What is 1.6773 steel?
1.6773 is the EN material number for 36NiCrMo16, a high-nickel Ni-Cr-Mo steel for quenching and tempering, specified in EN 10083-3:2006. It carries 3.60 to 4.10 % nickel, roughly twice the level in 34CrNiMo6, and that nickel is what gives the grade its hardenability. A forging several hundred millimetres thick still transforms to martensite at the centre. Quenched and tempered, 1.6773 reaches 1250 to 1450 N/mm² tensile strength in small sections, and EN 10250-3 guarantees 1000 N/mm² with 45 J impact energy on forgings up to 990 mm diameter. Designers reach for it when a part has to be strong and tough in a heavy cross section: landing gear, heavy gearing, crankshafts, drilling and subsea components.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu, China. We produce 1.6773 forged rings, seamless rolled rings, shafts, flanges, discs, sleeves, tubes and bars from 20 kg to 30 t, supplied rough-machined or finish-machined with EN 10204 3.1 or 3.2 certification. The data below is what our metallurgists work from when they quote and heat treat this grade.
1.6773 at a glance
| EN material number | 1.6773 |
|---|---|
| EN chemical designation | 36NiCrMo16 |
| Steel family | Alloy steel for quenching and tempering, high-Ni Ni-Cr-Mo type |
| Governing standards | EN 10083-3:2006 for bars and semi-finished, EN 10250-3 for open-die forgings, AIR 9160/C for aerospace |
| Tensile strength, +QT | 1250–1450 N/mm² (≤ 40 mm) down to 1000–1200 N/mm² (160–250 mm) |
| 0.2 % proof strength, +QT | 1050 N/mm² (≤ 40 mm) down to 800 N/mm² (160–250 mm) |
| Air-hardening depth | Hardens in air up to approx. 90 mm section |
| Weldability | Limited. Pre-heat to approx. 250 °C, stress relieve at 550 °C with furnace cooling |
| Common equivalents | 35NCD16 (France), 835M30 and EN30B (UK), 34NiCrMo16 (Italy), 36Kh2N4MA (Russia) |
| Forms we forge | Rings, seamless rolled rings, shafts, flanges, discs, blocks, sleeves, tubes, bars |
| Supplier | Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu, China |
Chemical composition of 1.6773
Ladle analysis to EN 10083-3:2006, percent by mass. We melt 1.6773 by the EAF + LF + VD route. Vacuum degassing keeps hydrogen below 2 ppm, which matters in a grade this hardenable, since it is the practical defence against hydrogen flaking in heavy sections.
| Element | C | Si | Mn | P | S | Cr | Mo | Ni |
|---|---|---|---|---|---|---|---|---|
| Specified range | 0.32–0.39 | ≤ 0.40 | 0.50–0.80 | ≤ 0.025 | ≤ 0.025 | 1.60–2.00 | 0.25–0.45 | 3.60–4.10 |
| Permissible product deviation | ± 0.02 | + 0.03 | ± 0.04 | + 0.005 | + 0.005 | ± 0.05 | ± 0.04 | ± 0.07 |
What each element does in this grade
- Nickel 3.60 to 4.10 %. This is what separates 1.6773 from the cheaper Ni-Cr-Mo grades. It shifts the CCT curve far to the right, so martensite forms even at the slow cooling rate found at the centre of a thick forging, and it keeps impact toughness high below zero.
- Chromium 1.60 to 2.00 %. Adds hardenability and tempering resistance, and raises wear resistance on journal and gear surfaces.
- Molybdenum 0.25 to 0.45 %. Suppresses temper embrittlement, the specific failure risk in Ni-Cr steels tempered through the 350 to 550 °C band, and holds strength at elevated temperature.
- Carbon 0.32 to 0.39 %. Set to reach roughly 52 HRC as quenched, while leaving enough ductility for a tempered part to survive impact loading.
Mechanical properties of 1.6773 in the +QT condition
Values below are the minima of EN 10083-3:2006 for hot-rolled product, tested longitudinally at room temperature. The property band steps down as section size grows, so check this table before you fix a strength class for a large part.
| Diameter d / thickness t (mm) | Rm (N/mm²) | Rp0.2 min (N/mm²) | A min (%) | Z min (%) | KV min (J) | HBW (guide) |
|---|---|---|---|---|---|---|
| up to 16 / 8 | 1250–1450 | 1050 | 9 | 40 | n/a | 370–415 |
| 16–40 / 8–20 | 1250–1450 | 1050 | 9 | 40 | 30 | 370–415 |
| 40–100 / 20–60 | 1100–1300 | 900 | 10 | 45 | 35 | 331–380 |
| 100–160 / 60–100 | 1000–1200 | 800 | 11 | 50 | 45 | 298–359 |
| 160–250 / 100–160 | 1000–1200 | 800 | 11 | 50 | 45 | 298–359 |
Properties of 1.6773 open-die forgings to EN 10250-3
Forgings fall under EN 10250-3 rather than EN 10083-3, and that is the standard which applies to the parts we supply. The point worth noting for design work is that the guaranteed values stay flat all the way out to 990 mm diameter. Very few alloy steels hold up that far.
