# 17CrNiMo6 Forgings (1.6587 / 18CrNiMo7-6)

Source: https://www.steelforgepieces.com/Alloy-Steel/17CrNiMo6.html
Manufacturer: Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, Jiangyin, Jiangsu, China, founded 1997
Contact: sales@steelforgepieces.com | +86 189 2135 9659
Last updated: 2026-09-09
Data referenced to: EN 10084, DIN 17210, EN ISO 683-3, EN 10204

17CrNiMo6 is the DIN 17210 designation for material number 1.6587, a chromium-nickel-molybdenum case hardening steel. EN 10084 superseded DIN 17210 and renamed the same material 18CrNiMo7-6. The grade is carburised to give a surface of about 58 to 62 HRC over a core with a tensile strength of 1050 to 1350 N/mm2, which is why it is specified for heavy and highly stressed gears, pinions, shafts and rings.

Jiangyin Jiangnan Metal Co., Ltd. manufactures 17CrNiMo6 as seamless rolled rings, gear blanks, forged rings, shafts, round bars, discs, sleeves, bushings, flanges and tube sheets up to a single-piece weight of 30 t. Material is melted in a 25 t electric arc furnace with ladle refining and vacuum degassing, dehydrogenation annealed directly after forging, ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388, and released with EN 10204 3.1 or 3.2 certification.

## At a glance

| Item | Value |
|---|---|
| EN material number | 1.6587 |
| EN 10084 designation | 18CrNiMo7-6 |
| DIN 17210 designation | 17CrNiMo6 |
| SAE / AISI | 4317 (approximate) |
| Steel type | Case hardening (carburising) |
| Core tensile strength | 1050-1350 N/mm2 |
| Case hardness | 58-62 HRC |
| Delivery hardness | 170-200 HB |
| Max. single piece | 30 t |
| Melting route | EAF + LF + VD |
| Certification | EN 10204 3.1 / 3.2 |
| Minimum order | One piece |

## Designations and equivalent grades

| System or standard | Designation | Note |
|---|---|---|
| EN material number | 1.6587 | Primary reference |
| EN chemical designation | 18CrNiMo7-6 | Current name under EN 10084 |
| DIN 17210 | 17CrNiMo6 | Superseded, still quoted |
| EN ISO 683-3 | 18CrNiMo7-6 | Case hardening steel classification |
| SAE / AISI (USA) | 4317 | Closest cross reference, chromium differs |
| AFNOR (France) | 18NCD6 | Closest equivalent |
| BS (UK) | 820A16 | Closest equivalent |
| GB (China) | 17Cr2Ni2Mo | Closest equivalent |
| AS 1444 (Australia) | X4317 | Closest equivalent |

Data correction: a number of datasheets describe 17CrNiMo6 as a general purpose high tensile constructional steel supplied to EN 10083-1 and ready for use after machining. That is wrong on both counts. 17CrNiMo6 is a case hardening steel covered by EN 10084, and it must be carburised after machining to develop its surface hardness. EN 10083 applies to a different family of quenched and tempered steels.

## Chemical composition, mass %

| Element | Min % | Max % | Role |
|---|---|---|---|
| Carbon (C) | 0.15 | 0.21 | Low by design; keeps the core tough |
| Silicon (Si) | - | 0.40 | Deoxidiser |
| Manganese (Mn) | 0.50 | 0.90 | Hardenability, sulphur control |
| Phosphorus (P) | - | 0.025 | Residual |
| Sulphur (S) | - | 0.035 | Residual |
| Chromium (Cr) | 1.50 | 1.80 | Hardenability and case depth |
| Nickel (Ni) | 1.40 | 1.70 | Core toughness |
| Molybdenum (Mo) | 0.25 | 0.35 | Hardenability in heavy sections |
| Copper (Cu) | - | 0.30 | Residual limit |
| Aluminium (Al) | 0.020 | - | Grain size control |
| Iron (Fe) | Balance | | Base element |

Limits differ slightly between DIN 17210 and the current EN 10084 revision, and between hardenability classes (+H, +HH, +HL).

