China Waspaloy Manufacturer – GH738 Bar, Disk Forging, Custom Machining

Shanghai COCESS Special Alloys Co., Ltd.​ is a China-based professional supplier of precipitation-hardened nickel-base superalloys, providing Waspaloy (UNS N07001 / W.Nr. 2.4654 / China GH738, formerly GH4738)​ in round bar, forged disk/ring stock, billet, plate, and finished machined parts. All material is controlled to AMS 5706 / AMS 5707 / AMS 5709 / ASTM B637​ and GB/T 14992 (GH738 / GH4738), melted by VIM + VAR (or VIM + ESR)​ route, and supplied in solution-annealed condition or full three-stage heat-treated condition (1080°C → 845°C stabilization → 760°C aging)​ with EN 10204 3.1 Mill Test Report.

Waspaloy is not a commodity stainless or solid-solution alloy. It is a γ′-hardened Ni–Cr–Co–Mo–Ti–Al alloy​ (Al+Ti ≈ 4.0–4.8 wt%, Co ≈ 13.5%, Mo ≈ 4.2%) designed for 650–870°C (1200–1600°F) creep-resistant rotating parts​ — turbine disks, compressor rear-stage disks, turbine shafts, seals, and high-temperature fasteners. Its properties are process-sensitive: double-vacuum cleanliness and the intermediate 845°C stabilization step​ decide whether the part survives 10⁴-hour service or fails by η-phase (Ni₃Ti) embrittlement. COCESS focuses on exactly that process discipline.

1. Grade Cross-Reference & Standards

2. Chemistry Control (AMS 5707 / ASTM B637)

PMI (XRF/OES) at outgoing inspection verifies Ni, Cr, Co, Mo, Ti, Al, Fe, and traces B/Zr against the ordered specification.

3. Three-Stage Heat Treatment (Non-Negotiable)

Waspaloy achieves design properties only via:

1. Solution:​ 1080°C ± 10°C × 2–4 h​ (per section) → oil quench or high-pressure water quench. Air cooling is acceptable only for very thin sections; bars/disks > 25–50 mm must be liquid-quenched to avoid γ′ pre-precipitation.

2. Stabilization:​ 843–855°C (commonly 845°C) × 4–24 h / AC. Precipitates primary γ′ and M₂₃C₆ at grain boundaries, occupying sites that would otherwise form η-phase (Ni₃Ti) during long service.

3. Aging:​ 760°C × 16 h / AC. Precipitates fine secondary γ′ (20–50 nm) for peak strength.

Skipping stabilization or substituting a simple 700°C age reduces 760–870°C stress-rupture life and invites ductility loss after 3000–5000 h at temperature.

Typical properties after full three-stage HT:

• Room temp: Rm 1200–1450 MPa​ (AMS 5707 min ≥ 1275 MPa), Rp0.2 800–1100 MPa​ (min ≥ 795 MPa), A₅₀ 15–25%, hardness 34–44 HRC.

• 650°C: Rm ≈ 920–980 MPa, Rp0.2 ≈ 620–670 MPa.

• 760°C: Rm ≈ 830–880 MPa, Rp0.2 ≈ 590–640 MPa.

• 815°C: Rp0.2 ≈ 500–600 MPa.

• Stress-rupture (representative): 760°C / 240 MPa ≈ 1000 h class; 815°C / 131 MPa ≈ 1000 h class; 870°C / 110 MPa marginal.

4. Product Forms & Supply Scope

Custom services: band-saw / abrasive cut to length, rough turning to leave machining allowance, centerless grinding, near-net forging to drawing, UT (ASTM A388 / SEP 1921) on forgings, export VCI + wooden crate packing.

5. Custom Machining & Forging Support

Because Waspaloy work-hardens and contains γ′ hard particles, finish machining is best done after final heat treatment on rigid CNC setups (low SFM 8–15 m/min, TiAlN carbide, flood coolant). COCESS supports two common paths:

• Path A (Customer final-HT):​ Supply solution-annealed bar/forging​ → customer rough-machines → performs own 845°C stabilization + 760°C aging. Reduces distortion risk on complex disks.

• Path B (Turnkey):​ COCESS performs full three-stage HT, then precision machines to drawing (retaining final grind allowance or delivering finished dimensions). MTR attaches the complete furnace time-temperature record including the 845°C stabilization segment.

For disk forgings, we control forge ratio ≥ 3–4​ and aim for ASTM 5–8 grain size​ to avoid mixed grain structure after final HT.

6. Typical Applications

Not recommended for large thin-wall welded sheet fabrications (SAC risk) — use Nimonic 263 there.

7. Quality Assurance Package

Every shipment includes:

• ✅ EN 10204 3.1 MTR​ — Heat No., VIM+VAR melt info, full chemistry (incl. B, Zr), room-temp tensile, grain size, complete three-stage HT record (1080 / 845 / 760°C segments).

• ✅ PMI report​ (XRF/OES).

• ✅ UT / PT / MT​ on forgings/disks per order.

• ✅ Dimensions inspection report.

• ✅ CO / Invoice / Packing List.

• ✅ Third-party witness (SGS / TÜV / BV) and EN 10204 3.2​ on request.

8. Why Source From Shanghai COCESS

• Process-first supply:​ We do not treat Waspaloy as “another nickel bar.” Melt route (VIM+VAR), quench medium, and 845°C stabilization are contractually fixed in the order, not left to the mill’s convenience.

• Form flexibility:​ From Φ10 mm test-bar quantities to Φ800 mm disk rings, one PO covers bar + forging + rough machining.

• Standard fluency:​ AMS 5706/5707/5709, ASTM B637, GB/T 14992 GH738/GH4738, GE/PWA cross-checks handled in the quote stage.

• Companion alloys:​ Nimonic 90 (N07090), Nimonic 263 (N07263), Inconel 718 (N07718), Haynes 188 (R30188) available for multi-alloy turbine assembly sourcing.

9. Request a Quote

For Waspaloy / GH738 availability, current bar diameters, disk forging lead time, or three-stage HT validation, contact:

Shanghai COCESS Special Alloys Co., Ltd.​

Email: sales@cocessalloys.com

Web: https://en.cocessalloys.com

Add: Shanghai, China