Grade summary
15CrNi6, material number 1.5919, is a chromium-nickel alloyed case-hardening (carburising) steel specified in DIN 17210 and grouped with the case-hardening steels of DIN EN 10084. It contains roughly 0.15 % carbon with about 1.55 % chromium and 1.55 % nickel. After carburising, hardening and low-temperature tempering it gives a hard, wear-resistant surface of about 58 to 62 HRC over a tough core at 900 to 1200 N/mm² tensile strength. It is used for driving bevel gears, crown wheels, gears, heavy-duty gear shafts and bolts in truck drivelines and general mechanical engineering.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu, China. We produce 15CrNi6 forged bars, hollow bars and sleeves, seamless rolled rings, discs, blocks and gear shafts to customer drawings, supplied normalised or soft annealed with EN 10204 3.1 certification.
- Material number 1.5919
- Standard DIN 17210 / DIN EN 10084
- Type Cr-Ni case-hardening steel
- Core tensile strength 900 to 1200 N/mm²
- Case hardness 58 to 62 HRC
- Forging range 1100 to 850 °C
- Carburising 880 to 980 °C
- Soft annealed max. 229 HB
- Certification EN 10204 3.1
What 15CrNi6 is used for
15CrNi6 is a low-carbon alloy steel. It is supplied soft, machined to shape, and then hardened only at the surface by carburising. The low base carbon keeps the core ductile. Chromium and nickel raise hardenability, so a fairly large section still transforms to a strong core structure when quenched. Nickel also helps the steel keep its impact toughness at the boundary between case and core, which is where fatigue cracks usually start.
This is why 15CrNi6 is used mainly as a gear steel. Gear teeth carry high contact stress on the flank and high bending stress at the root at the same time. Common parts include driving bevel gears, crown wheels, spur and helical gears, pinion shafts, planetary carriers, heavy-duty gear shafts and highly loaded bolts. Section sizes are usually moderate to large, so unalloyed case-hardening steels such as C15 are not suitable.
15CrNi6 contains around 1.5 % Cr and 1.5 % Ni, which makes it prone to hydrogen flaking. In forged sections this has to be handled at the mill before delivery. See forging and post-forge treatment below.
Chemical composition of 15CrNi6 / 1.5919
| Element | C | Si | Mn | P | S | Cr | Ni |
|---|---|---|---|---|---|---|---|
| Specification (DIN 17210) | 0.12-0.17 | 0.15-0.40 | 0.40-0.60 | max 0.035 | max 0.035 | 1.40-1.70 | 1.40-1.70 |
| Typical analysis | 0.15 | 0.25 | 0.50 | - | - | 1.55 | 1.55 |
Typical analysis taken from the Saarstahl material specification sheet for 1.5918 and 1.5919. Different editions of DIN 17210, DIN 1654-3 and DIN EN 10084 set slightly different limits, mainly on carbon and phosphorus. The specification named on the purchase order applies. We report the actual ladle analysis on the EN 10204 3.1 certificate for every heat.
Mechanical properties
Core properties after hardening and tempering at 200 °C
| Diameter d (mm) | d up to 16 | 16 to 40 | 40 to 100 |
|---|---|---|---|
| Tensile strength Rm (N/mm²) | min. 1200 | min. 1100 | min. 900 |
Core tensile strength drops as section size increases, because a thick section cools more slowly during the quench. For sections above 100 mm, please check the achievable core properties with us before the drawing is finalised. Above this size many customers change to 18CrNiMo7-6.
Hardness in the delivery condition
| Delivery condition | Symbol | Hardness | Used when |
|---|---|---|---|
| Treated for cold shearability | +S | max. 255 HB | Billet is cut cold before forming |
| Soft annealed | +A | max. 229 HB | Heavy rough machining before carburising |
| Treated for strength | +TH | 175-229 HB | A defined hardness band is required for automated machining |
| Ferrite and pearlite structure, defined hardness | +FP | 156-207 HB | Best and most consistent machinability |
The hardness values above describe the blank as shipped. 15CrNi6 only reaches its working properties after carburising, which is carried out either by us or by the customer.
