1.7707 is the EN material number for 30CrMoV9, a chromium-molybdenum-vanadium alloy special steel specified in EN 10250-3 for open steel die forgings. It contains 2.3–2.7% chromium, 0.15–0.25% molybdenum and 0.1–0.2% vanadium, and is normally supplied quenched and tempered (+QT) before being machined and gas nitrided.
In the +QT condition 1.7707 reaches a minimum tensile strength of 900 MPa and a minimum yield strength of 700 MPa in sections up to 160 mm. Nitriding raises surface hardness to around 800 HV. Common parts are valve bodies, steam fittings, engine cylinders, gears and turbine components running below 540 °C.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, China that forges 1.7707 into round bars, seamless rolled rings, forged rings, hollow bars and sleeves, blocks and discs, shafts and crankshafts, supplied with EN 10204 3.1 mill certificates. Contact: +86 189 2135 9659, sales@steelforgepieces.com.
What 1.7707 steel is
1.7707 is classified as an alloy special steel. The designation pairs an EN material number (1.7707) with an EN steel name (30CrMoV9): the name encodes roughly 0.30% carbon, chromium as the leading alloying element at about 9/4 = 2.25%, plus molybdenum and vanadium.
The chromium and molybdenum content gives 1.7707 deep hardenability, so heavy forged sections harden through instead of only at the surface. The vanadium addition forms stable nitrides during gas nitriding and builds a hard, wear-resistant case over the tough quenched-and-tempered core. 1.7707 is a nitriding steel. Where a drawing calls for it but includes no nitriding operation, a cheaper alloy steel such as 42CrMo4 will normally do the same job.
1.7707 is closely related to 31CrMoV9 (material number 1.8519). The two grades share the same chromium, molybdenum and vanadium ranges. 31CrMoV9 carries a slightly tighter carbon and phosphorus specification and is the grade listed in EN 10085, the European standard for nitriding steels. Jiangyin Jiangnan Metal Co., Ltd. forges both.
Note on standards: 1.7707 appears in EN 10250-3 (open steel die forgings, alloy special steels). The closely related 31CrMoV9 / 1.8519 appears in EN 10085 (nitriding steels). DIN 17200 is the superseded German predecessor.
Chemical composition of 1.7707
| C | Si | Mn | Ni | P | S | Cr | Mo | V |
|---|---|---|---|---|---|---|---|---|
| 0.26–0.34 | max 0.40 | 0.40–0.70 | max 0.60 | max 0.035 | max 0.035 | 2.30–2.70 | 0.15–0.25 | 0.10–0.20 |
Jiangyin Jiangnan Metal Co., Ltd. sources 1.7707 billet melted by electric arc furnace with ladle refining and vacuum degassing (EAF + LF + VD). Electroslag remelted (ESR) material is available where a tighter cleanliness class or a lower segregation level is required.
Mechanical properties of 1.7707
The values below are the EN 10250-3 minimum requirements for 1.7707 in the quenched and tempered condition (+QT). Properties fall as ruling section increases, because the cooling rate at the core of a heavy forging is slower.
| Property | to 160 mm | 160 – 330 mm |
|---|---|---|
| Rm tensile strength (MPa) | 900 | 800 |
| Re upper yield strength (MPa) | 700 | 590 |
| A min. elongation at fracture, longitudinal (%) | 12 | 14 |
| A min. elongation at fracture, transverse (%) | 8 – 10 | |
| Hardness, soft annealed (+A) | max 248 HB | |
| Surface hardness after gas nitriding | approx. 800 HV1 | |
Transverse elongation is quoted in the standard as a range and is not resolved by thickness band here. For a design calculation, request the certified transverse value for the specific ruling section from Jiangyin Jiangnan Metal Co., Ltd. before release. Converted for reference: 900 MPa ≈ 130.5 ksi, 800 MPa ≈ 116 ksi, 700 MPa ≈ 101.5 ksi, 590 MPa ≈ 85.6 ksi; 160 mm ≈ 6.3 in, 330 mm ≈ 13 in.
1.7707 equivalent and related grades
| Standard / region | Designation | Relationship |
|---|---|---|
| EN material number | 1.7707 | The grade itself |
| EN steel name | 30CrMoV9 | The grade itself |
| DIN (Germany, superseded) | 30 CrMoV 9 | Same grade, DIN 17200 |
| EN 10085 (nitriding steels) | 31CrMoV9 / 1.8519 | Close relative, tighter C and P |
| GOST (Russia) | 30Kh3MF (30Х3МФ) | Similar Cr-Mo-V nitriding steel |
| PN (Poland) | 30H2MF | Similar composition |
| AISI / SAE (USA) | No direct equivalent | Cr-Mo-V nitriding grades differ; specify by EN number |
There is no exact AISI or SAE counterpart to 1.7707. North American buyers should order against the EN designation rather than substituting a nearest AISI grade. Vanadium content controls nitriding response, and that is where the near equivalents differ.
