51CDV4
Open-die forged bars, seamless rolled rings, discs, sleeves and levelling rolls in 1.7701 / 51CrMoV4 / AISI 4150
51CDV4 is the French AFNOR designation for a chromium molybdenum vanadium quenched and tempered steel. It is the same grade as EN 51CrMoV4 and 52CrMoV4, material number 1.7701, and AISI/SAE 4150. The analysis runs 0.48 to 0.56 % carbon with about 1 % chromium, 0.2 % molybdenum and 0.2 % vanadium, which gives high toughness in bending together with a hard induction hardened surface. Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu, China that forges this grade to customer drawings, from 20 kg to 30 tonnes per piece, for shipment worldwide.
- AFNOR 51CDV4
- EN 51CrMoV4
- EN 52CrMoV4
- W.-Nr. 1.7701
- AISI/SAE 4150
- UNS G41500
- UNI 51CrMoV4
- UNE F-1460
Published by Jiangyin Jiangnan Metal Co., Ltd. Last updated .
What is 51CDV4 steel?
51CDV4 is a low alloy, medium to high carbon chromium molybdenum vanadium steel, standardised in Europe as 51CrMoV4 and 52CrMoV4 (1.7701) under EN 10089 and formerly DIN 17221. In the AFNOR system the letters stand for the alloying elements: C for chromium, D for molybdenum and V for vanadium, at roughly one quarter of the nominal chromium content.
Two things separate it from the more familiar 42CrMo4 and 50CrV4. Carbon sits higher, so the hardened surface comes out harder. And it carries molybdenum and vanadium together, so hardenability improves while the vanadium carbides pin the grain and hold hardness through tempering. A roll made from it can be surface hardened deeply and still stay tolerant of notches.
Normal delivery is hot rolled or forged and heat treated to 860 to 1000 N/mm², then medium frequency progressive induction hardened and stress relieved. The finished structure is a fine martensitic matrix carrying M3C type carbides, with chromium carbides at 900 to 1100 HV and a density of about 1.5 × 10⁵ per mm².
51CDV4 equivalent grades and standards
Use this table when converting a European drawing to a US or Asian specification. Grades marked as closest are not identical and should be checked against the actual analysis before ordering.
| Standard and country | Designation | Match |
|---|---|---|
| AFNOR, France | 51CDV4 | Base designation |
| EN 10089, Europe | 51CrMoV4, 52CrMoV4 | Direct |
| Werkstoff-Nr., Germany | 1.7701 | Direct |
| DIN 17221, Germany | 51CrMoV4 | Direct, superseded |
| AISI / SAE, USA | 4150 | Direct |
| UNS, USA | G41500 | Direct |
| UNI, Italy | 51CrMoV4 | Direct |
| UNE, Spain | F-1460 | Direct |
| JIS, Japan | SCM445 | Closest |
| GOST, Russia | 50KhGM, 5KhMA | Closest |
| GB, China | No exact grade | Supplied to EN 10089 analysis |
Related but not interchangeable: 51CrV4 (1.8159, AISI 6150) contains no molybdenum, 50CrMo4 (1.7228) contains no vanadium, and 58CrMoV4 runs higher in carbon.
Chemical composition of 51CDV4
| Condition | C | Si | Mn | P max | S max | Cr | Mo | V |
|---|---|---|---|---|---|---|---|---|
| EN 10089 range | 0.48-0.56 | ≤ 0.40 | 0.70-1.10 | 0.025 | 0.025 | 0.90-1.20 | 0.15-0.30 | 0.10-0.20 |
| Typical roll grade heat | 0.54 | 0.28 | 0.90 | ≤ 0.020 | ≤ 0.015 | 1.05 | 0.20 | 0.20 |
| Typical spring grade heat | 0.50 | 0.25 | 0.90 | ≤ 0.025 | ≤ 0.025 | 1.10 | 0.25 | 0.10 |
Balance iron. Residuals limited to Cu + 10 Sn < 0.6 %. Every heat ships with a ladle and product analysis on an EN 10204 3.1 certificate.