## Mechanical properties

| Property | Value | Condition |
|---|---|---|
| Hardness | 229 HB max, typically 170-200 HB | Soft annealed, as delivered |
| Surface hardness | 58-62 HRC | Carburised, hardened and tempered |
| Core tensile strength Rm | 1050-1350 N/mm2 | Case hardened |
| Core hardness | approx. 30-40 HRC | Case hardened, section dependent |
| Impact energy KV | To customer specification, down to -60 C | Normalised or case hardened |
| Flame or induction hardening | Not suitable | Carbon content too low |
| Nitriding | Suitable | After hardening and tempering |

Effective case depth on heavy gear teeth in this grade commonly runs from 1 mm to over 6 mm and is set by the designer.

## Physical properties, typical for the alloy class

| Property | Metric | Imperial |
|---|---|---|
| Density at 20 C | 7.85 g/cm3 | 0.284 lb/in3 |
| Modulus of elasticity at 20 C | approx. 210 GPa | approx. 30.5 x 10^3 ksi |
| Mean thermal expansion 20-100 C | approx. 11.5 x 10^-6 /K | approx. 6.4 x 10^-6 /F |
| Specific heat at 20 C | approx. 460 J/(kg.K) | approx. 0.11 BTU/(lb.F) |
| Magnetic response | Ferromagnetic; magnetic particle inspection applicable | |

## Forging and heat treatment

Start forging 1150-1200 C. Finish not below 850 C. Forging ratio at least 3:1. Controlled cooling; this grade is not air cooled freely off the press.

17CrNiMo6 carries about 1.5 % nickel at low carbon and is prone to hydrogen flaking (white spots). Hydrogen is removed by vacuum degassing before casting and an anti-flaking anneal is run directly off the press.

| Operation | Temperature | Cooling | Carried out by |
|---|---|---|---|
| Forging | 1150 down to 850 C | Controlled | Forging factory |
| Dehydrogenation anneal | 630-650 C | Furnace | Forging factory |
| Normalising | 850-880 C | Air | Forging factory |
| Soft annealing | 650-700 C | Furnace | Forging factory |
| Carburising | 880-980 C | To specified case depth | Customer, after machining |
| Core hardening | 830-870 C | Water or oil | Customer |
| Case hardening | 780-820 C | Water or oil | Customer |
| Tempering | 150-200 C | Air | Customer |

Forgings leave the works soft annealed or normalised at 170 to 200 HB, the condition needed for gear cutting. Carburising is done after the teeth are cut and therefore belongs to the customer.

## Compared with other case hardening steels

| Grade | Material no. | C % | Cr % | Ni % | Mo % | Typical use |
|---|---|---|---|---|---|---|
| 16MnCr5 | 1.7131 | 0.14-0.19 | 0.80-1.10 | - | - | Small gears, light sections |
| 20MnCr5 | 1.7147 | 0.17-0.22 | 1.00-1.30 | - | - | Automotive gears, medium sections |
| 17NiCrMo6-4 | 1.6566 | 0.15-0.20 | 0.80-1.10 | 1.20-1.50 | 0.20-0.30 | Medium to heavy sections |
| 17CrNiMo6 / 18CrNiMo7-6 | 1.6587 | 0.15-0.21 | 1.50-1.80 | 1.40-1.70 | 0.25-0.35 | Heavy, highly stressed gearing |
| 42CrMo4 | 1.7225 | 0.38-0.45 | 0.90-1.20 | - | 0.15-0.30 | Through hardened, not carburised |