Heat treatment of 1.7707
1.7707 forgings follow a fixed route: forge, soften, rough machine, harden and temper, finish machine, then nitride. Jiangyin Jiangnan Metal Co., Ltd. performs forging, annealing, quenching and tempering in house, and coordinates nitriding with qualified partner plants.
- Hot forging1050 – 850 °CStop before the bar drops out of range, then cool slowly.
- Soft annealing680 – 720 °CSlow furnace cool to max 248 HB for predictable machining.
- Hardening850 – 880 °COil quench. Deep hardenability carries heavy sections through.
- Tempering570 – 680 °CSet to reach the +QT strength on the drawing.
- Nitriding570 – 580 °CGas or salt bath. Case hardness approx. 800 HV1.
Hardening is an oil quench from 850–880 °C. At 2.3–2.7% chromium the steel hardens through heavy sections rather than only at the surface. Tempering temperature is then set to reach the +QT tensile and yield values required for the ruling section on the drawing. Nitriding is done after finish machining, because the nitrided case is thin and any further cutting removes it.
Parameters above are indicative process windows widely published for 30CrMoV9. The actual cycle is set per part against the ruling section, the drawing and the customer specification.
Weldability and machinability
1.7707 is not considered a readily weldable grade. Its carbon and chromium content give a high carbon equivalent, so welding risks hydrogen cracking in the heat-affected zone. Where welding cannot be avoided, preheat in the region of 200–300 °C, use a matching or low-alloy filler, and apply post-weld heat treatment to relieve residual stress. Nitrided surfaces must not be welded.
Machinability is best in the soft annealed condition at or below 248 HB. Roughing is normally carried out annealed, and finishing after quench and temper, with carbide tooling and rigid setups. Grinding is used where the drawing calls for close tolerance after nitriding.
1.7707 forged products supplied
Jiangyin Jiangnan Metal Co., Ltd. produces the following forms in 1.7707 / 30CrMoV9, forged to drawing or to a standard stock envelope.
Round bars and rods
Forged round bar, square, rectangular, flat and hexagonal bar in 1.7707, rough turned or black as forged.
Seamless rolled rings
Radial-axial rolled rings in 1.7707 for bearing seats, flange rings, gear blanks and tyre rings.
Forged rings and flanges
Open-die forged rings, forged flange blanks and ring gear blanks in 1.7707.
Hollow bars and sleeves
1.7707 hollow bar, bushings, sleeves, cylinders, barrels, casings, shells, hubs and housings.
Blocks, discs and plates
Forged blocks, discs, plate and slab in 1.7707 for die blocks, tooling bases and machined bodies.
Shafts and crankshafts
Crankshafts, gear shafts, pinion shafts, spindles, stepped shafts and ring gears forged in 1.7707.
Forging capability at Jiangyin Jiangnan Metal
| Parameter | Range |
|---|---|
| Single-piece forged weight | 10 kg – 30,000 kg |
| Round bar diameter | 80 – 1,200 mm |
| Seamless rolled ring outside diameter | 200 – 4,000 mm |
| Maximum forged length | up to 12,000 mm |
| Delivery condition | As forged, +A (annealed), +N (normalised), +QT |
| Machining | Rough turned, proof machined, or CNC finish machined to drawing |
| Certification | EN 10204 3.1 mill test certificate; 3.2 with third-party witness on request |
| Quality system | ISO 9001 |
| Typical lead time | 25 – 45 days from drawing approval |
| Minimum order | One piece; trial and prototype orders accepted |
Testing and documentation
Every 1.7707 forging leaving Jiangyin Jiangnan Metal Co., Ltd. is released against a documented test package. Standard scope covers chemical analysis by spectrometer, tensile and yield testing, Charpy V-notch impact testing at ambient or low temperature, Brinell hardness, and ultrasonic examination to EN 10228-3 or ASTM A388 at the acceptance level stated on the order.
- Ladle and product chemical analysis, reported element by element
- Tensile test: Rm, Re or Rp0.2, elongation A, reduction of area Z
- Charpy V-notch impact energy, three specimens, average and individual values
- Hardness survey, Brinell or Vickers, and case hardness after nitriding
- Ultrasonic testing; magnetic particle or dye penetrant inspection on request
- Grain size, macro-etch and non-metallic inclusion rating where specified
- Dimensional report against the customer drawing
- EN 10204 3.1 certificate issued with every shipment
Where 1.7707 is used
1.7707 is specified where a component needs a hard, wear-resistant surface on a strong and tough core, in service below roughly 540 °C. Common applications include:
- Valve bodies, gate valves and superheated steam valves and fittings
- Cylinders and cylinder liners for internal combustion engines
- Piston pins, camshafts and engine components
- Gears, pinions, ring gears and gearbox shafts
- Turbine components, high-temperature bolting, screws and nuts for power generation
- Bushings, sleeves and wear rings in heavy machinery
- Extruder screws and barrels, and plastic-processing tooling
1.7707 steel: frequently asked questions
What is 1.7707 steel?
