P355NH (1.0565) open-die forgings
Normalized weldable fine-grain steel for pressure purposes. Rings, tube sheets, valve bodies and nozzle necks forged to drawing in Jiangyin, China.
EN 10027-1 designation, read left to right
- P
- Steel for pressure purposes
- 355
- Minimum yield strength in MPa, thinnest thickness
- N
- Delivered normalized or normalized rolled
- H
- Elevated-temperature properties specified
P355NH, material number 1.0565, is a normalized weldable fine-grain steel for pressure purposes with specified elevated-temperature properties. In the normalized (+N) condition it gives a minimum upper yield strength of 355 MPa up to 16 mm and a tensile strength of 490–630 MPa up to 60 mm. Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges P355NH to EN 10222-4 as seamless rolled rings, sleeves, hollow bars, discs, tube sheets, valve bodies, girth flanges, channel covers and long welding neck nozzles, supplied with EN 10204 3.1 or 3.2 certification.
- Designation (EN 10027-1)
- P355NH
- Material number (EN 10027-2)
- 1.0565
- Classification
- Non-alloy, elevated temp.
- Delivery condition
- +N (normalized)
- Density
- 7.85 g/cm³
- Min. yield ReH (t ≤ 16 mm)
- 355 MPa
- Tensile Rm (t ≤ 60 mm)
- 490–630 MPa
- Min. elongation A (t ≤ 60 mm)
- 22 %
- Charpy, longitudinal at −20 °C
- ≥ 40 J
- Forging standard
- EN 10222-4
- Plate standard
- EN 10028-3
- Certification
- EN 10204 3.1 / 3.2
What P355NH is, and where it is used
P355NH is one of the weldable fine-grain steels used for pressure equipment. The grain refinement from normalizing is what lifts proof strength to 355 MPa without costing notch toughness at −20 °C. It also keeps the grade weldable with ordinary consumables.
The H suffix means EN 10028-3 also specifies minimum proof strength at elevated temperature, so the grade can be used for equipment running above ambient. Common applications:
- Pressure vessels, separators, reactors and columns
- Steam drums, boiler parts and economiser components
- Shell-and-tube heat exchangers, including tube sheets and channel covers
- LPG and compressed-gas storage tanks
- Valve bodies, bonnets and closures for process piping
- Structural forgings that require a pressure-grade certificate
P355N, P355NL1 and P355NL2 sit in the same strength class. They differ in impact test temperature, which is covered in the questions below.
Standards that cover P355NH
P355NH covers several product forms and the test requirements differ between them, so the purchase order needs to state the right standard.
| Standard | Product form | Relevance to forgings |
|---|---|---|
| EN 10222-4 | Steel forgings for pressure purposes | Primary standard for our parts |
| EN 10028-3 | Flat products, normalized fine grain | Reference for properties |
| EN 10216-3 | Seamless tubes for pressure purposes | Mating components |
| EN 10217-3 | Welded tubes for pressure purposes | Mating components |
| EN 10253-2 | Butt-welding pipe fittings | Mating components |
| EN 10273 | Hot-rolled weldable bars for pressure purposes | Bar stock input |
For forgings, state EN 10222-4, the delivery condition +N, the impact test temperature and the certificate type (EN 10204 3.1 or 3.2).
Chemical composition of P355NH
Ladle analysis limits from EN 10028-3:2009, percentage by mass.
| C | Si | Mn | Ni | P | S | Cr | Mo | V | N | Nb | Ti | Al | Cu | Combined |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤ 0.18 | ≤ 0.50 | 1.10–1.70 | ≤ 0.50 | ≤ 0.025 | ≤ 0.015 | ≤ 0.30 | ≤ 0.08 | ≤ 0.10 | ≤ 0.012 | ≤ 0.05 | ≤ 0.03 | ≤ 0.02 | ≤ 0.30 | Nb+Ti+V ≤ 0.12 |
These are specification limits, not typical values. Every heat ships with its own analysis on the certificate.
Forgings to EN 10222-4 use different limits: C ≤ 0.20, Si 0.10–0.50, Mn 0.90–1.65, Ni ≤ 0.30, Al 0.020–0.060. State the standard you are working to when you send an enquiry, because the acceptable ladle analysis changes with it.
Mechanical properties in the normalized condition
Strength values fall as section thickness rises. Check the governing thickness of the part against the tables below before fixing a design allowable. On a stepped forging that means the heaviest section, not the average.