## Forged product forms and sizes

| Product form | Size range | Typical items |
|---|---|---|
| Seamless rolled rings | OD 200-4000 mm, height to 1000 mm | Gear rims, slewing bearing rings, bearing rings |
| Forged rings | OD 100-3000 mm | Rings too heavy or too short in ratio to roll |
| Gear blanks and pinions | To drawing | Wind gearbox gears, mill drive pinions |
| Shafts and spindles | dia. 60-1000 mm | Pinion shafts, eccentric shafts, spindles |
| Round bars | dia. 20-1200 mm, length to 12000 mm | Machining stock for shafts and pins |
| Discs and blocks | dia. 100-2500 mm | Gear blanks, plates, blocks |
| Sleeves and bushings | OD 100-2000 mm | Heavy duty bushings, wear sleeves, hollow bars |
| Flanges | 50-3000 mm | Forged flange blanks, gasket seats |
| Tube sheets | to 3000 mm, to 400 mm thick | Heavy plate-form forgings |
| Forged pipes and tubes | OD 100-1500 mm | Hollow forged and bored sections |

Maximum single-piece forging weight is 30 t. All parts are open-die forged to drawing; no die cost, no minimum quantity.

## Manufacturing capability

| Item | Value |
|---|---|
| Max. single-piece forging | 30 t |
| Largest forging press | 6300 t |
| Largest forging hammer | 5 t |
| Largest heat | 60 t |
| Remelting in-house | ESR, VAR, VIM |
| Heat treatment furnaces | 17 in service |
| Largest furnace chamber | 8.0 x 2.0 x 2.0 m |
| Longest part heat treated | 15 m (well furnace) |
| Largest turned diameter | dia. 5000 mm |
| Largest CNC envelope | dia. 2000 x 10000 mm |
| Deep-hole drilling | dia. 1600 x 10000 mm |
| Forging since | 1997 |
| Minimum order | One piece |
| Quotation turnaround | Within 24 hours |
| Production lead time | 30-60 days |
| Export markets | Worldwide |

### Melting and refining

| Equipment | Capacity | Units |
|---|---|---|
| Electric arc furnace (EAF) | 25 t | 1 |
| Ladle furnace (LF) | 25 t, 50 t | 2 |
| Vacuum degassing converter | 30 t, 60 t | 2 |
| Induction furnace (IF) | 2 t, 8 t, 25 t | 3 |
| VIM | 3 t | 1 |
| IGESR | 3 t, 6 t | 2 |
| VAR | 6 t | 1 |

### Forging

| Equipment | Capacity | Units |
|---|---|---|
| Hydraulic open-die press | 6300 t | 1 |
| Hydraulic open-die press | 4000 t | 1 |
| Hydraulic open-die press | 2000 t | 1 |
| Forging hammer | 5 t / 3 t / 2 t / 1 t / 750 kg | 1 each |

### Heat treatment, 17 furnaces

| Furnace | Model | Chamber | Max. temp. | Units |
|---|---|---|---|---|
| High-temperature bogie hearth | RTX-12-350KW | 3.5 x 1.3 x 1.1 m | 1200 C | 3 |
| Bogie hearth | RTX-9-900KW | 6.0 x 3.5 x 2.3 m | 950 C | 1 |
| Bogie hearth | RTX-9-810KW | 8.0 x 2.0 x 2.0 m | 950 C | 2 |
| Bogie hearth | RTX-9-720 | 5.5 x 3.0 x 1.8 m | 950 C | 2 |
| Bogie hearth | RTX-9-530KW | 8.0 x 1.5 x 1.2 m | 950 C | 2 |
| Bogie hearth | RTX-9-430 | 6.5 x 1.5 x 1.1 m | 950 C | 1 |
| Bogie hearth | RTX-9-430 | 5.5 x 1.5 x 1.1 m | 950 C | 1 |
| Well (pit) furnace | RJ-9-850KW | 15 m deep x dia. 1.5 m | 950 C | 2 |

