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ASTM A420 WPL6 Low Temperature Pipe Fittings

A420 LTCS Buttweld Fittings: Elbows, Tees, Reducers & Caps

Dinesh Tube India is a supplier and stockist of ASTM A420 / ASME SA420 WPL6 pipe fittings in Mumbai, serving EPC contractors, LPG and ammonia plants, refineries and fabricators in India and abroad. A420 WPL6 is the standard low-temperature carbon steel (LTCS) butt-weld fitting, impact tested at −46 °C (−50 °F).

We supply seamless and welded A420 WPL6 elbows, tees, reducers, caps and stub ends from 1/2" to 48" NB to ASME B16.9, with an EN 10204 3.1 certificate showing impact test results. Send us your fitting type, size, schedule and quantity for a quote.


Table of Contents


What Is ASTM A420?

ASTM A420/A420M is the standard specification for wrought carbon steel and alloy steel pipe fittings for low-temperature service. ASME adopts it as SA420. It covers seamless and welded butt-weld fittings made to the dimensions of ASME B16.9 and related MSS standards, and every grade must pass a Charpy V-notch impact test at low temperature.

WPL6 is the carbon steel grade and by far the most common. It is the fitting partner of ASTM A333 Grade 6 pipe and A350 LF2 flanges, and together they make up a complete low-temperature carbon steel piping system for service down to −46 °C. For colder service, the nickel steel grades WPL9 and WPL3 are used.

ASTM A420 WPL6 low-temperature buttweld pipe fittings

A420 Fittings Specification

Standard

ASTM A420/A420M, ASME SA420

Grades

WPL6 (carbon steel); WPL9, WPL3 on request

Dimensions

ASME B16.9 butt-weld; MSS SP-43 stub ends

Size

1/2" – 48" NB

Schedule

SCH 10, 20, 40 / STD, 80 / XS, 160, XXS to match pipe

Type

Seamless (WPL6) or welded (WPL6W, WPL6WX)

Heat Treatment

Normalised, or normalised and tempered

Impact Test

Charpy V-notch at −46 °C (−50 °F) for WPL6

Ends

Bevelled ends for butt welding per ASME B16.25

Certification

EN 10204 3.1 with impact results; 3.2 on request
ASTM A420 pipe fittings specification

ASTM A420 Grades: WPL6, WPL9 & WPL3

GradeMaterialTensile StrengthYield, minImpact Test Temperature
WPL6Carbon steel415 – 585 MPa240 MPa−46 °C (−50 °F)
WPL92% nickel – copper steel435 – 610 MPa315 MPa−73 °C (−100 °F)
WPL33.5% nickel steel450 – 620 MPa240 MPa−101 °C (−150 °F)

A420 WPL6 Chemical Composition

C, maxMnP, maxS, maxSiNi, maxCr, maxMo, maxCu, maxV, max
0.300.60 – 1.350.0350.0400.15 – 0.400.400.300.120.400.08

Values in weight %. Fittings made from bar or plate may have different limits; see ASTM A420 for full requirements.

A420 WPL6 Mechanical Properties

Tensile StrengthYield Strength, minElongation, minHardness, maxImpact Test
415 – 585 MPa (60 – 85 ksi)240 MPa (35 ksi)22% (longitudinal)197 HBWCharpy V-notch at −46 °C

A420 Fitting Marking & Testing

MarkingMeaning
WPL6Seamless fitting
WPL6WWelded fitting
WPL6WXWelded fitting, welds 100% radiographed
WPL6WUWelded fitting, welds 100% ultrasonically examined

Each fitting is marked with grade, size, schedule and heat number for full traceability to the mill certificate. Testing covers chemical analysis, tensile, hardness and Charpy impact tests, with radiography of fusion welds. PMI and third-party inspection are available on request.

Need A420 WPL6 fittings for an LTCS line? Send your fitting type, size, schedule and quantity to kamlesh@dineshtube-india.com or call +91 83559 10913. You can also send an enquiry.

