Welding Symbols Weld Preparations

Embed Size (px)

DESCRIPTION

Welding Symbols

Citation preview

  • 7/18/2019 Welding Symbols Weld Preparations

    1/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    TWICSWIP 3.1

    WIS 5WELDING INSPECTION

    WELDING SYMBOLS ANDWELD PREPARATION

  • 7/18/2019 Welding Symbols Weld Preparations

    2/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Joints may be indicated:- by detailed sketches, showing every dimension

    - by symbolic representation

    Weld symbols on drawings

  • 7/18/2019 Welding Symbols Weld Preparations

    3/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    A method of transferring information from thedesign office to the workshop is:

    The above information does not tell us much aboutthe wishes of the designer. We obviously need somesort of code which would be understood by everyone.

    Most countries have their own standards for symbols.

    Some of them are BS 499 Part 2, AWS A2.4 &

    BS EN 22553 (ISO 2553)

    Please weld here

    Weld symbols on drawings

  • 7/18/2019 Welding Symbols Weld Preparations

    4/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Advantages of symbolic representation:

    Weld symbols on drawings

    Disadvantages of symbolic representation:

    simple and quick plotting on the drawing

    does not over-burden the drawing

    no need for additional view

    gives all necessary indications regardingthe specific joint to be obtained

    used only for usual joints

    requires training for properlyunderstanding of symbols

  • 7/18/2019 Welding Symbols Weld Preparations

    5/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Usually, the symbolic representationincludes:

    Weld symbols on drawings

    The elementary symbol may be completed by:

    an arrow line

    a reference line

    an elementary symbol

    a supplementary symbol

    a means of showing dimensions

    some complementary indications

  • 7/18/2019 Welding Symbols Weld Preparations

    6/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld elementary symbols

    Various categories of joints are characterised byan elementary symbol.

    This symbol is similar to the shape of the weld tobe made.

    Square butt weld

    Weld type Sketch Symbol

    Single V butt weld

  • 7/18/2019 Welding Symbols Weld Preparations

    7/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld elementary symbols

    Single-V buttweld with broadroot face

    Weld type Sketch Symbol

    Single bevelbutt weld

    Single bevel butt

    weld with broadroot face

    Backing run

  • 7/18/2019 Welding Symbols Weld Preparations

    8/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld elementary symbols

    Single-U

    butt weld

    Weld type Sketch Symbol

    Single-Jbutt weld

    Fillet weld

    Surfacing

  • 7/18/2019 Welding Symbols Weld Preparations

    9/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Convention of the arrow line (BS EN & AWS):

    Arrow line

    a) Shall touch the joint intersection

    b) Shall not be parallel to the drawingc) Shall point towards a single plate preparation(when only one plate has preparation)

  • 7/18/2019 Welding Symbols Weld Preparations

    10/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Convention of the reference line AWS A 2.4

    Reference linea) Shall touch the arrow line

    b) Shall be parallel to the bottom of the drawing

  • 7/18/2019 Welding Symbols Weld Preparations

    11/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Convention of the reference line(BS EN ISO 22553):

    or

    Reference linea) Shall touch the arrow line

    b) Shall be parallel to the bottom of the drawing

    c) There shall be a further broken line above orbeneath the reference line (Not necessary wherethe weld is symmetrical!)

  • 7/18/2019 Welding Symbols Weld Preparations

    12/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Welds on arrow sideof joint go underneath thereference line while welds the other sideof the joint,go on top of the reference line

    Symbols with a vertical line component must be drawnwith the vertical line to the left side of the symbol

    All CSA dimensions are shown to the left of the symbol

    All linear dimensions are shown on the right of thesymbol i.e. number of welds, length of welds, length of

    any spaces

    Included angle and root opening are shown on top ofthe symbol

    AWS A 2.4 rules

  • 7/18/2019 Welding Symbols Weld Preparations

    13/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    10 3 x 50 (70)

    AWS A 2.4 rules-example

    10

    50

    70

  • 7/18/2019 Welding Symbols Weld Preparations

    14/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Welds this side of joint, go on the unbroken reference

    line while welds the other side of the joint, go on thebroken reference line

    Symbols with a vertical line component must bedrawn with the vertical line to the left side of the

    symbol

    All CSA dimensions are shown to the left of thesymbol

    All linear dimensions are shown on the right of thesymbol i.e. number of welds, length of welds, lengthof any spaces

    Included angle and root opening are shown on top of

    the symbol

    BS EN 22553 rules

  • 7/18/2019 Welding Symbols Weld Preparations

    15/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    z 10 3 x 50 (50)

    BS EN 22553 rules - example

    10

    50

    50

    All leg lengths shall be preceded by z and throat by a

    or s (in case of deep penetration welds)

  • 7/18/2019 Welding Symbols Weld Preparations

    16/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    8

    8

    5

    5 x 8

    8

    Fillet weld dimensions according AWS A 2.4Fillet welds

    5 leg on

    vertical

    member

  • 7/18/2019 Welding Symbols Weld Preparations

    17/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    5

    a 5 (z 8)

    8

    Fillet weld dimensions according BS EN 22553

    or

    8

    z 8or

    z 8

    a 5 (z 8)

    Fillet welds

  • 7/18/2019 Welding Symbols Weld Preparations

    18/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Intermittent fillet welds

    Chain intermittent fillet weld

    length (l)pitch (e) a

    z

    a nl(e)a nl(e)

    z nl(e)z nl(e)

    or

    Symbol to BS EN 22553

  • 7/18/2019 Welding Symbols Weld Preparations

    19/54Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Intermittent fillet welds

    Chain intermittent fillet weld

    length (l)pitch (e)

    z

    z l - ez l - e

    Symbol to AWS A2.4

  • 7/18/2019 Welding Symbols Weld Preparations

    20/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Intermittent fillet welds

