Project Description
Greek Ascoloy 618 / S41800 — Overview
Greek Ascoloy 618, also designated as UNS S41800, AISI 615, and covered under AMS 5616, is a hardenable chromium-nickel-tungsten martensitic stainless steel engineered for high-stress service at temperatures up to 649°C (1200°F). The alloy delivers superior creep strength, deep hardenability, and excellent resistance to stress-corrosion cracking and temper embrittlement. Its unique chemistry — combining 12–14% chromium, 1.80–2.20% nickel, and 2.50–3.50% tungsten — provides a compelling balance of strength, toughness, and corrosion resistance that outperforms conventional 12% Cr stainless grades. SHUNFU METAL supplies Greek Ascoloy 618 bar stock manufactured under an ISO 9001 and API Q1 certified quality management system, ensuring full material traceability from certified mills through final inspection and delivery.
Equivalent Standards of Greek Ascoloy 618
| Standard | Specification | Grade |
|---|---|---|
| ASTM | A565 | 615 / S41800 |
| ASTM | A959 | 615 / S41800 |
| AMS | 5616 | Greek Ascoloy |
| AMS | 5508 | Greek Ascoloy (Sheet/Strip/Plate) |
| UNS | — | S41800 |
| AISI | — | 615 (Bar) / 418 (Sheet) |
| EN/DIN | — | No direct equivalent |
| GOST | — | No direct equivalent |
| JIS | — | No direct equivalent |
SHUNFU METAL sources Greek Ascoloy 618 from major certified special steel mills including Fushun Special Steel and Baosteel. Each heat is verified against applicable AMS and ASTM specifications with full 3.1 certification traceable to the originating melt.
Oil & Gas Applications of Greek Ascoloy 618
Greek Ascoloy 618 is widely adopted across the oil and gas industry for components requiring a combination of high-temperature strength, creep resistance, and resistance to SCC and H2S environments. Its deep hardenability and retention of mechanical properties up to 649°C make it a proven choice for demanding downhole and surface equipment.
Downhole Tools
Drill collars, stabilizers, crossover subs, non-magnetic drill collar bodies, rotary steerable system housings
Valves & Fittings
Gate valve stems, ball valve trunnions, choke valve components, high-pressure seat rings, check valve internals
Pumps & Compressors
Centrifugal pump shafts, plungers, reciprocating compressor rods, impeller hubs, wear rings
Wellhead & Xmas Tree
Hanger necks, bonnet studs, flange bolting, adapter spools, master valve component bodies
BOP & Pressure Control
Ram shafts, bonnet bolts, operating rods, shear blade carriers, annular packer actuator components
Fasteners
High-temperature stud bolts, hex cap screws, heavy hex nuts for flanged connections, tension rods
Turbomachinery
Gas turbine compressor blades, steam turbine buckets, rotor discs, nozzle rings, diffuser segments
Refinery & Petrochemical
Heat exchanger tie rods, reactor internal bolting, high-temperature process valve trims, FCC unit expansion joint hardware
Bar Stock Availability from SHUNFU METAL
SHUNFU METAL stocks Greek Ascoloy 618 in a comprehensive range of rolled and forged bar forms, supported by in-house heat treatment facilities including five car-type furnaces (up to 15 m effective length), continuous annealing lines, and medium-frequency induction quenching and tempering lines with a monthly processing capacity exceeding 3,000 tons. All heat treatment processes are managed under API Q1 and ISO 9001 controlled procedures.
| Product Form | Diameter / Thickness | Width | Length | Condition |
|---|---|---|---|---|
| Hot Rolled Round Bar | 6 mm – 300 mm | — | 3,000 mm – 9,000 mm | Annealed / Q&T |
| Hot Rolled Flat Bar | 5 mm – 100 mm | 20 mm – 400 mm | 3,000 mm – 8,000 mm | Annealed / Q&T |
| Forged Round Bar | 100 mm – 900 mm | — | 2,000 mm – 8,000 mm | Annealed / Q&T / Rough Machined |
| Forged Flat / Block | 30 mm – 500 mm | 150 mm – 1,200 mm | 1,000 mm – 6,000 mm | Annealed / Q&T / Rough Machined |
Chemical Composition per AMS 5616
The chemical composition of Greek Ascoloy 618 is governed by AMS 5616 (also aligned with ASTM A565 Grade 615). SHUNFU METAL verifies each heat through third-party optical emission spectrometry, maintaining full traceability under ISO 9001 and API Q1 documentation protocols. Certified 3.1 mill test reports are provided with every delivery.
| Element | C | Si | Mn | P | S | Cr | Ni | W | Mo | Fe |
|---|---|---|---|---|---|---|---|---|---|---|
| Range (wt%) | 0.15–0.20 | 0.50 max | 0.50 max | 0.040 max | 0.030 max | 12.0–14.0 | 1.80–2.20 | 2.50–3.50 | 0.50 max | Bal. |
Mechanical Properties of Greek Ascoloy 618
The following data represents typical mechanical properties of Greek Ascoloy 618 bar after hardening at 954°C, oil quenching, and tempering at the indicated temperatures for 4 hours followed by air cooling. SHUNFU METAL provides certified test reports for each production lot and can tailor heat treatment parameters to meet specific hardness and strength targets for oil and gas OEM requirements.
| Tempering Temp | Tensile Strength Rm (MPa) |
Yield Strength Rp0.2 (MPa) |
Elongation A% |
Reduction of Area Z% |
Hardness HBW |
|---|---|---|---|---|---|
| 260°C | 1441 | 1207 | 18 | 53 | 420–430 |
| 316°C | 1462 | 1241 | 17 | 55 | 425–435 |
| 427°C | 1496 | 1276 | 16 | 57 | 430–445 |
| 482°C | 1358 | 1138 | 17 | 58 | 390–400 |
| 538°C | 1138 | 945 | 17.5 | 59 | 340–355 |
| 593°C | 1000 | 827 | 18 | 60 | 295–310 |
| 649°C | 931 | 745 | 20 | 61 | 270–285 |
Heat treatment: 954°C austenitize, oil quench, temper 4 h, air cool. Elevated-temperature properties also available upon request. SHUNFU METAL’s in-house heat treatment furnaces with API Q1 controlled procedures deliver uniform and repeatable mechanical properties across entire production lots.