# 42CrMoS4 Forgings (1.7227)

42CrMoS4 alloy steel forgings, material 1.7227 to EN ISO 683-2, the free-machining grade of 42CrMo4.

Source page: https://www.steelforgepieces.com/Alloy-Steel/42CrMoS4.html
Supplier: Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, Jiangyin, Jiangsu, China
Jiangyin Jiangnan Metal Co., Ltd. Engineering Department. Updated 12 September 2026.

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## Summary

42CrMoS4 (material number 1.7227) is a chromium-molybdenum steel for quenching and tempering, specified in EN ISO 683-2 (formerly EN 10083-3). Sulphur is held at 0.020 to 0.040 % so that manganese-sulphide inclusions form and break the chip during machining, which is the one thing that separates it from 42CrMo4. Tensile strength in the quenched and tempered condition runs from 750 to 1300 MPa according to ruling section.

Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China, forges 42CrMoS4 into rolled rings, shafts, flanges, bars, discs, gear blanks and hollow bars to customer drawings, with ultrasonic testing and EN 10204 3.1 or 3.2 certificates.

## Designations

| System | Designation |
|---|---|
| EN ISO 683-2 | 42CrMoS4 |
| Material number | 1.7227 |
| SAE/AISI (USA) | 4140 / 4142 |
| JIS (Japan) | SCM440 |
| GB/T 3077 (China) | 42CrMo |
| NF (France) | 42CD4TS |
| BS 970 (UK) | 708M40 |

## 42CrMoS4 data

| Item | Value |
|---|---|
| Grade designation | 42CrMoS4 |
| Material number | 1.7227 |
| Standard | EN ISO 683-2:2018, which replaced EN 10083-3:2006 |
| Steel type | Cr-Mo steel for quenching and tempering, resulphurised for machinability |
| Sister grade | 42CrMo4 (1.7225), the same alloy with sulphur kept low |
| Equivalents | AISI 4140 and 4142, SCM440, 42CrMo, 42CD4TS, 708M40 |
| Tensile strength Rm | 750 to 1300 MPa (109 to 189 ksi), section dependent |
| Yield strength Re | 500 to 900 MPa minimum (73 to 131 ksi), section dependent |
| Annealed hardness | 241 HB maximum in the +A condition |
| Density | 7.85 g/cm3 (0.284 lb/in3) |
| Machinability | Better than 42CrMo4, because MnS inclusions give chip control |
| Weldability | Limited. Preheat and post-weld heat treatment needed, poorer than 42CrMo4 |
| Melting route | EAF + LF + VD, vacuum degassed |
| Delivery condition | Annealed, normalized or quenched and tempered |
| UT standards | EN 10228-3, SEP 1921, ASTM A388 |
| Certificate | EN 10204 3.1, or 3.2 with third-party inspection |

## Chemical composition

Chromium gives the grade its hardenability, and molybdenum improves through-hardening in heavy sections while reducing temper embrittlement. The only difference from 42CrMo4 sits in the sulphur window. 42CrMoS4 carries a controlled minimum of 0.020 %, where 42CrMo4 has a maximum and nothing else.

42CrMoS4 (1.7227) cast analysis, % by mass, EN ISO 683-2:

| Basis | C | Si | Mn | P | S | Cr | Mo | Fe |
|---|---|---|---|---|---|---|---|---|
| Cast analysis | 0.38-0.45 | max 0.40 | 0.60-0.90 | max 0.025 | 0.020-0.040 | 0.90-1.20 | 0.15-0.30 | Balance |
| Permissible deviation on product analysis | +/- 0.02 | + 0.03 | +/- 0.04 | + 0.005 | +/- 0.005 | +/- 0.05 | +/- 0.03 | n/a |

Every heat is melted by electric arc furnace, ladle refining and vacuum degassing (EAF + LF + VD), then checked by spectrometer before forging. Tighter limits on phosphorus or residuals can be agreed at order.

## Mechanical properties

Properties of quenched and tempered 42CrMoS4 depend on the ruling section, because the core of a large forging cools more slowly in the quench. Below, d is the diameter of a round bar and t is the thickness of a flat, in mm.

42CrMoS4 +QT, room temperature, longitudinal, EN ISO 683-2:

| Ruling section | Yield Re min (MPa) | Tensile Rm (MPa) | Elongation A min (%) | Reduction Z min (%) | Impact KV min (J) |
|---|---|---|---|---|---|
| d <= 16, t <= 8 | 900 | 1100-1300 | 10 | 40 | By agreement |
| 16 < d <= 40, 8 < t <= 20 | 750 | 1000-1200 | 11 | 45 | By agreement |
| 40 < d <= 100, 20 < t <= 60 | 650 | 900-1100 | 12 | 50 | By agreement |
| 100 < d <= 160, 60 < t <= 100 | 550 | 800-950 | 13 | 50 | By agreement |
| 160 < d <= 250, 100 < t <= 160 | 500 | 750-900 | 14 | 55 | By agreement |

On impact energy: EN ISO 683-2 specifies KV of 35 J for the non-resulphurised grade 42CrMo4 from 16 mm upward. In 42CrMoS4 the manganese-sulphide stringers cut toughness across the grain, so impact requirements, and transverse KV in particular, are agreed at order.

