What is a buttweld pipe fitting ?
· A butt weld pipe fittingis designed to be welded on site at its end(s) to connect pipe(s) together andallow change in direction or pipe diameter, or branching or ending.
· This fitting then becomes part of a systemfor transporting fluids (oil, gas, steam, chemicals, …) in a safe and efficientmanner, over short or long distances.
· Other types of fittings can be threaded orsocket welded.
What are advantages of butt welding over flanges ?
· Flanges connectpipes by bolting them together, whereas butt weld fittings connect pipes bywelding them together.
· Depending on size, butt weld fittingsrequire 10% to 75% less material than a flanged connection, which means lowermaterial cost and lower weight.
· Welded construction permits greaterfreedom in designing a layout; this system uses less space, is more compact,and has greater strength.
· Butt weld fittings provide optimum flowcharacteristics, without pockets or sharp corners, creating less frictionalresistance, no pressure loss, less turbulence, …
What is a seamless butt weld fitting ?
· A seamless butt weld pipefitting is made directly from a section of seamless pipe material, by applyingheat and pressure to transform pipe directly into an elbow or other shape.
· A seamless fitting has no welded parts byitself, a characteristic demanded in some critical applications.
· By comparison, a regular butt weld fittinghas one, two or more welds, depending on dimension, shape and manufacturingmethod.
· No weld means less risk of weld yield andporosities.
What is PVF ?
· PVF means Pipe, Valve and Fittings, and iswidely used as short-hand to describe this industry.
· PVFs can be made in a variety of metals orplastics.
· Manufacturers typically specialize inspecial types of materials; distributors can carry narrow or very broad productlines.
FITTINGS APPLICATIONS AND MARKETS
In what industriesare pipe fittings
Fittings are usedwherever liquids, gases, chemicals and other fluids are created, processed,transported, or used. Range of industries is very wide, as shown below:
· Energy related. Oil and gasindustries, including upstream (exploration and production), midstream(transportation by ships, pipeline, rail, trucks; storage and wholesale) anddownstream (refining into fuels or chemicals; marketing and distribution).Power plants using fossil or nuclear fuels. Geothermal energy for harnessingheat from the earth.
· Food and beverage production. From basic ingredients to elaborate desserts. From milk, to juices andother beverages. Cold chain to keep produce fresh, drinks and frozen foods at aset temperature. Desalination plants to transform seawater into drinking waterfor arid areas and various tropical islands.
· Pharmaceuticals and biotech production. Medicines and vaccines that treat illnesses and helprestore bodies and minds to their top conditions.
· Semiconductor manufacturing: Microchips that go into all electronics, including smartphones, tablets,computers, television sets, telecom networks, …
· Pulp and paper production. Newsprint, glossy paper, cardboard boxes, books, writing paper, …
· Production of construction materials andplastics. From roofing materials, to glassmaking for windows, to copper wiring fortransporting electricity, and various plastics throughout houses and officebuildings.
FITTING SIZES AND DIMENSIONS
How are pipe fittings measured ?
· Pipe fittings are measured by theirdiameter, wall thickness (known as “schedule”), and shape or configuration.(Fittings are also defined by their material grade and whether they are weldedor seamless.)
· Diameter refers to outside diameter of apipe or fitting.
· The North American standard is known asNominal Pipe Size (NPS). The International Standard is known as DiameterNominal (DN). Pipes and fittings are actually made in similar sizes around theworld: they are just labeled differently.
· From ½ in to 12 inch “Nominal Pipe Size”,outside diameters are slightly larger than indicated size; inside diameters getsmaller as schedules grow.
· From 14 in and larger “Nominal Pipe Size”,outside diameters are exactly as indicated size; inside diameters get smalleras schedules grow.
· As with other North American standards(inch, foot, yard, mile, …), many pipe standards (diameters up to 12 inch andwall thickness) are based on historical precedents (a toolmaker’s dies duringUS Civil War) rather than a “scientific” method.
