1.7765 Forgings (32CrMoV12-10 Nitriding Steel)

Short answer: what is 1.7765?

Material number

1.7765EN name 32CrMoV12-10

Steel type

CrMoVnitriding, quenched & tempered

Nominal Cr / Mo / V

3.0 / 1.0 / 0.3weight %

Density

7.82g/cm³ at 20 °C

Tensile, Q&T

900–1200MPa, section dependent

Nitrided surface

800–950HV typical

Nitriding range

480–570°C

Forging range

1100–850°C

Figures compiled by Jiangyin Jiangnan Metal Co., Ltd. from published 1.7765 / 32CrMoV12-10 datasheets. Screening values, not design allowables.

What 1.7765 forged products can you buy?

Jiangyin Jiangnan Metal produces 32CrMoV12-10 by three routes, chosen by geometry and order size. Open-die forging covers shafts, blocks, discs and heavy sections. Seamless ring rolling produces rings and bearing races, and is the cheaper route whenever the finished part has a through hole. Upset forging handles short, large-section hubs and flanges.

One decision matters more than the rest on this grade. Most 1.7765 parts are nitrided after machining, and nitriding cannot repair a poor forged structure underneath. Grain flow has to follow the loaded contour, so send the finished drawing rather than a billet size and let the forging route be chosen against it.

What is 1.7765 / 32CrMoV12-10, and why does it exist?

The name reads directly off the chemistry. In the EN system, 32 is 0.32 % carbon; CrMoV lists the alloying elements in order of importance; 12-10 gives chromium and molybdenum in multiples of four, so 12 ÷ 4 = 3.0 % chromium and 10 ÷ 4 rounded to about 1.0 % molybdenum.

Ordinary through-hardening steels solve one problem at a time. A gear tooth needs a surface hard enough to resist pitting and a core tough enough not to snap; a case-hardening steel such as 18CrNiMo7-6 gets there by carburising and then quenching from above the transformation temperature, which moves the part. On a large gear or a long shaft that distortion has to be ground out, and on a thin section it may not be recoverable at all.

1.7765 takes a different route. Enough chromium, molybdenum and vanadium are put in the steel that nitrogen, diffused in at 480–570 °C, precipitates as very fine, very stable alloy nitrides right where it enters. What that buys you:

• A hard case with no quench. Nitriding is a diffusion treatment below the transformation temperature. Nothing transforms and nothing is quenched, so distortion is a fraction of what carburising produces, and finished parts often need a light lap instead of a regrind.
• Core properties that survive the treatment. The part is hardened and tempered at 600–680 °C before it is nitrided. Nitriding then runs 100 °C or more below that tempering temperature, so the core hardness on the drawing is still there at the end.
• Hardness that holds when the part runs hot. Alloy nitrides do not coarsen the way tempered martensite softens. Nitrided 1.7765 holds its surface hardness in continuous service to roughly 400 °C. That is how the grade ends up in engine and hot hydraulic hardware and not only in room-temperature gearboxes.

There is a cost to all this. Three percent chromium with a molybdenum addition gives deep hardening, so heavy sections respond, but the same carbide formers make the steel slow to machine and unforgiving if the forging reduction is inadequate. It is a made-to-order grade, not a stock item.

What are the equivalents of 1.7765?

Buyers meet this steel under several names, because it was standardised in Germany, picked up in France for aerospace work and then cross-referenced into the American AMS system by individual producers. The designations in Table 2 all describe the same nominal 0.32C–3Cr–1Mo–0.3V chemistry, and we accept purchase orders under any of them. They are not interchangeable in their acceptance requirements: the product-form specification decides the test regime, not the chemistry.

1.7765 or 1.8522? Check before you order

This is the most common problem we see on enquiries for this grade. Settle it before anything else.

Two separate CrMoV nitriding steels sit next to each other in the standards. 1.7765 is 32CrMoV12-10. 1.8522 is 32CrMoV12-9, also written 33CrMoV12-9. Both carry about 3 % chromium, both are nitriding steels, both are supplied quenched and tempered, and both are sold in Europe under the market name 32CDV13. Several suppliers also cross-reference both of them to AMS 6481. The difference is in the molybdenum band and in the chemistry limits each standard applies.

