What is 50CrMo4 steel?
50CrMo4, material number 1.7228, is the 0.5 % carbon member of the EN 10083-3 chromium-molybdenum family: C 0.46–0.54 %, Cr 0.90–1.20 %, Mo 0.15–0.30 %, supplied quenched and tempered. Specify it over 42CrMo4 when the part needs more hardness, more wear resistance, or has to hold its yield strength through a heavy section. Jiangyin Jiangnan Metal Co., Ltd. open-die forges it in Jiangyin, China.
The grade sits at the top of the EN 10083-3 through-hardening family. Below it, 42CrMo4 and 34CrMo4 carry the same chromium and molybdenum but less carbon. The extra carbon in 50CrMo4 raises the hardness reachable after quenching. More usefully for forgings, it holds the yield strength up as the cross-section grows. That is why the grade turns up in crankshafts, ring gears, thrust rollers and heavy axles rather than in welded fabrications.
Molybdenum does two jobs here. It improves hardenability so that a thick forging transforms consistently from surface to core, and it suppresses temper embrittlement during the slow cooling a large section is forced to undergo after tempering.
Chemical composition of 50CrMo4
Heat analysis limits for 50CrMo4 to EN 10083-3, in mass %: C 0.46–0.54, Si max 0.40, Mn 0.50–0.80, P max 0.025, S max 0.035, Cr 0.90–1.20, Mo 0.15–0.30. Iron makes up the balance.
| Element | C | Si | Mn | P | S | Cr | Mo |
|---|---|---|---|---|---|---|---|
| Mass % | 0.46–0.54 | max 0.40 | 0.50–0.80 | max 0.025 | max 0.035 | 0.90–1.20 | 0.15–0.30 |
Source: EN 10083-3:2006, Steels for quenching and tempering, Part 3: Technical delivery conditions for alloy steels. Product analysis is permitted to deviate from heat analysis within the tolerances given in the standard.
Ordering note. The 0.035 % sulphur figure is a ceiling, not a machinability aid. If the part will be machined on an automatic lathe, ask about the resulphurised variant of the CrMo family instead. For sour-service or low-temperature work, state the restricted P and S limits you need at enquiry stage so the heat can be melted to order.
Mechanical properties of 50CrMo4 (+QT)
Section size decides everything here. At 16 mm and under, +QT material runs 1100–1300 MPa tensile with 900 MPa minimum proof strength. By 160–250 mm the same heat treatment gives 750–950 MPa tensile and 550 MPa proof. The quench cannot cool the core of a heavy forging as fast as the surface, and the numbers follow.
| Nominal diameter (mm) | ≤ 16 | >16–40 | >40–100 | >100–160 | >160–250 | >250–330 | >330–500 |
|---|---|---|---|---|---|---|---|
| Rm, tensile strength (MPa) | 1100–1300 | 1000–1200 | 900–1100 | 850–1000 | 750–950 | 750 min | 700 min |
| Nominal diameter (mm) | ≤ 16 | >16–40 | >40–100 | >100–160 | >160–250 |
|---|---|---|---|---|---|
| Re or Rp0.2 (MPa) min | 900 | 780 | 700 | 650 | 550 |
For flat products the thickness bands are ≤8, >8–20, >20–60, >60–100 and >100–160 mm respectively.
| Nominal thickness (mm) | ≤ 160 | >160–330 | >330–500 |
|---|---|---|---|
| Re (MPa) min | 550 | 540 | 490 |
| Nominal diameter (mm) | ≤ 16 | >16–40 | >40–100 | >100–160 | >160–250 |
|---|---|---|---|---|---|
| A, elongation, Lo = 5.65 √So (%) min, round products | 9 | 10 | 12 | 13 | 13 |
| Z, reduction of area at fracture (%) min | 40 | 45 | 50 | 50 | 50 |
| A, elongation, transverse (%) min | 9–11 depending on section | ||||
Source: EN 10083-3:2006. Values apply to test pieces taken from the position and direction defined in the standard. Confirm against the current edition and against your own drawing before ordering.