What does“schedule” mean for pipe fittings ?
What is schedule40, sch80 ?
· Schedule, often shortened as sch, is aNorth American standard that refers to wall thickness of a pipe or pipefitting. Higher schedules mean thicker walls that can resist higher pressures.
· Pipe standards define these wallthicknesses: 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 stainless steel. Sizes without anS are for carbon steel.)
· Higher schedules are heavier, require morematerial and are therefore more costly to make and install.
Why are fittings sometimes thicker and heavier than pipes to which they are connected ?
· Fittings are sometimes thicker than theirconnecting pipes to meet performance requirements or due to manufacturingreasons.
· Due to fitting geometry, stress is verydifferent when compared to a pipe. Using extra material is often necessary tocompensate for such additional stress, especially for tees and tight curveelbows.
· Fitting manufacturers may not always stockplates or pipes for all metal grades or sizes. When responding to an order,manufacturers always use the right metal or alloy, but sometimes made withnext-higher available plate or pipe size while still respecting specifiedinside diameters.
What does 45 SR or90 LR mean for pipe fittings ?
· 45 and 90 refer to angles for changingdirection of pipe flows: 45 degrees or 90 degrees. Most elbows are 45˚ or 90˚.
· SR means Short Radius; LR means LongRadius. Centerline radius of long radius (LR) elbows is smoother than of shortradius (SR).
· In SR fittings, radius equals nominaldiameter size. A 6 inch pipe will have a 6 inch radius center-to-end, giving ita sharp curve.
· In LR fittings, radius equals 1.5x nominaldiameter size. A 6 inch pipe will have a 9 inch centerline radius, for asmoother curve than SR.
What is the difference between a 3R and a 3D elbow?
· There is no difference between 3R and 3D.Both have a centerline radius of three times the nominal diameter size. Bothhave a smoother curve than an SR or LR.
· (In fittings, 3D does not refer tomodeling software or screens.)
What does 3D or 6Dmean for pipe fittings ?
· Larger numbers have smoother curves.
· Centerline radius is calculated based ondiameter and number that precedes it. For example, a 10″ 6D has a 60″centerline radius.
· Smoother curves are often used forapplications with higher pressure, abrasion or corrosion.
What is the difference between concentric and eccentric reducers ?
· A concentric reducer is symmetrical: bothends are aligned along the center.
· An eccentric reducer is not symmetrical:ends are off center of one another.
What is a lateralpipe fitting ?
· A lateral separates one line into two; thesecond line branches at a 45˚ angle.
FITTING STANDARDS AND CERTIFICATIONS
Who decides on standards and specifications for butt weld fittings ?
· Manufacturers of butt weld pipe fittingshave to meet specifications and requirements of many organizations, to assurequality, compatibility and performance of their products.
· Key national and international standardsorganizations focus on materials and end-user industries, including AmericanSociety for Testing and Materials (ASTM), American Society of MechanicalEngineers (ASME), International Organization for Standardization (ISO),Norway’s NORSOK, …
· Some international organizations alsofocus on quality standards across all industries, such as InternationalOrganization for Standardization (ISO).
· Large industrial end-users also have theirown programs to certify individual manufacturing plants as meeting theircriteria to be listed on their Approved Manufacturers List (AML).
· All these certifications and approvals arevalid for a specific period, and must be renewed regularly.
What is an MTR ?
· Material Test Reports (MTRs) are providedby manufacturers to certify physical properties and metal grade or alloy foreach fitting, flange, pipe, or valve. This MTR is essential for demandingapplications (pressure, temperature, corrosion, abrasion,…)
Why do manufacturers offer such a large variety of metals and materials ?
· Pipes and fittings are used in manyapplications and many industries that have widely different operatingconditions.
· To reach best performance (resistance tovarious types of corrosive fluids, operating temperature, …) at acceptablecosts, many metals have found unique niche applications in fittings.