What is the chemical composition of 1.7765?

Two sets of numbers circulate for this steel, and you need both. The nominal figures are what appears on most published 1.7765 datasheets and on the previous version of this page. The specification band is what raw material is actually bought against, and it is what will appear on your mill certificate.

What are the mechanical properties of 1.7765?

1.7765 is supplied in one of two conditions, and they answer different questions. Soft annealed material is for machining. Quenched and tempered material carries the load, and it is the condition a part is in when it goes to the nitriding shop. Properties fall with increasing ruling section, because a heavier section cools more slowly through the quench.

Toughness and the temper band

Impact energy on this grade is good in the tempered condition, and the reason is the molybdenum. A 3 % chromium steel tempered slowly through 400–550 °C is a candidate for temper embrittlement, where phosphorus segregates to prior-austenite grain boundaries and the transition temperature climbs. Around 1 % molybdenum suppresses it. Both of the following belong on the order:

• Temper above the embrittlement range, not through it. The 600–680 °C band is chosen deliberately.
• Cool briskly from the tempering temperature on heavy sections rather than letting the furnace cool slowly through 550–450 °C.

Service temperature

Nitrided 1.7765 components are normally rated for continuous service to about 400 °C. Above that the tempered core begins to soften and the design has to be checked against a tempering curve rather than against room-temperature strength. The nitrided case itself is more stable than the core, so on a hot part it is usually the core that sets the limit.

What are the physical properties of 1.7765?

How does 1.7765 respond to nitriding?

This is the property the grade is bought for. Nitrogen is introduced at the surface from dissociated ammonia (gas nitriding), from a nitrogen plasma (plasma or ion nitriding) or from a molten salt, at 480–570 °C, most often 500–530 °C. It diffuses inward and combines with the chromium, molybdenum and vanadium already dissolved in the matrix. The result is a shallow, extremely hard diffusion zone sitting on an unchanged tempered core.

What we do before the part reaches the nitriding shop

• Machine off the decarburised skin. A decarburised surface will not nitride to hardness. Forging stock is left so that the whole affected layer is removed at the machining stage, and the final stock allowance is agreed against your drawing.
• Set the temper high enough. The tempering temperature must sit above the nitriding temperature by a clear margin, or the core will soften during the nitriding soak.
• Stress relieve before final machining. On long shafts and thin rings, a stress-relief step after rough machining takes out the residual stress that would otherwise appear as movement during the nitriding hold.

How is 1.7765 forged and heat treated?

1. Raw materialElectric arc melting with ladle refining and vacuum degassing for industrial work; ESR or VIM plus VAR where an aerospace specification applies. Heat number traced, chemistry verified before forging.
2. SoakHeat to 1100 °C and hold long enough to bring the whole section to temperature, not just the surface. Thermal conductivity is lower than plain carbon steel, so a heavy billet needs longer than the rule of thumb suggests.
3. ForgeHot working from 1100 down to 850 °C. Stop deformation at 850 °C and reheat rather than pushing a cooling billet. Aim for a reduction ratio of at least 4:1 to break down the cast structure and put the grain flow along the loaded direction.
4. Cool and normaliseSlow cool from finish-forging, then normalise at 900–930 °C where the specification calls for it, to even out the grain size before hardening.
5. Soft anneal720–780 °C with slow cooling, giving a maximum of about 224–250 HB. This is the condition in which material is delivered for machining.
6. HardenAustenitise at 850–950 °C to the governing specification, then oil quench. Deep hardenability from 3 % chromium and 1 % molybdenum means heavy sections respond without a water quench.
7. Temper600–680 °C to the required core hardness, cooling briskly from the tempering temperature on heavy sections. The tempering temperature must stay well above any later nitriding temperature.
8. Machine, then nitrideFinal machining removes the decarburised layer. Nitriding at 480–570 °C follows final machining, with only grinding or lapping afterwards.
9. Test and examineTensile, impact, hardness and grain size; ultrasonic examination to EN 10228-3 or ASTM A388; magnetic particle to EN 10228-1 or ASTM E1444.
10. CertifyEN 10204 3.1 as standard, 3.2 with third-party witness. Marked, preserved and packed for export.