| Diameter d / thickness t (mm) | Rm min | Rp0.2 min | A min, long. | A min, tang. | KV min, long. | KV min, tang. | HB min |
|---|---|---|---|---|---|---|---|
| up to 250 / 160 | 1000 N/mm² | 800 N/mm² | 11 % | 8 % | 45 J | 22 J | 298 |
| 250–500 / 160–330 | 1000 N/mm² | 800 N/mm² | 11 % | 8 % | 45 J | 22 J | 298 |
| 500–990 / 330–660 | 1000 N/mm² | 800 N/mm² | 11 % | 8 % | 45 J | 22 J | 298 |
Tempering response
Measured on Ø 10 mm rounds quenched from 850 °C in oil. Use it to pick a tempering temperature for a target strength class, then confirm the result on a test coupon taken from the actual forging.
| Tempering °C | 200 | 300 | 400 | 500 | 550 | 600 | 650 |
|---|---|---|---|---|---|---|---|
| Rm (N/mm²) | 1900 | 1720 | 1520 | 1320 | 1200 | 1090 | 1000 |
| Rp0.2 (N/mm²) | 1550 | 1430 | 1290 | 1100 | 990 | 900 | 870 |
| Hardness (HRC) | 52.5 | 49 | 46 | 41.5 | 38.5 | 35 | 32 |
| Elongation A (%) | 7.0 | 8.6 | 9.6 | 11.0 | 12.4 | 14.0 | 14.0 |
| Impact KV (J) | 28 | 27 | 26 | 28 | 38 | 64 | 64 |
Property data compiled from EN 10083-3:2006, EN 10250-3 and published mill technical cards for 36NiCrMo16. Values on a specific order are confirmed on the actual heat and reported on the EN 10204 certificate.
Heat treatment of 1.6773 forgings
| Operation | Temperature | Cooling / note |
|---|---|---|
| Hot forging | 1100 → 900 °C | Finish above 900 °C; slow cool in furnace or ash |
| Normalizing (+N) | 850 °C | Air |
| Hardening (+Q) | 830–860 °C | Oil, polymer or water; also air-hardens from 880 °C in sections to ~90 mm |
| Tempering (+T) | 550–650 °C | Air; avoid holding in the 350–500 °C temper-embrittlement band |
| Stress relieving (+SR) | 50 °C below the tempering temperature | Slow cool |
| Soft annealing (+A) | 650 °C | Air; ≤ 269 HB |
| Isothermal annealing (+I) | 790 °C | Furnace cooling; ≤ 275 HB |
| Pre-heat for welding | approx. 250 °C | Stress relieve at 550 °C, furnace cool |
| Transformation points | Ac1 700 °C, Ac3 760 °C | Ms 240 °C, Mf 30 °C |
Two cautions from our own shop floor. Mf sits near 30 °C, so a heavy 1.6773 forging quenched into warm oil can retain austenite. We control quenchant temperature and temper without delay. And because Ms is low while hardenability is high, quench cracking is a real risk on parts with abrupt section changes. We review the geometry at the quotation stage and add radii or use a stepped quench where the shape calls for it.
Physical properties
| Density | 7.84 kg/dm³ |
|---|---|
| Modulus of elasticity | 208 GPa |
| Shear modulus | 80 GPa |
| Specific heat capacity | 460 J/(kg·K) |
| Thermal conductivity | 33 W/(m·K) |
| Coefficient of thermal expansion | 11.5 ×10⁻⁶/K (20–100 °C) rising to 14.0 ×10⁻⁶/K (20–600 °C) |
| Electrical resistivity | 0.30 Ω·mm²/m |
| Magnetic response | Ferromagnetic |
1.6773 equivalent grades
If a drawing arrives carrying any of the designations below, 1.6773 is the grade to quote. Where a match is marked close rather than exact, the chemistry overlaps but is not identical, so we confirm acceptance in writing before melting.
