1.6981

Grade, designations and standards

1.6981 is a German material number, or Werkstoffnummer. 21CrMoNiV4-7 is the same steel written in the EN naming system. A drawing that calls for 1.6981 and a drawing that calls for 21CrMoNiV4-7 specify identical material. The grade is covered by EN 10269, which sets requirements for steels and nickel alloys used in fasteners and components with specified elevated or low temperature properties, and by DIN 17240, the older German standard for creep-resistant bolting steels.

There is no exact AISI or ASTM equivalent. The usual substitute is 21CrMoV5-7 (1.7709), which shares the carbon, molybdenum and vanadium ranges but has no deliberate nickel addition. Nickel raises hardenability, so 1.6981 is normally specified for heavy turbine forgings while 1.7709 is more common on smaller bolting.

1.6981 compared with 1.7709

The two grades often appear on the same drawings. The chemistry is close, and nickel content is normally the deciding factor.

Composition ranges for 1.7709 are shown for orientation only. If you are considering a substitution, send us the drawing and the design temperature so we can assess it against your section size before the order is placed.

Chemical composition of 21CrMoNiV4-7

The table below gives the composition range Jiangyin Jiangnan Metal Co., Ltd. works to for 1.6981 forgings. Every heat is analysed at the ladle and the result is printed on the EN 10204 certificate supplied with the parts.

The aluminium content of the cast is determined and stated on the material certificate. Where a customer specification calls for tighter residual limits, trace-element control or a specific melting route, the limits are agreed before the heat is booked.

Why each alloying element is there

• Chromium and molybdenum provide creep strength, meaning resistance to slow deformation under load at temperature, together with resistance to temper embrittlement.
• Vanadium forms fine carbides that stabilise the microstructure and maintain strength at operating temperature. This is the main difference between a CrMoV turbine steel and a plain CrMo grade.
• Nickel increases hardening depth, so heavy sections transform to the core during quenching. This is the difference between 1.6981 and 1.7709.
• Phosphorus and sulphur are both capped at 0.020 % to keep grain boundaries clean, which supports long-term embrittlement resistance in service.

Heat treatment of 1.6981 forgings

1.6981 is delivered quenched and tempered. Jiangyin Jiangnan Metal Co., Ltd. carries out the full cycle in-house in eleven furnaces, the largest with a usable chamber of 8000 × 5000 × 1500 mm, and issues the recorded furnace chart with the certificate.

The tempering window matters if the part will be welded later. Post-weld heat treatment must stay below the tempering temperature used on the forging, otherwise the parent material will not hold the properties stated on the certificate. Tell us the intended fabrication route at enquiry stage and we set the tempering temperature to leave sufficient margin.

Mechanical properties

Room-temperature properties for 1.6981 depend on section size and on the tempering temperature selected within the 680–720 °C band, so they are agreed per order. The table below gives elevated-temperature acceptance data commonly specified for forged 21CrMoNiV4-7 discs, tested to EN ISO 6892-2 (formerly EN 10002-5).

Values are indicative acceptance minima for turbine disc forgings and do not replace the values in your own specification. Send us the specification you have to meet and we will confirm, before the order is placed, whether the section size can achieve it. Test-piece location, orientation and sampling frequency are agreed at the same time.

Additional testing available

• Room-temperature tensile, per EN ISO 6892-1.
• Charpy V-notch impact at ambient or specified sub-zero temperature.
• Brinell hardness survey across the section.
• Stress-rupture and creep testing at customer-nominated temperature, through an accredited external laboratory.
• Grain size, micro-structure and inclusion rating.

1.6981 forgings we produce

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory and 1.6981 parts are made to your drawing. The shapes below are the ones we run most often in this grade, with the practical size window for each.

• Seamless rolled ringsOD 100 – 6000 mm
• Forged rings and sleevesBushings, bushes, casings
• Discs, blocks and platesUp to 15,000 kg
• Round, square and flat barsRectangles and rods
• Hollow bars and cylindersBarrels, shells, hubs
• Steam turbine rotor shaftsForged and rough turned
• Turbine and compressor wheelsTorque discs
• Guide rings and gland seal ringsLabyrinth and packing seals
• Diaphragms and rotor end ringsContoured to drawing
• Valve stems, spindles and discsRods and shafts
• Turbine blades and vane blanksFlat rectangular stock
• Studs, double-end studs, boltingHigh-temperature fasteners

How a 1.6981 forging is made here

Every 1.6981 order runs through the same controlled sequence. Each stage is recorded so the finished part can be traced back to its heat number.