Machining, grinding and welding 1.7765

Machining

Machine in the soft annealed condition wherever the design allows it. At 224–250 HB the steel cuts predictably; at 320 HB after quench and temper, tool life drops sharply and the surface finish gets harder to hold. Three percent chromium with vanadium means abrasive carbides in the matrix, so carbide tooling with a rigid setup is the norm rather than a refinement.

• Rough machine soft annealed, stress relieve, then harden and temper, then finish machine.
• Leave grinding stock only where it is needed. After nitriding you can grind, but every micron removed comes out of a case that is only a few tenths of a millimetre deep.
• Do not leave a decarburised or burnt surface anywhere that will later be nitrided.

Grinding after nitriding

Grinding a nitrided surface is a real risk to the part, because the case is thin and grinding burn shows up as a soft patch or as a fine crack network that the customer finds in service. Use free-cutting wheels, light infeeds and generous coolant, and put a nital etch or equivalent grinding-burn inspection on the drawing for gear flanks and bearing races.

Welding

1.7765 is weldable with care, but it is not a structural welding grade and welding is not part of the normal route for a forging in this steel. If a joint is unavoidable:

• Preheat to roughly 200–300 °C and hold the interpass temperature.
• Use low-hydrogen consumables, matching or slightly under-matching.
• Apply post-weld heat treatment below the original tempering temperature, then check that the core hardness is still within the band.
• Never weld a nitrided surface. The compound layer will not survive it and the joint will crack. If a weld is needed, weld first, then heat treat, then machine, then nitride.

1.7765 against 42CrMo4, 34CrNiMo6, 31CrMoV9 and 18CrNiMo7-6

Most enquiries for this grade come down to one of two comparisons: against a through-hardening steel that would be used without a case, or against a case-hardening steel that would be carburised instead. 1.7765 is chosen when the part needs a hard surface, a tough core and almost no distortion, in that order, and when the cost of grinding out carburising distortion would exceed the price difference on the steel.

Questions that settle the choice

1. Can the part tolerate carburising distortion? If it is a long shaft, a thin ring or a finished-to-size component, the answer is usually no, and a nitriding steel is the right family.
2. How deep does the hardened layer need to be? Nitriding gives 0.3–0.7 mm. If the Hertzian contact stress needs 1.5 mm of hardened depth beneath it, no nitriding steel will do the job and 18CrNiMo7-6 or 17CrNiMo6 is the answer.
3. Does the part run hot? Above about 200 °C an induction-hardened 42CrMo4 surface starts to lose hardness, while a nitrided 1.7765 case holds to roughly 400 °C. That gap is often the whole reason for the specification.

How do 1.7765 parts fail, and how do you prevent it?

What can Jiangyin Jiangnan Metal forge in 1.7765?

1.7765 is a made-to-order grade. Raw material is bought against your specification rather than pulled from stock. Settle the drawing, the governing specification and the certificate type at enquiry stage, not after the order is placed.

Diameter

80–6000mm, plant envelope

Length

100–12000mm

Single piece

10–15000kg

Rolled ring OD

200–4000mm, 3 m and 6 m ring lines

Hammers

1–9tonne open-die

Presses

4500 / 5000tonne hydraulic

Employees

460incl. 9 senior, 32 intermediate engineers

Lead time

8–14weeks typical

Plant envelope across all grades at Jiangyin Jiangnan Metal Co., Ltd. Send the drawing and we confirm size, weight and lead time for your specific part before quoting.

Which standards and certificates apply to 1.7765 forgings?

