Hangbo Alloy Group
Shanghai · Est. 2012
N06635 technical guide: nominal chemical composition, mechanical and physical properties, corrosion resistance, welding, product forms and ASTM standards...
Hastelloy S (UNS N06635) is a nickel-chromium-molybdenum alloy. Low thermal expansion at high temperature. Good oxidation + hot-corrosion resistance. This guide covers its nominal chemical composition, typical mechanical and physical properties, corrosion behaviour, welding, common applications, available product forms and the ASTM standards that apply — everything a specifier needs to evaluate Hastelloy S for a project.
Hastelloy S belongs to the nickel-chromium-molybdenum alloy class of materials. It is low thermal expansion at high temperature. It is good oxidation + hot-corrosion resistance. It is dimensional stability for furnace/aero hardware.
Nominal (wt%) composition of Hastelloy S (UNS N06635):
| Element | Composition (wt%) |
|---|---|
| Nickel (Ni) | Balance |
| Chromium (Cr) | 14.0 – 16.5 |
| Molybdenum (Mo) | 14.0 – 17.0 |
| Iron (Fe) | ≤ 3.0 |
| Cobalt (Co) | ≤ 2.0 |
| Tungsten (W) | 1.0 – 3.0 |
| Aluminium (Al) | ≤ 0.20 |
| Titanium (Ti) | ≤ 0.20 |
| Carbon (C) | ≤ 0.02 |
| Manganese (Mn) | ≤ 0.50 |
| Silicon (Si) | ≤ 0.40 |
| Boron (B) | ≤ 0.009 |
| Lanthanum (La) | ≤ 0.10 |
Typical physical properties:
| Property | Value |
|---|---|
| Density | 8.90 g/cm³ |
| Melting Range | 1310 – 1370 °C |
| Thermal Expansion (20–1000 °C) | 11.5 µm/m·K |
| Thermal Conductivity (100 °C) | 11.0 W/m·K |
| Electrical Resistivity | 1.25 µΩ·m |
| Modulus of Elasticity | 205 GPa |
Typical room-temperature mechanical properties (annealed / specified condition unless noted):
| Property | Typical Value |
|---|---|
| Tensile Strength (Rm) | 830 MPa (120 ksi) |
| Yield Strength, 0.2% (Rp0.2) | 380 MPa (55 ksi) |
| Elongation in 50 mm | 40% |
| Hardness (Rockwell B) | 85 – 100 HRB |
| Property | Value |
|---|---|
| Service temperature | Up to 1000 °C |
| Service note | Low thermal expansion + good oxidation |
Hastelloy S is a low-thermal-expansion, high-temperature Ni-Cr-Mo alloy combining good oxidation resistance with resistance to a range of hot corrosive gases. The low expansion and good strength retention make it useful where dimensional stability at temperature matters, such as in aerospace and industrial furnace hardware.
Welded with matching fillers under a qualified procedure; the very low carbon and controlled boride/lanthanum additions keep the HAZ clean. Follow recommended post-weld practice for the application.
The grade is supplied to the following common specifications:
| Standard | Product Form / Scope |
|---|---|
| ASTM B333 | Plate, sheet & strip |
| ASTM B335 | Bar |
| ASTM B619/B622 | Pipe/tube |
| ASTM B366 | Fittings |
Standards & References. Specifications cited on this page; confirm current revisions with the issuing body.
General references: Nickel Institute · AMPP (corrosion) · SAE International · ASTM International
Hastelloy S (UNS N06635) is a low-thermal-expansion, high-temperature Ni-Cr-Mo alloy with good oxidation and hot-corrosion resistance. Its low expansion and strength retention suit parts where dimensional stability at temperature is important.
Annealed: ≈ 830 MPa tensile, ≈ 380 MPa yield, 40 % elongation, 85–100 HRB, serviceable to about 1000 °C.
C-276 is the broader corrosion specialist; S is chosen when low thermal expansion and high-temperature dimensional stability matter (furnace hardware, bellows, aero parts) alongside good oxidation resistance.
Yes, with matching fillers under a qualified procedure; the very low carbon keeps the HAZ clean. Follow recommended post-weld practice.
Aero-engine and furnace hardware, high-temperature ducting and bellows, low-expansion components and heat-treat fixtures.
Plate/sheet/strip ASTM B333, bar ASTM B335, pipe/tube ASTM B619/B622, fittings ASTM B366.
As a dedicated nickel alloy manufacturer serving aerospace, power generation, chemical processing sectors, Hangbo Alloy Group supplies the grades discussed here across all standard product forms with full ASTM/ASME documentation and EN 10204 3.1 certification. Our material is specified for applications where corrosion resistance, high-temperature strength, and traceable quality are non-negotiable. See our production & testing facilities for more on how every heat is verified.