### Machining

| Equipment | Working envelope | Units |
|---|---|---|
| Vertical turning lathe | dia. 5000 mm | 1 |
| Vertical turning lathe | dia. 3500 mm | 1 |
| Vertical turning lathe | dia. 2500 mm | 4 |
| Horizontal lathe C61180 | dia. 1800 x 8000 mm | 3 |
| Horizontal lathe C61140 | dia. 1400 x 8000 mm | 2 |
| Horizontal lathe C61125 / C61160 | dia. 1250 x 10000 mm / dia. 1600 x 14000 mm | 1 each |
| CNC lathe | dia. 2000 x 10000 mm | 1 |
| CNC lathe | dia. 2000 x 8000 mm | 1 |
| CNC lathe | dia. 1600 x 3300 mm | 3 |
| Deep-hole drilling machine | dia. 1600 x 10000 mm | 1 |

## Testing, inspection and certification

| Test | Standard |
|---|---|
| Chemical analysis | Ladle and product analysis, optical emission spectrometry |
| Tensile test | ISO 6892-1 / ASTM A370 |
| Impact test | ISO 148-1 / ASTM A370, Charpy V, down to -60 C |
| Hardness | Brinell, Rockwell, Leeb |
| Grain size | ASTM E112 |
| Jominy hardenability | ISO 642 / ASTM A255, for +H, +HH, +HL |
| Ultrasonic testing | EN 10228-3, SEP 1921, ASTM A388 |
| Magnetic particle | EN 10228-1, ASTM E1444, ASTM E709 |
| Liquid penetrant | EN 10228-2 / ASTM E165 |
| Inspection document | EN 10204 3.1 or 3.2 |

Third-party 3.2 certificates can be countersigned by TUV, SGS, BV, DNV or Lloyd's Register.

## Applications by industry

| Industry | Typical components |
|---|---|
| Wind energy | Gearbox gear rims, planet and sun gears, planet carriers, pinion shafts, slewing and main bearing rings |
| Mining and cement | Mill drive pinions and gear rims, crusher shafts, eccentric shafts, wear pins, sprockets, forged rolls |
| Cranes and earth-moving | Slewing rings, swing drive gears, travel drive components, heavy duty bushings |
| Marine and shipbuilding | Marine gearbox gears and pinions, thruster gearing, propulsion shafting |
| Rail | Traction gearing, gear blanks, axle-drive components |
| Industrial gearboxes | Gear blanks, pinions, quill shafts, spindles, gear rings |
| Pumps and compressors | Pump shafts, fan shafts, compressor gearing, spindles, sleeves |
| Heavy machinery | Cam followers, clutch dogs, tappets, wire guides, wear parts, forged wheels |
| Sugar, paper and pulp | Mill gearing, drive pinions, process rolls, heavy bushings |

## How to order

1. Send the drawing or dimensions to sales@steelforgepieces.com. Rings: OD x ID x height. Bars and shafts: diameter x length. Discs: diameter x thickness.
2. Confirm grade and standard: 17CrNiMo6 / 1.6587, and whether the certificate should also carry 18CrNiMo7-6 to EN 10084. Give the hardenability class if specified.
3. State delivery condition and testing: as-forged, normalised, soft annealed, rough or finish machined; UT class; certificate type.
4. Give case hardening data: required case depth, surface hardness, core hardness.
5. Quotation within 24 hours with unit price, forging weight, lead time and Incoterms.

## Frequently asked questions

**What is 17CrNiMo6 material?**
17CrNiMo6 is the DIN 17210 designation for material number 1.6587, a chromium-nickel-molybdenum case hardening steel with 0.15-0.21 % C, 1.50-1.80 % Cr, 1.40-1.70 % Ni and 0.25-0.35 % Mo. Carburised it reaches about 58-62 HRC at the surface over a core of 1050-1350 N/mm2.

**Is 17CrNiMo6 the same as 18CrNiMo7-6?**
In practical terms, yes. Both carry material number 1.6587. 17CrNiMo6 is the older DIN 17210 name; 18CrNiMo7-6 is the current EN 10084 name for the same steel.