Why choose a specificmaterial, or grade, or schedule for a fitting ?
· Choice of material or grade or schedule isnot made by distributors or by fitting manufacturers, but by engineers whodesign pipelines or systems based on performance requirements and acceptablecosts.
· Engineers take into account key operatingconditions and environment: pressure, temperature, abrasion, corrosion,vibrations, …
· Fitting materials also have to bechemically compatible with pipe materials to which they are connected to avoidinter-metal corrosion, and for weldability.
· Finally, cost of various materials variesgreatly.
What does “highyield” (“HY”) mean for pipe fittings ?
· Yield strength refers to ability ofmaterials to maintain a load or pressure without permanent deformation. (Inthis case, yield does not refer to manufacturing productivityof materials or equipment.)
· Fitting design is based on yield strength.
· Steel products do not all have similarpotential. Yield strength can be changed by steel thickness, its chemicalcomposition and heat treatments.
What is thedifference between a manufacturer and a supplier of fittings ?
· Manufacturers own machines, presses andequipment to actually make fittings from pipe or plate.
· Suppliers are intermediaries betweenmanufacturers and end-users: suppliers can be wholesalers, distributors, EPCs,…
· In some cases, end-users need to speakdirectly to manufacturers to get the fittings they need when they need them.
Can fitting manufacturers in North America and Europe compete with low-labor-cost countries?
· Butt weld fittings are used in the mostdemanding applications: oil & gas, nuclear, chemicals, …
· A butt weld pipe fitting looks like asimple product, but many things can go wrong during design and manufacturing,causing problems later in the field: scratched inner surface, thinner wall atoutside radius, oval fittings, out-of-specs welding-end finish, invisiblecracks, wrong chemical composition of steel grade, …
· Manufacturing close to end-users in NorthAmerica or Europe with experienced and highly skilled workers assures highestquality.
· Also Western manufacturers can compete byemphasizing technology, product development and highly efficient manufacturingprocesses.
· (Of course, dumping by foreign competitorsof imported fittings at prices below production costs is not an acceptablecompeting practice.)
How are pipefittings manufactured ?
Key steps inmanufacturing process are as follows:
· Planning: based on fittingspecifics and client requirements; includes creating part identification inmanufacturing system.
· Selection of raw material: metal; plate or pipe.
· Welding: for fittingsthat are not simple elbows, returns, bends, reducers or caps.
· Inspection and tests: according to standards and client requirements.
· Coating (ifrequired).
· Preparation of documentation.
What is a heatinduction mandrel ?
· In this very efficient manufacturingmethod, a pipe is pushed over a die called “mandrel”, then expanded and bent todesired dimensions.
· In this process, heat is transferred to apipe by applying an electric current (known as “induction”) around the steelpipe and gas flames under the neck (intrados) to minimize material thinning onthis region and to make forming operation easier. Mandrels are used to makeelbows from ½ inch to 72 inch diameters.
DESTRUCTIVE AND NON-DESTRUCTIVE TESTING
Why and how oftenare pipe fittings tested ?
· Pipe fittings are tested to assureconformity with standards and performance in their applications.
· Standard, commodity fittings are tested bysampling during manufacturing process, with both destructive andnon-destructive approaches.
· Custom-made fittings are regularly testedduring manufacturing process with non-destructive approaches, as required forthe application or as specified by end-users.
What is the difference between a destructive and a non-destructive test ?
· After a destructive test,fittings can no longer be used in the field, because they were bent, pulled orabused until breakage point. For this reason, destructive tests can only beperformed on a small sample of fittings; otherwise, all fittings would bedestroyed during tests.
· A non-destructive testmeasures performance for regular operating conditions, or by means that do notdestroy the fitting.
What are mostfrequent destructive tests for fittings?
· Bending: fittings arebent until deformation appears on their side, face or root.
· Charpy impact: named afterGeorges Charpy who developed it, this test measures toughness of a fitting bydetermining the amount of energy absorbed during its fracture from impacts.
