Frequently Asked Questions

Our sales staff is available to answer any questions you have concerning our products, services or their uses. E-mail us at: inquiry@hackneyladish.com

Frequently Asked Questions Concerning Fittings

• Where do you produce?
  
  Hackney Ladish, Inc.'s Plants have multiple capabilities and capacity but generally the following products are produced / distributed at these locations:

  	GeneralDescription	Primary Production	Distribution Center
  Fittings - Tees	1/2"to 8" 10"  to 24" 26"& Larger	Enid, OK Enid, OK Russellville, AR	Russellville, AR Russellville, AR Russellville, AR
  Fittings - Elbows	Cold Form Elbows < 4" Hot Form Ells 5" & > Heavy Wall Elbows HY/Alloy Elbows 3R Elbows	Russellville, AR Russellville, AR Russellville, AR Russellville, AR Russellville, AR	Russellville, AR Russellville, AR Russellville, AR
  Fittings - Weld Cap	All	Enid, OK	Russellville, AR
  Fittings - Reducers	Up to 10" 10" & Larger	Enid, OK Enid, OK	Russellville, AR Russellville, AR

• If a weld fitting to A234 requirements has a reported yield strength in excess of 42,000, can it be used as an SP 75 fitting of grade WPHY 42?
  
  NO! SP 75 would require the fitting to be heat-treated and impact tested to be certified as compliant. Further, A234 would allow use of mill tensile results in the as formed condition under some forming methods and this may or may not represent the actual properties in the fitting. The only sure way of knowing whether the fitting has uniform properties throughout is to heat treat and test. This may not be done on a WPB fitting.
• What is "sour service" and do Hackney Ladish, Inc. fittings comply?
  
  Sour service is generally defined as service involving hydrogen sulfide bearing hydrocarbon fluids of varying concentrations. This service presents special problems relating to sulfide stress cracking (SSC). In order to maximize resistance to SSC, the oilfield industry and NACE developed the standard MR0175 for Sulfide Stress Cracking Resistant Metallic Materials for Oilfield Equipment. All Hackney Ladish, Inc. fittings comply with requirements of MR0175 and can be used in nearly all-sour service applications. If severe service applications require additional precautions beyond MR0175, we can supply those fittings on request.
• Why are fittings "heavier" than mating pipe and what controls the end preparation for welding?
  
  Fittings require reinforcement to make them as strong as seamless pipe of the same diameter, wall and material grade as designated by the marking on the fitting. In addition, forming methods or pipe availability could dictate use of heavier material to ensure adequate strength. This results in a heavier body thickness and a requirement to machine the welding ends to match the pipe. ASME B16.9 or B16.25 Figure 1 shows the maximum machining envelope for welding end transitions to comply with the B31 Piping Code requirements for matching components of unequal wall thickness. This figure provides for taper boring the ID at 18 degrees maximum, taper turning the OD at 30 degrees maximum, or a combination of both to hold the specified fitting end tolerances.
• What is the difference between a 3R and a 3D elbow?
  
  There is no difference. Both have a centerline radius of three times the nominal size. MSS SP75 calls them 3R rather than 3D as usually associated with bend radii.
• What does "field segmentable" mean?
  
  Elbows are sometimes required to be cut in the field to odd angles to change the direction of the pipeline. When this is done, it is hoped that the cut end of the elbow segment will match up to the pipe with little fit-up required. This is accomplished by ordering elbows suitable for segmenting. They will be sized within 1% out-of-round throughout the fitting. Normal production of elbows can be up to 2 1/2% out-of-round and may be difficult to segment and match to pipe. 1% out of roundness is guaranteed only before torching and we highly recommend the use of fit up clamps for all field work with segmentable fittings.
• What is "out-of-round?"
  
  Out-of-round is defined as the difference between the maximum diameter (I.D. or O.D.) and the minimum diameter as measured in any plane cut through a fitting.
• What is the pressure rating of a butt welding fitting?
  
  Butt welding fittings have ratings equivalent to the pipe they are intended to mate as indicated by the diameter, wall and material designation stamped on the fitting. Calculate the pipe thickness required based on the appropriate piping code formula and match the fitting of the same wall and material grade.
• What is the DOT Certification for fittings?
  
  This refers to the requirement in the Department of Transportation, Title 49, Code of Federal Regulations, Part 192 or 195, which requires a fitting manufacturer to certify that his fittings are as strong as the mating pipe based on prototype testing. Hackney Ladish, Inc. will provide a letter of certification upon request.
• Do the tolerances on diameters and wall thickness given in B16.9 or MSS SP75 apply throughout the fitting?
  
  No. The tolerances on diameters (I.D. or O.D. ) apply only at the ends. The minimum wall thickness applies throughout the fitting, but there is no maximum wall other than that implied at the ends based on diameter tolerances.
• What is the difference between diametric tolerances and circumferential tolerances?
  
  When measuring diametrically by scale, all diameters measured in a given plane must fall within the tolerance band. The resultant out-of-round can be no greater than the sum of the plus and minus tolerance. When measuring circumferentially, you take a series of diameter readings in a given plane, add them all together, and take the average. The average diameter must fall within the specified tolerance range. Or you can get the same result by measuring with a pi tape that measures the circumference and converts it to a equivalent diameter. When using this method, you must also have a maximum out-of-round. Since some diameters can be over or under the specified diameter and tolerance (but average within), you must also take the difference between the highest and lowest reading and this out-of-round cannot exceed that specified.
• Can concentric or eccentric reducers be supplied without straight sections on the ends (bell shaped)?
  
  Yes. However, the piping Codes require conical reducers to be designed in accordance with rules that typically would limit the cone angles and require thicker sections to compensate for the high resultant stress levels when mating to pipe.
• Can tees be produced by cutting a hole in straight pipe and "nipple" in another pipe at ninety degrees and meet ASME B16.9?
  
  No. B16.9 specifically prohibits intersection type welds. Such methods of manufacture have design rules in the piping codes that must be complied with. The parts cannot be stamped WPB.
• What are your recommendations for cutting field segment elbows?
  
  This document details our recommendations for cutting field segment elbows.