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Butt weld pipe fittings

Butt weld pipe fittings are weldable pipe fittings that allow for change of direction of flow, to branch off, reduce pipe size or attach auxiliary equipment.

Pipe elbows

Pipe elbows are used to be installed between two lengths of pipe or tube allowing a change of direction,usually these elbows distinguished by connection ends.

Pipe tee

A pipe tee is also called triplet,three way and “T” pieces and it can be used to either combine or split a fluid flow.

Pipe bending

Pipe bending is any metal forming processes used to permanently form pipes or tubing.

Pipe Cross

A pipe cross is a kind of pipe fitting that be used in the place where four pipes meet together.

Stub ends

Stub ends are buttweld fittings that can be used (in combination with a lap joint flange) alternatively to welding neck flanges to make flanged connections.

Pipe cap

Pipe caps act as protective device and are designed to protect pipe ends of various shapes.

Pipe reducers

Pipe Reducers are the component in a pipeline that reduces the pipe size from a larger to a smaller bore (inner diameter).

Recommended pipe fittings

Welded pipe fittings in carbon steel and stainless steel are the joining components that make possible the assembly of valves, pipes and equipment onto the piping system.

Forged Steel buttweld fittings are manufactured in accordance with ANSI / ASME B16.9. Butt weld fittings are available as elbows, tees, caps, reduces and out lets (olets). These fittings are the most common type of welded pipe fitting and are specified by nominal pipe size and pipe schedule. Buttweld fittings use seamless or welded pipe as the starting material and are formed (through multiple processes) to get the shape of elbows, tees and reducers etc. Just as the pipe is sold from Schedule 10 to Schedule 160, butt weld pipe fittings are sold the same way. Welded butt weld fittings are more common in stainless steel due to cost advantage. Sch 10 fittings are also more common in stainless steel butt weld fitting.

Welded fittings compliment pipe flanges in any piping system and allows;

  • Change direction of flow in a piping system
  • Connect or joint pipes and equipment
  • Provide branches, access and takeoffs for auxiliary equipment

FAQ

Welded pipe fittings in carbon steel and stainless steel are the joining components that make possible the assembly of valves, pipes and equipment onto the piping system.

These fittings are the most common type of welded pipe fitting and are specified by nominal pipe size and pipe schedule. Buttweld fittings use seamless or welded pipe as the starting material and are forged (through multiple process) to get he shape of elbows, tees and reducers etc.

Fitting standards and certifications

In pipe fittings as well, standards play a vital role.

The manufacture and installation of pipe fittings is tightly regulated by various standards and codes.

Who decides on standards and specifications for butt weld fittings ?

Manufacturers of butt weld pipe fittings have to meet specifications and requirements of many organizations, to assure quality, compatibility and performance of their products.

Key national and international standards organizations focus on materials and end-user industries, including American Society for Testing and Materials (ASTM), American Society of Mechanical Engineers (ASME), International Organization for Standardization (ISO), Norway’s NORSOK, …

Some international organizations also focus on quality standards across all industries, such as International Organization for Standardization (ISO).
Large industrial end-users also have their own programs to certify individual manufacturing plants as meeting their criteria to be listed on their Approved Manufacturers List (AML).

All these certifications and approvals are valid for a specific period, and must be renewed regularly.

Types of pipe fitting standards:

Some widely used pipe fitting standards are as follows:

ASME: American Society for Mechanical Engineers

This is one of the reputed organizations in the world developing codes and standards. The schedule number for pipe fitting starts from ASME/ANSI B16.

The schedule number for pipe fitting starts from ASME/ANSI B16. The various classifications of ASME/ANSI B16 standards for different pipe fittings are as follows:

  • ASME/ANSI B16.1 – 1998 – Cast Iron Pipe Flanges and Flanged Fittings
  • ASME/ANSI B16.3 – 1998 – Malleable Iron Threaded Fittings
  • ASME/ANSI B16.4 – 1998 – Cast Iron Threaded Fittings
  • ASME/ANSI B16.5 – 1996 – Pipe Flanges and Flanged Fittings
  • ASME/ANSI B16.11 – 2001 – Forged Steel Fittings, Socket-Welding and Threaded
  • ASME/ANSI B16.14 – 1991 – Ferrous Pipe Plugs, Bushings and Locknuts with Pipe Threads
  • ASME/ANSI B16.15 – 1985 (R1994) – Cast Bronze Threaded Fittings
  • ASME/ANSI B16.25 – 1997 – Buttwelding Ends
  • ASME/ANSI B16.36 – 1996 – Orifice Flanges etc.



