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The Housing, Bolts and Nuts |
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The Housing |
| Standard coupling housings are cast of ductile iron to ASTM A- 536, Grade 65-45-12. Ductile iron conforming to ASTM A-395, grade 65-45-15, is available upon special request. Ductile iron was chosen because of its special combination of better physical characteristics and relative ease of manufacturing to demanding standards. The 65-45-12 refers to the 65,000 psi (448110 kPa) minimum tensile strength, 45,000 psi (310230 kPa) minimum yield strength and 12% minimum elongation. This compares favorably with A53ERW steel pipe having minimum tensile of 60,000 psi (413640 kPa), 35,000 psi (241290 kPa) yield and 25% elongation (typical).Housings are normally two identical castings for couplings through 24" (600 mm) sizes. From 26" (650 mm) up through 102" (2600 mm) sizes, coupling housings are cast in multiple identical segments for assurance of concentricity and ease of handling.Regardless of the style and pressure ratings, certain basic criteria remain for all grooved pipe couplings. The housing is designed to provide the optimum combination of pressure and end load conditions while maintaining reasonable weight and manufacturing characteristics. Every grooved pipe “coupling”, be it a flange adapter, reducing coupling, outlet, rigid or flexible coupling has a similar key section. This engages fully into the groove tying the joint integrally to the pipe. Housing
Materials Product testing is thorough and
continuous during the manufacturing process and after, to assure
final product performance. Quality control starts with testing
raw materials with spectrochemical and physical analysis, computerized
spectrographic and carbon-sulphur analysis. Daily tensile, metallographic
and impact tests are performed.Finished casting integrity is checked
by hydrostatic, air bend and Brinell testing, as well as radiography
and magnetic particle testing. Products are gauged and, where
appropriate, precision dimensions are verified on our optical
comparator.Finished product checks include 100% hydrostatic testing
of all valves. Flow tests are run on appropriate products on our
own test loop which is calibrated to NBS standards. Test loops
have been in operation since 1970 to simulate 24 hour field operating
conditions for various temperatures and fluids. |
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Product Materials |
| Victaulic piping products are available in a variety of materials for assembling pipe of widely varied types. While basic couplings, fittings, valves and accessories are cast of ductile iron, many options are available as outlined below. Always check specific product submittal data for full materials specifications. For gasket materials, refer to the Gasket Selection, Section 05.01.
Ductile Iron
Standard ductile iron to ASTM A-536 (Grade 65-45-12) is the primary metal used for casting couplings, housings, fittings, valves, valve discs and accessory bodies.Ductile iron conforming to ASTM A-395, grade 65-45-15, is available upon special request. • Standard coating – alkyd enamel paint • Optional coating – hot dip galvanizing to ASTM A-153 or zinc electroplating to ASTM B-633 (depend-ing on product) NOTE: Certain specialized castings may optionally be supplied in malleable iron to ASTM A-47 (Grade 32510); specialized fittings may be forged steel conforming to ASTM A-234 Grade WPB or segmentally welded carbon steel pipe conforming to: 3 / 4 - 3 1 / 2 " (20 - 90 mm) ASTM, A-53, Type F; 4- 10" (100 - 250 mm) ASTM A-53, Type E or S, Grade B; 12 - 24" (300 - 600 mm) 0.375" wall to ASTM A-53, Type E or S, Grade B. Bolts and nuts are heat-treated plated carbon steel, trackhead meeting the physical and chemical requirements of ASTM A-449 and physical requirements of ASTM A-183.
Stainless Steel
Stainless steel couplings and valve bodies are cast of Type 316 stainless steel, conforming to ASTM A-351, A-743, A-744, Grade CF-8M. • Optional – Type 304 stainless steel, conforming to ASTM A-351, Grade CF-8 Bolts and nuts are Type 316 stainless steel, oval neck track bolts and heavy hex nuts with chemical and physical properties of ASTM F-593, Group 2, Condition CW. Fittings are Schedule 10 316 (Schedule 5 or 40 and Type 304 available options), made from material conforming to ASTM A-403. Certain configurations requiring fabrication are made from pipe to ASTM A-312.
Aluminum
Aluminum couplings are cast of aluminum alloy 356-T6 to ASTM B-26. Fittings are cast of aluminum alloy 356-T6 to ASTM B-26 or segmentally fabricated from aluminum pipe conforming to ASTM B-241, alloy 6061-T6, Schedule 40; nipples to ASTM B-210 alloy 6061-T6 or 6063-T6, Schedule 40.
Copper (CTS)
Copper tubing (CTS) coupling housings are cast of ductile iron conforming to ASTM A-536 (Grade 65-45-12) and ASTM A-395 (Grade 65-45-15) with a copper colored alkyd enamel coating. Fittings are made from drawn seamless copper tube conforming to ASTM B-75 C 12200 or fabricated from ASTM B-152 C 11000 or bronze sand castings conforming to ASTM B-584 copper alloy C83600(85-5-5-5). Valve bodies are cast bronze per alloy C83600 (85-5-5-5).
AWWA
AWWA couplings and fittings are cast of ductile iron with plated bolts and nuts as above. Fittings conform to specific requirements as outlined in the AWWA Products Section 23.05. |
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Bolts and Nuts |
The
bolts/nuts secure the entire joint together. Unlike flanged systems,
the bolts are not taking the primary load, nor are they functional
in the sealing process. The bolts hold the coupling housings into
the grooves and contain the gaskets. Once tightened (metal-to-metal,
with an offset on rigid couplings), the bolts require no further
tightening. There are no torque specifications for most grooved
couplings as with flange bolts. |
Anatomy of a Groove Pipe Joint Systems and Components