Heat treatment schedule
| Operation | Temperature | Cooling medium | Purpose |
|---|---|---|---|
| Forging and hot rolling | 1100-850 °C | Controlled, still air | Shape the part and close porosity |
| Normalising | 850-880 °C | Air | Refine grain after forging |
| Soft annealing | 650-700 °C | Furnace | Lower hardness to max. 229 HB for machining |
| Carburising | 880-980 °C | - | Raise surface carbon to about 0.7 to 0.9 % |
| Intermediate annealing | 630-650 °C | Furnace | Soften for machining between carburising and hardening |
| Core hardening | 830-870 °C | Oil | Develop core strength on the single-quench route |
| Case hardening | 780-820 °C | Oil | Refine and harden the carburised case |
| Tempering | 150-200 °C | Air | Relieve quench stress and retain 58 to 62 HRC |
Direct quenching from the carburising temperature can be used on less critical parts. Double quenching, with core hardening followed by case hardening, gives a finer structure and better root bending fatigue strength, but it adds a cycle and increases the risk of distortion.
Case hardening depth (CHD)
Case hardening depth is the perpendicular distance from the surface to the point where hardness falls to 550 HV1. It is written on drawings as CHD 550 HV1. Getting this value wrong is a common problem. If the case is too deep, the carburising cycle runs longer, cost goes up and distortion increases. If it is too shallow, the tooth pits early, because the boundary between case and core then sits inside the highly stressed volume.
| Normal module mn | Typical CHD 550 HV1 | Typical application |
|---|---|---|
| Up to 4 | 0.6 to 1.0 mm | Automotive and light industrial gearing |
| 5 to 10 | 1.0 to 1.8 mm | Truck drivelines, general gearbox pinions |
| 12 and above | 2.0 to 4.0 mm | Heavy industrial gearing, large bevel sets |
A common rule of thumb is CHD of 0.15 to 0.25 times mn. The correct value comes from the contact and bending stresses in the actual gear rating calculation. Please state CHD, surface hardness range and core hardness range as separate items on the drawing.
Forging and post-forge treatment
15CrNi6 is hot formed between 1100 °C and 850 °C. We stop forging before the workpiece falls below about 850 °C. Forging below this range can cause cracking and leaves an uneven grain structure.
The chromium and nickel content also makes 15CrNi6 prone to hydrogen flaking. These are internal cracks that can appear hours or days after forging, and they are usually found later during ultrasonic inspection, once machining work has already gone into the part. Our standard practice on 15CrNi6 forgings is controlled slow cooling straight out of the forging heat, followed by an anneal at 650 to 700 °C. This removes the flaking sensitivity, produces a uniform ferrite and pearlite structure for machining, and improves the as-forged surface.
Every forging is ultrasonically inspected after heat treatment. The acceptance class is agreed before production starts, normally EN 10228-3 or SEP 1921 depending on the customer's own standard.
Equivalent and related grades
| Country and standard | Designation | Relationship |
|---|---|---|
| Germany, DIN 17210 and W.-Nr. | 15CrNi6, 1.5919 | The grade itself |
| Europe, DIN EN 10084 | 17CrNi6-6, 1.5918 | Current European grade. Superseded 15CrNi6 in most specifications |
| USA, SAE | 3115 | Cross-reference published by the mill |
| France, AFNOR | 16NC6 | Cross-reference published by the mill |
| Germany, cold forming | 15CrNi6 per DIN 1654-3 | Same grade, cold-heading delivery conditions |
| Higher-hardenability alternative | 18CrNiMo7-6, 1.6587 | Not equivalent. Adds Mo for larger sections |
| Lower-cost alternative | 20MnCr5, 1.7147 | Not equivalent. No nickel, lower core toughness |
Cross-references are for guidance only. No two national grades have exactly the same composition limits, inclusion requirements or hardenability bands. If a drawing calls out a foreign grade, check which properties the design actually depends on before substituting.
