Introduction

Pipe fittings are piping component that helps in changing the direction of the flow such as elbows, tees; changes the size of the pipe such as reducers, reducing tees; connect different components such as couplings and stop the flows such as caps, fittings.

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As one of the biggest manufacturer of steel pipes and pipe fittings manufacturer in India, Metallica carries inventory of over 15,000 tons in its warehouses in Mumbai, Maharashtra India.

Pipe Fittings Manufacturing Process

Pipe fittings are manufactured from Seamless Pipe and from Welded Pipe with filler material. Large diameter fittings are manufactured from plate. Various methods used are: &#;

Butt-Welding Manufacturing Processes

1. Elbow Manufacturing Process

a. Mandrel Method/Hot Forming Method

• One of the most common manufacturing methods for manufacturing Elbows from pipes.
• After heating the raw material, it is pushed over a die called &#;mandrel&#; which allows the pipe to expand and bend simultaneously. Applicable to a wide size range.
• Characteristics of mandrel bending strongly depend on the integrated shape and dimensions of the mandrel.
• Elbows manufactured by using hot mandrel bending have advantages of small thickness deviation and shorter bending radius than those of any other bending method type.

b. Extrusion Method/Cold Forming Method

• In the cold extrusion method, a pipe with the same diameter as a finished product is pushed through a die and formed into its desired shape. Usually applied to stainless steel small to medium sizes elbows.

c. &#;UO&#; Method (Welding)

• In this method the plate is cut out into a specially designed shape, it is formed first into a U-shape using a die and then into an O-shape or tubular form using another die, that is why this method is known as UO method. Once the fittings formed in tumbler shaped it is welded from inside and outside of the closing seam. A cut plate is 1st from in U shape and then in O shape

d. Hot Forming Die Bending Method

• In this method the pipe is been inspected before any process. Then after cutting out pipe into specified length, it goes under elliptical forming using a die shown in the picture. For producing a specified radius for elbow, it bends in another die. In the next step the elbow goes under heat treatment. In the end shot blasting, cleaning, beveling and coating are done respectively to finalize the product.

2. Tee Manufacturing Process

a. Hydraulic Bulge Method (Cold Forming)

• Cut piece of Pipe is placed in hydraulic die and liquid is fill inside the pipe, Hydraulic pressure pushes out the branch, in the fixed opening in the die.
• This method gives the good surface finish. However, higher thickness Tee cannot be manufactured by this method.

b. &#;Monaka&#; Method

• This manufacturing method is similar to Elbows, using steel plates as the raw material.
• In this method two pieces of raw material plates cut out symmetrically and are press-formed and welded together.

c. Hot Extrusion Method

• Tee with large diameters, heavy wall thickness and/or special material with challenging workability that cannot be manufactured using the hydraulic bulge method are manufactured using hot Extrusion Method.
• In Hot Extrusion Method, normally bigger diameter pipe is used than the finished product size, the branch outlet is extruded from the pipe with help of extrusion tool.
• Other dimensions of body and branch can also be adjusted by pressing the die if required.

3. Reducer Manufacturing Process

a. Outer Die Method

• One of the most common method for manufacturing Reducers is using an outer die.
• The pipe is cut and pressed in the outer die; compressing the one end of the pipe into a smaller size. This method is useful for manufacturing of small to medium size of reducers.

b. Plate Forming Method

• Plates can also be used to manufacture Reducers.
• In an UO method, plate is cut in a specially designed shape which is formed into a U-shape and an O-shape respectively, then finished with a single weld seam.

4. Cap Manufacturing Process

a. Deep Drawing Method

• CAPs are manufactured by Deep Drawing method. In this method, Plate is cut out in a circle and formed by deep drawing die.

5. Stub End Manufacturing Process

a. Flaring Method

• Stub Ends or Lap Joints Flange are manufactured by flaring method. Pipe end is a flare or spared out to form flange face. Stub ends are also manufactured by forging in which forge block are machined to final dimension.

Forged Fittings Manufacturing Processes

1. Open-Die Forging

Open die forging is the process of deforming a piece of metal between multiple dies that do not completely enclose the material. The metal is altered as the dies &#;hammer&#; or &#;stamp&#; the material through a series of movements until the desired shape is achieved. Products formed through open forging often need secondary machining and refining to achieve the tolerances required for the finished specifications. Open die forging is often used for short run forgings of parts that are simple, rather than complex, in design, such as discs, rings, sleeves, cylinders and shafts. Custom shapes can also be produced with open die forging. The repeated working of the material through the deformation process increases the strength of the grain structure. Some additional benefits of open die forging include improved fatigue resistance and strength.

