# 1.7220 (34CrMo4) open-die forgings

**Supplier:** Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
**Address:** No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
**Telephone:** +86-189-2135-9659
**Email:** sales@steelforgepieces.com
**Page:** https://www.steelforgepieces.com/Alloy-Steel/1.7220.html
**Updated:** 7 September 2026

1.7220 is the EN material number for 34CrMo4, a chromium-molybdenum steel for quenching and tempering specified in EN 10083-3. Jiangyin Jiangnan Metal Co., Ltd. forges 1.7220 into rings, seamless rolled rings, shafts, flanges, discs, sleeves, blocks and bars at its works in Zhouzhuang Town, Jiangyin, Jiangsu Province, China. Heat treatment, rough machining and ultrasonic testing are done in house, and every piece ships with an EN 10204 3.1 or 3.2 certificate.

## At a glance

| Item | Value |
| --- | --- |
| EN material number | 1.7220 |
| EN steel name | 34CrMo4 (34CrMoS4 = 1.7226) |
| Nearest US grade | AISI / SAE 4135, 4137 |
| Material standard | EN 10083-3, ISO 683-2 |
| Forging standard | EN 10250-3 |
| Melting route | EAF + LF + VD |
| Delivery condition | +A, +N or +QT |
| Forged +QT strength | Rm 650 to 800 MPa min |
| Single-piece weight | 5 kg to 30 t |
| Certification | EN 10204 3.1 / 3.2 |

## What 1.7220 is

1.7220 is the material number given to 34CrMo4 under EN 10027-2. It is an alloy special steel for quenching and tempering, carrying about 0.34% carbon, 1.05% chromium and 0.22% molybdenum.

Chromium raises hardenability and resistance to tempering. Molybdenum holds strength at temperature and suppresses temper embrittlement. Between them they let a 1.7220 forging develop tempered martensite well into the section, so the grade holds up under fatigue loading. That is why it turns up in crankshafts, drive shafts, gear blanks, high-pressure cylinders and pressure-containing rings.

In carbon content, 34CrMo4 sits between 25CrMo4 (1.7218) and 42CrMo4 (1.7225). The lower carbon costs some strength and gains weldability and impact toughness. When a forging has to be welded into an assembly, or has to pass Charpy testing at low temperature, 1.7220 is usually the grade a designer lands on.

The resulphurised version, 34CrMoS4 or material number 1.7226, carries 0.020 to 0.040% sulphur for easier machining. Mechanical minima are the same. Tell us which one the drawing calls for, because the free-machining variant behaves differently under the tool and in transverse impact testing.

## Chemical composition of 1.7220

Heat analysis to EN 10083-3, mass %, with the deviations allowed on product analysis underneath.

| Element | C | Si | Mn | P | S | Cr | Mo | Cu |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Heat analysis, % | 0.30 to 0.37 | 0.10 to 0.40 | 0.60 to 0.90 | max 0.025 | max 0.035 | 0.90 to 1.20 | 0.15 to 0.30 | max 0.40 |
| Deviation allowed on product | ± 0.02 | ± 0.03 | ± 0.04 | + 0.005 | ± 0.005 | ± 0.05 | ± 0.03 | + 0.05 |
| 34CrMoS4 (1.7226) | 0.30 to 0.37 | 0.10 to 0.40 | 0.60 to 0.90 | max 0.025 | 0.020 to 0.040 | 0.90 to 1.20 | 0.15 to 0.30 | max 0.40 |

Steel may be supplied with a lower silicon content, in which case an alternative deoxidation method is used. Tighter internal limits can be agreed at enquiry stage. Sulphur held below 0.010% for sour service or low-temperature toughness is a common one. Whatever is agreed gets reported on the mill certificate.

## Mechanical properties of 1.7220

Which table applies depends on what you are buying. For a forging, the minima come from EN 10250-3. For hot-rolled bar they come from EN 10083-3 and ISO 683-2. Forging minima are lower at the same section size, because properties are guaranteed in the transverse direction as well as the longitudinal.

