In the field of superalloys, even a deviation of just 0.1% in trace element content can lead to a huge difference between a 10-year service life and catastrophic failure. Our Nimonic 75 (GH3030/EI435) is manufactured using a high-precision vacuum electrofusion + electroslag remelting process, ensuring a perfect balance of each element's content and meeting UNS N06075 and W.Nr. 2.4951 standards. As a certified nickel alloy manufacturer, Gnee Steel offers materials with ultra-low impurity content to meet the stringent structural integrity requirements of your aerospace and nuclear energy projects.
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Nimonic 75 GH3030/UNS N06075 Chemical Composition: Elements and Standards
Nimonic 75 GH3030/UNS N06075 Chemical Composition: Elements and Standards
Nimonic 75 (UNS N06075), commonly known as GH3030 (Chinese standard) or W.Nr. 2.4951/2.4630 (German standard), is a nickel-chromium alloy (nickel-chromium ratio approximately 80/20) designed for high-temperature environments up to 1000°C. It is a solid solution-strengthened alloy that, through controlled addition of titanium and carbon, exhibits excellent oxidation resistance and moderate strength.
What are the components of NIMONIC 75?
Nimonic 75 (UNS N06075) is an 80/20 nickel-chromium alloy. Its main component is nickel, with a chromium content of 18.0%–21.0%, and small amounts of titanium and carbon. It possesses excellent oxidation resistance and high-temperature strength, and is commonly used in gas turbines and furnace components. It also contains small amounts of iron, silicon, and manganese.
1. Introduction to Nimonic 75
Nimonic 75 is one of the earliest developed high-temperature nickel-chromium alloys. Unlike precipitation-hardening Nimonic alloys, it primarily enhances its strength through solid solution strengthening and work hardening. Its excellent oxidation resistance and microstructure stability make it suitable for temperatures up to approximately 1000°C.
2. Nimonic 75 Chemical Composition Overview
| Element | Composition (%) |
|---|---|
| Nickel (Ni) | Balance |
| Chromium (Cr) | 19 – 21 |
| Iron (Fe) | ≤ 5 |
| Manganese (Mn) | ≤ 1 |
| Silicon (Si) | ≤ 1 |
| Carbon (C) | ≤ 0.12 |
| Sulfur (S) | ≤ 0.015 |
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3. Detailed Chemical Composition of Nimonic 75 Alloy
Role of Nickel (Ni)
Nickel forms the base of Nimonic 75 and provides excellent resistance to high-temperature oxidation and corrosion. It also contributes to good ductility and structural stability at elevated temperatures.
Effect of Chromium (Cr) on Oxidation Resistance
Chromium is responsible for the formation of a protective oxide layer on the alloy surface. This oxide film prevents further oxidation and enables the alloy to maintain stability in high-temperature environments such as furnaces and gas turbines.
Iron (Fe) Content Control
Iron is present as a secondary element and helps reduce alloy cost while maintaining structural strength. However, excessive iron content may reduce oxidation resistance, so its amount is carefully controlled.
Carbon (C) and Its Influence on Properties
Carbon improves strength through carbide formation but must remain within strict limits. High carbon levels could reduce ductility and increase susceptibility to cracking during welding.
Role of Silicon (Si)
Silicon contributes to oxidation resistance by improving the stability of the oxide layer formed on the alloy surface. It also assists in deoxidation during the melting process.
Role of Manganese (Mn)
Manganese helps remove sulfur impurities during alloy production and improves hot-working properties. It also contributes to overall alloy stability during manufacturing.
Control of Trace Elements such as Sulfur (S)
Sulfur and other trace elements must be carefully controlled because they can cause hot shortness and reduce mechanical integrity at high temperatures.
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4. International Standards for Nimonic 75 Alloy
USA: UNS N06075 / Alloy 75
Germany: W.Nr. 2.4951 / NiCr20Ti
China: GB GH3030 / GJB 2297
Russia: EI435 (ЭИ435) / VZh98 (ВЖ98)
5. Comparison with Other Nimonic Alloys
| Alloy | Main Strengthening Mechanism | Typical Use |
|---|---|---|
| Nimonic 75 | Solid solution strengthening | Furnace components, heat shields |
| Nimonic 80A | Precipitation hardened (Al + Ti) | Turbine blades |
| Nimonic 90 | Precipitation hardened | High-temperature aerospace components |
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FAQ
Q1: Why is ultra-low Sulfur (S) critical for Nimonic 75?
A: High Sulfur content in nickel alloys leads to "hot shortness" or cracking during welding. By keeping Sulfur below 0.005% via ESR refining, our materials ensure excellent weldability and smooth fabrication of complex high-temp parts.
Q2: Does your factory provide a full EN 10204 3.1 Mill Test Certificate?
A: Absolutely. Every shipment from our China superalloy mill includes a comprehensive MTC 3.1 documenting the exact chemical heat analysis and mechanical test results for your specific batch.
Q3: Is GH3030 truly 100% equivalent to W.Nr. 2.4951?
A: From a metallurgical and service-life standpoint, yes. Both are defined as Ni-20Cr-Ti solid-solution alloys. We have successfully supplied Nimonic 75 equivalents to major German and Italian thermal engineering firms for years.