Quality management at Jiangyin Jiangnan Metal Co., Ltd. is certified to ISO 9001:2015. Third-party witness certificates are issued through the inspection body you nominate: Lloyd's Register, DNV, Bureau Veritas, ABS, TÜV or SGS. Customers keep an unrestricted right to witness any production stage, including chemistry, forging, heat treatment and mechanical testing.

How do you specify a 1.7765 forging order?

1. Give the material number, not just the nameWrite 32CrMoV12-10 / W.Nr. 1.7765. A name alone is ambiguous, because 1.8522 shares market names with this grade.
2. State the delivery conditionSoft annealed for machining, or quenched and tempered to a stated core hardness band ready for nitriding. Say which, and give the band.
3. Give the nitriding requirement in fullSurface hardness in HV with the test load, effective case depth with the hardness limit that defines it, and what happens to the compound layer.
4. Name the melt route if it mattersElectric arc with ladle refining and vacuum degassing for industrial work; ESR or VIM plus VAR where an aerospace specification applies. This changes price materially, so decide before quoting.
5. Define the ruling section and the test positionAbove 100 mm section, say whether tensile and impact tests are longitudinal or transverse, and where the test piece is cut from.
6. Define non-destructive examination“UT per EN 10228-3, quality class 3” is a specification. “Ultrasonic test” on its own is not.
7. Name the certificateEN 10204 3.1 as standard, or 3.2 with a named third-party inspection body.
8. Give the commercial dataQuantity, required date, Incoterm, destination port and marking requirements.

Drawing callout you can copy

MATERIAL:      32CrMoV12-10 / W.Nr. 1.7765 (0.32C-3Cr-1Mo-0.3V nitriding steel)
               NOT 1.8522 / 32CrMoV12-9 - material number governs
FORM:          Open-die forging / seamless rolled ring, forged to drawing
               Minimum forging reduction ratio 4:1
MELT ROUTE:    EAF + LF + VD  (state ESR or VIM+VAR if required by the spec)
CONDITION:     Quenched and tempered, oil quench, temper 600-680 deg C
               Core hardness ______ to ______ HB, tempering temp on cert
NITRIDING:     Surface hardness ______ HV0.5 min
               Effective case depth ______ mm measured to 400 HV
               Compound layer: retain / max ______ um / fully removed
               (nitriding by purchaser after final machining)
CHEMISTRY:     Ladle analysis, all elements. P 0.025 max, S 0.010 max
TESTING:       Tensile ISO 6892-1, impact ISO 148-1 at ______ deg C
               Test position: ______ , orientation: longitudinal / transverse
GRAIN SIZE:    ASTM E112, ______ or finer
NDE:           UT per EN 10228-3 quality class 3 (or ASTM A388)
               MT per EN 10228-1 (or ASTM E1444)
CERTIFICATE:   EN 10204 3.1  (3.2 with third-party witness if stated on the PO)
MARKING:       Heat number, material number, condition and drawing number,
               low-stress stamped or vibro-etched

Six mistakes buyers make with 1.7765

1. Ordering by name only. “32CDV13” or “AMS 6481” without a material number can be filled with 1.8522. Put 1.7765 on the order.
2. Writing “nitride” with no numbers. Without a surface hardness, a case depth and a defining hardness limit, the requirement cannot be inspected and cannot be rejected either.
3. Tempering too low for the nitriding cycle. If the core is tempered at 550 °C and the part is nitrided at 530 °C, the core softens during the hold and the drawing hardness is gone.
4. Leaving too little machining stock. The decarburised skin from forging and heat treatment must be machined off entirely, or the case will not reach hardness in that area.
5. Using it where a deep case is needed. Nitriding gives a few tenths of a millimetre. For heavy Hertzian contact, a carburising grade is the correct answer and 1.7765 is an expensive way to fail.
6. Grinding hard after nitriding. The case is thin. Heavy grinding removes it or burns it, and the damage is often invisible until the part is in service.

Ask for a 1.7765 quotation

Send the drawing, the governing specification, the quantity and the certificate you need. Jiangyin Jiangnan Metal Co., Ltd. answers within 24 hours with price, lead time and the standards it will certify to.