Minimum upper yield strength, ReH
| Nominal thickness (mm) | ≤ 16 | >16–40 | >40–60 | >60–100 | >100–150 | >150–250 |
|---|---|---|---|---|---|---|
| ReH, min. (MPa) | 355 | 345 | 335 | 315 | 305 | 295 |
Tensile strength, Rm
| Nominal thickness (mm) | ≤ 60 | >60–100 | >100–150 | >150–250 |
|---|---|---|---|---|
| Rm (MPa) | 490–630 | 470–610 | 460–600 | 450–590 |
Elongation at fracture, A
| Nominal thickness (mm) | ≤ 60 | >60–250 |
|---|---|---|
| A, min. (%) | 22 | 21 |
Charpy V-notch impact energy, KV
Impact values are specified in both orientations. Transverse values are lower and harder to meet on a forged ring, so confirm the sampling orientation before test rings are cut.
| Test temperature | −20 °C | 0 °C | +20 °C |
|---|---|---|---|
| Longitudinal, min. (J) | 40 | 47 | 55 |
| Transverse, min. (J) | 27 | 35 | 39 |
Test material comes from a prolongation or a sacrificial ring forged with the part, at the sampling position given in EN 10222-4. If you need a different position, or a through-thickness specimen, put it on the order before the forging is heat treated.
Source: EN 10028-3:2009 and EN 10222-4:1999. Values apply to the specified delivery condition. Actual results for your heat appear on the mill test certificate. EN 10028-3 also specifies Rp0.2 at temperatures up to 400 °C; ask us for the values that apply to your section thickness.
P355NH equivalent grades
These are cross-references for guidance only. Chemistry limits, test temperatures, thickness ranges and certification rules differ between standards, so any substitution needs written acceptance from the design authority or notified body.
| Country or system | Grade | Note |
|---|---|---|
| Europe, EN | P355NH / 1.0565 | The grade itself |
| Germany, DIN / WNr | WStE 355 | Former designation |
| United States, ASTM | A662 Gr. C | Nearest, not identical |
| France, AFNOR | A510AP | Nearest |
| United Kingdom, BS | 224 Gr. 490 | Nearest |
| Italy, UNI | FeE355-2 | Nearest |
| China, GB | Q345R | Nearest pressure-vessel grade |
P355NH components we forge
Everything here is forged to the customer drawing, or to a dimensional standard where there is no drawing. Machining allowance is agreed at the quotation stage.
- Forged rings and seamless rolled rings
- Sleeves, bushes, bushings thick-wall, machined bore
- Forged pipes and tubes barrels, casings, shells
- Round bars and hollow bars cylinders, stepped shafts
- Hubs and housings bored and faced
- Discs and disks solid and bored blanks
- Tube sheets and tube plates drilled to layout on request
- Valve bodies and blocks bonnets, stems, closures, seat rings
- Girth flanges and cover flanges
- Channel covers for shell-and-tube exchangers
- LWN nozzle necks long welding neck nozzles
- FVC self-reinforced nozzles forged from solid
- Heat exchanger parts shell flanges, spacers, baffles
- Shafts forged and rough machined
How we make and certify P355NH forgings
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging plant. Parts are forged from ingot or billet, ring rolled where the geometry suits it, normalized, tested and rough machined before shipment.
Process route
- Material input. Ingot or continuous-cast billet from qualified steel mills, each heat traceable to its own analysis.
- Open-die forging. Upsetting, drawing out and punching on hydraulic presses, to the forging reduction ratio agreed for the part.
- Ring rolling. Seamless rolled rings for shell flanges, girth flanges and cylindrical sections.
- Heat treatment. Normalizing for the +N condition, or normalizing and tempering where the specification calls for it. Furnace charts go out with the certificate. Simulated post-weld heat treatment on test coupons on request.
- Non-destructive testing. Ultrasonic to EN 10228-3 or ASTM A388, magnetic particle to EN 10228-1, dye penetrant where specified. Rings are rough turned before ultrasonic testing so the scan runs on a clean surface.
- Mechanical testing. Tensile at room temperature, Charpy V-notch at the ordered test temperature, hardness survey, grain size.
- Machining. Rough or finish machining on CNC lathes and boring mills to the customer drawing.
Certification and inspection
- EN 10204 3.1 mill test certificate as standard, covering chemistry, mechanical results and heat treatment records
- EN 10204 3.2 certificate countersigned by TUV, Lloyd’s Register, Bureau Veritas, DNV or SGS when stated on the order
- Documentation to support fabrication under PED 2014/68/EU, including material traceability and heat treatment charts
- Third-party or customer witness inspection welcome at any hold point
- Dimensional report against the customer drawing before packing
Supply condition
Parts leave the works as forged, rough machined or finish machined, according to the order. Export packing is on fumigation-free plywood cases or steel pallets, with rust preventive on machined surfaces. Send the drawing and we will confirm what can be held on the press and what needs to be split into more than one piece.
