{"id":2061,"date":"2025-04-25T11:18:46","date_gmt":"2025-04-25T03:18:46","guid":{"rendered":"https:\/\/www.ductileironsuppliers.com\/?p=2061"},"modified":"2025-06-17T15:10:24","modified_gmt":"2025-06-17T07:10:24","slug":"can-ductile-iron-pipe-be-threaded","status":"publish","type":"post","link":"https:\/\/www.ductileironsuppliers.com\/ar\/can-ductile-iron-pipe-be-threaded.html","title":{"rendered":"\u0647\u0644 \u064a\u0645\u0643\u0646 \u0631\u0628\u0637 \u0623\u0646\u0627\u0628\u064a\u0628 \u062d\u062f\u064a\u062f \u0627\u0644\u062f\u0643\u062a\u0627\u064a\u0644 \u0628\u0627\u0644\u062e\u064a\u0648\u0637\u061f"},"content":{"rendered":"

While ductile iron pipe is predominantly joined using push-on, mechanical, or flanged connections, it can<\/strong> be threaded\u2014but only in specific contexts such as flanges, fittings, and tapped bell ends rather than plain-end pipe. The American Water Works Association (AWWA) codifies threaded flanges for ductile iron pipe under ANSI\/AWWA C115<\/strong>, and common pipe\u2010thread standards (e.g., ASME B1.20.1<\/strong> NPT) apply to companion flanges and fittings. Threading plain-end pipe is not standard practice because it reduces wall thickness and can compromise pressure rating; instead, manufacturers provide threaded flanges<\/strong>, threaded mechanical joint bells<\/strong>, and threaded fittings<\/strong> (elbows, tees, nipples) to facilitate NPT connections when needed. For most underground water-main installations, push-on or mechanical joints (AWWA C111) are preferred due to ease of assembly and deflection capability, with threaded options reserved for service taps, wall pipes, and above-ground connections.<\/p>\n

\"Can<\/a>
Can Ductile Iron Pipe Be Threaded?<\/figcaption><\/figure>\n

1. Joint Methods for Ductile Iron Pipe<\/h2>\n

1.1 Push-On (Slip-Type) Joints<\/h3>\n

The push-on joint<\/strong> is the simplest bell-and-spigot connection, relying on a rubber gasket compressed by the spigot to form a seal without threading. It allows up to 5\u00b0 deflection per joint and is widely used for buried mains.<\/p>\n

1.2 Mechanical (Gland-Type) Joints<\/h3>\n

Mechanical joints use a gland and bolts to compress a gasket in the bell, offering restraint options and easy installation; these joints are not<\/strong> inherently threaded, but the bell or companion flange may be tapped<\/strong> for studs with NPT threads for mounting or restraint.<\/p>\n

1.3 Flanged Joints<\/h3>\n

Flanged ductile iron pipe ends are either cast or welded-on, then drilled and tapped per AWWA C110<\/strong> and ASME B16.42<\/strong>; companion flanges conform to ASME B1.20.1<\/strong> (NPT) for threaded connections above ground.<\/p>\n

2. Threaded Connections in Detail<\/h2>\n
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 <\/p>\n

\n\n\n\n\n\n\n\n
Threaded Component<\/th>\nStandard<\/th>\nApplication<\/th>\n<\/tr>\n<\/thead>\n
Companion Flange<\/strong><\/td>\nAWWA C115, ASME B1.20.1<\/td>\nAbove-ground or wall-pipe connections; tapped for NPT studs.<\/td>\n<\/tr>\n
Threaded Fittings<\/strong> (Elbows, Tees, Nipples)<\/td>\nASTM A536, ASME B16.3<\/td>\nNPT threaded cast & ductile-iron fittings for service lines.<\/td>\n<\/tr>\n
Mechanical Joint Bell (Tapped)<\/strong><\/td>\nAWWA C111<\/td>\nBell end tapped to accept threaded studs or connectors.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n
    \n
  1. \n

    Companion Flanges<\/strong>: 150 lb and 300 lb ductile-iron flanges are available with NPT threads per ASME B1.20.1<\/strong>, conforming to AWWA C115<\/strong>.<\/p>\n<\/li>\n

  2. \n

    Threaded Fittings<\/strong>: Cast & ductile iron elbows, tees, and cross fittings offered in NPT sizes up to 6\u2033, meeting ASTM A536<\/strong> and ASME B16.3<\/strong>.<\/p>\n<\/li>\n

  3. \n

    Tapped Bells<\/strong>: \u201cWall pipe\u201d assemblies often use mechanical joint bells tapped (threaded) for studs or service connections, enabling through-wall piping without threading the pipe barrel.<\/p>\n<\/li>\n<\/ol>\n

    3. Advantages & Limitations of Threading<\/h2>\n

    3.1 Advantages<\/h3>\n