For sections above 250 mm, properties and the test location, for example 1/3 radius or 1/4 thickness, are agreed at order and verified on a prolongation or a sacrificial test block taken from the forging. In the soft annealed condition (+A) hardness is 241 HB maximum.

## Delivery conditions

| Symbol | Condition | Typical hardness | Why it is ordered |
|---|---|---|---|
| +A | Soft annealed | 241 HB maximum | Best condition for heavy machining ahead of final heat treatment |
| +N | Normalized | Typically 190 to 240 HB | Refines forging grain, evens out the structure, helps machinability |
| +QT | Quenched and tempered | Commonly 28 to 34 HRC | Final strength and toughness for loaded parts |
| +H, +HH, +HL | Specified hardenability band | Jominy end-quench limits | Ordered when hardness depth through the section must be guaranteed |

The suffix +QT is sometimes written 42CrMoS4V, from the German vergutet. Both mean the same thing.

## Heat treatment and forging temperature

1. **Heating for forging, 1150 to 1200 C (2100 to 2190 F).** Soak until the section is through-heated. Ingot or billet is charged below 400 C and ramped to avoid thermal cracking.
2. **Open-die forging, finish above 850 C (1560 F).** Upsetting and drawing with a forging ratio of at least 3:1, which closes porosity and develops grain flow along the axis of the part. Forging below 850 C work-hardens the steel and leads to cracking.
3. **Slow cooling after forging.** Furnace or insulated cooling. At 0.42 % carbon and 1 % chromium, still-air cooling of a heavy section can form untempered martensite and quench cracks.
4. **Normalizing, 840 to 880 C (1545 to 1615 F), air cool.** Refines the coarse as-forged grain and gives a uniform structure before hardening.
5. **Soft annealing, 680 to 720 C (1255 to 1330 F), furnace cool.** Ordered when the part gets heavily machined before hardening. Hardness afterwards is 241 HB or below.
6. **Hardening, 820 to 880 C (1510 to 1615 F), quench.** Oil or polymer for complex geometry and crack-sensitive parts, water for large sections where oil does not give enough quench severity.
7. **Tempering, 540 to 680 C (1005 to 1255 F), air cool.** Higher tempering buys ductility and gives up strength. Tempering between roughly 250 and 450 C is avoided in this grade because of tempered-martensite embrittlement.
8. **Stress relieving, 550 to 650 C (1020 to 1200 F).** Applied after rough machining or welding, always below the final tempering temperature.

## 42CrMoS4 vs 42CrMo4

The two grades share the same carbon, chromium and molybdenum, and the same strength classes. What separates them is machinability set against transverse toughness.

| Property | 42CrMoS4 (1.7227) | 42CrMo4 (1.7225) |
|---|---|---|
| Sulphur | 0.020 to 0.040 %, added on purpose | 0.035 % maximum, kept as low as practical |
| C, Cr, Mo | Identical: 0.38-0.45 C, 0.90-1.20 Cr, 0.15-0.30 Mo | Identical |
| Strength after +QT | Identical, the same classes in EN ISO 683-2 | Identical |
| Machinability | Better. MnS inclusions break chips, tool wear drops, feeds go up | Good, though chips run longer |
| Transverse toughness | Lower and directional, because MnS stringers elongate during forging | Higher and more isotropic |
| Weldability | Limited, poorer than 42CrMo4, since sulphur raises hot-cracking risk | Limited. Preheat 200 to 350 C plus post-weld heat treatment |
| Polishing and plating | Inclusions can open up at the surface | Cleaner surface finish |
| Order it for | High machining content: shafts, spindles, valve stems, bar-turned parts | Safety-critical forgings, tight UT acceptance, parts that will be welded |

If the part carries load mainly along its axis and has a lot of machining in it, 42CrMoS4 saves time in the machine shop. For transverse load, welded joints or tight ultrasonic acceptance, specify 42CrMo4 instead.

