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Shanghai COCESS Special Alloys Co., Ltd. builds GH5188 (old GH188 / Haynes 188 / UNS R30188 / W.Nr. 2.4683) parts for overseas buyers who cannot afford a paperwork gap between Chinese aviation specs and Western AMS/ASTM chains. This is a cobalt-base solid-solution alloy — Co bal (~39%), Cr 21–23%, Ni 20–24%, W 13–15%, La 0.03–0.12% — and it is made for 870–1095°C oxidizing gas paths, not for age-hardened disk duty. We don't sell it as "super alloy parts"; we sell combustion-liner segments, nozzle extensions, seal lanches, bellows stock, and machined rings with a heat certificate that survives both a GJB audit and an FAA-style source inspection.
1. Which standards actually apply to a GH5188 part
A finished part does not carry "GH5188 standard" as one document. It carries layers:
Chemistry mother standard: GB/T 14992-2005 (H51880) in China; AMS 5608 / AMS 5772 embedded chemistry in the US system (Co bal, Cr 21–23, Ni 20–24, W 13–15, La 0.03–0.12, Fe≤3.0, S≤0.015, P≤0.020).
Product form / semifinished spec:
Sheet & strip → AMS 5608 (solution annealed), cross-walk to GJB 1952 (cold-rolled thin plate), GJB 3317 (hot-rolled plate), GJB 3318 (cold-rolled strip).
Bar & forging → AMS 5772, cross-walk to GJB 3165 (hot-rolled/forged bar for aircraft load-bearing parts), GJB 2611 (cold-drawn bar), GJB 3020 (ring blank).
Wire & welding filler → AMS 5801 (sometimes quoted AMS 5796 for ERNiCoCrMo-1 class), cross-walk to GJB 2612 (cold-drawn wire), GJB 3167 (cold-heading wire).
Industrial pipe/plate forms → ASTM B435 (sheet/plate), B572 (bar), B622 (seamless pipe) where the buyer is a pressure-equipment shop rather than an aero engine OEM.
Part-level acceptance: customer drawing + ITAR-free PO + heat MTR (EN 10204 3.1) + dimensional report + NDE report (PT per ASTM E165 / MT per E1444, UT per E2375 on forgings).
We do not issue "GJB + ASTM compliant" as a slogan. On the COC we name the exact clauses: e.g. "Material melted to GB/T 14992 H51880 chemistry, rolled bar inspected to GJB 3165-1998, equivalent chemistry to AMS 5772 / UNS R30188, solution anneal 1180°C±10°C rapid cool, PT per ASTM E165 Class 2."
2. What we actually machine and form
GH5188 is a sheet-dominant alloy. The parts we run most:
Combustion liner segments — 0.5–1.5 mm sheet, laser/waterjet cut, roll-formed, TIG welded with homologous R30188 wire, post-weld solution anneal 1175–1190°C rapid cool.
Afterburner liner / interconnect duct — 0.8–2.0 mm sheet, punched cooling holes (ECM or laser), assembled tack-welded fixtures.
Nozzle extension / tailpipe flap blank — 1.5–4.0 mm plate, press brake, spin-forming on thin sections.
Bellows / flexible joint stock — 0.1–0.8 mm strip, hydro-formed, solution annealed after forming.
Machined rings and flanges — forged ring blanks OD 300–1200 mm, rough turned, solution treated, finish machined to drawing.
Bolts and studs (low-load hot-end) — Φ6–Φ40 mm bar, turned, rolled thread, solution anneal; not for 760°C high-preload disk bolts (that is Waspaloy/GH4738 territory).
3. Heat treatment and workmanship limits buyers miss
GH5188 has no aging step. Strength comes from Co-Cr-Ni-W solid solution plus grain-boundary carbides. The only correct final thermal state for a formed part is:
1165–1190°C soak → rapid air cool or water quench (thin sheet) → no aging.
Typical production window we run: 1180°C ±10°C, 1 h per 25 mm section, rapid cool. If a vendor offers you "GH5188 aged condition" — walk away, the grade does not age-harden.
Forming rules we enforce internally:
Cold forming >10–15% reduction needs intermediate anneal at 1065–1175°C rapid cool, or edge cracking shows up at 0.5 mm sheet.
Hot forming 1150–1180°C, finish not below 950°C.
Welding: TIG preferred, ERNiCoCrMo-1 / AMS 5801 wire, interpass ≤100°C, post-weld full solution anneal for structural parts; localized stress relief is acceptable only for non-flight secondary brackets.
Furnace atmosphere: H₂/N₂ or high-purity dissociated ammonia for thin strip; no carbonaceous atmosphere, no copper fixtures (Cu contamination causes hot cracking).
4. Dimensional and inspection package for export
For an overseas PO we ship:
MTR (EN 10204 3.1) — heat number, VIM+VAR or VIM+ESR melt route, full chemistry including La (0.04–0.08% typical we hold), RT tensile (Rm 895–1030 MPa, Rp0.2 415–485 MPa, A₅₀ ≥45%), solution anneal furnace chart.
Dimensional inspection report — ISO 2768-m or drawing GD&T, CMM where needed, thickness tolerance per AMS 2242 / GB/T 708.
NDE — PT ASTM E165 (sheet welds, formed corners), UT ASTM E2375 (forged ring >20 mm section), MT only if ferritic contamination suspected (GH5188 is nonmagnetic, so MT is not routine).
Weld map — if we assemble, wire heat number, welder ID, parameters, post-weld HT recorded.
Dual label — every tag reads: GH5188 (GH188) / Haynes 188 / UNS R30188, with GJB reference and AMS reference side by side.
5. Lead time and MOQ reality
Sheet part from stock (0.5–3.0 mm): cut+form+PT, 10–20 working days.
Ring blank from forged stock: rough turn + HT + UT, 4–6 weeks.
Welded liner assembly (multi-segment): 6–10 weeks including weld tooling.
MOQ: 1 piece for prototype (sheet part), 3 pieces for welded assembly, 1 ring for forged blank.
Drawing review is free but mandatory: we will tell you if your 980°C preloaded bolt spec is wrong for GH5188 before we quote, not after.
GH5188 parts are not complicated because the alloy is exotic — they are complicated because the traceability has to satisfy two worlds at once. COCESS closes that gap by locking the heat to GB/T 14992 H51880, processing the semifinished form against GJB 1952/3165/3317, proving chemistry against AMS 5608/5772/5801, and shipping with a 3.1 MTR that an American shop and a Chinese auditor can both read without a translator.
Mail: sales@cocessalloys.com