Types of A420 WPL6 Fittings

ASTM A420 WPL6 buttweld elbow

A420 WPL6 Elbows

45° and 90° long and short radius, 180° returns.
ASTM A420 WPL6 equal and reducing tee

A420 WPL6 Tees

Equal and reducing tees to ASME B16.9.
ASTM A420 WPL6 concentric and eccentric reducer

A420 WPL6 Reducers

Concentric and eccentric reducers.
ASTM A420 WPL6 buttweld cross

A420 WPL6 Crosses & Caps

Equal and reducing crosses, pipe caps.
ASTM A420 WPL6 lap joint stub end

A420 WPL6 Stub Ends

Long and short pattern lap joint stub ends.
LTCS long radius pipe bend

LTCS Pipe Bends

3D and 5D long radius bends on request.

A420 WPL6 vs A234 WPB

A420 WPL6A234 WPB
ServiceLow temperature, down to −46 °CModerate and elevated temperature
Impact testMandatory Charpy at −46 °CNot required as standard
Min tensile / yield415 / 240 MPa415 / 240 MPa
Heat treatmentNormalisedAs required by forming process
Matching pipeASTM A333 Gr 6ASTM A106 Gr B
Matching flangeASTM A350 LF2ASTM A105

For general carbon steel piping, see our A234 WPB fittings and carbon steel pipe fittings pages. For low-temperature flanges, see A350 LTCS flanges.

A420 WPL6 Fitting Applications

  •   LPG, propane and butane storage and transfer lines
  •   Ammonia and refrigeration plants
  •   Gas processing and NGL plants
  •   Refinery and petrochemical cold-service piping
  •   Fertiliser plants
  •   Pipelines and plants in cold climates
  •   Gas pressure-reduction (Joule-Thomson cooling) stations
Industries using ASTM A420 WPL6 low-temperature fittings

ASTM A420 Pipe Fittings: FAQs

What is ASTM A420?

ASTM A420 (ASME SA420) is the standard specification for wrought carbon steel and alloy steel pipe fittings for low-temperature service. It covers seamless and welded butt-weld fittings such as elbows, tees, reducers and caps. Every grade is Charpy impact tested at low temperature, so the fittings stay tough in cold service.

What is ASTM A420 WPL6?

WPL6 is the carbon steel grade of ASTM A420 and the most widely used low-temperature fitting grade. It is normalised and impact tested at −46 °C (−50 °F), with a minimum tensile strength of 415 MPa and yield of 240 MPa. WPL6 fittings are used with ASTM A333 Grade 6 pipe and A350 LF2 flanges in LTCS piping systems.

What is the difference between A420 WPL6 and A234 WPB?

Both are carbon steel butt-weld fittings with the same minimum room-temperature strength. A234 WPB is for moderate and elevated temperatures and is not impact tested as standard. A420 WPL6 is made for low-temperature service and must pass a Charpy impact test at −46 °C, so it is specified for LTCS piping where WPB could become brittle.

What do the markings WPL6, WPL6W and WPL6WX mean?

WPL6 marks a seamless fitting. WPL6W marks a welded fitting. WPL6WX means the welds are 100% radiographed, and WPL6WU means the welds are ultrasonically examined. Each fitting is also marked with size, schedule, heat number and the manufacturer's identification.

Which grade of A420 is used below −46 °C?

For colder service, nickel steel grades are used: WPL9 (about 2% nickel) is impact tested at −73 °C, and WPL3 (3.5% nickel) at −101 °C. For cryogenic service such as LNG, stainless steel fittings to ASTM A403 are normally used instead.

What sizes of A420 WPL6 fittings are available?

A420 WPL6 butt-weld fittings are supplied from 1/2" to 48" NB to ASME B16.9, in schedules from SCH 10 to XXS to match the pipe. Smaller sizes are usually seamless; larger sizes are welded. Send your fitting type, size, schedule and quantity for a quote.

Export Destinations for A420 Fittings

We export ASTM A420 WPL6 fittings to the Middle East (UAE, Saudi Arabia, Qatar, Kuwait, Oman, Bahrain, Iraq, Jordan), Africa (Nigeria, Egypt, South Africa, Kenya, Ghana, Algeria, Morocco, Tunisia), Asia (Japan, South Korea, Singapore, Malaysia, Indonesia, Thailand, Vietnam, Philippines, Bangladesh, Sri Lanka), Europe (Italy, Spain, Portugal, France, Netherlands, Belgium, Poland, Romania, Turkey, United Kingdom), and the Americas (United States, Canada, Mexico, Brazil, Chile, Peru, Colombia, Argentina).