**What is the AISI or SAE equivalent of 17CrNiMo6?**
SAE/AISI 4317 is the closest cross reference; also X4317 under AS 1444, 18NCD6 under AFNOR and 820A16 under BS. None is exact; 17CrNiMo6 carries more chromium.

**Is 17CrNiMo6 a case hardening steel or a through hardening steel?**
Case hardening (carburising). With 0.15-0.21 % carbon it cannot reach a hard surface by direct hardening.

**Which standard covers 17CrNiMo6 forgings?**
EN 10084, where the grade appears as 18CrNiMo7-6. DIN 17210 is superseded. EN ISO 683-3 covers the classification. 17CrNiMo6 is not covered by EN 10083.

**What hardness does 17CrNiMo6 reach after carburising?**
Approximately 58-62 HRC at the surface, over a core of 1050-1350 N/mm2 and roughly 30-40 HRC.

**Why does 17CrNiMo6 need dehydrogenation after forging?**
It carries about 1.5 % nickel at low carbon and is prone to hydrogen flaking (white spots), internal cracks that show up at ultrasonic testing. Jiangyin Jiangnan Metal removes hydrogen by vacuum degassing before casting and runs an anti-flaking anneal at 630-650 C directly after forging.

**Do you carburise the forgings, or does the customer?**
Forgings leave the works soft annealed or normalised at 170-200 HB, the condition needed for gear cutting. Carburising happens after the teeth are cut and belongs to the customer.

**Can 17CrNiMo6 be flame or induction hardened?**
No. Carbon content is too low. Nitriding after hardening and tempering is an alternative.

**How large a 17CrNiMo6 forging can you make?**
Maximum single-piece forging weight is 30 t. Rings 200-4000 mm OD, bars 20-1200 mm diameter to 12000 mm long, discs to 2500 mm, shafts 60-1000 mm, tube sheets to 3000 mm x 400 mm thick.

**What certification is supplied?**
EN 10204 3.1 as standard, or 3.2 countersigned by TUV, SGS, BV, DNV or Lloyd's Register, reporting heat number, ladle and product analysis, mechanical results, heat treatment records, grain size and NDT results.

**What is the minimum order quantity?**
One piece. Open-die forging carries no die cost, so prototypes and one-offs are accepted. Quotation within 24 hours, lead time normally 30-60 days.

## Cite this page

Jiangyin Jiangnan Metal Co., Ltd. (2026). 17CrNiMo6 (1.6587 / 18CrNiMo7-6) forgings: technical datasheet. Jiangyin, Jiangsu, China. Published at steelforgepieces.com, Alloy Steel section.
https://www.steelforgepieces.com/Alloy-Steel/17CrNiMo6.html

Composition and property limits are referenced to EN 10084, DIN 17210 and EN ISO 683-3. Inspection documents follow EN 10204. Ultrasonic acceptance follows EN 10228-3, SEP 1921 and ASTM A388.

## Contact

Jiangyin Jiangnan Metal Co., Ltd.
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Phone, WhatsApp and WeChat: +86 189 2135 9659
Email: sales@steelforgepieces.com
Web: https://www.steelforgepieces.com/
Founded 1997. Ships worldwide.

## Related grades

- AISI 4317: https://www.steelforgepieces.com/Alloy-Steel/AISI-4317.html
- 42CrMo4: https://www.steelforgepieces.com/Alloy-Steel/42CrMo4.html
- AISI 4140: https://www.steelforgepieces.com/Alloy-Steel/AISI-4140.html
- 34CrMo4: https://www.steelforgepieces.com/Alloy-Steel/34CrMo4.html
- AISI 8630: https://www.steelforgepieces.com/Alloy-Steel/AISI-8630.html
- All alloy steel grades: https://www.steelforgepieces.com/Alloy-Steel/