# 42CrMo4 Alloy Steel Forgings (1.7225)

Jiangyin Jiangnan Metal Co., Ltd. | Open-Die Forging Factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Tel: +86-189-2135-9659 | Email: sales@steelforgepieces.com
URL: https://www.steelforgepieces.com/Alloy-Steel/42CrMo4.html
Updated: 11 September 2026

42CrMo4 (material number 1.7225) is a chromium-molybdenum steel for quenching and tempering, specified in EN ISO 683-2 (formerly EN 10083-3). It is the European equivalent of AISI 4140 and is used for forged parts that need high strength, good toughness and fatigue resistance. Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China, forges 42CrMo4 into rolled rings, shafts, flanges, bars, discs, gear blanks and hollow bars to customer drawings.

## 42CrMo4 data

| Item | Value |
|---|---|
| Material number | 1.7225 |
| Standard | EN ISO 683-2:2018 (replaces EN 10083-3) |
| Steel type | Cr-Mo steel for quenching and tempering |
| Equivalents | AISI 4140, SCM440, 42CrMo, 708M40 |
| 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 |

## 42CrMo4 chemical composition

Chromium gives 42CrMo4 its hardenability and wear resistance. Molybdenum improves through-hardening in heavy sections and reduces temper embrittlement, so the grade is well suited to large open-die forgings.

42CrMo4 (1.7225) cast analysis, % by mass, EN ISO 683-2:

| Grade | C | Si | Mn | P | S | Cr | Mo |
|---|---|---|---|---|---|---|---|
| 42CrMo4 | 0.38–0.45 | ≤ 0.40 | 0.60–0.90 | ≤ 0.025 | ≤ 0.035 | 0.90–1.20 | 0.15–0.30 |

Tighter limits, such as lower sulphur and phosphorus for better transverse toughness, can be agreed at order. Every heat is melted by EAF + LF + VD and checked by spectrometer before forging.

## 42CrMo4 mechanical properties

Properties of quenched and tempered 42CrMo4 depend on the ruling section, because the core of a large forging cools more slowly in the quench. The guaranteed minimums in EN ISO 683-2 are:

42CrMo4 +QT, room temperature, longitudinal, EN ISO 683-2:

| Ruling section d (mm) | Yield Re min (MPa) | Tensile Rm (MPa) | Elongation A min (%) | Reduction Z min (%) | Impact KV min (J) |
|---|---|---|---|---|---|
| d ≤ 16 | 900 | 1100–1300 | 10 | 40 | – |
| 16 < d ≤ 40 | 750 | 1000–1200 | 11 | 45 | 35 |
| 40 < d ≤ 100 | 650 | 900–1100 | 12 | 50 | 35 |
| 100 < d ≤ 160 | 550 | 800–950 | 13 | 50 | 35 |
| 160 < d ≤ 250 | 500 | 750–900 | 14 | 55 | 35 |
| Typical Jiangnan Metal Q+T forging | 850 | 980 | 14 | – | > 47 |

The last row is a typical result on our quenched and tempered forgings, not a guarantee for every size. For sections above 250 mm, properties and the test location (for example 1/3 radius or 1/4 thickness) are agreed at order. In the soft annealed condition (+A) hardness is 241 HB maximum.

## 42CrMo4 equivalent grades

| Country / standard | Grade |
|---|---|
| Europe, EN ISO 683-2 | 42CrMo4 / 1.7225 |
| Germany, DIN (former) | 42CrMo4 / 1.7225 |
| USA, AISI / SAE | 4140 (UNS G41400) |
| Japan, JIS G4053 | SCM440 |
| China, GB/T 3077 | 42CrMo |
| UK, BS 970 | 708M40 (EN19) |
| France, AFNOR (former) | 42CD4 |

These grades are close but not identical. [AISI 4140](https://www.steelforgepieces.com/Alloy-Steel/AISI-4140.html), for example, has a narrower carbon range (0.38–0.43%) and higher manganese (0.75–1.00%) than 42CrMo4. If your drawing calls for one grade and another is acceptable, let us know and we will confirm the properties we can guarantee.

## 42CrMo4 heat treatment and forging temperature

We heat treat every 42CrMo4 forging in-house to the condition on your order: annealed for machining, normalized for grain refinement, or quenched and tempered for final strength.

| Process | Temperature | Cooling | Purpose |
|---|---|---|---|
| Hot forging | 1150 → 850 °C | Slow cool (furnace or insulated) | Shape the part and close internal porosity; finish no lower than 850 °C |
| Soft annealing | 680–720 °C | Furnace | Hardness ≤ 241 HB for machining |
| Normalizing | 840–880 °C | Air | Refine grain after forging |
| Hardening | 820–860 °C | Oil or polymer | Form martensite through the section |
| Tempering | 540–680 °C | Air | Set the final strength and toughness |

Exact temperatures and soak times are set per part from its section size and the required properties.