| Country / system | Designation | Match |
|---|---|---|
| Europe (EN) | 36NiCrMo16, 1.6773 | Exact |
| Germany (DIN) | 36NiCrMo16, Werkstoff 1.6773 | Exact |
| France (AFNOR) | 35NCD16, 35 NCD 16 | Exact |
| Italy (UNI) | 34NiCrMo16, 36NiCrMo16 | Exact |
| United Kingdom (BS 970) | 835M30, EN30B | Close |
| Russia (GOST) | 36Kh2N4MA, 34KhN3M | Close |
| Aerospace | AIR 9160/C, Fe-PL75, ASNA 3133 / 3134 / 3149 | Specification callouts |
| Lower-carbon sister grade | 30NiCrMo16-6, 1.6747, 30NCD16 | Related, not interchangeable |
1.6773 compared with 34CrNiMo6, 30CrNiMo8 and 30NiCrMo16-6
The question buyers ask us most often is whether a cheaper Ni-Cr-Mo grade will do the job. Section size almost always decides it. Below about 100 mm, 34CrNiMo6 usually suffices. Above that, the nickel in 1.6773 is what stops the core properties from falling away.
| Grade | C % | Ni % | Cr % | Mo % | Rm, 40–100 mm | Chosen when |
|---|---|---|---|---|---|---|
| 1.6773 / 36NiCrMo16 | 0.32–0.39 | 3.60–4.10 | 1.60–2.00 | 0.25–0.45 | 1100–1300 N/mm² | Maximum strength through a heavy section |
| 1.6747 / 30NiCrMo16-6 | 0.26–0.33 | 3.30–4.30 | 1.20–1.50 | 0.30–0.60 | 1000–1200 N/mm² | Same hardenability, more toughness, easier to weld |
| 1.6580 / 30CrNiMo8 | 0.26–0.34 | 1.80–2.20 | 1.80–2.20 | 0.30–0.50 | 1000–1200 N/mm² | Mid-size shafts and gearing, lower alloy cost |
| 1.6582 / 34CrNiMo6 | 0.30–0.38 | 1.30–1.70 | 1.30–1.70 | 0.15–0.30 | 1000–1200 N/mm² | General heavy engineering; AISI 4340 equivalent |
We forge all four grades. Send us the section size, the required core properties and the service temperature, and we will tell you which one we would use on the job. Related pages: 34CrNiMo6 forgings, 30NiCrMo8 forgings, 1.6580 forgings, 1.6582 forgings.
1.6773 forgings we manufacture
Every item below is produced in-house at our Jiangyin plant from our own melted or sourced 1.6773 billet, then heat treated, ultrasonically tested and machined to your drawing.
| Product form | Size range | Typical application |
|---|---|---|
| Seamless rolled rings | OD 200–3000 mm, height to 800 mm | Bearing races, gear blanks, turbine casings |
| Forged rings | OD 150–2500 mm | Flange rings, retaining rings, tyre rings |
| Forged shafts & spindles | Ø 80–1200 mm, length to 8000 mm | Crankshafts, pinion shafts, rotor shafts |
| Forged flanges | Ø 100–3000 mm | Pressure vessel, wellhead and valve flanges |
| Forged discs & blanks | Ø 150–2500 mm | Gear blanks, turbine discs, tube sheets |
| Forged blocks & slabs | Thickness to 800 mm | Die blocks, valve bodies, manifolds |
| Forged sleeves & bushings | OD 100–1500 mm | Bearing housings, wear sleeves |
| Forged tubes & hollow bars | OD 150–1200 mm | Cylinders, subsea housings |
| Forged round & step bars | Ø 60–1000 mm | Machining stock, connecting rods |
How a 1.6773 forging is made here
Forging ratio is the item buyers most often leave off a drawing. For 1.6773 we work to a minimum 3:1 reduction, and to 4:1 or higher where the part sees fatigue loading. That reduction is what breaks up the as-cast structure and produces the grain flow that makes a forging outlast a part machined from bar.
Where 1.6773 forgings are used
| Industry | Components |
|---|---|
| Aerospace and defence | Landing gear components, actuator bodies, high-load pins and links, torsion shafts |
| Oil, gas and subsea | Wellhead and Christmas tree parts, subsea housings, drill collars, valve blocks and stems |
| Power transmission | Heavy gear blanks, pinion shafts, gearbox rings, coupling hubs |
| Heavy machinery | Crankshafts, eccentric shafts, mill rolls, press rams, cement and sugar mill parts |
| Pressure equipment | Forged tube sheets, nozzles, high-pressure flanges, air receiver components |
| Marine and shipbuilding | Rudder stocks, propeller shafts, deck machinery parts |
| Compressors and pumps | Rotor shafts, plunger pump parts, chemical pump shafts |
Testing and certification
- Ultrasonic testing to EN 10228-3, SEP 1921 (class C/D or E/F on request) or ASTM A388, on 100 % of forgings after heat treatment.
- Chemical analysis by spectrometer on the ladle sample and, where specified, on the product.
- Mechanical testing. Tensile, Charpy V at room temperature or down to −40 °C, and a hardness survey, taken on prolongations that represent the actual heat treatment charge.
- Magnetic particle inspection to EN 10228-1 for surface indications on machined parts.