What the symbols mean
| Symbol | Meaning | Unit |
|---|---|---|
| Rm | Tensile strength, the maximum stress the test piece carries before fracture | MPa |
| Re | Upper yield strength, where the steel shows a distinct yield point | MPa |
| Rp0.2 | 0.2 % proof strength, the stress at 0.2 % permanent strain, used where there is no distinct yield point | MPa |
| A | Elongation at fracture over gauge length Lo = 5.65 √So | % |
| Z | Reduction of area at fracture, the best single indicator of through-thickness ductility in a forging | % |
| +QT | Delivery condition: quenched and tempered | |
| +N | Delivery condition: normalised | |
| +A | Delivery condition: soft annealed |
50CrMo4 equivalent grades
The nearest designations are 1.7228 (Werkstoff), 4150 and UNS G41500 (USA), 50CrMo to GB/T 3077 (China), 48CD4 (France) and SCM445 (Japan). None of them is a drop-in substitute. Carbon, manganese, phosphorus and sulphur bands shift from standard to standard, so the ordering standard decides what you actually get.
| Region / standard | Designation | Closeness |
|---|---|---|
| Europe, EN 10083-3 | 50CrMo4 | Reference grade |
| Europe, Werkstoff-Nr. | 1.7228 | Identical |
| International, ISO 683-2 / 683-18 | 50CrMo4 | Identical |
| Germany, DIN 17200 (superseded) | 50CrMo4 | Identical |
| USA, SAE / AISI | 4150 | Close |
| USA, UNS | G41500 | Close |
| USA, ASTM A29 / A322 / A331 | 4150 | Close |
| China, GB/T 3077 | 50CrMo | Close |
| France, AFNOR NF A35-552 | 48CD4 / 50CD4 | Close |
| Japan, JIS G4105 | SCM445 | Nearest |
| Italy, UNI | 50CrMo4 | Close |
| UK, BS 970 | 823M30 | Nearest |
| Russia, GOST 4543 | 50KhGM / 50HMA | Nearest |
| Sweden, SS | 2512 | Nearest |
Read this before substituting. "Close" means the chromium and molybdenum ranges overlap and the carbon band is within about 0.02 %. "Nearest" means the grade is used for the same duty but at least one element differs enough to change heat-treatment response. Treat a cross-reference table as a starting point for an enquiry. The ordering standard, the drawing and the mill certificate govern. If your drawing calls AISI 4150 and you need EN certification, say so at enquiry and the heat can be melted to satisfy both.
50CrMo4 vs 42CrMo4: which should you specify?
Carbon, and nothing else. 50CrMo4 runs 0.46–0.54 % against 0.38–0.45 % for 42CrMo4, and the chromium and molybdenum ranges are identical. You gain hardness, wear resistance and about 50 MPa of proof strength in the 40–100 mm band. You lose toughness and most of what little weldability 42CrMo4 had.
| Property | 50CrMo4 (1.7228) | 42CrMo4 (1.7225) |
|---|---|---|
| Carbon, mass % | 0.46–0.54 | 0.38–0.45 |
| Chromium, mass % | 0.90–1.20 | 0.90–1.20 |
| Molybdenum, mass % | 0.15–0.30 | 0.15–0.30 |
| Manganese, mass % | 0.50–0.80 | 0.60–0.90 |
| Rp0.2 min at 40–100 mm, +QT | 700 MPa | 650 MPa |
| Attainable as-quenched hardness | Higher | Lower |
| Wear resistance | Better | Adequate |
| Impact toughness | Lower | Better |
| Weldability | Difficult, preheat and PWHT essential | Difficult but more forgiving |
| Induction or flame hardening | Well suited | Suited |
| Availability | Specialist | Commodity |
| Typical use | Crankshafts, ring gears, thrust rollers, wear parts | General shafts, flanges, couplings, fasteners |
Full data for the lower-carbon grade is on the 42CrMo4 datasheet and its American counterpart AISI 4140.
How is 50CrMo4 heat treated?
Austenitise at 830–860 °C, quench in oil, temper at 540–680 °C. The tempering temperature is the one variable that sets the final strength band. For machining, soft anneal at 680–720 °C with a slow furnace cool, which brings hardness down to roughly 248 HB.
| Operation | Temperature | Cooling | Result |
|---|---|---|---|
| Forging | 1150 to 850 °C | Slow, in sand or furnace | Shape, avoids quench cracks |
| Normalising (+N) | 840–880 °C | Still air | Refines forged grain structure |
| Soft annealing (+A) | 680–720 °C | Slow, in furnace | Max about 248 HB, machinable |
| Hardening | 830–860 °C | Oil quench | Martensitic structure |
| Tempering | 540–680 °C | Air | Sets the final strength band |
| Stress relieving | 600–650 °C | Slow | Removes machining stress |
Austenitising, tempering and annealing ranges are those given in EN 10083-3. Forging temperatures and cooling practice are typical works practice at Jiangyin Jiangnan Metal and are adjusted to section size and geometry.
Three things that go wrong with this grade
- Cooling too fast after forging. At 0.5 % carbon with 1 % chromium, air cooling a heavy forged section can produce enough martensite to crack it before it ever reaches the furnace. Sand or furnace cooling is not optional on thick work.
- Tempering below the range to chase hardness. Tempering between roughly 250 and 400 °C puts the steel into tempered martensite embrittlement. If the drawing demands hardness that only that range delivers, the grade selection is wrong, not the heat treatment.