15CrNi6 compared with 18CrNiMo7-6 and 20MnCr5
| Property | 15CrNi6 (1.5919) | 18CrNiMo7-6 (1.6587) | 20MnCr5 (1.7147) |
|---|---|---|---|
| Carbon | about 0.15 % | about 0.18 % | about 0.20 % |
| Chromium | about 1.55 % | about 1.65 % | about 1.15 % |
| Nickel | about 1.55 % | about 1.55 % | - |
| Molybdenum | - | about 0.30 % | - |
| Hardenability | Medium to high | High | Medium |
| Suits section up to | About 100 mm ruling section | Large, including heavy ring gears and pinions | Small to moderate |
| Core toughness | Very good | Very good | Moderate |
| Relative cost | Medium | Highest | Lowest |
| Typical use | Bevel gears, crown wheels, gear shafts, bolts | Wind turbine and mining gearing, large bevel sets | Volume automotive gears, splined shafts |
In most cases the choice comes down to section size. If 15CrNi6 cannot reach the required core strength at the ruling section, changing to 18CrNiMo7-6 usually costs less than redesigning the part. See our pages for 18CrNiMo7-6 and 17CrNiMo6.
15CrNi6 forged product forms we supply
All shapes below are made by open-die forging or ring rolling from solid stock. None are cut from plate or fabricated by welding. Sizes are rough forged dimensions before machining.
| Form | Rough forged size range | Typical finished parts |
|---|---|---|
| Round, square, flat and hexagon bars | Dia. 80 to 1000 mm, length to 8000 mm | Pinion blanks, shaft blanks, bolt stock |
| Hollow bars, sleeves, bushings, cylinders | OD 200 to 2000 mm, wall from 40 mm | Bushes, housings, hubs, casings, shells |
| Seamless rolled rings | OD 300 to 3000 mm, height to 800 mm | Ring gear blanks, bearing races, flange rings |
| Forged rings and flanges | OD 200 to 2000 mm | Retaining rings, mounting flanges |
| Discs, blocks and plates | Dia. or width 200 to 2000 mm, thickness 60 to 800 mm | Gear blanks, die blocks, carrier plates |
| Gear shafts, pinion shafts, spindles | Dia. 100 to 1200 mm, length to 6000 mm | Bevel gears, crown wheels, crankshafts, spindles |
Delivered as-forged, normalised, soft annealed (+A) or normalised and tempered, with rough turning or full machining to drawing on request. Sizes outside these ranges are quoted case by case.
What to specify when ordering 15CrNi6 forgings
A complete enquiry lets us quote a firm price and lead time without a second round of questions. Please include:
- Grade and governing standard with edition. For example 15CrNi6 to DIN 17210, or 17CrNi6-6 to DIN EN 10084 if the current European grade is acceptable.
- Finished dimensions and rough dimensions, or the finished drawing plus the machining allowance you want us to add.
- Delivery condition: as-forged, normalised, +A soft annealed, +FP or +TH.
- Required core mechanical properties and the section at which they are verified, since core strength depends on section size.
- Ultrasonic testing class: EN 10228-3, SEP 1921 or your own internal standard.
- Grain size, cleanliness and hardenability band, if the part is a rated gear.
- Certificate type. EN 10204 3.1 is our default. EN 10204 3.2 with third-party witness is available on request.
- Who carries out carburising. We can supply blanks for your own heat treatment, or manage carburising and hardening to your CHD specification.
- Marking, packing and destination port.
Send drawings in PDF or STEP format to sales@steelforgepieces.com. We normally return a quotation within one working day.
Quality control on 15CrNi6 forgings
- Chemical analysis: ladle and product analysis by spectrometer, reported for each heat.
- Mechanical testing: tensile, impact and hardness on test blanks representing the ruling section.
- Ultrasonic inspection: 100 % of forgings after heat treatment, to the agreed acceptance class.
- Dimensional inspection: full report against the customer drawing before packing.
- Metallography: grain size and inclusion rating on request, normally required for rated gear work.
- Certification: EN 10204 3.1 as standard. EN 10204 3.2 with an inspection body on request.
Industries we supply
15CrNi6 forgings from Jiangyin Jiangnan Metal Co., Ltd. are used in gearboxes and drivelines throughout heavy industry. Applications include commercial vehicle axles and transfer cases, industrial and marine gearboxes, mining and cement mill drives, construction machinery final drives, and general mechanical engineering work where a carburised surface has to run on a tough core.
Frequently asked questions about 15CrNi6
What is 15CrNi6 steel?
15CrNi6, material number 1.5919, is a chromium-nickel alloyed case-hardening (carburising) steel specified in DIN 17210 and grouped with the case-hardening steels of DIN EN 10084. It contains roughly 0.15 % carbon with about 1.55 % chromium and 1.55 % nickel. After carburising, hardening and low-temperature tempering it gives a hard, wear-resistant surface of about 58 to 62 HRC over a tough core at 900 to 1200 N/mm² tensile strength. It is used for driving bevel gears, crown wheels, gears, shafts and bolts.