· Corrosion: fittings areexposed to corrosive fluids or materials until corrosion appears.
· Metallographic: this test studiesphysical structure and components of metal samples, typically by microscopy.Samples are taken from actual fittings.
· Tension: fittings arestretched until deformation appears; measures are taken for strength, yield,elongation.
What are most frequent non-destructive tests for fittings?
· Dye or liquid penetrant: low-cost test to detect surface hairline cracks or porosity in fittings,by applying a special liquid to its surface.
· Ferrite content: ferrite content in Duplex, Super Duplex and stainless steel has to bejust right to achieve yield strength, fracture toughness and corrosionresistance. Ferrite content is measured in weld seams by magnetic induction.
· Hydrostatic: a fitting isfilled with a liquid, often colored water, and pressure is applied; measurementsare taken to see if there is pressure loss due to any defects.
· Magnetic particles: uses a magnetic field to detect surface or slightly subsurfacediscontinuity or weakness in a fitting.
· Macrography: makesphotographs, sometimes in 3 dimensions, of items visible to naked eye.
· Micrography: uses microscopesto make photographs of metal and obtain information about its properties.
· Pneumatic pressure: a fitting is filled with pressurized air; measurements are taken to seeif there is pressure loss due to any defects.
· Positive material identification: analysis of a metal alloy by identifying percentage for each of itselements. Uses specialty equipment, including X-ray fluorescence or opticalemission spectrometry.
· Radiography: uses X-rays orgamma rays to detect any weakness in fittings.
FLANGES DIMENSION AND TYPE
How do I Inquiry a flange?
Quantity / Size (nominal pipe size) / Pressure Class (150-2500) / Facing(RF, FF, RTJ, ect.) / Type (WN, SO, Threaded, Blind, SW, LJ) / Bore (if SW orWN) / Material / Example 2EA 4” 300# RFWN STD 304
Do you sell Reducing Flanges? If so, why can’t I find dimensions for them?
Yes, we sell reducing flanges (WN, SW, SO, Thrd) with the hubs or madefrom blinds (in the cases of SO or Thrd). B16.5 gives rules for how we do thereductions, but to my knowledge nobody produces the cut sheets. If you considerthe various combinations possible it would get quite lengthy.
For reducing flanges with hubs, all dimensions except the Length Thru Hub(or OAL) come straight from the regular flange dimensions.
From the larger size:
OD, Thk, Bolt pattern, RF Dia
From the smaller size:
OD at base of hub
OD at point of weld
IF (dependent on schedule)
Using abbreviations found in the catalog, here’s how you can calculate theOAL for a reducing weldneck:
Hub height = L2 – thk [all dims per smaller size]
LTH = Hub height + thk(of larger size) + face height
As an example, for a 4” x 3” 600# RF Red WN XH, one would calculate theLTH as follows: Hub height = 3.25 – 1.25 = 2.00” LTH – 2.00 + 1.50 + 0.25 =3.75”
How do I call out a Slip On Flange above 24”?
Depends entirely on what you are trying to accomplish. It you want a partthat is automatically covered under ASME Code then forget the Slip-on ‘s anduse a Weld Neck from B16.47 Series A or B. If you don’t need to meet code orcan run the calculations for your application then the options open up:
For the Standard 150# drilling we offer the “Class 125/ 150#” series.These are made per B16.1 which is a cast Iron Spec. We make them most often inCarbon Steel per A105. In addition we run them in Stainless 304 and 316 and allthe other alloys too. Since the spec is for Cast Iron and the applications inindustry usually call for another material these are made “per B16.1 Dimensionsonly.” There is also a much less commonly used Class 250 option.
