What P355NL2 is used for
P355NL2 belongs to the EN group of weldable fine grain steels for pressure equipment. Normalizing refines the grain structure, and the tight limits on nitrogen, sulphur and micro-alloying elements let the steel keep usable toughness well below freezing. It gets specified where a component has to hold 355 MPa proof strength and still pass a 27 J Charpy test at −50 °C.
Jiangyin Jiangnan Metal Co., Ltd. supplies P355NL2 as open-die forgings rather than plate. Forging suits the grade where a part needs continuous grain flow around a bore, a wall thickness beyond normal plate availability, or a shape that would otherwise be built up from several welded pieces. Common end uses include separator and accumulator shells, heat exchanger channel sections and tubesheets, nozzle reinforcement, and valve bodies on cold service hydrocarbon lines.
P355NL2 is made to drawing. Send the finished dimensions, the machining allowance you want left on, the design minimum metal temperature and the governing code, and we will confirm the achievable section size and the test position.
P355NL2 forged product forms we make
Every item below is produced in P355NL2 (1.1106) on open-die hammers and presses, with ring rolling for circular sections.
Rings and rolled rings
Seamless rolled rings, forged rings, sleeves, bushes and bushings, barrels, casings, cases, shells, cylinders, hubs and housings.
Discs and tubesheets
Forged discs and disks, tubesheets, tube sheets and tube plates for shell-and-tube heat exchangers.
Flanges and covers
Girth flanges, channel covers, cover flanges, long welding neck flanges, nozzle necks and FVC-type self-reinforced nozzles.
Valve components
Valve bodies and blocks, bonnets, stems, closures, seat rings and other machined valve parts.
Bars and shafts
Forged round bars, hollow bars, stepped shafts and pipe, piping, tube and tubing blanks.
Heat exchanger sets
Matched component sets for shell-and-tube exchangers, supplied from one heat where the specification calls for it.
P355NL2 chemical composition
Ladle analysis limits for P355NL2 (1.1106), expressed as a percentage by mass.
| C | Si | Mn | Ni | P | S | Cr | Mo | V | N | Nb | Ti | Al | Cu | Combined |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| max 0.18 | max 0.50 | 1.10–1.70 | max 0.50 | max 0.020 | max 0.010 | max 0.30 | max 0.08 | max 0.10 | max 0.012 | max 0.05 | max 0.03 | max 0.02 | max 0.30 | Nb+Ti+V < 0.12 |
For seamless tubes to EN 10216-3:2014 the manganese range is 0.90 to 1.70 %, with S at most 0.005 %, N at most 0.020 % and Ti at most 0.04 %. Aluminium in fine grain steels is controlled for grain refinement, so check whether your order calls for a minimum total aluminium content. The figures that bind any specific order are the ones on the mill test certificate.
P355NL2 mechanical properties
All values below apply to the normalized condition (+N) and are quoted against nominal thickness, since the strength of P355NL2 steps down as section size increases.
Yield strength
| Nominal thickness | to 16 mm | 16–40 mm | 40–60 mm | 60–100 mm | 100–150 mm | 150–250 mm |
|---|---|---|---|---|---|---|
| ReH, minimum yield strength (MPa) | 355 | 345 | 335 | 315 | 305 | 295 |
Tensile strength and elongation
| Nominal thickness | to 60 mm | 60–100 mm | 100–150 mm | 150–250 mm |
|---|---|---|---|---|
| Rm, tensile strength (MPa) | 490–630 | 470–610 | 460–600 | 450–590 |
| Nominal thickness | to 60 mm | 60–250 mm |
|---|---|---|
| A, minimum elongation at fracture (%) | 22 | 21 |
Low-temperature impact toughness at −50 °C
The L2 suffix is what separates this grade from the rest of the P355 family. P355NL2 carries a guaranteed Charpy V-notch impact energy at −50 °C, while the otherwise similar P355NL1 is qualified only to −40 °C. Transverse specimens govern, since they are the weaker orientation, and longitudinal values run considerably higher.
| Specimen orientation | −50 °C | −40 °C | −20 °C | 0 °C | +20 °C |
|---|---|---|---|---|---|
| KV, transverse (J) | 27 | 30–33 | 40–47 | 60 | 70 |
| KV, longitudinal (J) | 40–42 | 45–50 | 55–70 | 75–90 | 85–100 |
On forgings, impact coupons are taken from a prolongation or a sacrificial test ring in the position agreed at order stage, and heat treated with the parts they represent. For thick sections, state whether you need mid-wall or quarter-thickness sampling, since this changes the result that can be achieved.
