Hastelloy G-3 Bar
Hastelloy G-3 Bar
Hastelloy G-3 (UNS N06985) is a solid-solution-strengthened, corrosion-resistant nickel-chromium-iron-molybdenum-copper alloy. It is an improved wrought version of the G-series alloys, designed to address the issue of insufficient corrosion resistance in the weld heat-affected zone (HAZ) associated with the original Alloy G.
The primary role of G-3 is to provide balanced corrosion resistance in mixed-acid environments containing both oxidizing and reducing agents, while also offering excellent resistance to intergranular corrosion in the as-welded condition. Unlike C-series alloys (such as C-276), G-3 is not designed for service in extremely reducing acids; instead, it focuses on applications involving sulfuric acid, phosphoric acid, and mixed acids containing fluoride or chloride ions.
While the G-3 represents the generation within the G-series that addressed fundamental challenges, the G-30 and G-35 are specialized variants engineered specifically to conquer the demands of phosphoric acid environments.
If your primary application involves wet-process phosphoric acid, the G-30 or G-35 offers a more specialized and suitable solution. However, the G-3 retains its relevance in applications involving sulfuric acid, mixed acids, and general corrosion-resistant scenarios requiring good weldability-all while typically being more cost-effective than the G-30 and G-35. Amidst competition from "super stainless steels" (such as 904L and 254SMO), the G-3 is positioned to deliver superior weld corrosion resistance compared to standard stainless steels, while offering a cost advantage over the higher-end G-30 and G-35 grades.
Size Reference
Cold-drawn bright bars Φ4 – 60 mm
Hot-rolled/forged round bars Φ60 – 280 mm Customizable
Hexagonal/square bars Across-flats 6 – 120 mm
Overall round bar range Φ3 – 600 mm
chemical composition
| Ni | Rest |
| Cr | 21.0-23.5 |
| Fe | 18.0-21.0 |
| Mo | 6.0-8.0 |
| Cu | 1.5-2.5 |
| Co | ≤5.0 |
| W | ≤1.5 |
| Nb+Ta | ≤0.50 |
| C | ≤0.015 |
| Si | ≤1.0 |
| Mn | ≤1.0 |
| P | ≤0.04 |
| S | ≤0.03 |
Physical properties
| Density | 8.14 – 8.30 g/cm³ |
| Melting range | 1260 – 1343°C (solidus 1260°C, liquidus 1343°C) |
| Modulus of elasticity | 199 GPa (room-temperature tensile) |
| Electrical resistivity | 112.37 μΩ·cm |
| Thermal conductivity (25°C) | 10.0 W/(m·K) |
Mechanical Properties
Tensile strength: Approx. 690 MPa
Yield strength: Approx. 305 – 321 MPa
Elongation: Approx. 50%
Hardness: HRB 85 – 95
Note: Cold working can significantly increase the strength of G-3, though elongation decreases markedly; it is suitable for applications such as Oil Country Tubular Goods (OCTG) requiring high strength and corrosion resistance.
Key points for processing
When processing and procuring Hastelloy G-3 bars, the key lies in managing its narrow hot-working window, rapid work-hardening rate, and the absolute necessity of proper solution heat treatment.
Hot Working
The hot-working temperature range for G-3 is strict; deviations can easily compromise material performance.
Recommended temperature range: 1100–1240°C (research-validated optimal range). Some sources suggest a range of 980–1200°C.
Cold Working
G-3 has a higher work-hardening rate than austenitic stainless steels, requiring equipment with greater power capacity.
Deformation control: Intermediate annealing is mandatory for cold deformation where outer-fiber elongation exceeds 7–10%; otherwise, cracking is likely to occur.
Machining
G-3 is classified as a difficult-to-machine material. Machining requires rigid tooling, a strategy of low cutting speeds combined with high feed rates, and an ample supply of high-pressure coolant.
Note: The above information is for reference only; please refer to the final purchase order for specific details. Our company reserves the right of final interpretation.
Lork Group
Marketing Operations Department
Email: layla@lorkgroup.com
WhatsApp: +86 199 3707 5488
Hot Tags: Hastelloy G-3 Bar,UNS N06985,Alloy G-3,W.Nr. 2.4619, Phosphoric Acid Service, ASTM B581, Weldable Nickel Alloy
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