Lecture 1 Las-lasan

8/20/2019 Lecture 1 Las-lasan

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BK20A0401 Modern Welding Technology 1

Responsibles Persons: Dr. Paul Kah and Lic. Raimo Suoranta

Theoretical work load is 182 hours.

• Lectures (1stperiod) – 24 h

• Lectures ( 2nd Period)-24 h

• Laboratory tutorials (1st &2ndperiod) – 14 h

o Obligatory

• Term paper, with presentation (1st period 1st&2ndperiod)- 16 h

o Obligatory

• Evaluation

o Exam 80%- term paper with presentation 20%

28 September2014 BK20A0401 ModernWeldingTechno logy

3

• Slides

• Your own notes

• Literatures

-ModernWeldingTechnology, SixthEdition: Howard B. Cary &Scott c. Helzer

-WeldingScience & Technology, Ninth Edition, Volume 1, AWS

• Internet

8 S eptember 2 014 BK 20A0401 Modern Wel di ng Technology

• Welding is the only way of joining material to formuniformconnection and the mostcommon way of joining

• Welding isvery efficient way to join materials

• Welding is vital to economy

• Welding ranks high among

industrial processes andinvolves more sciences andvariables than those involved inany other industrial process

• It is often said that over 50 –70% of the gross nationalproduct is related to welding inone way or another

8 September 2014 4BK20A0401 ModernWelding Technology




• The most common joining method on mechanicalengineering

• Parts are joint together or gladded utilizing heatand/or pressure so that the parts make up uniformconnection

• Filler material may be used

o Melting point about same as parent material

• Weldingprocessesaredividedin twogroups:

o Fusion welding

o Pressure welding

• Solid state welding


Some of the advantages of welding are:

• lowest cost,

• permanent joining method.

• lighter weight through better use of materials

• It joints all commercial metals

• It can be used anywhere

• It provides design flexibility


7

Welding has limitations. Some of this limitations are:

• Requires suitable procedures .

• Manual weldingis humanfactor dependent.

• Required suitable inspections to assure quality.

These limitations can be overcome bymeans of:

• Nondestructive test,

• Good supervision,• Qualified procedures,

• Qualified personals,

• Mechanized welding methods.

8 September 2014 BK20A0401 Modern Welding Technology 8

• Weldingis expectedtogrowdue toitseconomic advantage:

o Intelligently designed weldments will be always lessexpensive than similarapplications than products madebyothermanufacturingmethods.

• Welding will continue to dominate the materials joiningindustry because the productivity of welding is being

increased. This is due to reduce of overall cost as aconsequenceof:

o Improvedfiller metalswithhigherdepositionrate

o Increaseusedof computercontrolledweldingequipmentandprocesses.





5500 B.C. Egyptians recognize “forge welding” forcopper and gold

800 “Damascus Sword”-steel forge weldedto high strength

1877 Electric resistance welding possibility

1905 Concept of coated electrodes

1910 Oxyacetylene cutting and weldingtechniques

1932 Gas shielded welding

1960 Laser and electron beam welding,friction welding

1990 Robotics

2000-> Hybrid processes

8 September 2014 9BK20A0401 Modern Welding Technology 8 September 2014 10

• Fumes

• UV-radiation

• Noise

•Ergonomcs

•…

Work

env ronment

•Processes

•Equipment

• Mechan zation/Automaton

/ Robotization

Welding

• Base materals

• Fil ler materials

• Assi stant materials

•Weld

Metalurgy • Strengh calcuations

• Fat igue design

• DFM

Design

• Qualitysystems

• Qualified welders

• Testing

• …

Quality

BK20A0401 ModernWelding Technology

• Processes

• Metallurgy

• Automation

• Productivity

• Quality


• MIG/MAG

• TIG

• PAW

• SAW

• Beam processes

• Hybrid welding processes

• Friction

• EGW/ESW

• SMAW

• Cutting





13

The industries where welding is either a primary product or a critical enablingtechnology:

o Miningandoil andgasextraction.

o Heavyconstruction,i.e.cross-countrypipingandotherpipelines.

o Primarymetalmanufacturing,weldingis mostlyusedfor maintenancepurposes.

o Fabricated metal products (e.g. pressure vessels, tanks, machine bases, prefabricatedmetalbuildings).

o Machinery manufacturing (e.g. agricultural, mining, metal working machine, cranes,bulldozers).

o Welding andsoldering equipment, (e.g.manufacturingof welding equipment, machines a

robots).

o Electricalequipment

o Transportation-motorvehicle

o Transportation-railroadrollingstock

o Transportation-shipandboatbuilding

o Repair andmaintenance


A number of safety and health problems areassociated with welding. These hazards are:

• Electrical shock• Arc radiation• Air contamination• Fire and explosion

• Compressed gases• Welding cleaning• Other hazards related to specific welding

processes or occupations.