ASTM International:
American Society for Testing and Materials

This is one of the largest voluntary standards development organizations in the world. It was originally known as the American Society for Testing and Materials (ASTM).

  • ASTM A105 / A105M – Specification for Carbon Steel Forgings for Piping Applications
  • ASTM A234 / A234M – Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
  • ASTM A403 / A403M – Specification for Wrought Austenitic Stainless Steel Piping Fittings
  • ASTM A420 / A420M – Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low-Temperature Service

AWWA
American Water Works Association

AWWA About – Established in 1881, the American Water Works Association is the largest nonprofit, scientific and educational association dedicated to managing and treating water, the world’s most important resource.

  • AWWA C110 – Ductile-Iron and Gray-Iron Fittings, 3 Inch Through 48 Inch (75 mm Through 1200 mm), for Water and Other Liquids
  • AWWA C208 – Dimensions for Fabricated Steel Water Pipe Fittings

ANSI:
The American National Standards Institute

The American National Standards Institute
ANSI is a private, non-profit organization. Its main function is to administer and coordinate the U.S. voluntary standardization and conformity assessment system. It provides a forum for development of American national standards. ANSI assigns “schedule numbers”. These numbers classify wall thicknesses for different pressure uses.


MSS STANDARDS
Manufacturers Standardization Society

The Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry is a non-profit technical association organized for development and improvement of industry, national and international codes and standards for: Valves, Valve Actuators, Valve Modification, Pipe Fittings, Pipe Hangers, Pipe Supports, Flanges and Associated Seals

  • MSS SP-43 – Wrought Stainless Steel Butt-Welding Fittings Including Reference to Other Corrosion Resistant Materials
  • MSS SP-75 – Specifications for High Test Wrought Buttwelding Fittings
  • MSS SP-73 – Brazing Joints for Copper and Copper Alloy Pressure Fittings
  • MSS SP-83 – Class 3000 Steel Pipe Unions, Socket-Welding and Threaded
  • MSS SP-97 – Integrally Reinforced Forged Branch Outlet Fittings — Socket Welding, Threaded, and Buttwelding Ends
  • MSS SP-106 – Cast Copper Alloy Flanges and Flanged Fittings Class 125,150, and 300
  • MSS SP-119 – Factory-Made Wrought Belled End Socket Welding Fittings

Difference between “Standard” and “Codes”:

Piping codes imply the requirements of design, fabrication, use of materials, tests and inspection of various pipe and piping system. It has a limited jurisdiction defined by the code. On the other hand, piping standards imply application design and construction rules and requirements for pipe fittings like adapters, flanges, sleeves, elbows, union, tees, valves etc. Like a code, it also has a limited scope defined by the standard.


Factors affecting standards:

“Standards” on pipe fittings are based on certain factors like as follows:

  • Pressure-temperature ratings
  • Size
  • Design
  • Coatings
  • Materials
  • Marking
  • End connections
  • Dimensions and tolerances
  • Threading
  • Pattern taper etc.

BSP:
British Standard Pipe

BSP is the U.K. standard for pipe fittings. This refers to a family of standard screw thread types for interconnecting and sealing pipe ends by mating an external (male) with an internal (female) thread. This has been adopted internationally. It is also known as British Standard Pipe Taper threads (BSPT )or British Standard Pipe Parallel (Straight) threads (BSPP ). While the BSPT achieves pressure tight joints by the threads alone, the BSPP requires a sealing ring.


JIS:
Japanese Industrial Standards

This is the Japanese industrial standards or the standards used for industrial activities in Japan for pipe, tube and fittings and published through Japanese Standards Associations.


NPT:
National Pipe Thread

National Pipe Thread is a U.S. standard straight (NPS) threads or for tapered (NPT) threads. This is the most popular US standard for pipe fittings. NPT fittings are based on the internal diameter (ID) of the pipe fitting.

BOLTS & NUTS

We are manufacturer of Flange bolts & Nuts and supply high quality

  • A193 = This specification covers alloy and stainless steel bolting material for pressure vessels, Valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications.
  • A320 = Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for Low-Temperature Service.
  • A194 = Standard specification for nuts in many different material types.

AN:
Here, “A” stands for Army and “N” stands for Navy

The AN standard was originally designed for the U.S. Military. Whenever, a pipe fitting is AN fittings, it means that the fittings are measured on the outside diameter of the fittings, that is, in 1/16 inch increments.

