2.4983 Forgings Seamless rolled rings, discs, shafts, flanges and bars in UNS N07500 / Udimet 500, forged to drawing by Jiangyin Jiangnan Metal Co., Ltd.

§ 01What 2.4983 is

2.4983 is an age-hardenable nickel-chromium-cobalt superalloy. It was developed for parts that carry load in the hot section of gas turbines, and it is now specified across industrial equipment with comparable duty.

Strength comes from a gamma-prime phase precipitated during a multi-stage ageing treatment. The mechanical values on a certificate therefore belong to a stated heat-treatment condition, not to the grade on its own. Cobalt and molybdenum strengthen the matrix, chromium provides oxidation and hot-corrosion resistance, and the titanium and aluminium additions form the strengthening precipitate.

The alloy is ductile enough to work hot, so open-die forging and ring rolling produce a grain flow that machining from solid cannot reproduce. It also work-hardens quickly under a cutting edge, which means machining allowance and tooling need to be settled before the part is quoted. Fatigue life depends heavily on cleanliness, and that is why we melt 2.4983 by EAF + VOD and follow with an ESR remelt.

§ 02Equivalent designations and cross-reference

The same alloy appears on drawings under several names. Every designation below covers the material this page describes, so a drawing calling for any one of them is supplied to the same chemistry.

Confirm the ordering standard on the purchase order. The standard, not the grade name, fixes the acceptance limits.

§ 03Chemical composition of 2.4983

The nominal composition of 2.4983 / UNS N07500 is set out below. Nickel is the balance element. Minimum and maximum limits are those of the ordering standard, usually ASTM B637 or AMS 5751 / 5753.

Values are nominal and given for grade identification. Heat analysis and, on request, product analysis of the material actually supplied are reported on the EN 10204 3.1 certificate that accompanies each 2.4983 forging from Jiangyin Jiangnan Metal Co., Ltd.

§ 04Mechanical and physical properties

Room-temperature mechanical properties of 2.4983 in the aged condition are shown first. Since this is a precipitation-hardening alloy, a strength figure quoted without its heat-treatment condition carries no meaning, so state the condition on the enquiry.

Typical values for grade comparison, not guaranteed minima. Certified test results for the specific heat and section are issued with the material.

§ 05Melting and forging route

Fatigue and creep life in a 2.4983 part depend as much on cleanliness as on chemistry, so the melting route belongs in the specification. Jiangyin Jiangnan Metal Co., Ltd. produces 2.4983 through the sequence below.

1. EAF + VOD primary meltingElectric arc melting followed by vacuum oxygen decarburisation, bringing carbon, sulphur and gas content down and setting the chemistry accurately.
2. ESR remeltingElectroslag remelting refines the ingot structure, reduces segregation and improves transverse properties, which matters for rings and discs loaded across the grain.
3. Ingot heating and open-die forgingCogging and upsetting on open dies, with reduction ratio controlled to break down the cast structure and develop grain flow following the part contour.
4. Ring rollingFor seamless rolled rings, the pierced blank is rolled to the finished section, giving circumferential grain flow that suits rotating and pressure-containing parts.
5. Heat treatmentSolution treatment and double ageing to the cycle in § 06, or delivery in the solution-treated condition where the customer performs final ageing after machining.
6. Rough or finish machiningSawing, turning and boring to the drawing, with machining allowance agreed in advance.
7. Non-destructive and mechanical testingUltrasonic inspection, dimensional check, chemical analysis and mechanical testing as described in § 09.
8. Certification and dispatchEN 10204 3.1 certificate, or 3.2 with third-party witness, issued with the forgings before packing and export.

§ 06Heat treatment of 2.4983

Forged 2.4983 develops its full high-temperature strength through a solution treatment followed by two ageing stages. The standard three-stage cycle is:

A four-stage variant with an additional intermediate hold is used where maximum creep-rupture life is required. Annealing, where a soft condition is needed for further working, is carried out at 1079 °C with rapid air cooling.

Order the delivery condition explicitly: as-forged, solution treated or fully aged. Parts with heavy machining after forging are often shipped solution treated, so that ageing distortion is taken out before finishing.

§ 072.4983 forged forms and size range

All 2.4983 parts are forged to the customer's drawing and there is no standard catalogue. The table gives the forms we produce most often, with the dimensional envelope to design within.

Supplied as-forged, rough machined or finish machined. Send the drawing and we will confirm feasibility, machining allowance and lead time.

§ 08Where 2.4983 forgings are used

2.4983 is specified where a part has to hold strength at temperature, resist creep under sustained load, or survive a combination of heat and aggressive media. The industries below account for most of the 2.4983 forgings leaving our works.

Gas turbines and rotating equipment

Hot-section discs, rings, spacers, shafts and fasteners, together with gas-compressor and turbine gearbox components. The three-stage age hardening exists to serve this duty.

Oil, gas and offshore

Subsea and deepwater production hardware, wellhead and Christmas-tree components, downhole tooling, sleeves and bushings for high-pressure service, and forged bodies for industrial air compressors and nitrogen generators.

Valves and flow control

Valve bodies, blocks, bonnets, seat rings and stems for ball, gate, globe, check, plug and strainer assemblies working above the comfortable range of stainless grades.

Pressure vessels and heat exchangers

Forged flanges, tube sheets, nozzles, hollow bars and shell sections for shell-and-tube heat exchangers, air receivers, columns, towers, tanks, silos, preheaters and process modules.

Pumps and process machinery

Chemical pump and plunger-pump shafts, impeller and rotor blanks, and seamless rolled rings for casings. Also crankshafts, rolls, wheels, manifolds and mixer components in cement, sugar, concrete, pulp and paper, pharmaceutical and biochemical plant.

§ 09Testing, inspection and certification

Every 2.4983 forging is released against a documented test scope agreed at order stage. The standards below are the ones customers specify most often.

Heat numbers are hard-stamped or colour-marked on the forgings and carried through to the certificate, so every piece stays traceable to its melt.

§ 10Machining, welding and handling notes

2.4983 work-hardens rapidly under the cutting edge and cuts gummy compared with steel. The usual failure is a glazed hardened skin that ruins the following pass.

• Use rigid machines with short tool overhang. Chatter is what starts the hardened skin.
• Keep speeds low and feeds positive so the tool cuts under the hardened layer, and never dwell in the cut.
• Water-based coolant for turning, milling and grinding; heavy sulphurised lubricant for drilling, boring, broaching and tapping.
• Sharp positive-rake carbide with generous radii, changed on a set schedule rather than at failure.
• Welding by GTAW, GMAW or SMAW. Surfaces must be clean of oil, paint and marking crayon, and post-weld heat treatment follows the ageing cycle.
• Cold forming is possible but limited. Use heavy-duty lubricant, soft die material, liberal radii and clearances, then remove all lubricant to avoid embrittlement in service.

§ 11Frequently asked questions about 2.4983

§ 13Related nickel and cobalt alloy forgings

Jiangyin Jiangnan Metal forges the grades below in the same product forms as 2.4983.