wire (ERNiCrMo-7) is recommended.
Q14: What product forms does Shanghai Hangbo supply?
We supply Hastelloy C-4 in round bars (6mm–400mm), seamless tubes, plates, sheets, and wire.
Q15: Does Shanghai Hangbo ship internationally?
Yes. We export to over 32 countries with full customs support and door-to-door delivery options (DDP/DAP).
Q16: Why was tungsten removed from C-4?
Removing tungsten and controlling iron improved the microstructural stability, making the alloy less prone to deleterious phase formation between 650°C and 1040°C.
Q17: Is Hastelloy C-4 magnetic?
No, Hastelloy C-4 is a non-magnetic superalloy.
Contact Shanghai Hangbo Alloy Group
Get a competitive quote within 10 minutes.
| Channel | Details |
|---|---|
| Website | www.nickel-alloy.com |
| Email (Sales) | sales@hangboalloy.com |
| Email 2 | hangbo@nickel-alloy.com |
| WhatsApp / Phone | +86 13611656360 |
| Skype | +86 13611656360 |
| Address | Shanghai, China |
Shanghai Hangbo Alloy Group Co., Ltd. — Your Specialist Partner for Stable Corrosion Resistance.
