{"id":1548,"date":"2026-09-09T02:34:35","date_gmt":"2026-09-09T06:34:35","guid":{"rendered":"https:\/\/www.songhaiflange.com\/?p=1548"},"modified":"2026-09-09T02:34:35","modified_gmt":"2026-09-09T06:34:35","slug":"stainless-steel-stub-end-types-specifications-lap-joint-flange","status":"publish","type":"post","link":"https:\/\/www.songhaiflange.com\/it\/2026\/09\/09\/stainless-steel-stub-end-types-specifications-lap-joint-flange\/","title":{"rendered":"Stainless Steel Stub End Types and Specifications for Lap Joint Flange Systems"},"content":{"rendered":"

In a piping system that uses a rotating backing flange, the small fitting at the pipe end often decides whether installation is easy or expensive. That fitting is the stainless steel stub end<\/strong>. It is welded to the pipe, while the loose lap joint flange rotates behind it so bolt holes can be aligned without twisting the pipe.<\/p>\n

For buyers, engineers and maintenance teams, choosing the right stub end type<\/strong> is not only a dimensional decision. Material grade, face design, length pattern, pipe schedule and flange compatibility all affect sealing performance and total replacement cost. This guide explains common stub ends<\/strong>, including Type A, Type B and Type C, with a practical table for procurement.<\/p>\n

\n\n\n\n\n\n\n\n\n\n
Stub end option<\/th>\nTypical matching flange<\/th>\nBest use<\/th>\nBuyer note<\/th>\n<\/tr>\n<\/thead>\n
Type A<\/td>\nLap joint flange<\/td>\nGeneral lap joint flange stub end assemblies<\/td>\nMost common choice when the system is designed for a standard lap joint flange.<\/td>\n<\/tr>\n
Type B<\/td>\nSlip-on flange used as loose backing<\/td>\nProjects using a slip-on style backing flange<\/td>\nCheck radius and seating area before ordering.<\/td>\n<\/tr>\n
Type C<\/td>\nLap joint or slip-on backing flange<\/td>\nCustom layouts and repair work<\/td>\nUseful when flange fit must be flexible, but dimensions still need confirmation.<\/td>\n<\/tr>\n
Long pattern<\/td>\nUsually paired with higher-spec pipework<\/td>\nIndustrial piping, chemical and marine service<\/td>\nGives more weld length and transition area.<\/td>\n<\/tr>\n
Short pattern<\/td>\nCompact lap joint assemblies<\/td>\nLow pressure or space-limited systems<\/td>\nCan reduce weight and cost where allowed by specification.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

What Is a Stub End in Piping?<\/h2>\n

A stub end is a short pipe fitting with one flared or lapped end and one welding end. The welding end connects to the pipe. The flared end provides the sealing surface and mechanical shoulder for the loose flange. In daily purchasing language, people may call it a pipe stub<\/strong>, piping stub<\/strong>, stub end flange<\/strong> connection or lap joint flange stub end<\/strong> set.<\/p>\n

The important point is that the loose flange is not welded to the pipe. It can rotate around the stub end. That makes bolt alignment much easier, especially on stainless steel pipe runs, water treatment lines, chemical equipment, marine systems and export projects where repeated dismantling may be required.<\/p>\n

Why Use Stainless Stub Ends?<\/h2>\n

Stainless stub ends<\/strong> are widely used when corrosion resistance matters. Common grades include 304, 304L, 316 and 316L stainless steel. For chloride, seawater or chemical environments, 316L is often selected because of its improved corrosion resistance and good weldability.<\/p>\n

The main advantages are:<\/p>\n

    \n
  • Lower flange cost:<\/strong> only the wetted stub end must be stainless steel in some designs, while the backing flange may use a different material if the specification allows.<\/li>\n
  • Easy bolt alignment:<\/strong> the loose flange rotates after the stub end is welded.<\/li>\n
  • Faster maintenance:<\/strong> the joint can be opened without cutting off a welded neck flange.<\/li>\n
  • Better inventory control:<\/strong> plants can stock standard backing flanges and order specific stub end materials as needed.<\/li>\n<\/ul>\n

    Stub End Type A: The Standard Lap Joint Choice<\/h2>\n

    Stub end type A<\/strong> is designed for use with a lap joint flange. It normally has a machined lap face and a radius that fits the lap joint flange bore. For many pipe specifications, Type A is the first option to check because the geometry is made for the lap joint system from the start.<\/p>\n

    Use Type A when the drawings call for a conventional lap joint flange assembly, when the backing flange must rotate freely, or when the sealing face must remain consistent across repeated assembly and disassembly. If a quotation simply says stainless steel stub end<\/strong> for lap joint flange service, the buyer should confirm whether Type A is required before production.<\/p>\n

    Type B and Type C Stub Ends<\/h2>\n

    Type B is usually associated with slip-on flanges used as loose backing flanges. Its radius and lap details are different from Type A, so substituting one for the other without checking can create poor seating or assembly interference.<\/p>\n

    Type C is more universal in concept. It can be used with lap joint or slip-on style backing flanges in some systems. However, universal does not mean automatic fit. The flange bore, corner radius, lap outside diameter, gasket surface and pipe schedule still need to match the drawing or standard.<\/p>\n