Mechanical properties after heat treatment
| Property | Machining condition | Finished roll condition |
|---|---|---|
| Tensile strength Rm | 860-1000 N/mm² | 950-1250 N/mm² |
| Yield strength Rp0.2 | ≥ 620 N/mm² | ≥ 750 N/mm² |
| Elongation A5 | ≥ 12 % | ≥ 10 % |
| Core hardness | 255-300 HB | 280-370 HB |
| Induction hardened surface | not applicable | 58-62 HRC typical |
| Chromium carbide hardness | not applicable | 900-1100 HV |
| Austenitic grain size | ASTM E112 ≥ 5 | |
| Inclusion rating | ASTM E45 method D, types A/B/C/D, max 2.0 thin and 1.5 heavy | |
| Forging reduction ratio | minimum 4:1 | |
| Ultrasonic acceptance | SEP 1921 class D/d, or ASTM A388 by agreement | |
Values are indicative for sections up to 300 mm ruling diameter and are agreed per order. For heavier sections the achievable band is stated on the order confirmation.
Forging and heat treatment of 51CDV4
| Operation | Temperature | Cooling |
|---|---|---|
| Hot forging and hot forming | 1050 °C down to 850 °C finish | Slow cool, covered |
| Normalising | 850-880 °C | Air |
| Soft annealing | 640-680 °C | Furnace |
| Hardening | 830-860 °C | Oil |
| Tempering | 430-500 °C | Air |
| Surface hardening | Medium frequency progressive induction | Stress relieve afterwards |
Vanadium carbides resist coarsening, so 51CDV4 stands up to the repeated local heating of progressive induction hardening better than plain Cr-Mo grades. Stress relieving straight after hardening is what keeps a long roll barrel straight, and we specify it on every roll we treat.
51CDV4 forged products and size range
Everything below is open-die forged to order from our own feedstock. There is no die cost and no minimum quantity. Send a drawing and we forge to it.
| Forged form | Size range | Typical use |
|---|---|---|
| Round bars, rods and shafts | Ø 60-1200 mm, length to 8000 mm | Torsion bars, stressed shafts, roll blanks |
| Square, rectangular, flat and hexagonal bars | 60-1000 mm across flats | Leaf spring stock, machine bases, tooling blanks |
| Hollow bars, sleeves, bushings, pipes and cylinders | OD 150-1500 mm, ID from 80 mm | Casings, shells, hubs, housings, barrels |
| Seamless rolled rings | OD 100-2500 mm, height to 800 mm | Bearing races, gear rims, flange rings |
| Forged rings | OD up to 2000 mm | Retaining rings, spacers, tyre rings |
| Blocks, discs, disks and plates | Thickness 40-800 mm | Die blocks, end plates, cover discs |
| Cold mill work rolls and back-up rolls | Barrel Ø 80-900 mm | Cold rolling mills |
| Leveller, straightening and intermediate rolls | Barrel Ø 60-600 mm | Tension levellers, cut to length lines |
| Scale breaker rolls | Barrel Ø 60-400 mm | Pickling line cassettes, thin gauge material |
Maximum single piece weight 30 tonnes. Supply condition: as forged, normalised, annealed, quenched and tempered, rough machined or finish machined.
51CDV4 vs 42CrMo4 vs 50CrV4: which grade for levelling rolls?
