High-Temperature Alloys / Superalloys
GH4708 (ЭП742) (UNS —) — Composition, Properties & Supply
GH4708 is a Ni-Cr-Co base superalloy strengthened by W/Mo solid-solution and Al/Ti γ′ precipitation, giving high strength, oxidation resistance and thermal-fatigue resistance, for turbine discs, blades and fasteners in aero-engines and industrial gas turbines.
What is the chemical composition of GH4708 (ЭП742)?
| Element | Symbol | Content (wt%) |
|---|---|---|
| Ni | Ni | Balance |
| Cr | Cr | 17.0–20.0 |
| Co | Co | 12.0–15.0 |
| W | W | 5.5–7.0 |
| Mo | Mo | 3.5–5.0 |
| Al | Al | 1.0–1.8 |
| Ti | Ti | 2.5–3.5 |
| Fe | Fe | ≤ 4.0 |
| C | C | 0.05–0.10 |
Values are typical specification limits. Actual heat analysis is reported on the EN 10204 3.1 mill test certificate supplied with each shipment.
What are the mechanical properties of GH4708 (ЭП742)?
| Property | Value | Note |
|---|---|---|
| Tensile strength | ≥ 1275 MPa | Room temperature |
| Yield strength (0.2% offset) | ≥ 835 MPa | Room temperature |
| Elongation | ≥ 12 % | Gauge length 50 mm / 4D |
| Hardness | 320–380 HBW | Brinell / Rockwell |
What are the physical properties of GH4708 (ЭП742)?
| Property | Value |
|---|---|
| Density | 8.35 g/cm³ |
| Melting range | 1320–1360 °C |
| Thermal conductivity | 11.0 W/m·K |
| Elastic modulus | 210 GPa |
| Maximum service temperature | 800 °C |
What are the key characteristics of GH4708 (ЭП742)?
- Co+W+Mo combined solid-solution strengthening
- γ′ (Al+Ti) precipitation, RT tensile ≥ 1275 MPa
- Good resistance to thermal fatigue
- Stable structure at high temperature
Where is GH4708 (ЭП742) used?
- Turbine discs, blades and high-temperature fasteners
- Gas-turbine rotors and load-bearing shafts
- Aero-engine hot-section parts
- Compressor and turbine high-temperature components
Which standards and specifications cover GH4708 (ЭП742)?
What product forms are available?
Frequently asked questions
What is the heat treatment for GH4708?
GH4708 uses a standard three-step treatment: solution at 1120 °C ±10 °C for 2–4 h followed by air cooling, then staged ageing to precipitate fine γ′ for optimum combined properties.
Need GH4708 (ЭП742) bar, tube, plate or forgings?
Send the grade, dimensions, standard and quantity. We answer within 10 minutes on working days and quote within 24 hours, with EN 10204 3.1 certification.
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