In addition there are 150#, 300#, 400#, 600#, 900# Slip-on’s that weredesigned by Tube Turns to match the MSS-SP-44 spec (which was almost 100%brought into ANSI B16.47 under Series A. These were designed to meet ASME Codeunder current revision but they were designed in prehistoric times so in manycases they do not meet current design criteria. Nevertheless they are used on afrequent enough basis that we stock the contoured forgings in A105 and do adecent amount of business getting the rolled rings to make them in othermaterials.
Also we are asked to make Slip-on’s to match the B16.47 Series Bdimensions. For this there is an agreed upon industry standard method thatprovides no calculations but has gained wide acceptance. The basic designincludes cutting down the weld neck forging and opening the ID.
Still more options remain as Taylor Forge designed many “Boiler Code”flanges that serve to add Slip-On options in various classes. These parts aredrilled per their design and do not match any other standard. The classesoffered are 75, 175, and 350. For the dated information on pressure temperatureallowance see Taylor Forge Catalog 541 or contact us.
Finally, the American Waterworks Association (AWWA) under their spec C207has designs on a series of plate Slip-on flanges in Class B, D, E, and F. Theyalso have hubbed slip-on’s in Class D and E.
What’s the difference between Series A andSeries B?
The short answer is Series A tend to be larger, heavier, have fewer boltholes, and cost more. The longer answer is these were competing specificationsthat where brought together in B16.47 as is put forth in a note from ourcatalog: ASME has incorporated most of the MSS-SP44 specification into B16.47Series A and most of the API 605 Specification into B16.47 series B. They havealso added Blinds to these two specs. You may note that these specs includeonly Weld Necks and Blinds. For Slip-On’s over 24” you must refer to eitherIndustry Standard (which are not automatically covered by ASME) or Boiler CodeFlanges. If you need help deciding which flange best suits your applicationfeel free to contact us.
Do you provide expedited service? How muchextra does it cost?
We have a joke around the office about the fellow who calls up and askshow much a flange costs. “Depends, which one of the 82 million differentconfigurations do you need?” We do offer expedited service, but giving any kindof rule of thumb on cost is hard to do. It really comes down to what materialis needed and which processes have to be interrupted or ran in overtime.Suffice to say, we will always trade sleep for money and can usually turn partsout in a much quicker manner than “standard lead time” if you need it. The onecaveat to this is if it takes 5 hours to machine the part then the quickest wewill ever be able to quote is 5 hours. With that in mind, please feel free toask for the impossible and we’ll quote what we can.
Why doesn’t your catalog show API dimensions?
API doesn’t let us publish them in table format. For this reason, wepioneered the concept of the electronic slide rule for API flanges. Check itout here.
What’s the difference between Sch40, True 40and Sch40s in larger sizes?
The industry standard is to specify “TRUE 40” to distinguish Sch40 boresfrom Std bores for 12” NPS and larger when the application calls for theheavier wall.
The industry standard is to specify “TRUE 80” to distinguish Sch80 boresfrom XH bores for 10” NPS and larger when the application calls for the heavierwall.
Normally, when “Sch80” and “Sch40” are used without any other qualifiersuch as wall thickness or ID, XH and Std bores (respectively) will be supplied.
When Sch40 or 80 are specified followed by a “S” they are automaticallyassumed to refer to Std and XH respectively.
What type of Carbon Steel Should I specifyfor AWWA Flanges?
AWWA C207 specifies parameters for the carbon steel. The criteria givenallows for A283, A36, A516-70, A105, and A181-60 to be used. Limiting your specto any of one of those can double or triple your costs. So for general purposeswe recommend leaving the material callout for AWWA Carbon steel flanges as“Carbon Steel per AWWA.” You will get a part that meets the design criteria setforth in AWWA and you won’t pay a premium for a “preferred” material.
What's a DSA?
DSA stands for Double Studded Adaptor. DSA's are designed to joindissimilar endpoints through bolting each side into it. The DSA is faced andpartially drilled and tapped to match the flange or the flanged connection oneach opposing side . An example is shown here with nuts and bolts but these aresold separately as particular applications can require nonstandard lengths.