- Stress relieving above the tempering temperature. Keep stress relief at least 30 °C below the temper. Otherwise the mechanical properties on the certificate no longer describe the part in your hand.
50CrMo4 forged products and size range
Bars in round, square, flat and hex section. Hollow bars, sleeves and bushes. Seamless rolled rings. Discs, blocks and plates. Gear shafts, pinion shafts and ring gear blanks. The works takes single pieces to about 20 tonnes, rolled rings to 4000 mm outside diameter and shafts to 8000 mm long.
| Product form | Size range | Typical use |
|---|---|---|
| Round bars and rods | Ø 80–1200 mm, length to 8000 mm | Shafts, spindles, pins |
| Square, rectangular, flat and hex bars | 100–1000 mm across flats | Machined blocks, tool holders |
| Hollow bars, sleeves, bushes, cylinders | OD 200–2000 mm, ID from 80 mm | Bushings, housings, casings |
| Seamless rolled rings | OD 300–4000 mm, height to 1000 mm | Ring gears, bearing rings, flanges |
| Forged rings (mandrel forged) | OD 200–2500 mm | Small-batch rings, retaining rings |
| Discs, blocks and plates | Ø or width to 1500 mm, thickness to 600 mm | Gear blanks, die blocks, tube sheets |
| Gear shafts, pinion shafts, spindles | Ø 100–1000 mm, length to 8000 mm | Gearboxes, mill drives, crushers |
| Ring gears and gear wheel blanks | OD to 4000 mm | Slew drives, kiln and mill girth gears |
Figures show the works envelope. Confirm against your drawing at enquiry stage. Non-standard geometries are quoted from a dimensioned drawing or a 3D model.
Testing and certification
- EN 10204 3.1 mill test certificate with every consignment, covering heat number, ladle analysis, heat-treatment record and mechanical test results.
- Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, to the acceptance class you nominate.
- Magnetic particle inspection to EN 10228-1 for surface indications.
- Impact testing (Charpy V-notch) at ambient or a specified sub-zero temperature.
- Hardness survey across the section, plus grain size, inclusion rating or macro-etch on request.
- Third-party inspection by SGS, BV, TÜV, Lloyd's Register or your own inspector, witnessed at the works.
What is 50CrMo4 used for?
Anywhere a part has to resist wear and carry load at the same time. The grade turns up in crankshafts and heavy axles, in ring gears and pinion shafts for mill and kiln drives, in thrust rollers and thrust rings, in guides and bushes, and in high-tensile bolting. Section size is usually what decides it over 42CrMo4.
| Sector | Components | Why this grade |
|---|---|---|
| Gearbox and drive | Pinion shafts, ring gears, gear blanks, couplings | Holds yield strength through thick gear rims |
| Mining and cement | Crusher shafts, mill girth gear segments, thrust rollers | Wear resistance under abrasive load |
| Heavy vehicle and engine | Crankshafts, heavy axles, torsion components | Fatigue strength under bending and torsion |
| Oil, gas and drilling | Drill collars, tool joints, mandrels, stabiliser bodies | Deep hardenability in large diameters |
| Steel and rolling mills | Work roll necks, guides, thrust rings, sleeves | Surface hardness with a tough core |
| General engineering | High-tensile bolting, hydraulic rods, hinge pins | Strength-to-cost in medium sections |
50CrMo4 forgings supplier
Jiangyin Jiangnan Metal Co., Ltd. forges 50CrMo4 to drawing at its works in Zhouzhuang Town, Jiangyin, Jiangsu, and ships worldwide from Shanghai or Ningbo. Bars, hollow bars, rolled rings, discs, blocks and gear shafts, supplied +QT with a 3.1 certificate. Send a drawing to sales@steelforgepieces.com or call +86 189 2135 9659.
Jiangyin Jiangnan Metal Co., Ltd.
- Works No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, 214423, China
- Phone +86 189 2135 9659 (0086-189-2135-9659)
- Email sales@steelforgepieces.com
- Website www.steelforgepieces.com
- Process Open-die forging, seamless ring rolling, heat treatment, rough and finish machining
- Ships to Worldwide, ex-works Shanghai or Ningbo
To get a quotation in one email, send:
- Grade and standard, for example 50CrMo4 to EN 10083-3, +QT
- Drawing or dimensions, with forged or finish-machined stated
- Quantity and required delivery date
- Testing and certification required (3.1, UT class, impact temperature)
- Destination port
Frequently asked questions about 50CrMo4
What is 50CrMo4 steel?
