Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
Alloy 188 is a solid-solution-strengthened cobalt–nickel–chromium–tungsten alloy with a small, deliberate addition of lanthanum, developed for outstanding oxidation resistance combined with excellent high-temperature strength. This datasheet presents the material within the American (SAE-AMS / UNS) standard system.
The cobalt base with ~22% chromium and ~22% nickel provides high-temperature strength and a stable face-centred-cubic structure, while ~14% tungsten gives solid-solution strengthening. The defining feature is the lanthanum addition (~0.02–0.12%), which promotes a tenacious, self-healing protective oxide scale — extending useful oxidation resistance to about 1095 °C (2000 °F), beyond that of L-605/alloy 25. It also offers excellent resistance to sulfate-deposit hot corrosion, molten-chloride salts and gaseous sulfidation. The alloy is non-magnetic, work-hardens rapidly, and retains good ductility even after prolonged elevated-temperature exposure.
Typical applications are concentrated in gas-turbine hot sections — combustor cans, liners, flame holders, transition ducts and afterburner components — together with other aerospace and industrial high-temperature parts exposed to oxidising and corrosive gas streams. It is supplied solution-heat-treated (~1175 °C, rapid quench) and is readily fabricated and welded.
Values per manufacturer (Haynes) data, solution-annealed condition.
| Property | Value | Unit |
|---|---|---|
| Density | 8.98 | g/cm³ |
| Melting range | 1302–1330 | °C |
| Young's modulus (20 °C) | 232 | GPa |
| Specific heat capacity (20 °C) | 403 | J/kg·K |
| Thermal conductivity (20 °C) | 10.8 | W/m·K |
| Electrical resistivity (20 °C) | 1.01 | µΩ·m |
| Coefficient of thermal expansion (25–100 °C) | 11.9 | µm/m·°C |
| Magnetic response | Non-magnetic | — |
| Maximum oxidation-resistance temperature | ~1095–1150 | °C |
Limiting composition per AMS 5608 (UNS R30188).
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Cobalt | Co | Balance (~37–39) | — | Base element; high-temperature strength |
| Nickel | Ni | 20.0 | 24.0 | FCC structure stability; toughness |
| Chromium | Cr | 20.0 | 24.0 | Oxidation + hot-corrosion resistance |
| Tungsten | W | 13.0 | 16.0 | Solid-solution strengthening |
| Iron | Fe | — | 3.0 | Residual |
| Manganese | Mn | — | 1.25 | Deoxidiser |
| Silicon | Si | 0.20 | 0.50 | Deoxidiser; aids oxidation resistance |
| Carbon | C | 0.05 | 0.15 | Carbide strengthening |
| Lanthanum | La | 0.02 | 0.12 | Key addition — tenacious protective oxide scale |
| Boron | B | — | 0.015 | Grain-boundary strengthening |
| Phosphorus | P | — | 0.020 | Residual impurity |
| Sulphur | S | — | 0.015 | Residual impurity |
Key feature: the lanthanum addition is what distinguishes alloy 188 from L-605/alloy 25, giving superior oxidation resistance to ~1095 °C.
Typical room-temperature properties, solution-annealed condition.
| Property | Value | Source |
|---|---|---|
| Ultimate tensile strength | ~960–1000 MPa | Solution-annealed (Haynes data) |
| 0.2% proof strength (yield) | ~445–485 MPa | Solution-annealed |
| Elongation at break | ~50–56 % | Solution-annealed |
| Hardness | ~240–280 HB | Solution-annealed |
The alloy work-hardens rapidly and can be strengthened by cold work, remaining non-magnetic. It retains good post-exposure ductility (e.g. after thousands of hours at 650–870 °C). Values are typical; confirm against the mill test certificate for each delivery.
| Environment | Performance | Notes |
|---|---|---|
| High-temperature oxidation | Outstanding | La-stabilised scale; to ~1095 °C (better than L-605) |
| Sulfate-deposit hot corrosion | Excellent | Key advantage |
| Molten-chloride salts | Very Good | Resists molten chloride attack |
| Gaseous sulfidation | Excellent | Cobalt base + Cr |
| High-temperature strength | Excellent | Solid-solution + carbides |
| Wear / galling | Very Good | Cobalt base |
| Post-exposure ductility | Excellent | Retains ductility after long exposure |
A solid-solution cobalt-base alloy; strengthened by solid solution, carbides and cold work. Heat treatment is solution annealing.
Solution Anneal Temperature: ~1175 °C (2150 °F), followed by rapid air or water quench Purpose: dissolves carbides, restores ductility and develops optimum oxidation resistance.
Forming note: the alloy work-hardens rapidly, so intermediate solution anneals are recommended for complex forming. Hot working is carried out from ~1175 °C (2150 °F).
Readily welded by gas-tungsten-arc (GTAW), gas-metal-arc (GMAW), shielded-metal-arc (SMAW), electron-beam and resistance welding, using matching-composition filler. Submerged-arc welding is not recommended (high heat input promotes cracking).
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG · GMAW / MIG | Excellent | AMS 5801 matching wire (188-type) |
| SMAW / stick | Good | Matching coated electrode |
| EB / resistance | Good | — |
Use matching-composition filler (AMS 5801-type). Keep joints clean; avoid submerged-arc welding.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Work hardening | Rapid; rigid setup, sharp tooling, positive rake, low speeds |
| Intermediate anneal | Solution anneals for complex multi-stage forming |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Hot working | From ~1175 °C (2150 °F) |
| Cold forming | Good formability; work-hardens rapidly; intermediate anneals |
| Solution anneal | ~1175 °C, rapid quench, to restore ductility |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Gas turbines | Combustor cans, liners, flame holders, transition ducts | Oxidation to 1095 °C + hot strength |
| Aerospace | Afterburner parts, hot-section sheet components | Oxidation + sulfidation resistance |
| Industrial turbines | High-temperature structural hardware | Thermal stability + strength |
| Process / power | Components in oxidising/corrosive gas streams | Hot-corrosion resistance |
| High-temperature ducting | Sheet fabrications running hot | Oxidation resistance + formability |
| Product Form | AMS Standard | Notes |
|---|---|---|
| Sheet, strip and plate | AMS 5608 | Solution-annealed |
| Bar, forging and ring | AMS 5772 | Solution-annealed |
| Welding wire | AMS 5801 | Matching filler |
| Aerospace specifications | GE B50A712 · PWA-LCS | OEM specs |
| Welding consumables | AWS A5.21 matching Co-Ni-Cr-W filler | — |
Cobalt-base high-temperature alloy. UNS R30188. Used widely in gas-turbine hot sections.
| Alloy | Co/Ni | Cr % | Other | Best Used For |
|---|---|---|---|---|
| Alloy 188 | Co bal | 20–24 | W 13–16, Ni 22, La | Oxidation to 1095°C (La); turbine hot section |
| Alloy 25 / L605 | Co bal | 19–21 | W 14–16, Ni 10 | Strongest fabricable Co alloy; to 980°C |
| Alloy 230 | Ni bal | 20–24 | W 14, Mo 2 | Ni-base; high-temp strength + stability |
| Alloy X | Ni bal | 20.5–23 | Mo 8–10, Fe | Ni-base; combustor; oxidation to 1200°C |
| Alloy 625 | Ni bal | 20–23 | Mo 9, Nb | Ni-base; aqueous corrosion + strength |
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