• A Alloy 20 Seamless Socket Weld Fittings is made directly from a section of seamless pipe material, by applying heat and pressure to transform pipe directly into an elbow or other shape.
• A seamless fitting has no welded parts by itself, a characteristic demanded in some critical applications.
• By comparison, a regular Socket Weld fitting has one, two or more welds, depending on dimension, shape and manufacturing method.
• No weld means less risk of weld yield and porosities.

• ASTM B462 Alloy 20 Socket Weld Fittings are measured by their diameter, wall thickness (known as “schedule”), and shape or configuration. (Fittings are also defined by their material grade and whether they are welded or seamless.)
• Diameter refers to outside diameter of a pipe or fitting.
• The North American standard is known as Nominal Pipe Size (NPS). The International Standard is known as Diameter Nominal (DN). Alloy 20 Socket Weld Fittings are actually made in similar sizes around the world: they are just labeled differently.
• From ½ in to 12 inch “Nominal Pipe Size”, outside diameters are slightly larger than indicated size; inside diameters get smaller as schedules grow.
• From 14 in and larger “Nominal Pipe Size”, outside diameters are exactly as indicated size; inside diameters get smaller as schedules grow.
• As with other North American standards (inch, foot, yard, mile, …), many pipe standards (diameters up to 12 inch and wall thickness) are based on historical precedents (a toolmaker’s dies during US Civil War) rather than a “scientific” method.

What is schedule 40, sch80 ?

• Schedule, often shortened as sch, is a North American standard that refers to wall thickness of a pipe or Socket Weld fitting. Higher schedules mean thicker walls that can resist higher pressures.
• Pipe standards define these wall thicknesses: SCH 5, 5S, 10, 10S, 20, 30, 40, 40S, 60, 80, 80S, 100, 120, 140, 160, STD, XS and XXS. (S following a number is for Alloy 20. Sizes without an S are for carbon steel.)
• Higher schedules are heavier, require more material and are therefore more costly to make and install.

• 45 and 90 refer to angles for changing direction of pipe flows: 45 degrees or 90 degrees. Most elbows are 45˚ or 90˚.
• SR means Short Radius; LR means Long Radius. Centerline radius of long radius (LR) elbows is smoother than of short radius (SR).
• In SR fittings, radius equals nominal diameter size. A 6 inch pipe will have a 6 inch radius center-to-end, giving it a sharp curve.
• In LR fittings, radius equals 1.5x nominal diameter size. A 6 inch pipe will have a 9 inch centerline radius, for a smoother curve than SR.

• A Alloy 20 concentric reducer is symmetrical: both ends are aligned along the center.
• An Alloy 20 eccentric reducer is not symmetrical: ends are off center of one another.

• Fitting design is based on yield strength.
• Steel products do not all have similar potential. Yield strength can be changed by steel thickness, its chemical composition and heat treatments.
• Yield strength refers to ability of materials to maintain a load or pressure without permanent deformation. (In this case, yield does not refer to manufacturing productivity of materials or equipment.)

• Planning : based on B462 Alloy 20 Socket Weld Fittings specifics and client requirements; includes creating part identification in manufacturing system.
• Selection of raw material: metal; plate or pipe.
• Cutting
• Heating.
• Forming.
• Welding: for Alloy 20 Socket Weld Pipe Fittings that are not simple elbows, returns, bends, reducers or caps.
• Inspection and Tests: according to standards and client requirements.
• Coating (if required).
• Preparation of documentation.
• Shipping.

ASTM B462 Alloy 20 Socket Weld Fittings  covers the standard for wrought austenitic Alloy 20 Socket Weld Fittings for pressure piping applications. The material for fittings shall consist of forgings, bars, plates, or seamless or welded tubular products. Forging or shaping operations shall be performed by hammering, pressing, piercing, extruding, upsetting, rolling, bending, fusion welding, machining, or by a combination of two or more of these operations. All fittings shall undergo heat-treatment.

ASTM B462 Alloy 20 Socket Weld Fittings  covers the standard for is a standard specification for Alloy 20 Socket Weld Fittings. These Socket Weld Fittings have very good ductility, good weldability. These Alloy 20 Socket Weld Fittings are manufactured in both seamless and welded forms such as elbow, tee, reducers, cap, bend, stub-end, collar, cross, etc.

ASME SB462 Alloy 20 Welded Fittings  "as‐welded" fittings are welded using ASME qualified welding procedures and can be  supplied in a wide range of diameters and wall thicknesses frim any of the weldable corrosion resistant alloys. Welding elbows can be provided with smooth flow or mitered construction, tees and crosses can be drawn outlet or nozzle‐ welded types and reducers can be conical or bell‐shaped manufacturers "as‐ welded" fittings to ANSI B16.9, ANSI B16.28 or MSS SP‐43 dimensions, with weld ends furnished square cut. Fitting with special dimensions or those that require beveled. belied or roll‐grooved ends ca be provided. Spot radiography or 100% radiography of weld de seams can also be perf d orme . its fittings to maintain corrosion resistance and to prevent surface discoloration from free iron oxidation. "As‐welded" fittings are commonly used with "as‐welded" pipe and tubing in pulp and paper mills, food processing plants and other industries where corrosion resistance is essential.