### Forged, quenched and tempered, EN 10250-3

| Ruling section d / t, mm | Rm, MPa min | Rp0.2, MPa min | A % min (L) | A % min (T) | KV J min (L) | KV J min (T) | HB min |
| --- | --- | --- | --- | --- | --- | --- | --- |
| up to 100 / 70 | 800 | 550 | 14 | 14 | 45 | 45 | 240 |
| over 100 / 70 to 250 / 160 | 700 | 450 | 15 | 10 | 40 | 22 | 213 |
| over 250 / 160 to 500 / 330 | 650 | 410 | 16 | 12 | 33 | 17 | 200 |

d = diameter, t = thickness. L = longitudinal, T = tangential. KV is the average of three Charpy-V specimens.

### Hot-rolled bar, quenched and tempered, ISO 683-2 and EN 10083-3

| Ruling section d / t, mm | Rm, MPa | Rp0.2, MPa min | A % min | Z % min | KV J min | HBW, for information |
| --- | --- | --- | --- | --- | --- | --- |
| up to 16 / 8 | 1000 to 1200 | 800 | 11 | 45 | not specified | 298 to 359 |
| over 16 / 8 to 40 / 20 | 900 to 1100 | 650 | 12 | 50 | 40 | 271 to 331 |
| over 40 / 20 to 100 / 60 | 800 to 950 | 550 | 14 | 55 | 45 | 240 to 286 |
| over 100 / 60 to 160 / 100 | 750 to 900 | 500 | 15 | 55 | 45 | 225 to 271 |
| over 160 / 100 to 250 / 160 | 700 to 850 | 450 | 15 | 60 | 45 | 213 to 253 |

### Hardness control and sour service

Annealed, 1.7220 is supplied at 223 HB maximum. After isothermal annealing it runs 180 to 225 HB. Tempering at 530 °C typically leaves about 280 HB below 200 mm section and 250 HB above 400 mm. At 620 °C those figures drop to roughly 250 HB and 200 HB.

For wet H2S service, NACE MR0175 / ISO 15156 caps carbon and low-alloy steels at 22 HRC. We supply 1.7220 to that limit in the quenched and tempered condition and report the hardness survey on the certificate. Put "sour service" and the applicable annex on the enquiry, so the tempering temperature and the hardness test plan are set from the start.

## Heat treatment of 1.7220

1.7220 forgings are worked hot between roughly 1100 °C and 850 °C, then given a normalising, annealing or quench and temper cycle depending on the condition ordered. All heat treatment runs in our own furnaces on charted, calibrated cycles.

| Operation | Temperature | Cooling and result |
| --- | --- | --- |
| Hot forming, forging | 1100 to 850 °C | Finish forging above 850 °C, then cool in still air or in the furnace |
| Normalising +N | approx. 870 °C | Air cool, refines the as-forged grain |
| Soft annealing +A | approx. 700 °C | Slow cool 10 °C/h to 600 °C then air, 223 HB max |
| Isothermal annealing +I | approx. 830 °C | Furnace cool to 670 °C, then air, 180 to 225 HB |
| Spheroidising +AC | approx. 735 °C | Furnace cooling |
| Hardening +Q | 830 to 870 °C | Quench in oil, polymer or water |
| Tempering +T | 540 to 680 °C | Air cool, sets the final strength and hardness |
| Stress relieving +SR | 50 °C below tempering temperature | 340 HB max |
| Preheat for welding | approx. 250 °C | Required, and keep the interpass temperature up |
| Post-weld stress relief | approx. 550 °C | Furnace cooling |

Transformation points are Ac1 745 °C, Ac3 800 °C, Ms 360 °C and Mf 150 °C. The high Ms is useful in practice. Thick 1.7220 sections take an oil quench without the cracking risk you get with a higher-carbon grade, which is part of why the grade is common in large ring and shaft work.

## Physical properties of 1.7220

| Property | Value at 20 °C |
| --- | --- |
| Density | 7.81 kg/dm3 (7810 kg/m3) |
| Modulus of elasticity | 212 GPa, falling to 207 GPa at 100 °C and 199 GPa at 200 °C |
| Thermal conductivity | 41.8 W/(m·K) |
| Specific heat capacity | 461 J/(kg·K) |
| Coefficient of thermal expansion | approx. 12.1 x 10-6 K-1 over 20 to 200 °C |
| Transformation points | Ac1 745 °C, Ac3 800 °C, Ms 360 °C, Mf 150 °C |

## 1.7220 equivalent grades

The closest international equivalents are listed below. They are near equivalents, not drop-in substitutes. Composition windows, permitted deviations and test requirements differ between standards, so name the ordering standard on the purchase order and on the certificate.