50CrMo4 is a chromium-molybdenum alloy structural steel to EN 10083-3, material number 1.7228. It contains 0.46-0.54% carbon, 0.90-1.20% chromium and 0.15-0.30% molybdenum, and is normally supplied quenched and tempered (+QT). It is the higher-carbon version of 42CrMo4 and is chosen when higher hardness, higher yield strength in heavy sections and better wear resistance are needed.
What is 50CrMo4 equivalent to?
50CrMo4 corresponds to material number 1.7228 in the European system, AISI/SAE 4150 and UNS G41500 in the United States, 50CrMo to GB/T 3077 in China, 48CD4 or 50CD4 to AFNOR in France, and SCM445 to JIS in Japan as the nearest grade. Equivalence is approximate: the permitted ranges for carbon, manganese, phosphorus and sulphur differ between standards, so the ordering standard and the mill certificate always govern.
What is the difference between 50CrMo4 and 42CrMo4?
The difference is carbon content. 50CrMo4 carries 0.46-0.54% carbon against 0.38-0.45% for 42CrMo4, with the same chromium and molybdenum ranges. The extra carbon gives 50CrMo4 higher attainable hardness, higher yield strength in sections above about 40 mm and better wear resistance, at the cost of weldability and impact toughness. 42CrMo4 remains the general-purpose choice. Specify 50CrMo4 when the part is wear-critical or must hold yield strength in a heavy cross-section.
What is the tensile strength of 50CrMo4?
In the quenched and tempered (+QT) condition to EN 10083-3, the tensile strength of 50CrMo4 is 1100-1300 MPa up to 16 mm nominal diameter, 1000-1200 MPa from 16 to 40 mm, 900-1100 MPa from 40 to 100 mm, 850-1000 MPa from 100 to 160 mm and 750-950 MPa from 160 to 250 mm. Above 250 mm the tabulated minima are 750 MPa to 330 mm and 700 MPa to 500 mm.
Can 50CrMo4 be welded?
50CrMo4 is weldable with conventional processes but it is not a freely weldable grade. With a carbon equivalent typically around 0.85, it requires preheat, controlled interpass temperature, low-hydrogen consumables and post-weld heat treatment. Welding in the hardened condition will alter the mechanical properties. Where a welded joint is unavoidable, 42CrMo4 or 34CrMo4 is usually the better specification.
What is 50CrMo4 used for?
50CrMo4 is used for crankshafts, heavy-duty axles and shafts, gears, ring gears and pinion shafts, thrust rollers and thrust rings, guides, bushes and sleeves, high-tensile bolting, mining and crushing equipment components, and drilling tool components. Typical sectors are gearbox and drive manufacture, mining, cement, oil and gas, and heavy vehicle production.
Who supplies 50CrMo4 open-die forgings?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing 50CrMo4 / 1.7228 / AISI 4150 forged bars, hollow bars and sleeves, seamless rolled rings, discs and blocks, and gear and pinion shafts. Enquiries: sales@steelforgepieces.com, +86-189-2135-9659.
What heat treatment condition are 50CrMo4 forgings supplied in?
50CrMo4 forgings are normally supplied +QT, quenched and tempered. Austenitising is at 830-860 °C with an oil quench, followed by tempering at 540-680 °C selected to reach the required strength band. Forgings can also be supplied normalised at 840-880 °C, soft annealed at 680-720 °C for machining, or as-forged where the customer heat treats in house.
What certification is supplied with 50CrMo4 forgings?
Every 50CrMo4 forging is supplied with an EN 10204 3.1 mill test certificate covering heat number, ladle analysis, heat-treatment record and mechanical test results. Ultrasonic testing to EN 10228-3 or SEP 1921, magnetic particle inspection, hardness survey, impact testing at specified temperatures and third-party inspection by SGS, BV, TÜV or Lloyd's can be added on request.
What sizes can 50CrMo4 be forged to?
At Jiangyin Jiangnan Metal, 50CrMo4 is open-die forged as round bars from 80 to 1200 mm diameter, seamless rolled rings from 300 to 4000 mm outside diameter, discs and blocks up to 1500 mm, and shafts up to 8000 mm long, with single-piece weights up to about 20 tonnes. Confirm the exact envelope for your drawing before ordering.
Data source and reuse
The composition and property tables above are taken from EN 10083-3:2006. You are welcome to quote them in specifications, tenders and technical reports. Please credit the source:
Jiangyin Jiangnan Metal Co., Ltd. "50CrMo4 (1.7228) Forgings: EN 10083-3 Datasheet." steelforgepieces.com, last reviewed 12 September 2026. https://www.steelforgepieces.com/Alloy-Steel/50CrMo4.html
For certified values on a specific heat rather than the standard limits, ask for the mill certificate: sales@steelforgepieces.com. A plain-text version of this page is at 50CrMo4.md.