For example, an AN 4 fitting means a fitting with an external diameter of approximately 4/16″ or ¼”. It is to be noted that approximation is important because AN external diameter is not a direct fit with an equivalent NPT thread.

Dash (-) size

Dash size is the standard used to refer to the inside diameter of a hose. This indicates the size by a two digit number which represents the relative ID in sixteenths of an inch. This is also used interchangeably with AN fittings. For example, a Dash “8” fitting means an AN 8 fitting.

ISO:
International Organization for Standardization

ISO is the industrial pipe, tube and fittings standards and specifications from the International Organization for Standardization. ISO standards are numbered. They have format as follows:

“ISO[/IEC] [IS] nnnnn[:yyyy] Title” where

  • nnnnn: standard number
  • yyyy: year published, and
  • Title: describes the subject

A standard hose guide is given

Hose Size In Nominal ID Inch Dash Size Standard Dash Size
1/4 3/16 -04
3/8 5/16 -06
1/2 13/32 -08
3/4 5/8 -12
1 7/8 -16
1 ½
1 ¼ 1 1/8 -20

Flanges: Ratings in Classes and Pressure Numbers (PN)

Flange Class 150 300 600 900 1500 2500
Flange Pressure Number, PN 20 50 100 150 250 420

A standard hose guide is given below:

Hose Size In Nominal ID Inch Dash Size Standard Dash Size
1/4 3/16 -04
3/8 5/16 -06
1/2 13/32 -08
3/4 5/8 -12
1 7/8 -16
1 ½
1 ¼ 1 1/8 -20

ISO: International Organization for Standardization
ISO is the industrial pipe, tube and fittings standards and specifications from the International Organization for Standardization. ISO standards are numbered. They have format as follows:

“ISO[/IEC] [IS] nnnnn[:yyyy] Title” where

  • nnnnn: standard number
  • yyyy: year published, and
  • Title: describes the subject

JIS: Japanese Industrial Standards

This is the Japanese industrial standards or the standards used for industrial activities in Japan for pipe, tube and fittings and published through Japanese Standards Associations.

NPT: National Pipe Thread

National Pipe Thread is a U.S. standard straight (NPS) threads or for tapered (NPT) threads. This is the most popular US standard for pipe fittings. NPT fittings are based on the internal diameter (ID) of the pipe fitting.

What is an MTR ?

Material Test Reports (MTRs) are provided by manufacturers to certify physical properties and metal grade or alloy for each fitting, flange, pipe, or valve. This MTR is essential for demanding applications (pressure, temperature, corrosion, abrasion,…)

Buttweld Pipe Fitting Specification & Standards

Welded pipe fittings are made as per ASME spec B16.9. ASME B16.9 covers factory made wrought steel butwelding fittings in sizes 1/2″ to 48″. This standard however does not cover low pressure corrosion resistant buttwelding fittings.

ASTM A234 WPB is the Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service.

Specifications 

A234 WPB is the most common material used for carbon steel butt welded fittings.

  • ASTM: A234 WPB
  • ASME: B16.9, B.11
  • NACE: MRO175
  • MSS: SP-83, SP-95

WPB Chemical Composition(%)

Grade

C

Mn

P

S

Si

Cr

Mo

Ni

Cu

Others

max

max

WPB

0.3

0.29-1.06

0.05

0.058

0.1

0.4

0.15

0.4

0.4

V 0.08

(1,2,3,4,5)

max

min

max

max

max

max

max

  • Fittings made from bar or plate may have 0.35 max carbon.
  • Fittings made from forgings may have 0.35 max Carbon and 0.35 max Silicon with no min.
  • For each reduction of 0.01% below the specified Carbon maximum, an increase of 0.06% Manganese above the specified maximum will be permitted, up to a maximum of 1.35%.
  • The sum of Copper, Nickel, Niobium, and Molybdenum shall not exceed 1.00%.
  • The sum of Niobium and Molybdenum shall not exceed 0.32%.

In ASME/ANSI standard, butt welding pipe fittings technical requirements are specified in the standard ASME/ANSI B16.9, including all the types of pipe fittings. In EN standard, it is EN10253 standard for the butt welding pipe fittings.

In JIS, DIN, Ghost standard, different type of butt welding fittings are in different standard number. For example, JIS B2311, B2312, B2313  or GOST 17373, GOST 17375, GOST 17376, GOST 17378 etc.

There are also some other standards about butt welding pipe fittings like:

  • MSS SP-43
  • MSS SP-75
  • ASME B16.49

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