| Region | Standard | Designation |
| --- | --- | --- |
| Europe | EN 10083-3 | 34CrMo4, 34CrMoS4, material no. 1.7220 / 1.7226 |
| Germany | DIN 17200 | 34CrMo4 |
| United States | AISI / SAE | 4135, 4137 |
| Japan | JIS G4053 | SCM435, also SCM432 |
| China | GB/T 3077 | 35CrMo, ML30CrMo for fasteners |
| France | AFNOR NF | 34CD4, 35CD4 |
| United Kingdom | BS 970 | 708A37 |
| Italy | UNI | 34CrMo4 |
| Russia | GOST | 34KhM, 35KhM |
| International | ISO 683-2 | 34CrMo4 |

We forge to whichever standard the drawing calls up. Dual certification to two standards is possible where the composition windows overlap, which comes up often on European designs built for a North American end user.

## 1.7220 vs 42CrMo4 (1.7225)

These two get mixed up more than any other pair in our enquiry inbox. Chromium and molybdenum levels are the same. Almost all of the difference is carbon.

| Property | 1.7220 / 34CrMo4 | 1.7225 / 42CrMo4 |
| --- | --- | --- |
| Carbon, % | 0.30 to 0.37 | 0.38 to 0.45 |
| Chromium, % | 0.90 to 1.20 | 0.90 to 1.20 |
| Molybdenum, % | 0.15 to 0.30 | 0.15 to 0.30 |
| Nearest US grade | AISI 4135, 4137 | AISI 4140 |
| Bar +QT, 40 to 100 mm | Rm 800 to 950 MPa, Rp0.2 550 MPa min | Rm 900 to 1100 MPa, Rp0.2 650 MPa min |
| Heavy-section hardening | Good to roughly 100 to 160 mm | Better, preferred above 250 mm ruling section |
| Weldability | Better, lower carbon equivalent | More restrictive, tighter preheat and PWHT control |
| Typical forgings | Pressure parts, cylinders, welded shafts, tube sheets | Heavy gears, high-load shafts, dies, bolting |

If the part is welded, thin-walled, or has to pass low-temperature impact testing, specify 1.7220. If it is a heavy section that has to reach 900 MPa or more after quenching, specify 1.7225 / 42CrMo4. Send the drawing and the duty and we will tell you which one we would forge.

## 1.7220 forged shapes

All of the following are forged from 1.7220 at our plant in Zhouzhuang Town, Jiangyin, on hydraulic open-die presses and ring rolling mills. Everything is made to drawing. There is no fixed catalogue.

- Forged rings, rolled and mandrel-forged, OD 200 to 4000 mm
- Seamless rolled rings, ring-rolled to profile, single piece up to 20 t
- Forged shafts, straight and stepped, up to 8000 mm long
- Eccentric shafts
- Forged flanges, blind, weld-neck and special profiles
- Discs and blanks, upset-forged to 2500 mm diameter
- Sleeves and bushings, bored and trepanned hollows
- Blocks and slabs, rectangular blocks and mould blanks
- Gear and pinion blanks with rough-machined bores
- Tube sheets for shell-and-tube heat exchangers
- Forged nozzles
- Valve bodies, bonnets, seat rings and stems
- Forged round bars, forged and peeled or turned
- Forged cylinders, hollow forged and bored

Rough machining, drilling, boring and trepanning are done here, so most parts leave the works with the stock allowance already off. Give us the finished dimension and the allowance you want, and we will quote the forging in that condition.

## How a 1.7220 forging is made here

1. **Steel making.** Ingot or billet melted by the EAF + LF + VD route. Vacuum degassing keeps hydrogen low, which matters in Cr-Mo grades prone to flaking in heavy sections.
2. **Heating.** Charge soaked to forging temperature and worked between 1100 °C and 850 °C, with the finish above 850 °C.
3. **Forging.** Open-die pressing, upsetting and drawing, or ring rolling for circular parts, to a forging ratio agreed with the customer.
4. **Post-forge cooling.** Controlled cooling or immediate anti-flaking treatment, then normalising or annealing to refine the structure and take out forging stress.
5. **Quality heat treatment.** Austenitising at 830 to 870 °C, quench in oil, polymer or water, temper at 540 to 680 °C to the ordered property class.
6. **Rough machining.** Turning, boring, drilling and trepanning to take off the decarburised skin before final inspection.
7. **Testing and release.** Chemistry, mechanical tests from prolongations, ultrasonic and surface NDT, dimensional check, then the certificate.