For work and intermediate rolls on levellers, 51CDV4 gives better hardenability and a higher induction hardened surface hardness than 42CrMo4, 50CrMo4 or 50CrV4, without the brittleness those grades can show in a roll body. Use 42CrMo4 where cost matters more than surface hardness, 50CrV4 for lighter springs, and 51CDV4 where the part has to be hard at the surface and tough in bending at the same time.
| Criterion | 51CDV4 (1.7701) | 42CrMo4 (1.7225) | 50CrV4 (1.8159) |
|---|---|---|---|
| Nominal carbon | 0.51 % | 0.42 % | 0.51 % |
| Molybdenum | 0.15-0.30 % | 0.15-0.30 % | none |
| Vanadium | 0.10-0.20 % | none | 0.10-0.25 % |
| Hardenability | High | Medium to high | Medium |
| Induction hardened surface | 58-62 HRC | 52-56 HRC | 55-58 HRC |
| Toughness in bending | Very high | High | High |
| Temper resistance | Best of the three | Good | Good |
| Relative cost | Highest | Lowest | Middle |
| Best suited to | Leveller and straightening rolls | General shafts and gears | Leaf and coil springs |
Full datasheets: 42CrMo4 forgings, AISI 4140 forgings, 34CrNiMo6 forgings.
Where 51CDV4 forgings are used
Rolling mill and processing line rolls
This is the main use. Work and intermediate rolls for levellers, rolls for cut to length lines and tension levellers in galvanizing and electrolytic tinning lines, and scale breaker rolls handling thin gauge material in pickling line cassettes. In all of these the roll bends repeatedly under load while the surface has to resist wear from strip contact, which is the load case 51CDV4 was developed for.
Highly stressed springs and torsion components
Under its EN name 51CrMoV4 and 52CrMoV4 the grade is a long standing spring steel: leaf springs, helical vehicle springs, stabiliser bars, torsion bars and disc springs, quenched and tempered to strength.
General heavy engineering
Forged shafts, pins, couplings, wear rings and die blocks where a through hardened core has to carry a hard running surface.
Testing, certification and traceability
Each 51CDV4 forging leaves the works with an EN 10204 3.1 mill certificate carrying the heat number, which is hard stamped on the piece. The certificate covers:
- Ladle and product chemical analysis by spectrometer
- Mechanical test results after final heat treatment: Rm, Rp0.2, A5, Z and impact energy where specified
- Brinell or Rockwell hardness, plus a surface hardness traverse after induction hardening
- Austenitic grain size to ASTM E112 and inclusion rating to ASTM E45
- Ultrasonic examination to SEP 1921 class D/d, ASTM A388 or EN 10228-3 as agreed
- Dimensional report against the drawing
EN 10204 3.2 certification with third party witness by SGS, BV, TUV or Lloyd's Register is available on request, as are magnetic particle inspection, hardness mapping and PMI.
How to request a 51CDV4 quotation
Quotations normally go back within one working day. To price the piece we need:
- The grade. 51CDV4, or whichever equivalent your drawing uses: 51CrMoV4, 52CrMoV4, 1.7701, AISI 4150, UNS G41500.
- The geometry. A drawing, or OD by ID by length or thickness plus the machining allowance you expect.
- The delivery condition. As forged, normalised, annealed, quenched and tempered to a hardness band, or rough machined and induction hardened.
- The test requirements. Test position, ultrasonic class, grain size, inclusion rating, EN 10204 3.1 or 3.2.
- Quantity and destination port. For a single prototype or a production batch.
Supplier of record for the data on this page
Jiangyin Jiangnan Metal Co., Ltd., open-die forging factoryNo.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Phone, WhatsApp and WeChat: +86-189-2135-9659
Email: sales@steelforgepieces.com
Web: www.steelforgepieces.com
51CDV4 frequently asked questions
What is 51CDV4 steel?
51CDV4 is the French AFNOR designation for a chromium molybdenum vanadium quenched and tempered spring and roll steel. It is the same grade as EN and DIN 51CrMoV4 and 52CrMoV4, material number 1.7701, and AISI/SAE 4150 (UNS G41500). The analysis runs 0.48 to 0.56 % C, 0.90 to 1.20 % Cr, 0.15 to 0.30 % Mo and 0.10 to 0.20 % V. Jiangyin Jiangnan Metal Co., Ltd. open-die forges this grade into bars, rings, discs, sleeves and levelling rolls.