1. Steel melting and ingot supplyThe heat is melted to the 21CrMoNiV4-7 analysis and cast into ingot. Ladle analysis is verified before the ingot is released to the forge shop.
2. Heating and open-die forgingThe ingot is soaked and forged on a hydraulic press or hammer, with a minimum 3:1 reduction ratio to break down the cast structure and close internal porosity.
3. Ring rolling, where applicablePierced blanks are expanded on the ring mill to produce seamless rolled rings up to 6000 mm outside diameter.
4. Quenching and temperingHardening at 900–950 °C with an air, oil or water quench, followed by tempering at 680–720 °C for at least two hours. Furnace charts are recorded.
5. Rough machiningThe part is turned, bored or drilled to a UT-ready surface, which also removes the decarburised skin before testing.
6. Non-destructive examination100 % ultrasonic testing to EN 10228-3, plus MT, PT or RT where the specification calls for it.
7. Mechanical testingTest pieces are cut from prolongations at the agreed location and orientation, then tensile, impact and hardness tested.
8. Finish machining and final inspectionDimensional report against the drawing, surface protection applied, then packing for sea or air freight.

Forging and machining equipment

The equipment below determines the maximum 1.6981 part we can take on. All of it is installed in our own plant.

Inspection, testing and certificates

1.6981 is used in turbine components, so documentation requirements are usually strict. Standard scope on every order from Jiangyin Jiangnan Metal Co., Ltd. is a raw-material certificate with the chemical analysis, the heat-treatment chart, a dimensional inspection report and a UT report.

Non-destructive examination

Ultrasonic testing is carried out to EN 10228-3 on 100 % of the volume, in the delivery condition, after rough machining. The inspection type follows the geometry:

• Type 1 for bar-shaped components. May alternatively be inspected to EN 10308.
• Type 2 for discs and plate-like components.
• Type 3 for rings, sleeves and bushing-like components.

Magnetic particle testing, dye penetrant testing and radiography are added when the specification or the class society requires them. Visual inspection and positive material identification are performed on every piece.

Certificates

Material certificates are issued to EN 10204 3.1, or to 3.2 with an independent third party or class surveyor witnessing the tests. The factory approvals held are listed below.

Where 1.6981 is used

21CrMoNiV4-7 was developed for turbine service and that is still its main application. The steel holds proof strength across the 500–570 °C range typical of high-pressure and intermediate-pressure steam paths. Vanadium carbides resist the softening that a plain CrMo steel would show over long service periods.

• Steam turbines. Rotor shafts, torque discs, wheels, guide rings, diaphragms, gland and labyrinth seal rings, rotor end rings, casing rings.
• Gas turbines. Compressor discs and wheels, blade and vane blanks, seal rings, spacer rings.
• Valves for high-temperature service. Valve stems, spindles, rods, valve discs and seats.
• High-temperature bolting. Studs, double-end studs and nuts to EN 10269, the original purpose of the DIN 17240 family.
• Power plant pressure parts. Sleeves, hollow bars, hubs and housings running at elevated temperature.

Machining and welding notes

Machining

In the quenched-and-tempered condition 1.6981 machines like a medium-strength alloy steel. Use rigid setups, sharp carbide tooling and moderate speeds with a reasonable depth of cut. Repeated light finishing passes can work-harden the surface. For blanks, sawing is preferred to thermal cutting because it leaves a homogeneous edge structure that can be milled or drilled without an intermediate anneal.

Welding

21CrMoNiV4-7 is weldable. As a hardenable creep-resistant steel it requires preheat, a controlled interpass temperature, low-hydrogen consumables matched to a CrMoV deposit, and post-weld heat treatment. The PWHT temperature must be below the tempering temperature used on the forging, otherwise the certified properties no longer apply. Tell us at enquiry stage if the part will be welded and we set the tempering temperature accordingly.

1.6981 questions and answers

Related grades we forge

These are the grades customers most often compare with 1.6981 or move to. Each links to its own data page.

• AISI 4140
• 42CrMo4
• 1.7225
• 34CrMo4
• AISI 4130
• 42CrMo4V
• Inconel 706
• Nimonic 80A
• Nimonic 263
• Waspaloy
• Rene 41
• 17-4PH

Technical data on this page is maintained by the engineering department of Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China. Sources: EN 10269, DIN 17240, EN 10204, EN 10228-3 and our own works practice. Last reviewed 6 September 2026. Composition and property values are indicative. Please confirm them against your own specification before ordering.