Where is 1.7765 used?

The grade also appears under the German aerospace and defence materials designation WL 1.7765, which covers quenched and tempered tube and bar. If your drawing cites the WL number, say so at enquiry stage, because the acceptance and documentation requirements differ from a commercial order to the material number alone.

Worked example: why the ring route is cheaper than the disc route

Given. A finished ring in 1.7765, 620 mm outside diameter × 480 mm inside diameter × 210 mm high, quenched and tempered to 280–320 HB, to be nitrided by the customer after machining.

Method. Net volume = π/4 × (0.620² − 0.480²) × 0.210 = 0.0254 m³. At 7,820 kg/m³ that is about 199 kg finished. Rolled as a seamless ring with 25 % stock the forging is roughly 249 kg. Machined instead from a solid forged disc of the same outside diameter and height, the input is π/4 × 0.620² × 0.210 = 0.0634 m³, about 496 kg, and 297 kg of it goes to swarf.

Result. Ring rolling halves the purchased weight on this geometry. It also does something the weight comparison hides: the rolled ring has circumferential grain flow, so the fatigue properties around the ring are better than those of a ring cut out of a disc, where the grain flow runs across the section. On a nitrided race that difference shows up directly in service life, because the fatigue crack starts under the case and travels through the core structure.

So send the finished drawing rather than a billet size. On a made-to-order grade like this, choosing the right forging route usually saves more than any other decision on the order.

Glossary

1.7765 frequently asked questions

References

1. EN 10027-1 and EN 10027-2, designation systems for steels: steel names and steel numbers. The source of both “32CrMoV12-10” and “1.7765”.
2. Published mill datasheets for W.Nr. 1.7765 / 32CrMoV12-10 from European producers, including Böhler (V361), Ovako (398Q), SIJ Metal Ravne (SIQUAL 7765 / PO209) and BGH. Chemistry bands, delivery conditions and heat-treatment guidance.
3. WL 1.7765, German aerospace and defence materials designation for 32CrMoV12-10 quenched and tempered steel. Hot working, annealing, hardening and tempering data.
4. SAE International, AMS 6481, cited as a cross-reference to 3Cr–Mo–V nitriding steel by several European producers. Confirm the chemistry band against the revision on your drawing.
5. ASM Handbook, Volume 4, Heat Treating, ASM International. Nitriding of alloy steels: case formation, compound layer, distortion behaviour.
6. ASM Handbook, Volume 14A, Metalworking: Bulk Forming, ASM International. Open-die forging and ring rolling of alloy steels.
7. ISO 18203 and DIN 50190-3, determination of the thickness of hardened and nitrided case layers.
8. EN 10228-1 and EN 10228-3, magnetic particle and ultrasonic examination of steel forgings; ASTM A388 and ASTM E1444 for the equivalent American practice.
9. EN 10250-3, open-die steel forgings for general engineering purposes: alloy special steels.
10. EN 10204, Metallic products: types of inspection documents, CEN.

Standards are cited by number; always work to the revision in force at your contract date. Property values on this page are published typical figures for screening and are not design allowables. Test results on our certificates are independent and traceable to calibrated equipment.

About the manufacturer, and how to cite this page

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, with 460 employees including 9 senior and 32 intermediate engineers. The plant runs 1 t to 9 t open-die hammers, 4,500 t and 5,000 t hydraulic presses and seamless ring mills on 3 m and 6 m ring lines, with in-house heat treatment, machining, mechanical testing and non-destructive examination. Alongside 1.7765 / 32CrMoV12-10 the company forges carbon, alloy and tool steels, the precipitation-hardening and duplex stainless families, and the nickel and cobalt high-temperature alloys. Quality management is certified to ISO 9001:2015; material is supplied with EN 10204 3.1 certification as standard and 3.2 with third-party witness on request.

Contact for technical questions or a quotation: Jiangyin Jiangnan Metal Co., Ltd., No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China · 0086-189-2135-9659 · sales@steelforgepieces.com · WhatsApp