    Short Pattern vs Long Pattern Stub Ends<\/h2>\n

    Stub ends are also ordered by length pattern. Short pattern parts are compact and can save space and weight. Long pattern parts provide a longer body and are common in more demanding industrial pipework. The correct choice depends on the governing standard, pressure class, pipe schedule and owner specification.<\/p>\n

    For stainless steel piping, buyers often request wall thickness by schedule, such as Schedule 5S, 10S, 40S or 80S. A reliable supplier should confirm the pipe outside diameter, nominal pipe size, schedule, material grade, standard and face finish before quoting.<\/p>\n

    Key Specifications to Confirm Before Ordering<\/h2>\n

    When sourcing stub ends<\/strong>, do not rely on the product name alone. A complete inquiry should include the following details:<\/p>\n

      \n
    • Nominal pipe size and outside diameter<\/li>\n
    • Wall schedule or actual wall thickness<\/li>\n
    • Material grade, such as 304L or 316L stainless steel<\/li>\n
    • Stub end type: Type A, Type B or Type C<\/li>\n
    • Short pattern or long pattern length<\/li>\n
    • Matching flange type and pressure class<\/li>\n
    • Standard, such as ASME B16.9 or MSS SP-43 where applicable<\/li>\n
    • Surface finish, packing and inspection requirements<\/li>\n<\/ul>\n

      How a Lap Joint Flange Stub End Works<\/h2>\n

      A lap joint flange stub end<\/strong> assembly works in three parts: the pipe, the stub end and the loose backing flange. The stub end is welded to the pipe. The gasket sits against the lap face. The backing flange applies bolt load from behind the lap. Because the flange is loose, installers can rotate it until the bolt holes align with the mating flange.<\/p>\n

      This is especially helpful for large pipe diameters, prefabricated spools and field installation where fixed flange orientation can create alignment problems. For corrosive service, stainless steel stub ends can protect the wetted area while allowing a cost-controlled backing flange strategy.<\/p>\n

      Applicazioni comuni<\/h2>\n

      Stainless steel stub end assemblies are used in many systems where the pipe may need inspection, cleaning or replacement. Typical applications include chemical processing, water treatment, food-grade utility piping, shipbuilding, desalination systems, pharmaceutical utilities, tank connections and general industrial piping.<\/p>\n

      For export projects, the advantage is not only price. A correctly specified stub end flange<\/strong> connection can reduce installation time, simplify bolt alignment and help maintenance teams remove pipe sections without damaging expensive flanges.<\/p>\n

      FAQ About Stub Ends<\/h2>\n

      What is the difference between a stub end and a flange?<\/h3>\n

      The stub end is welded to the pipe and provides the lap face. The flange is the loose backing ring that supplies bolt force. Together they form a detachable joint.<\/p>\n

      Which stub end type is most common?<\/h3>\n

      Type A is commonly used with lap joint flanges. It is often the first choice when the drawing specifies a standard lap joint flange assembly.<\/p>\n

      Are stainless steel stub ends suitable for corrosion service?<\/h3>\n

      Yes. Stainless steel grades such as 304L and 316L are common. For stronger corrosion resistance, chemical compatibility and chloride exposure should be reviewed before selecting the grade.<\/p>\n

      Can a pipe stub be customized?<\/h3>\n

      Yes. Custom length, special thickness, non-standard material, bevel preparation, marking and inspection documents can be supplied when the buyer provides drawings or detailed specifications.<\/p>\n

      Final Thoughts<\/h2>\n

      The right stainless steel stub end<\/strong> improves fit-up, reduces maintenance cost and helps a lap joint flange system work as intended. Before placing an order, confirm the stub end type<\/strong>, material grade, pipe schedule, length pattern and matching flange dimensions. Songhai Flange can support standard and custom stub ends for industrial piping projects, including stainless stub ends, pipe stub fittings and lap joint flange stub end assemblies for export applications.<\/p>","protected":false},"excerpt":{"rendered":"

      A practical guide to stainless steel stub end options, stub end type A, pipe stub dimensions, lap joint flange stub end selection and piping stub applications.<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[420,417,450,419,421],"tags":[611,613,434,460,612,436,607,608,610,462,605,465,609,603,606,604],"class_list":["post-1548","post","type-post","status-publish","format-standard","hentry","category-engineering-guide","category-flange-knowledge","category-flange-selection","category-industrial-piping","category-technical-resources","tag-asme-b16-9","tag-industrial-piping","tag-lap-joint-flange","tag-lap-joint-flange-stub-end","tag-mss-sp-43","tag-pipe-fittings","tag-pipe-stub","tag-piping-stub","tag-stainless-steel-pipe-fittings","tag-stainless-steel-stub-end","tag-stainless-stub-ends","tag-stub-end-flange","tag-stub-end-specifications","tag-stub-end-type","tag-stub-end-type-a","tag-stub-ends"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/posts\/1548","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/comments?post=1548"}],"version-history":[{"count":1,"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/posts\/1548\/revisions"}],"predecessor-version":[{"id":1549,"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/posts\/1548\/revisions\/1549"}],"wp:attachment":[{"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/media?parent=1548"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/categories?post=1548"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.songhaiflange.com\/it\/wp-json\/wp\/v2\/tags?post=1548"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}