What is the equivalent grade of 51CDV4?
The direct equivalents are 51CrMoV4 and 52CrMoV4 to EN 10089, Werkstoff number 1.7701, UNI 51CrMoV4 in Italy, F-1460 in Spain, and AISI/SAE 4150 or UNS G41500 in the United States. The closest Japanese grade is JIS SCM445. There is no exact GB grade in China, so Jiangyin Jiangnan Metal Co., Ltd. supplies the grade to the EN 10089 or AFNOR analysis.
Is 51CDV4 the same as 51CrV4?
No, and mixing the two up is the most common ordering error on this grade. 51CrV4 (1.8159, AISI 6150) is a chromium vanadium spring steel with no deliberate molybdenum. 51CDV4 and 51CrMoV4 (1.7701) carry 0.15 to 0.30 % molybdenum, which raises hardenability and temper resistance and lets a heavier section be through hardened.
What hardness and strength can 51CDV4 reach?
Quenched and tempered 51CDV4 forgings are normally delivered at 860 to 1000 N/mm² for machining, and 950 to 1250 N/mm² with a yield strength of at least 750 N/mm² and elongation of at least 10 % for finished rolls. After medium frequency progressive induction hardening the surface typically reaches 58 to 62 HRC, with chromium carbides of 900 to 1100 HV in a fine martensitic matrix.
Why choose 51CDV4 instead of 42CrMo4 or 50CrV4 for levelling rolls?
51CDV4 carries the molybdenum of 42CrMo4 and 50CrMo4 together with the vanadium of 50CrV4, at a higher carbon level. Against those grades it gives better hardenability and a higher induction hardened surface hardness without the brittleness they can show in a roll body, along with high toughness and a large capacity to work in high bending conditions. That is why it is the usual choice for work and intermediate rolls for levellers, cut to length and tension levelling lines, and scale breaker rolls.
What forged products are available in 51CDV4?
Round, square, flat and hexagonal bars and shafts, hollow bars, sleeves, bushings, cylinders, casings and housings, seamless rolled rings and forged rings, blocks, discs and plates, and cold mill work rolls, back-up rolls, intermediate rolls, leveller and straightening rolls and scale breaker rolls. Bars run from 60 mm to 1200 mm diameter, rings up to 2500 mm outside diameter, and single pieces up to 30 tonnes.
Who supplies 51CDV4 forgings from China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. It forges 51CDV4, 51CrMoV4 and 1.7701 to customer drawings and ships worldwide. Enquiries go to +86-189-2135-9659 or sales@steelforgepieces.com.
What testing and certificates are supplied?
Standard supply includes an EN 10204 3.1 mill certificate covering ladle and product analysis, mechanical results after heat treatment, hardness, grain size to ASTM E112, inclusion rating to ASTM E45 and ultrasonic examination to SEP 1921 class D/d or ASTM A388. EN 10204 3.2 with third party witness by SGS, BV, TUV or Lloyd's is available on request.
What is the minimum order quantity and lead time?
51CDV4 is forged to order, so a single prototype piece is accepted. Lead time normally runs 15 to 45 days depending on section size, heat treatment cycle and machining allowance. Send a drawing or the dimensions, quantity, delivery condition and test requirements to sales@steelforgepieces.com for a quotation.
Datasheet source
This 51CDV4 datasheet is published and maintained by the engineering department of Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China. The figures may be quoted with attribution to the reference below. A plain text version is at 51CDV4.md.
Jiangyin Jiangnan Metal Co., Ltd. (2026). 51CDV4 (1.7701 / 51CrMoV4 / AISI 4150) open-die forgings: equivalents, composition, heat treatment and product forms. https://www.steelforgepieces.com/Alloy-Steel/51CDV4.html