What to put on a P355NH enquiry
Include these eight items and we can quote without a second round of questions. Send to sales@steelforgepieces.com.
- Drawing or dimensioned sketch, in PDF, DWG or STEP
- Grade and standard: P355NH to EN 10222-4
- Delivery condition: +N, or +NT if your code requires it
- Impact test temperature and orientation
- Certificate type: EN 10204 3.1 or 3.2, and the inspection body if 3.2
- NDT scope and acceptance class
- Machining state: as forged, rough machined or finish machined
- Quantity and required delivery date
Questions about P355NH
What is P355NH steel?
P355NH is a normalized, weldable fine-grain steel for pressure purposes with specified elevated-temperature properties, material number 1.0565. It is covered by EN 10028-3 for plate, EN 10222-4 for forgings, EN 10216-3 and EN 10217-3 for tubes, EN 10253-2 for fittings and EN 10273 for bars, and is used for pressure vessels, boilers, heat exchangers and gas storage equipment.
What does P355NH stand for?
Under EN 10027-1, P means steel for pressure purposes, 355 is the minimum yield strength in MPa at the thinnest product thickness, N means the steel is delivered normalized or normalized rolled, and H means elevated-temperature properties are specified.
What is the material number of P355NH?
1.0565, assigned under EN 10027-2. P355NH and 1.0565 are the same grade and both normally appear on the mill test certificate.
What is the yield strength of P355NH?
In the normalized condition the minimum upper yield strength ReH is 355 MPa up to 16 mm, 345 MPa from 16 to 40 mm, 335 MPa from 40 to 60 mm, 315 MPa from 60 to 100 mm, 305 MPa from 100 to 150 mm and 295 MPa from 150 to 250 mm. Tensile strength Rm is 490 to 630 MPa up to 60 mm, falling to 450 to 590 MPa in the 150 to 250 mm range.
Which standard applies to P355NH forgings?
EN 10222-4, Steel forgings for pressure purposes, Part 4: weldable fine grain steels with high proof strength. EN 10028-3 is the plate standard and is often quoted for property reference, but forged rings, tube sheets and valve bodies should be ordered to EN 10222-4.
What is the difference between P355NH, P355NL1 and P355NL2?
All three sit in the same 355 MPa strength class with similar chemistry. The difference is the guaranteed impact test temperature: P355NH is qualified for elevated-temperature service, P355NL1 is impact tested to −40 °C and P355NL2 to −50 °C for low-temperature duty. Choose NL1 or NL2 if the vessel sees cold minimum design metal temperatures.
Is P355NH weldable?
Yes. It is classified as a weldable fine-grain steel and is welded by SAW, SMAW, GTAW and GMAW in pressure vessel shops. Calculate the carbon equivalent from the actual ladle analysis on the certificate rather than from the specification maxima, and set preheat and post-weld heat treatment from your qualified welding procedure. We report CEV on the EN 10204 3.1 certificate on request.
What is the ASTM equivalent of P355NH?
ASTM A662 Grade C is the nearest American cross-reference. Others in common use are WStE 355 in Germany, A510AP in France, 224 Gr. 490 in the UK, FeE355-2 in Italy and Q345R in China. None of these is an automatic substitution. The design authority has to accept the change in writing.
Who manufactures P355NH forgings in China?
Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges P355NH into seamless rolled rings, sleeves, hollow bars, discs, tube sheets, valve bodies, girth flanges, channel covers and long welding neck nozzles. Enquiries go to sales@steelforgepieces.com or +86 189 2135 9659.
Can P355NH forgings be supplied with EN 10204 3.2 certification?
Yes. An EN 10204 3.1 certificate is standard. A 3.2 certificate countersigned by TUV, Lloyd’s Register, Bureau Veritas, DNV or SGS can be arranged when it is stated on the purchase order, along with witness points for forging, heat treatment and testing.
Request a P355NH quotation
Send a drawing and we will reply with price, finished weight, lead time and the test plan. Technical questions go straight to the forging team.
Jiangyin Jiangnan Metal Co., Ltd.Open-die forging factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone and WhatsApp: +86 189 2135 9659
Email: sales@steelforgepieces.com
Web: www.steelforgepieces.com
Datasheet published by Jiangyin Jiangnan Metal Co., Ltd. Data compiled from EN 10028-3:2009 and EN 10222-4:1999. Last reviewed . A plain-text version of this page is available at P355NH.md. Figures are the values specified by the standards and are given for guidance. The governing values for any delivery are those on the mill test certificate.