ME 333 – Manufacturing Processes IIME 333 Manufacturing Processes II
Chapter 8Chapter 8
Pipe and Tube Manufacturing
Dr. A. Tolga Bozdanawww.gantep.edu.tr/~bozdana
Mechanical EngineeringUniversity of Gaziantep
Introduction
Pipe & Tube ManufacturingManuf Welded SeamlessManuf. Method
Welded
– Butt or electric welding of
cold forged or rolled sheet
Seamless
– Extrusion
Continuous castingcold forged or rolled sheet – Continuous casting
– Centrifugal casting
– Piercing (Mannesmann, Stiefel, Ehrhardt)
– Röckner
– Spinning
– Swaging
Area of Use
Low & Medium Pressure Applications
– Pipeline constructions
High Temp. & High Pressure Applications
– Hydraulic equipment
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– General purpose – Boiler pipes
Welding of Rolled Sheets
spiral welded pipe
straight-welded pipe
spiral-welded pipe
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Impact Extrusion
forwardextrusion
backwardextrusion
forward & backwardextrusion
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Tube Extrusion
Extrusionfrom solidbillet
Extrusion
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from hollowbillet
Rotary Tube Piercing
R b i i i h i fRotary tube piercing process is the starting stage forseamless pipe and tube manufacturing.
It is about making a void at the core of a solid round barIt is about making a void at the core of a solid round bar(max. Ø12′′) by applying compressive and tensile forcesin reverse directions, and enlarging it between two rolls.
Rotational speeds of rolls are not equal: N1 ≠ N2
Cross angle is about 6°.g
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(1) Void initiation in solid round bar
(2) Cavity formation by enlarging the void
(3) Rotary tube piercing using two rolls and mandrel
Plug-Mill Process (Mannesmann Method)
Thi i d d f ki l i i f hi ll i l l bThis is a standard process for making large quantities of thin-wall stainless steel tube orpipe of uniform size and roundness throughout its entire length:
1 Pi i Th bill t i i d i t h t t i f th t d ti1. Piercing: The billet is pierced in two hot rotary piercers for the greater reduction.
2. Plugging: The pierced billet is placed in a plug-mill to reduce diameter by rotating the tubeover a mandrel.
3. Reeling: Having some ovality, the tube is inserted between rolls of reelers that provide fordimensional correction and burnish inside and outside diameters of the tube.
4. Sizing: Finally, after reheating, the tube reenters a reeler and sizing rollers to provide fort di i l if itgreater dimensional uniformity.
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Plug-Mill Process (Mannesmann Method)
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Tube Drawing
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Tube Spinning
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Other Tubing Methods
Röckner MethodUsed for increasing the inner diameter
f thi ll d t b b f h li l
Ehrhardt MethodPressing into a hot billet with a punch to
l th bill t t di ll (th i
1010
of thin-walled tubes by means of helicalmotion of rollers (Ø800 to Ø1800 mm).
enlarge the billet up to die walls (the innerdiameter of tube is punch diameter).
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