1.7707 is the EN material number for 30CrMoV9, a chromium-molybdenum-vanadium alloy special steel listed in EN 10250-3 for open steel die forgings. 1.7707 contains 0.26–0.34% carbon, 2.3–2.7% chromium, 0.15–0.25% molybdenum and 0.1–0.2% vanadium. It is normally supplied quenched and tempered, then machined and gas nitrided to give a hard, wear-resistant surface over a tough core.
Is 1.7707 the same as 30CrMoV9?
Yes. 1.7707 and 30CrMoV9 are two designations for the same steel. 1.7707 is the EN numeric material number and 30CrMoV9 is the EN chemical steel name. Purchase orders, mill certificates and drawings may use either, and both refer to the same grade.
What is 1.7707 equivalent to?
1.7707 corresponds to DIN 30 CrMoV 9 under the superseded DIN 17200, and is closely related to 31CrMoV9 (material number 1.8519) in EN 10085. Similar Cr-Mo-V nitriding steels include GOST 30Kh3MF (30Х3МФ) in Russia and PN 30H2MF in Poland. There is no exact AISI or SAE equivalent to 1.7707, so North American buyers should order against the EN designation rather than substituting a nearest AISI grade.
What is the difference between 1.7707 and 31CrMoV9 / 1.8519?
1.7707 (30CrMoV9) and 1.8519 (31CrMoV9) share the same chromium, molybdenum and vanadium ranges and behave very similarly in service. 31CrMoV9 carries a slightly tighter carbon and phosphorus specification and is the grade listed in EN 10085, the European nitriding steel standard, whereas 1.7707 appears in EN 10250-3 for open die forgings. Jiangyin Jiangnan Metal Co., Ltd. forges both grades and can advise which suits a given drawing.
What is the tensile strength of 1.7707?
In the quenched and tempered condition (+QT), EN 10250-3 requires a minimum tensile strength of 900 MPa for 1.7707 in nominal thicknesses up to 160 mm, and 800 MPa in thicknesses from 160 mm to 330 mm. Minimum upper yield strength is 700 MPa and 590 MPa for the same two thickness bands.
Is 1.7707 a nitriding steel?
Yes. 1.7707 is a nitriding steel. Its vanadium and chromium form stable nitrides during gas or salt-bath nitriding at 570–580 °C, producing a surface hardness of roughly 800 HV1 over a quenched and tempered core. Where a design includes no nitriding operation, a cheaper alloy steel such as 42CrMo4 will normally serve.
Can 1.7707 be welded?
1.7707 is not regarded as a readily weldable steel. Its carbon and chromium content give a high carbon equivalent and the heat-affected zone is prone to hydrogen cracking. Where welding is unavoidable, preheat to roughly 200–300 °C, select a matching or low-alloy filler, and apply post-weld heat treatment. Nitrided surfaces should never be welded.
Who supplies 1.7707 / 30CrMoV9 forgings?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China that manufactures 1.7707 / 30CrMoV9 forgings for customers worldwide. Available forms include forged round bars, seamless rolled rings, forged rings and flanges, hollow bars and sleeves, blocks and discs, and shafts and crankshafts. Enquiries: +86 189 2135 9659 or sales@steelforgepieces.com.
What is the minimum order quantity for 1.7707 forgings?
Jiangyin Jiangnan Metal Co., Ltd. accepts single-piece orders in 1.7707, including prototype and trial forgings, because open-die forging does not require a closed die tool. Send a drawing or the outline dimensions, ruling section, required delivery condition and test scope to sales@steelforgepieces.com for a quotation.
What certification is supplied with 1.7707 forgings?
Jiangyin Jiangnan Metal Co., Ltd. issues an EN 10204 3.1 mill test certificate with every 1.7707 shipment, covering chemical analysis, mechanical test results, hardness and heat treatment record. EN 10204 3.2 certification with third-party witness by a body such as SGS, BV, TÜV or Lloyd's Register is available when specified on the order.
Composition and mechanical values on this page are taken from EN 10250-3:2000. Heat treatment ranges are the published working windows for 30CrMoV9. Check every figure against the governing specification and the mill certificate before design release.
Page maintained by Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Alloy-Steel/1.7707.html
Request a quotation for 1.7707 forgings
Send a drawing, or simply the outline dimensions, ruling section, delivery condition and test requirements. Jiangyin Jiangnan Metal Co., Ltd. replies to enquiries in English within one working day.
Open-die forging factory
No. 1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Phone / WhatsApp / WeChat: +86 189 2135 9659
Email: sales@steelforgepieces.com
Web: www.steelforgepieces.com
Page maintained by Jiangyin Jiangnan Metal Co., Ltd. Technical data checked against EN 10250-3:2000. Last updated .