## Equivalent grades

The grades below are close but not identical. Manganese, sulphur and permitted residuals differ from one system to the next.

| Country or standard | Grade | Note |
|---|---|---|
| Europe, EN ISO 683-2 | 42CrMoS4 / 1.7227 | The governing specification |
| Europe, EN 10083-3 (withdrawn) | 42CrMoS4 / 1.7227 | Superseded in 2018, still quoted on older drawings |
| Europe, bright bar, EN 10277 | 42CrMoS4 | Cold drawn, peeled or ground |
| Europe, sister grade | 42CrMo4 / 1.7225 | Low-sulphur version |
| USA, AISI / SAE | 4140, also 4142 (UNS G41400) | Higher manganese at 0.75 to 1.00 |
| Japan, JIS G4053 | SCM440 | Widely interchanged |
| China, GB/T 3077 | 42CrMo | Slightly higher C and Cr limits |
| France, AFNOR (former) | 42CD4TS | TS denotes the resulphurised variant |
| UK, BS 970 | 708M40 (EN19) | Nearest |
| Russia, GOST 4543 | 38KhM | Approximate only |

Confirm any substitution against the governing standard and the mill certificate before release. We issue dual certification where the heat analysis genuinely satisfies both specifications.

## 42CrMoS4 forgings we make

- Seamless rolled rings and ring blanks
- Forged shafts, stepped shafts and spindles
- Eccentric shafts and crankshaft blanks
- Forged flanges and tube sheets
- Forged discs, discs with hub, and blanks
- Forged round bars and square bars
- Forged sleeves, bushings and hollow bars
- Forged pipes, tubes and cylinders
- Forged blocks, plates and die blocks
- Gear blanks and pinion blanks
- Valve bodies, stems, seat rings and blocks
- Forging rolls, wheels and nozzles

All parts are open-die forged or ring rolled to your drawing, then supplied as forged, rough machined or finish machined, as agreed.

## Manufacturing route

Jiangyin Jiangnan Metal is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, on the Yangtze River between Shanghai and Nanjing.

| Item | Scope |
|---|---|
| Melting route | EAF + LF + VD, with ESR on request |
| Forming | Open-die forging on hydraulic press, radial ring rolling, upsetting and drawing |
| Heat treatment | Annealing, normalizing, quenching in oil, polymer and water, tempering and stress relief, all in house |
| Machining | As forged, rough machined to drawing, or finish machined |
| Non-destructive testing | Ultrasonic, magnetic particle and dye penetrant |
| Certification | EN 10204 3.1, or 3.2 with third-party witness |
| Quantity | Single prototypes through to repeat production runs |
| Export markets | Europe, North America, Middle East, Southeast Asia, India, Australia |

## Testing and certificates

- Steel making by electric arc furnace, ladle refining and vacuum degassing for low hydrogen and clean steel
- Ultrasonic testing to EN 10228-3, SEP 1921, ASTM A388 or ASME Section V, at the quality class you specify
- Magnetic particle to EN 10228-1 or ASTM A275 for surface indications
- Chemical analysis by spectrometer, reported as cast and product analysis
- Tensile, impact and hardness on prolongations or sacrificial blocks in the delivery condition
- Grain size, macro and micro structure examination on request
- Mill certificate to EN 10204 3.1, or 3.2 witnessed by a third-party inspector you nominate
- Marking and traceability by heat number and piece number, hard stamped or vibro-etched

## Applications

| Industry | Forged parts |
|---|---|
| Power transmission | Gear blanks, pinion shafts, gearbox covers, coupling hubs, turbine and compressor shafts |
| Oil and gas | Wellhead and Christmas tree bodies, subsea connectors, drilling tool joints, manifold blocks |
| Valves | Ball valve bodies and balls, gate and globe valve bodies, stems, seat rings, plug valve parts |
| Pumps and compressors | Pump shafts, plunger pump parts, chemical pump sleeves, compressor rods and crankshafts |
| Process equipment | Forged flanges, tube sheets, nozzles, shell rings and closures for vessels and heat exchangers |
| Mills and heavy machinery | Mill pinions, crusher eccentric shafts, cement and sugar mill parts, mixer shafts |
| Marine and shipbuilding | Propeller shafts, rudder stocks, stern tube parts, deck machinery components |
| Automotive and rail | Axle journals, connecting rods, steering knuckles, forged wheels and hubs |

Because sulphur lowers toughness across the grain, 42CrMoS4 goes into parts where load runs along the forged fibre and there is a lot of metal to remove. For high transverse stress or strict ultrasonic acceptance, engineers normally move to 42CrMo4.

## FAQ

**What is 42CrMoS4 steel?**
42CrMoS4 (material number 1.7227) is a chromium-molybdenum alloy steel for quenching and tempering, specified in EN ISO 683-2 (formerly EN 10083-3). It holds about 0.42 % carbon, 1 % chromium and 0.2 % molybdenum, with sulphur controlled to 0.020 to 0.040 % so the steel machines more freely than 42CrMo4.

**What is the difference between 42CrMoS4 and 42CrMo4?**
Only the sulphur. 42CrMoS4 (1.7227) has a sulphur range of 0.020 to 0.040 %. 42CrMo4 (1.7225) limits sulphur to 0.035 % maximum and mills keep it far lower than that. Carbon, chromium, molybdenum and the mechanical property classes are the same in both. The sulphur forms manganese-sulphide inclusions that break chips and improve machinability, at the cost of toughness measured across the grain direction.