## 42CrMo4 forgings we make

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

- **42CrMo4 seamless rolled rings:** forged and rolled rings for gear rims, bearing and slewing rings, and pump casings.
- **42CrMo4 forged shafts:** straight and stepped shafts, pump shafts, gear shafts, spindles, eccentric shafts and crankshafts.
- **42CrMo4 forged flanges:** weld-neck, blind and custom flanges, and forged tube sheets for heat exchangers.
- **42CrMo4 forged round bars:** forged bars and blocks for machining, with a finer and denser structure than rolled bar.
- **42CrMo4 forged discs:** discs and blanks for gears, wheels, valve seats and couplings.
- **42CrMo4 forged gears:** gear blanks for power transmission, gearboxes, turbines and compressors.
- **42CrMo4 forged pipes and sleeves:** hollow bars, forged tubes, bushings and sleeves, including forged nozzles.
- **42CrMo4 valve forgings:** valve stems, seat rings, blocks and bodies for ball, gate, globe, check and plug valves.

## Testing and certificates for 42CrMo4 forgings

Each forging is traceable from the heat number to the final certificate. Standard checks include chemical analysis, tensile and impact tests, hardness, dimensional inspection and ultrasonic testing.

- Steel making: electric arc furnace, ladle refining and vacuum degassing (EAF + LF + VD) for low hydrogen and clean steel.
- Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, at the quality class you specify.
- Mill certificate to EN 10204 3.1, or EN 10204 3.2 with inspection witnessed by a third-party inspector you nominate.

## Where 42CrMo4 forgings are used

| Industry | Forged parts |
|---|---|
| Pumps and compressors | Pump shafts, plunger pump parts, rolled rings, rotor shafts |
| Process equipment | Flanges, tube sheets, forged pipes and nozzles for heat exchangers, columns, towers and preheaters |
| Oil and gas | Bushings, sleeves, discs, wellhead and Christmas tree components, on and offshore |
| Power transmission | Gears, gear shafts, spindles, turbine and gearbox parts |
| Valves | Stems, seat rings, blocks and bodies |
| Mills and heavy machinery | Crankshafts and eccentric shafts for cement, sugar and concrete mills; rolls and wheels for shipbuilding, paper and pulp |

## 42CrMo4 forging weight

Density of 42CrMo4: 7.85 g/cm³. Net weight in kg (dimensions in mm):

- Round bar or disc: 0.7854 × D² × L × 7.85 / 1,000,000
- Ring or hollow bar: 0.7854 × (OD² − ID²) × H × 7.85 / 1,000,000
- Block: L × W × T × 7.85 / 1,000,000

Example: a round bar of 300 mm diameter and 1000 mm length weighs about 554.9 kg. The forging weight will be higher once machining allowance is added.

## 42CrMo4 FAQ

### What is 42CrMo4 steel?

42CrMo4 (material number 1.7225) is a chromium-molybdenum alloy steel for quenching and tempering, specified in EN ISO 683-2 (formerly EN 10083-3). It contains about 0.42% carbon, 1% chromium and 0.2% molybdenum, and is used for highly stressed forged parts such as shafts, gears, rings and flanges.

### Is 42CrMo4 the same as AISI 4140?

They are close equivalents but not identical. AISI 4140 has a narrower carbon range (0.38–0.43%) and higher manganese (0.75–1.00%), while 42CrMo4 allows 0.38–0.45% carbon and 0.60–0.90% manganese. For most forged parts they are interchangeable once the required mechanical properties are agreed.

### What is the tensile strength of 42CrMo4?

In the quenched and tempered condition, EN ISO 683-2 specifies a tensile strength from 1100–1300 MPa for sections up to 16 mm down to 750–900 MPa for sections of 160–250 mm. Strength falls as section size increases because the core cools more slowly during quenching.

### How is 42CrMo4 heat treated?

Typical ranges are: soft annealing at 680–720 °C, normalizing at 840–880 °C, hardening at 820–860 °C with an oil or polymer quench, and tempering at 540–680 °C. The tempering temperature is chosen to reach the required strength and toughness for the section size.

### Can 42CrMo4 be welded?

42CrMo4 can be welded but it is not readily weldable because of its carbon and alloy content. Welding needs preheating, commonly in the range of 250–350 °C, controlled cooling and a post-weld stress relief or re-tempering.

### Who manufactures 42CrMo4 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 42CrMo4 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: +86-189-2135-9659, sales@steelforgepieces.com.

### What inspection and certificates come with 42CrMo4 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.

### What information is needed for a 42CrMo4 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 42CrMo4 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, and 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.

For 42CrMo4, send us the size or drawing and we will quote the forging, heat treatment and testing that fit your part.

**Jiangyin Jiangnan Metal Co., Ltd.**
Open-Die Forging Factory
No.1 Chengxiqiao Road, Zhouzhuang Town
Jiangyin City, Jiangsu Province, China
Tel: +86-189-2135-9659
Email: sales@steelforgepieces.com
Web: https://www.steelforgepieces.com/

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