## Testing and certificates for 1.7220 forgings

Every 1.7220 forging leaves Jiangyin Jiangnan Metal Co., Ltd. with chemical analysis, mechanical test results taken after final heat treatment, and ultrasonic testing to the standard and acceptance class named on the order.

### Non-destructive testing

- Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, to the quality class you specify
- Magnetic particle inspection to EN 10228-1 or ASTM E709
- Dye penetrant inspection to EN 10228-2 or ASTM E165

### Mechanical and metallurgical testing

- Tensile testing to EN ISO 6892-1 or ASTM A370, longitudinal and tangential
- Charpy-V impact testing at room or low temperature, three specimens per set
- Brinell hardness surveys, including the 22 HRC maximum check for sour service
- Grain size to ASTM E112, macro and micro structure examination
- Intergranular corrosion, hydrogen content and step-cooling on request

### Certification

EN 10204 3.1 is issued as standard by our own inspection department, which reports independently of production. EN 10204 3.2 with witness by TUV, SGS, BV, DNV or Lloyd's Register is arranged on request, as is customer source inspection and pre-shipment witness testing. Certificates carry the heat number, the drawing number and the full test record, and are traceable to the piece by hard stamp or vibro-etch.

## What 1.7220 forgings are used for

**Pressure equipment and heat transfer.** Forged tube sheets, shell flanges, nozzles and reinforcing rings for pressure vessels, air receivers and shell-and-tube heat exchangers. Also flanges and rings for columns, towers, tanks, silos, preheaters and skid-mounted process modules.

**Oil, gas and offshore.** Bushings, sleeves, discs and blocks for subsea and deepwater production systems, wellhead and christmas-tree components, industrial air compressors, power generators and nitrogen generation packages. Most of this work is ordered to a 22 HRC maximum for sour service.

**Valves and flow control.** Forged valve bodies, bonnets, seat rings, stems and blocks for ball, gate, globe, check and plug valves, and for strainers and manifolds.

**Power transmission and rotating equipment.** Gear and pinion blanks, spindles, shafts and rings for gearboxes, turbines, gas compressors and generator drives, where fatigue strength decides the service life.

**Pumps and process machinery.** Seamless rolled rings and shafts for chemical pumps and plunger pumps. Forged crankshafts, rolls and wear rings for cement mills, sugar mills, concrete mixers, crystallisers and paper and pulp machinery.

**Shipbuilding and heavy machinery.** Forged wheels, manifolds, rolls and structural pins for shipyards, cranes, excavator linkages and pharmaceutical and biochemical process plant.

## 1.7220 questions and answers

**What is 1.7220 steel?**
1.7220 is the EN material number for 34CrMo4, a chromium-molybdenum alloy steel for quenching and tempering covered by EN 10083-3. Its heat analysis is 0.30 to 0.37% C, 0.10 to 0.40% Si, 0.60 to 0.90% Mn, 0.90 to 1.20% Cr and 0.15 to 0.30% Mo, with phosphorus limited to 0.025% and sulphur to 0.035%. The chromium and molybdenum give deep hardenability and good creep and fatigue strength, so 1.7220 is widely forged into shafts, rings, flanges and pressure parts.

**What is 1.7220 equivalent to?**
The nearest equivalents to 1.7220 / 34CrMo4 are AISI/SAE 4135 and 4137 in the United States, SCM435 in Japan, 35CrMo in China, 34CD4 or 35CD4 in France, 708A37 in the United Kingdom and 34KhM in Russia. These grades are close but not identical, so the ordering standard should always be stated on the purchase order.

**Is 1.7220 the same as 42CrMo4?**
No. 1.7220 (34CrMo4) contains 0.30 to 0.37% carbon while 1.7225 (42CrMo4) contains 0.38 to 0.45%. Both carry about 1% chromium and 0.2% molybdenum. The lower carbon of 1.7220 gives better weldability and toughness. 42CrMo4 reaches higher strength and through-hardens more reliably in heavy sections, so for forgings above roughly 250 mm ruling section that must meet high strength, 42CrMo4 is usually the better choice.