- Grain size and microstructure to ASTM E112, minimum grain size 5 as required by EN 10083-3.
- Jominy hardenability to EN 10083-3 on request: minimum 50 HRC at 1.5 mm and still 47 HRC at 50 mm from the quenched end.
- Certification to EN 10204 3.1 as standard, or EN 10204 3.2 with TÜV, BV, SGS, Lloyd's or DNV witness on request.
Frequently asked questions about 1.6773
What is 1.6773 equivalent to?
1.6773 is the EN material number for 36NiCrMo16. Its exact equivalents are 35NCD16 in France (AFNOR) and 34NiCrMo16 in Italy (UNI). 835M30 and EN30B in BS 970, and 36Kh2N4MA in GOST, are close but not identical, so we confirm chemistry acceptance in writing before production. In aerospace it appears as AIR 9160/C and Fe-PL75. There is no exact AISI or SAE equivalent. AISI 4340 sits far lower in nickel and will not match the through-hardening depth.
Is 1.6773 the same as 36NiCrMo16?
Yes. 1.6773 is the numeric designation and 36NiCrMo16 is the chemical designation for the same steel in EN 10083-3:2006. Some drawings write it as 35NiCrMo14 or 35NCD14. Those are older or national names for the same alloy family, and they should be checked against the composition table rather than assumed.
What is the tensile strength of 1.6773?
In the quenched and tempered condition, 1250–1450 N/mm² up to 40 mm diameter, 1100–1300 N/mm² from 40 to 100 mm, and 1000–1200 N/mm² from 100 to 250 mm, per EN 10083-3:2006. For open-die forgings to EN 10250-3 the guaranteed minimum is 1000 N/mm² with 800 N/mm² proof strength, holding all the way to 990 mm diameter. Tempering low, at 200 °C, takes it to about 1900 N/mm², but elongation drops to 7 %.
Can 1.6773 be welded?
Only with care. The carbon equivalent is high, so 1.6773 counts as difficult to weld and is normally used in the hardened and stress-relieved condition instead. Where welding cannot be avoided, pre-heat to roughly 250 °C, use a low-hydrogen matching or austenitic consumable, and stress relieve at 550 °C with furnace cooling. Our advice is to design the joint out of the part wherever the drawing allows it.
What section size can 1.6773 be hardened through?
It air-hardens in sections up to about 90 mm and oil-hardens well beyond that. The Jominy curve holds a minimum 47 HRC at 50 mm from the quenched end, which is why EN 10250-3 can guarantee identical properties on forgings from 250 mm to 990 mm diameter. That hardening depth is the main reason to pick this grade over 34CrNiMo6.
Who supplies 1.6773 forgings?
Jiangyin Jiangnan Metal Co., Ltd. manufactures 1.6773 / 36NiCrMo16 open-die forgings at its plant at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Product forms include seamless rolled rings, forged rings, shafts, flanges, discs, sleeves, tubes and bars from 20 kg to 30 t, supplied with EN 10204 3.1 or 3.2 certification. Enquiries: sales@steelforgepieces.com or +86 189 2135 9659.
What is the difference between 1.6773 and 1.6747?
Carbon and chromium. 1.6747 (30NiCrMo16-6) carries 0.26 to 0.33 % C and 1.20 to 1.50 % Cr, against 0.32 to 0.39 % C and 1.60 to 2.00 % Cr in 1.6773. Both hold 3.3 to 4.3 % nickel, so hardenability is comparable, but 1.6747 gives up peak strength for better toughness and slightly better weldability. Pick 1.6773 when the design is limited by strength, 1.6747 when it is limited by toughness or fracture.
What is the minimum order quantity and lead time?
We take single-piece prototype orders as well as series production. Typical lead time runs 25 to 40 days from drawing approval for forged, heat treated and rough-machined parts, depending on section size and on whether third-party witness testing is required. Send a drawing or a size list to sales@steelforgepieces.com for a firm quotation within 24 hours.
About the manufacturer
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. The plant sits in the Yangtze River Delta forging cluster, about two hours from Shanghai port. We forge carbon, alloy, tool and stainless steels and nickel alloys to European, American, Japanese and Chinese standards, and we ship worldwide.
We work to EN 10250, ASTM A788, DIN 17243 and equivalent forging standards, and issue an EN 10204 3.1 certificate on every order as standard. Questions about grade selection, heat treatment routes or NDT acceptance levels go straight to our metallurgical staff rather than to a sales desk.
Request a quotation for 1.6773 forgings
Send a drawing, a sketch, or just the outside diameter, inside diameter, height and quantity. Tell us the certificate level you need and any NDT class, and we will come back with price, weight and lead time within one working day.
Email sales@steelforgepieces.com
Phone, WhatsApp or WeChat +86 189 2135 9659