Standards · ASME and ASTM · ASTM A420/A420M

ASTM A420/A420M: Piping fittings of wrought carbon steel and alloy steel for low-temperature service

The low-temperature counterpart of A234: buttwelding and forged fittings whose notch toughness is tested at the design temperature – the fitting that belongs to A333 pipe and A350 flanges.

Issued by: ASTM
Edition (publisher, as of 2 October 2026): 2026
Material specification: Piping fittings of wrought carbon steel and alloy steel for low-temperature service
European counterpart: EN 10253-2 (P265NL 1.0453, 12Ni14 1.5637)
Belongs with: ASME B16.9 · ASTM A333/A333M · ASTM A350/A350M · ASTM A234/A234M
At Zickwolff: we carry – from stock or to order, lead time on request

Scope: sizes, classes, grades

Grades WPL6 (impact test at −46 °C / −50 °F, average min. 18 J), WPL9, WPL3 (3.5 % Ni, −101 °C) and WPL8 (9 % Ni, −196 °C). WPL6: tensile min. 415 MPa, yield min. 240 MPa, carbon max. 0.30 %, manganese 0.60 to 1.35 %, fine-grain practice, normalised. Dimensions to B16.9 and B16.11.

Product form

Wrought fittings, seamless or welded, from killed fine-grain steel.

Grades and their European counterparts

ASTM A420/A420M - Grades and their European counterparts
Grade	Type	Impact test at	Tensile / yield min. (MPa)	European counterpart	Limits of the comparison	At Zickwolff
WPL6	low-temperature steel	−46 °C	415 / 240	P265NL 1.0453 · EN 10253-2	comparable low-temperature steel, impact test temperature and energy differ	deliverable
WPL3	low-temperature steel	−101 °C	not stated in our sources	12Ni14 1.5637 · EN 10253-2	comparable low-temperature steel, impact test temperature and energy differ	on request
WPL8	nickel steel	−196 °C	690 / 515	X10Ni9 1.5682	comparable low-temperature steel, impact test temperature and energy differ	on request

WPL6 is compared with P265NL, WPL3 with 12Ni14 – both fittings to EN 10253-2 – a European grade for WPL8 (9 % Ni) is X10Ni9 1.5682.

Use in Europe: the Pressure Equipment Directive

Under the Pressure Equipment Directive an ASTM material has no presumption of conformity: it needs a European material approval or a particular material appraisal (PMA) by the equipment manufacturer, in categories III and IV assessed by the notified body. Comparisons with EN grades are orientation, never a one-to-one equivalence – chemistry bands, test scope and certificate differ. WPL6 and WPB look alike and share the strength – only the certificate with the impact values at −46 °C separates them. Never substitute WPB in a low-temperature line.

Marking on the part

Via B16.9: manufacturer, WPL6, schedule or wall, NPS, heat number.

The standard family: dimensions, material, pipe

ASME B16.9 · ASTM A333/A333M · ASTM A350/A350M · ASTM A234/A234M

At Zickwolff

Low-temperature fittings A420 WPL6 to B16.9 are part of our range, WPL3 we procure – with certificate 3.1 including impact values and the matching A333 Gr. 6 pipe and A350 LF2 flanges.

Dimensions Dimension tables for this standard are available on request – we work from manufacturer catalogues, not from copied standard tables.

Frequently asked questions about ASTM A420/A420M

Can I use this ASTM material in a pressure line under the PED?

Yes, but without presumption of conformity: the equipment manufacturer needs a European material approval or a particular material appraisal (PMA), in categories III and IV assessed by the notified body. For equipment under Article 4(3) (sound engineering practice) this does not apply. We supply the material with certificate 3.1 – the appraisal is the manufacturer's.

Must a plant with ASME parts be inspected more often?

No – the inspection interval comes from the operating law of the country, not from the code of the part. In Germany the Betriebssicherheitsverordnung (Annex 2 Section 4) sets maximum intervals, the operator fixes the interval in the risk assessment and the inspector may shorten it (TRBS 1201 Part 2) where design or manufacture give reason to. Operators often inspect more frequently anyway. This is general information, not legal advice – the legal text is binding.

WPL6 or WPB – can I mix them?

Not in a low-temperature line: they look alike and share the strength, but only WPL6 carries the impact test at −46 °C. Keep them apart in the warehouse and read the stamp.

Which European fitting corresponds to WPL6?

P265NL to EN 10253-2 is the comparable low-temperature grade – with its own impact test table, so compare the certificate values, not the names.

Parts to ASME and ASTM – from one source

Tell us standard, size (NPS and schedule or Class), material grade, certificate and quantity – we check what is in stock, what we procure and which European part would do the same job.

Send an inquiry

Your inquiry to Zickwolff

Send us what you have – designation, standard, quantity, date. We will clarify the rest with you.

One item or a question

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Not in stock? We procure it – single items too.

Designation, standard and quantity are enough.

Several items

Send bill of materials

200 items? One parts list is enough – we deliver complete.

Attach it as a file.

Helpful if already known: project and country, date needed, certificates, packaging and language of the packing lists. If anything is missing, we will ask.

It is urgent

Request express

When do you need it? Express delivery, to the site if required.

Tell us by when you need the material – we will tell you what is possible.

← Back to ASME and ASTM standards

Basis: the publicly accessible scopes and abstracts of ASME and ASTM (editions as of 2 October 2026), manufacturer catalogues, a trade reference catalogue DIN/EN/ASME and specialist sources for marking and impact test values – the legal statements follow Directive 2014/68/EU and the German Betriebssicherheitsverordnung. No standard text was reproduced – the current original edition is binding. Comparisons with EN grades are orientation, not equivalence. Information without guarantee, no legal advice, no prices.