• Aircraft and Airspace

all connections are done bywelding

8 September 2014 15

Welding assembly of an airplane chassis

BK20A0401 Modern Welding Technology 8 September 2014 16


all connections are done bywelding







• Shipbuilding and offshore

SAW welding, MIG/MAG welding



Hybrid and laser welding







• Automotive and land transport

8 September 2014 21

Welding assembly of a

truck chassis

Automotive robotic welding

assembly of a car body


Parts of an automobile

assembly which arewelded


• Automotive

8 September 2014 23

Automotive production use alot of welding for cars

aluminium frames


• Automotive





• Automotive

8 September 2014 25

Welding of dissimilarmaterials


• Trains and railroad


• Thermite welding


• Bicycles

MIG and MAG, TIG

welding





• Bicycles


• Bicycles


• Oil industry and pipelines

8 September 2014 31

Welding pipeline in severeenvironment conditions

GMAW welding of a pipe in afactory

Winter welding shelter


• Oil storage tanks

8 September 2014 32

Welding for oilrelatedapplicationsshould be goneaccording to

strict regulations,as even smallamount ofdefects in a weldcan cause afailure





• Nuclear reactors


• Household appliances


• Furniture


• Bridges and structures





• Buildings

8 September 2014 37

Nowadays welding isused in constructionmoreand moreoften


• Leisure structures


• Jewelry ndustry


• Jewelry ndustry





8 September 2014 41

• Artand sculptures


• Repairwelding

TIG welding

1

2

3


8 September 2014 43

• Repairwelding


• Underwaterwelding

8 September 2014 44

Underwater weldingmask





• Underwaterwelding

8 September 2014 45

UnderwaterweldingchamberUnderwater inspectingand weldingrobot


• Etc…


8 September 2014 BK20A0401 Modern Welding Technology

47

48

Butt Tee

Lap Corner

Edge





49

Tounderstandweldingitisnecessarytobefamiliarwiththebasictermsusedbyindustry.

•Weldng: is a joiningprocessthatproducescoalescence a ofmaterialsbyheatingthemtotheweldingtemperature,with or withoutapplication ofpressureor bythe applicationof pressurealone,andwithor withouttheuseof fillermetal.

•Weldment:is anassemblywhosecomponentpartsarejoinedbywelding.

• Joint: is thejunction of members orthe edge ofmembers that areto bejoinedor havebeenjoined.

•Weld: it is veryimportantto distinguishbetween jointand weld. Thereare differenttypesofweldandtheyarebestdescribedbytheirshapewhenshownincross-section.

•Fillermetal:is ametaloralloytobe addedinmakingwelded,brazed,orsolderedjoint.

a. Coalescenceis defineda s thegrowingtogetheror growthinto onebodyof thematerials beingwelded.

8 September2014 BK20A0401 ModernWelding Techno logy

• Groove weld

Used to weld members aligned in the same plane

• Fillet weld

Typically members are perpendicular situated


• Butt weld

o Between mating members

o High weld preparation cost

• accuracy

o “Difficult” to weld

• Fillet weld

o

Easypreparationo Asymmetric loads, lower design loads

• Plug & slot welds

o Modified fillet welds in lap joints,using holes through one member


• Simple & cheap to assemble &weld

• Stress concentrations at toes &root

• Notch at root (fatigue, toughness)

• Critical dimension is throatthickness

• Root gap affects throat thickness• Radiography & ultrasonic testing is

of limited use

• Large fillets use a lot of weld metal& therefore are uneconomic

Lap joint





Single vee

can be s ingle

or double welded

Single bevel

Double vee

Backing permanent or temporary)


Flat Horizontal

VerticalUp or Down

Overhead

Horizontal vertical


Axis vertical Axis horizontal Axis inclined 45°


Land

Root radius“U” preparation

Double “U” butt





57

Joint root is “ that portion of a joint

to be welded where the membersare closest to each other”

The joint roots are shown as shaded

areas in (A)-(D) and lines in (E) (F)


Groove face is “ that surface of a

member included in the groove”Root face (land) is “that portion ofthe groove face within the joint

root”

Root edge is a root face of zero

width


Fusion face

Root face

Rootgap

Included angle

Bevel angle

Root run Toe

Toe

Reinforcement

Groove

Weld

8 September 2014 BK20A0401 Modern Welding Technology 59 60

• Root opening isthe separationbetween thework pieces atthe joint root

• Bevel is anangular edgepreparation





Weld face

Root

Toe

Toe

Base

metal

Base

metal

Weld

metal

Weldmetal

Throatthickness Throat

thickness8 September 2014 BK20A0401 Modern Welding Technology 61

Root penetration

Total throat

thickness

Effective

penetration



• Proper groove is one of the things that ensure good quality

• Proper groove is essential also in relation to welding costs

64

Groove angle

Shape

Size

Cleanliness

Root face

Fusion face

Root edge

Edge angle

Bevel angle

Root face





• Welding process

• Welding position

• Material

• Mechanization

• Possible root support

658 S eptember 2 014 BK 20A0401 Modern Wel di ng Technology

• I-groove =>2 mm, mechanized welding =>4 mm

– Air gap ~material thickness

– Mechanized welding – no air gap

• V – groove 5-15 mm material thickness, groove angle 60o

• Thicker materials – narrow gap or U-groove


• Thin materials – lap joint

• I – groove 1-4 mm

• Against support ->8 mm

• V-groove >5mm (>50o)

o Air gap 1-3 mm


• I – groove

o =>8 mm, single side

o =>16 mm, single sided against backing

o =>20 mm, double sided

• Y -groove

o =>25 mm, double sided

• X – groove

o 16 - 35 mm, two runs

o Root face 2-8 mm

• Narrow gap





• Typically always I – groove

o =>8 mm (12 mm)

o Zero air gap

• Typically always I – groove

o =>8 mm (20 mm)/ =>300 mm

o Zero air gap


• If the fluidity of molten material is low, the groove anglemust be wider

• The groove must be very clean when welding Ti, Cu, Ni


• Natural groove from the joint

• Thick plates -bevel

o Over 12 mm


Documents

Lecture 1 Las-lasan