What is the equivalent of 15CrNi6?
The closest current European grade is 17CrNi6-6 (1.5918) under DIN EN 10084, which superseded 15CrNi6 in most specifications. The mill cross-reference gives SAE 3115 for the USA and 16NC6 for France. 18CrNiMo7-6 (1.6587) is a related grade with higher hardenability for larger sections because it adds molybdenum. Cross-references are for guidance only. Always confirm against the mill certificate.
What is the chemical composition of 1.5919?
Typical specification limits are C 0.12 to 0.17 %, Si 0.15 to 0.40 %, Mn 0.40 to 0.60 %, P max 0.035 %, S max 0.035 %, Cr 1.40 to 1.70 % and Ni 1.40 to 1.70 %. A published typical analysis is C 0.15, Si 0.25, Mn 0.50, Cr 1.55 and Ni 1.55. Standard editions set slightly different limits, so the governing specification on the purchase order applies.
What is the forging temperature of 15CrNi6?
15CrNi6 is hot formed between 1100 °C and 850 °C. Forging stops before the workpiece drops below about 850 °C to avoid cracking. Because the grade carries roughly 1.5 % chromium and 1.5 % nickel it is prone to hydrogen flaking, so Jiangyin Jiangnan Metal Co., Ltd. applies controlled slow cooling and a post-forge anneal at 650 to 700 °C before the forging is released for machining.
How is 15CrNi6 heat treated?
The standard route is: normalise at 850 to 880 °C in air; soft anneal at 650 to 700 °C in the furnace to a maximum of 229 HB for machining; carburise at 880 to 980 °C; intermediate anneal at 630 to 650 °C if required; core harden at 830 to 870 °C in oil; case harden at 780 to 820 °C in oil; then temper at 150 to 200 °C.
What case hardness and case depth can 15CrNi6 reach?
Correctly carburised and tempered at 150 to 200 °C, 15CrNi6 reaches about 58 to 62 HRC at the surface over a tough core. Case hardening depth is normally specified as CHD at 550 HV1. Typical ranges are 0.6 to 1.0 mm for modules up to about 4, 1.0 to 1.8 mm for modules 5 to 10, and 2.0 to 4.0 mm for heavy industrial gearing above module 12. Confirm the value against the applicable gear rating standard rather than copying a general table.
What is the difference between 15CrNi6 and 18CrNiMo7-6?
Both are chromium-nickel case-hardening steels with similar Cr and Ni content, but 18CrNiMo7-6 (1.6587) adds about 0.30 % molybdenum and slightly more carbon. The molybdenum raises hardenability, so 18CrNiMo7-6 holds core strength in thicker sections and is the usual choice for large wind turbine and mining gearing. 15CrNi6 costs less and works well where section sizes are moderate and core toughness matters more than maximum core strength.
Who supplies 15CrNi6 open-die forgings?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, produces 15CrNi6 (1.5919) forged round and flat bars, hollow bars and sleeves, seamless rolled rings, discs, blocks and gear shafts to customer drawings. Enquiries: sales@steelforgepieces.com or +86 189 2135 9659.
Standards and sources
- DIN EN 10084, Case hardening steels: technical delivery conditions.
- DIN 17210, Case hardening steels: quality specifications. Superseded by EN 10084 but still cited on many drawings.
- DIN 1654-3, Steels for cold heading and cold extrusion: case hardening steels.
- EN 10228-3 and SEP 1921, Ultrasonic testing of ferritic and martensitic steel forgings.
- EN 10204, Types of inspection document for metallic products.
- Saarstahl material specification sheet, 17CrNi6-6 and 15CrNi6, material numbers 1.5918 and 1.5919.
About the manufacturer
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory located at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We forge carbon steel, alloy steel, tool steel, stainless steel and nickel alloys into bars, seamless rolled rings, sleeves, discs, blocks, flanges and gear shafts, working to customer drawings and to international standards including DIN, EN, ASTM, SAE, JIS and GB.
For 15CrNi6 enquiries, drawings or a sample material certificate, contact sales@steelforgepieces.com or call +86 189 2135 9659.