**Is 42CrMoS4 the same as AISI 4140?**
They are close equivalents but not identical. AISI 4140 has a narrower carbon range and higher manganese at 0.75 to 1.00 %, while 42CrMoS4 allows 0.38 to 0.45 % carbon and 0.60 to 0.90 % manganese, plus the controlled sulphur addition. For most forged parts they are interchangeable once the required mechanical properties are agreed.

**What is the material number for 42CrMoS4?**
1.7227. The related low-sulphur grade 42CrMo4 is 1.7225.

**What is the tensile strength of 42CrMoS4?**
In the quenched and tempered condition, EN ISO 683-2 specifies 1100 to 1300 MPa for sections up to 16 mm, falling to 750 to 900 MPa for sections of 160 to 250 mm. Minimum yield strength over that same range falls from 900 MPa to 500 MPa. Strength falls as section size increases because the core cools more slowly during quenching.

**How is 42CrMoS4 heat treated?**
Typical ranges are soft annealing at 680 to 720 C, normalizing at 840 to 880 C, hardening at 820 to 880 C with an oil, polymer or water quench, and tempering at 540 to 680 C. Hot forging runs from 1150 C down to a finish no lower than 850 C.

**Can 42CrMoS4 be welded?**
Weldability is limited, and poorer than 42CrMo4. The carbon and alloy content give a high carbon equivalent, and the added sulphur raises the risk of hot cracking in the weld metal. Welding needs preheating, commonly 200 to 350 C, low-hydrogen consumables, controlled cooling and a post-weld stress relief or re-tempering. If a part is designed to be welded, specify 42CrMo4 instead.

**What sizes of 42CrMoS4 forgings can you supply?**
Jiangyin Jiangnan Metal forges 42CrMoS4 rings, shafts, discs, flanges, sleeves, blocks and bars to drawing. Send the finished dimensions together with the machining allowance you want, or send the drawing itself, and we confirm feasibility, forged weight and price.

**What inspection and certificates come with 42CrMoS4 forgings?**
Jiangyin Jiangnan Metal supplies chemical analysis, mechanical tests, hardness, dimensional inspection and ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, documented on an EN 10204 3.1 certificate, or a 3.2 certificate witnessed by a third-party inspector.

**Who manufactures 42CrMoS4 forgings in 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 42CrMoS4 into rolled rings, shafts, flanges, bars, discs, gear blanks and hollow bars to customer drawings, with ultrasonic testing and EN 10204 3.1 or 3.2 certificates. Contact: 0086-189-2135-9659, sales@steelforgepieces.com.

**What information is needed for a 42CrMoS4 forging quotation?**
Send a drawing or the finished dimensions, quantity, delivery condition (as forged, annealed, normalized or quenched and tempered), required mechanical properties and test location, the ultrasonic testing standard and class, the certificate type, and the delivery destination.

## How to order 42CrMoS4 forgings

1. **Send your drawing and specification.** Email sales@steelforgepieces.com with dimensions, quantity, delivery condition, required properties, UT standard and certificate type.
2. **Technical proposal and price.** We confirm the forging route, machining allowance, heat treatment and test location, then quote.
3. **Production and inspection.** Melting, forging, heat treatment, testing and, if ordered, third-party witness inspection.
4. **Certificates and shipment.** You receive the EN 10204 certificate and the forgings are packed for export.

## About Jiangyin Jiangnan Metal

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory in Jiangyin, Jiangsu Province, on the Yangtze River between Shanghai and Nanjing. We forge carbon steel, alloy steel, tool steel, stainless steel and nickel alloys into rings, shafts, flanges, bars, discs and custom forgings for customers worldwide.

**Jiangyin Jiangnan Metal Co., Ltd.**
Open-Die Forging Factory
No.1 Chengxiqiao Road, Zhouzhuang Town
Jiangyin City, Jiangsu Province, China
Tel: 0086-189-2135-9659
Email: sales@steelforgepieces.com
Web: https://www.steelforgepieces.com/

## Related grades

- 42CrMo4 forgings: https://www.steelforgepieces.com/Alloy-Steel/42CrMo4.html
- 1.7225 forgings: https://www.steelforgepieces.com/Alloy-Steel/1.7225.html
- AISI 4140 forgings: https://www.steelforgepieces.com/Alloy-Steel/AISI-4140.html
- SCM440 forgings: https://www.steelforgepieces.com/Alloy-Steel/SCM440.html
- All alloy steel grades: https://www.steelforgepieces.com/Alloy-Steel/

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Technical data on this page is taken from EN ISO 683-2 and given for guidance. It does not replace the standard or a mill certificate.