• This specification covers wrought ASTM B462 Alloy 20 Socket Weld fittings for pressure piping applications.
• Several grades of austenitic Alloy 20 alloys are included in this specification. Grades are designated with a WP or CR based on the applicable ANSI or MSS dimensional and rating standards, respectively.
• For each of the Alloy 20 grades, several classes of fittings are covered, to indicate whether seamless or welded construction was used. Class designations are also used to indicate the nondestructive test method and extent of nondestructive examination (NDE). A table gives the general summary of the fitting classes applicable to all grades of Alloy 20 covered by this specification. There are no classes for the CR grades. Specific requirements are covered under another specification.
• This specification is expressed in both inch-pound units and in SI units. However, unless the order specifies the applicable "M" specification designation (SI units), the material shall be furnished to inch-pound units.
• The values stated in either inch-pound units or SI units are to be regarded separately as the standard. (A combination of values from the two systems may result in nonconformance with the specification.) 
• This specification does not apply to cast steel fittings. Austenitic Alloy 20 castings are covered in Specifications A 351/A 351M, A 743/A 743M, and A 744/A 744M.

Several grades of austenitic Alloy 20 alloys are included in this specification. Grades are designated with a prefix, based on the applicable ASTM/ASME or MSS standards. For each of the Alloy 20 grades, several classes of fittings are specified, to indicate whether seamless or welded construction was utilized. Class designations are also utilized to indicate the nondestructive test method and extent of nondestructive examination. A general summary of the fitting classes applicable to all Alloy 20 grades of Alloy 20 follows. There are no classes for the CR grades.

Material furnished to B/SB462* shall conform to the requirements of Specification including any supplementary requirements that are indicated in the purchase order. In case of conflict between B/SB462* and Specification A960/A960M, this specification shall prevail.

Long Radius Elbows,Long Radius Reducing Elbows,Long Radius Returns,Short Radius Elbows,Short Radius 180-deg Rerurns,3D elbows,Straight Tees,Straight Crosses,Reducing Outlet Tees,Reducing Outlet Crosses,Lap Joint Stub Ends, Caps,Reducers.as per standard ASME B16.9 /B16.28 /MSS SP43 /MSS SP75 .

• Standard : ASME/ANSI B16.9, ASME B16.28, MSS-SP-43
• Manufacturers of Socket Weld 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.

150 lb Alloy 20 cast Socket Weld fittings are manufactured through the process of heating metal to a molten/liquid state and pouring the metal into a vessel creating the desired shape. The fitting product is then created to specification through a finishing process. Cast products are sometimes larger in size because it is an easier and more affordable process compared to forging, which creates a product from a solid state. Casting also has advantages with custom alloys where these metals can be added in the molten stage.

"This Standard covers overall dimensions, tolerances, ratings, testing, and markings for wrought Alloy 20 factory-made Socket Welding fittings of NPS 1/2 through 48. It covers fittings of any producible wall thickness. This standard does not cover low pressure corrosion resistant Socket Welding fittings. See MSS SP-43, Wrought Alloy 20 Socket Weld Fittings. Short radius elbows and returns, which were previously included in ASME B16.28-1994, are included in this standard. ANSI B16.9 is to be used in conjunction with equipment described in other volumes of the ASME B16.9 series of standards as well as with other ASME standards, such as the Boiler and Pressure Vessel Code and the B31 Piping Codes".

ANSI B16.9 - ‘Factory-Made Wrought Socket Welding Fittings”

ASTM B462 Alloy 20 Socket Weld Fittings are the most common type of steel fittings used for pipelines above 2 inches of diameter. They are used to change the pathway of the pipeline (elbows), reduce / increase its flow size (reducers), branch (tees, cross) or close it (cap), and are connected to pipes by welding. Socket Welding fittings are available in multiple shapes as elbows, tees, reducers, crosses, etc and in a wide range of diameters (from 1/2 to 48 inches), schedules (5/5s, 10/10s, 40/40s, 80/80s, XS/XH, XXS, 160, etc) and material grades (the most common are ASTM B462 for Alloy 20 wrought fittings). BW fittings are available in seamless and wekded execution (respectively < 24 / > 24 inch)

• A Alloy 20 Socket Weld pipe fittings is designed to be welded on site at its end(s) to connect pipe(s) together and allow change in direction or pipe diameter, or branching or ending.
• This fitting then becomes part of a system for transporting fluids (oil, gas, steam, chemicals, …) in a safe and efficient manner, over short or long distances.
• Other types of fittings can be threaded or socket welded.