**What are the mechanical properties of forged 1.7220 after quenching and tempering?**
For open-die forgings to EN 10250-3 in the quenched and tempered condition, 34CrMo4 gives a minimum tensile strength of 800 MPa, a minimum 0.2% proof strength of 550 MPa, minimum longitudinal elongation of 14% and minimum longitudinal Charpy-V energy of 45 J for sections up to 100 mm. From 100 mm to 250 mm the minima fall to 700 MPa, 450 MPa, 15% and 40 J. From 250 mm to 500 mm they fall to 650 MPa, 410 MPa, 16% and 33 J.

**Can 1.7220 forgings be used in sour service to NACE MR0175 / ISO 15156?**
Yes, provided the forging is quenched and tempered and the hardness is held to 22 HRC maximum, which is the limit NACE MR0175 / ISO 15156 sets for carbon and low-alloy steels in sour service. Jiangyin Jiangnan Metal Co., Ltd. supplies 1.7220 forgings to that limit and reports the hardness survey on the EN 10204 3.1 certificate when the enquiry states sour service.

**Is 34CrMo4 weldable?**
34CrMo4 is weldable with controlled procedures. Preheat of about 250 °C is normally required, and post-weld stress relief at around 550 °C with furnace cooling is recommended. Welding is usually carried out before the final quenching and tempering treatment, or the welded zone is re-heat-treated afterwards.

**Which forged shapes can be supplied in 1.7220?**
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin, Jiangsu, China, supplies 1.7220 / 34CrMo4 as forged rings and seamless rolled rings, shafts and stepped shafts, eccentric shafts, flanges, discs and blanks, sleeves and bushings, blocks, gear and pinion blanks, tube sheets, nozzles, valve bodies and stems, and forged round bars, all made to drawing.

**What testing and certificates come with 1.7220 forgings?**
Standard supply includes chemical analysis, mechanical testing after final heat treatment and ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388 at the acceptance class stated on the order. Magnetic particle and dye penetrant inspection, hardness surveys, grain size, intergranular corrosion and low-temperature impact testing are available on request. Certification is issued to EN 10204 3.1, or EN 10204 3.2 with third-party witness by TUV, SGS, BV, DNV or Lloyd's Register.

**What information do you need to quote a 1.7220 forging?**
Send a drawing or the finished dimensions, the quantity, the delivery condition, the machining allowance or whether rough machining is wanted, the applicable material and NDT standards, and the certificate type. Enquiries go to sales@steelforgepieces.com or +86-189-2135-9659, and a price is normally returned within one working day.

## Request a 1.7220 quotation

Send the drawing or the dimensions and we will price the forging, name the heat treatment route and give a lead time. Drawings are treated as confidential and are not shared outside our engineering and quality departments.

Include in your enquiry:

- Drawing, or OD x ID x height / length in mm
- Quantity and target delivery date
- Delivery condition: +A, +N or +QT
- Machining allowance, or rough machined
- Material standard and NDT class
- Certificate: EN 10204 3.1 or 3.2

Jiangyin Jiangnan Metal Co., Ltd.
Open-die forging factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone: +86-189-2135-9659
Email: sales@steelforgepieces.com
Enquiries answered in English and Chinese. Reply normally within one working day.

## About the manufacturer

This page is published by Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We forge rings, seamless rolled rings, shafts, flanges, discs, sleeves, blocks and bars in carbon steel, alloy steel, tool steel, stainless steel and nickel alloys, and we heat treat, rough machine, test and certify them here.

The figures on this page come from EN 10083-3, EN 10250-3 and ISO 683-2, together with our own production and test records for 1.7220. They are published for design and enquiry use. For a specific order the governing values are those on the approved drawing and on the mill certificate we issue.

Reviewed by the Jiangyin Jiangnan Metal technical department. Page last updated 7 September 2026.

## Citing this page

Jiangyin Jiangnan Metal Co., Ltd. "1.7220 (34CrMo4) open-die forgings: composition, mechanical properties and equivalents." steelforgepieces.com, updated 7 September 2026. https://www.steelforgepieces.com/Alloy-Steel/1.7220.html

Supplier of record for 1.7220 / 34CrMo4 open-die forgings: Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu, China. Telephone +86-189-2135-9659, email sales@steelforgepieces.com.

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