Standards and comparable grades
P355NL2 appears in several parts of the EN pressure equipment material system, depending on product form. For forgings the controlling document is EN 10222-4, which classifies P355NL2 as a non-alloy special steel. General delivery conditions for open-die forgings, ring-rolled products and forged bars are set by EN 10222-1.
| Product form | Standard | Title |
|---|---|---|
| Forgings, rolled rings, forged bars | EN 10222-4 | Steel forgings for pressure purposes. Weldable fine grain steels with high proof strength |
| General conditions for open-die forgings | EN 10222-1 | Steel forgings for pressure purposes. General requirements for open die forgings |
| Plate and flat products | EN 10028-3 | Flat products made of steels for pressure purposes. Weldable fine grain steels, normalized |
| Seamless tube | EN 10216-3 | Seamless steel tubes for pressure purposes. Alloy fine grain steel tubes |
| Certification | EN 10204 | Inspection documents, type 3.1 and type 3.2 certificates |
Comparable grades
No ASTM grade matches P355NL2 one for one. The grades below sit in a similar strength class and serve similar duties, and buyers often consider them as alternatives, but chemistry, carbon equivalent, impact test temperature and heat treatment requirements all differ.
| Grade | System | Relationship to P355NL2 |
|---|---|---|
| P355NL1 (1.1104) | EN | Same strength class, impact tested at −40 °C instead of −50 °C |
| P355NH (1.0565) | EN | Same strength class, elevated-temperature variant without the low-temperature guarantee |
| ASTM A350 LF2 | ASTM / ASME | Closest comparison for forged piping components requiring notch toughness |
| ASTM A516 Gr. 70 | ASTM / ASME | Closest comparison for plate, when normalized and impact tested |
| 16MnDR | GB (China) | Chinese low-temperature pressure vessel steel of broadly similar duty |
Grade substitution on pressure equipment is a design decision. Check it against the governing code, EN 13445, AD 2000 or ASME VIII, and get the purchaser's written approval before material is released.
How we forge and test P355NL2
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory, so P355NL2 components are forged to shape from ingot or billet rather than cut from plate. The route below is the one followed on pressure purpose orders.
Forging and heat treatment
Material is upset and drawn on open dies, and circular sections are ring rolled so that grain flow follows the circumference instead of being cut through. Parts are then normalized, which is the delivery condition P355NL2 is specified in. Where the customer's code calls for it, stress relief can be added after rough machining and before final machining, so that residual stress is released while there is still material left to correct any movement.
Testing and documentation
Standard scope on a P355NL2 order covers chemical analysis, tensile testing, Charpy V-notch impact testing at the specified temperature, hardness and ultrasonic examination. Magnetic particle inspection, grain size determination and dimensional reports are added when the specification calls for them. Each heat is supplied with an EN 10204 3.1 certificate, and 3.2 certification with a nominated third party inspector is available on request.
Capability, tonnage range and approvals should be confirmed against your specific enquiry. Send the drawing and we will reply with what can be achieved and what the test plan would look like.
Frequently asked questions about P355NL2
What is P355NL2 steel?
P355NL2 is a normalized, weldable fine-grain steel for pressure purposes, carrying EN material number 1.1106. The designation reads as P for pressure purposes, 355 for a minimum yield strength of 355 MPa in thicknesses up to 16 mm, N for the normalized delivery condition, and L2 for guaranteed Charpy V-notch impact toughness at −50 °C. It is specified in EN 10028-3 for flat products, EN 10216-3 for seamless tubes and EN 10222-4 for forgings.
