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

11

– General purpose – Boiler pipes

Welding of Rolled Sheets

spiral welded pipe

straight-welded pipe

spiral-welded pipe

22

Impact Extrusion

forwardextrusion

backwardextrusion

forward & backwardextrusion

33

Tube Extrusion

Extrusionfrom solidbillet

Extrusion

44

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

55

(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.

66

Plug-Mill Process (Mannesmann Method)

77

Tube Drawing

88

Tube Spinning

99

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).