2. Closed-Die Forging

Closed die forging (also referred to as impression die forging) is a metal deformation process that uses pressure to compress a piece of metal to fill an enclosed die impression. In some closed die forging processes, a succession of impression dies is used to modify the shape of the material into the final desired shape and form. The type of material, tightness of tolerances, and need for heat treatment can determine the number of passes the product requires through the dies.

Advantages and Disadvantages of Open Die Forging and Closed Die Forging

Open Die ForgingClosed Die ForgingAdvantagesBetter fatigue resistance and improved microstructureThe internal grain structure formation increases the tightness and strength of the productsContinuous grain flow and finer grain sizeEconomic for large runs of productsValuable cost of savingsDimensions of tighter tolerances and net shapes can be achievedLess material wasteNo material limitationIncreased strength and longer part lifeBetter surface finishReduced chance of voidsLess or no matching required DisadvantagesIt is not capable of forming close tolerance and higher precision partsIt is not very economical for short runs due to high cost of die productionMachining is often required to achieve accuracies and the desired featuresClosed die forging presents a dangerous working environmentThe setup cost is very high as the machines and furnaces are costlySpecial building provisions must be in place to cope with the powerful vibrations

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Fittings are divided into the following 4 groups:

Metallica is a specialist manufacturer and supplier of various types of pipe fittings in India such as butt-welding pipe fittings (both weld and no weld), socket welding and threaded pipe fittings, and flanged pipe fittings. We are a professional manufacturer of stainless steel pipes, carbon steel pipes and alloy steel pipes, seamless butt-welding pipe fittings, forged fittings and flanges. We have the CE PED & ISO etc. certificates.

One of the Largest Manufacturer, and Supplier of Pipe, Pipe Fittings, Flanges and Fasteners in India &#; If you are interested in purchasing high quality pipe fittings, please contact us now for prices and product details. Us on | Call Us On +.

Ziheng are exported all over the world and different industries with quality first. Our belief is to provide our customers with more and better high value-added products. Let's create a better future together.

Butt Welded

Elbows

Manufacturing

Introduction to Hot Forming

The principal methods of hot working are extrusion, drawing, forging and rolling. Rolling is the most extensive employed forming process, though some limitations may apply to the process. Rolling mainly consists of three major sub-categories.. flat rolling, shape rolling (with specifically designed roll grooves) and pipe rolling (including piercing). Forging may be sub-categorized as hamming, pressing, etc.

Forging may be performed under hammers, in mechanical presses and upsetters or by a method known as roll forging. Pressing generally includes the manufacture of forged articles in hydraulic presses. Extrusion usually is performed in hydraulic presses which force the hot steel through a die. Rolling is performed in rolling mills of a variety of types.

The two principal reasons for perform metal forming at elevated temperatures (hot working) are to reduce the forming loads through the reduction of the resistance of the steel to deformation, and to develop preferred metallurgical structures for strength and ductility of the finish products.

The most appropriate manufacturing method of a product will be decided with consideration of its material, sizes, shape, use, standards and other properties.

There are numerous processes for manufacturing butt weld fittings, several examples listed as follows.

Elbow.. Mandrel method (Hot Forming)

One of the most common manufacturing methods for manufacturing Elbows from pipes. After heating the raw material, it is pushed over a die called "mandrel" which allows the pipe to expand and bend simultaneously. Applicable to a wide size range.

Elbows of steel pipe joints are used in the industrial plants and are mainly manufactured by the hot mandrel bending from raw material of straight steel pipe. Elbows are generally manufactured at elevated temperature by means of pushing, expanding and bending of pipes simultaneously, using the inner tool of mandrel. Characteristics of mandrel bending strongly depend on the integrated shape and dimensions of the mandrel.

Elbows manufactured by using hot mandrel bending have advantages of small thickness deviation and shorter bending radius than those of any other bending method type.

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Result

All the steps mentioned above give a brief explanation (the basic principle) about Hot forming, extrusion method. Many more steps are needed, but hopefully the pictures give a good description.

References..
Benkan Japan KK
G. Dieter.. Mechanical Metallurgy, 2nd Ed.
Making, Shaping and Treating of Steel.
Kurt Lange.. Hand Book of Metal Forming. SME.

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