What is the material number for P355NL2?
The EN material number for P355NL2 is 1.1106. P355NL2 is the chemical designation and 1.1106 is the numeric designation; both refer to the same steel. Under EN 10222-4, P355NL2 is classified as a non-alloy special steel.
Which standard covers P355NL2 forgings?
Forgings in P355NL2 are ordered to EN 10222-4, Steel forgings for pressure purposes. Part 4: Weldable fine grain steels with high proof strength. The general technical delivery conditions for open-die forgings, ring-rolled products and forged bars are given in EN 10222-1. Jiangyin Jiangnan Metal Co., Ltd. forges P355NL2 to EN 10222-4 with EN 10204 3.1 or 3.2 certification.
What is the difference between P355NL1 and P355NL2?
The two grades share a strength class but differ in low-temperature impact requirements. P355NL1 is impact tested at −40 °C, while P355NL2 is impact tested at −50 °C and carries tighter limits on sulphur and nitrogen. P355NL2 is therefore specified when the design minimum metal temperature drops below what P355NL1 covers.
What is the minimum yield strength of P355NL2?
In the normalized condition, P355NL2 has a minimum yield strength ReH of 355 MPa up to 16 mm nominal thickness. It steps down with section size: 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.
Is P355NL2 suitable for low-temperature service?
Yes. P355NL2 is a low-temperature pressure vessel steel. The L2 suffix means Charpy V-notch impact energy is verified at −50 °C, with a minimum of 27 J on transverse specimens and typically 40 J or more longitudinally. It is commonly specified for cold climate pressure vessels, LPG and LNG related equipment, and offshore and Arctic service.
What is the ASTM equivalent of P355NL2?
No ASTM grade matches P355NL2 one for one. For forged piping components the closest comparable grade is ASTM A350 LF2, also a notch-toughness-tested carbon steel forging grade; for plate, the nearest comparison is ASTM A516 Grade 70 in the normalized and impact-tested condition. These sit in the same strength class and serve similar duties but differ in chemistry, carbon equivalent, test temperature and heat treatment, so they are not automatic substitutes. Check any substitution against the design code and get purchaser approval before ordering.
Is P355NL2 weldable, and does it need post-weld heat treatment?
P355NL2 is classed as a weldable fine-grain steel and is routinely welded by SMAW, SAW, GTAW and GMAW with low-hydrogen consumables. Preheat, interpass control and post-weld heat treatment are set by section thickness, carbon equivalent and the governing fabrication code such as EN 13445, AD 2000 or ASME VIII. Because the grade is bought for its −50 °C toughness, the welding procedure qualification should include impact testing of weld metal and heat-affected zone at the design minimum temperature.
What forged shapes can be supplied in P355NL2?
Jiangyin Jiangnan Metal Co., Ltd. supplies P355NL2 as seamless rolled rings, forged rings, sleeves, bushings, barrels, casings, shells, cylinders, hollow bars, round bars, discs, tubesheets and tube plates, hubs, housings, shafts, girth flanges, channel covers, cover flanges, long welding neck flanges, FVC-type self-reinforced nozzles and nozzle necks, valve bodies, bonnets, stems, closures and seat rings, and shell-and-tube heat exchanger components.
Who supplies P355NL2 forgings from China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, manufacturing P355NL2 (1.1106) forgings to EN 10222-4. Enquiries: sales@steelforgepieces.com, telephone +86 189 2135 9659.
Request a quotation for P355NL2 forgings
Send a drawing or a dimensional sketch with the design minimum metal temperature and the governing code. We reply with the achievable forged size, the proposed test plan and a price.
Manufacturer
Jiangyin Jiangnan Metal Co., Ltd.
Open-die forging factory
Factory address
No.1 Chengxiqiao Road
Zhouzhuang Town, Jiangyin City
Jiangsu Province, China
Telephone and WhatsApp