    Staggered intermittent fillet weld

    length (l)pitch (e) a

    z

    a nl (e)a nl (e)

    z nl (e)

    z nl (e)

    or

    Symbol to BS EN 22553

  • 7/18/2019 Welding Symbols Weld Preparations

    21/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Intermittent fillet welds

    Staggered intermittent fillet weldlength (l)pitch (e)

    z

    z l - ez l - e

    Symbol to AWS A2.4

    e/2

  • 7/18/2019 Welding Symbols Weld Preparations

    22/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Concave or Convex

    Supplementary weld symbols

    Toes to be groundsmoothly (BS EN only)Site Weld

    Weld all round

    Supplementary symbols

  • 7/18/2019 Welding Symbols Weld Preparations

    23/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Supplementary weld symbols

    Ground flush

    111

    Further supplementary information, such as WPSnumber, or NDT may be placed in the fish tail

    Supplementary symbols

    Welding processnumerical BS EN

    MR

    Removable

    backing strip Permanent

    backing strip

    M

  • 7/18/2019 Welding Symbols Weld Preparations

    24/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Fillet weld

    Double V

    Double bevel

    Double U

    Double J

    Representation of welds done from both sidesofthe joint intersection, touched by the arrow head

    Double side weld symbols

  • 7/18/2019 Welding Symbols Weld Preparations

    25/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Example:

    Produce a drawing giving symbols for the weld givenas shown below to the specification AWS A2.4

    Weld Drawing

    Symbol Drawing

    MMA

    Weld symbols on drawings

  • 7/18/2019 Welding Symbols Weld Preparations

    26/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Example:

    Draw the symbols for the weld given as shownbelow to the specification BS EN 22553

    Weld drawing

    Symbol Drawing 111

    Weld symbols on drawings

    MMA

  • 7/18/2019 Welding Symbols Weld Preparations

    27/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    1020

    30

    35

    15

    7

    Student symbols exerciseComplete a symbols drawing for the welded jointgiven below to AWS A2.4 & BS EN 22553

    All fillet weld leg lengths are 10 mm

    Weld symbols on drawings

  • 7/18/2019 Welding Symbols Weld Preparations

    28/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Solution AWS A2.4 10302010

    10351510

    Weld symbols on drawings

  • 7/18/2019 Welding Symbols Weld Preparations

    29/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Solution BS EN 22553 z 10s 30s 20z 10

    a 7 z 10s 35s 15z 10

    Weld symbols on drawings

  • 7/18/2019 Welding Symbols Weld Preparations

    30/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    This has major effects on economics and distortioncontrol!

    The basic rule is this:

    The more you take out, then the more you must putback in!

    The purposes of a weld preparation is to allowaccess for the welding process, penetration andfusion through the area of the joint and its faces

    Weld preparations

  • 7/18/2019 Welding Symbols Weld Preparations

    31/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Weld preparation depend on:welding process

    preparation method available

    access

    type of joint

    type of parent material

    thickness

    welding position

    in-service type of loadingWeld preparation for arc welding - see BS EN 29692!

  • 7/18/2019 Welding Symbols Weld Preparations

    32/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Welding process impacts upon weld preparation

    Arc welding EBW

  • 7/18/2019 Welding Symbols Weld Preparations

    33/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Welding process impacts upon weld preparation

    MMA MAGhigh heat input process allow a larger root face, less weldmetal required, less distortions, higher productivity

    if gap is too big risk of possible burn-through

    if gap is too small risk of lack of penetration

  • 7/18/2019 Welding Symbols Weld Preparations

    34/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Preparation method impacts upon weld

    preparation

    Requires machining slow andexpensive

    Tight tolerance easier set-upCan be flame/plasma cut fastand cheap

    Large tolerance set-up can bedifficult

  • 7/18/2019 Welding Symbols Weld Preparations

    35/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Preparation method impacts upon weld preparation

    Variations incutting line

    Root face too large lack ofpenetration

    Root face too small burn-through

    Variations incutting angle

    Included angle too largeheavy distortions, increase

    amount of filler metalrequired

    Included angle too smalllack of penetration, lack ofside wall fusion

  • 7/18/2019 Welding Symbols Weld Preparations

    36/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Preparation method impacts upon weld

    preparation - corrective measures

    Backing strip (6 mm ormore, same material)

    No root face

    Root face too large Recut groove preparationIncrease root gap anduse backing strip

  • 7/18/2019 Welding Symbols Weld Preparations

    37/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Preparation method impacts upon weldpreparation - corrective measures

    Too big/too smallincluded angle Recut groove preparation

    Increase root gap anduse backing strip

    Warning! Backing strips give a built-in crevice

    susceptible to corrosion

    give a lower fatigue life

  • 7/18/2019 Welding Symbols Weld Preparations

    38/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Access impacts upon weld preparation

  • 7/18/2019 Welding Symbols Weld Preparations

    39/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Access impacts upon weld preparation

  • 7/18/2019 Welding Symbols Weld Preparations

    40/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Access impacts upon weld preparationPipe weld preparation - one side access only!

    for wall thickness up to 3 mm

    for wall thickness 3 to 20 mmfor wall thickness over 20 mm

  • 7/18/2019 Welding Symbols Weld Preparations

    41/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Access impacts upon weld preparationPipe weld preparation - one side access only!

    self-adjusting items

    no danger of burn-through

    susceptible to corrosion

    lower fatigue lifeTo ensure minimum rootmismatch, the internalbore is sometimesmachined with a lowangled bevel

  • 7/18/2019 Welding Symbols Weld Preparations

    42/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Type of joint impacts upon weld preparation

    danger of burn-through

    difficult to set-upeasy set-up

    no burn-through

    corner joints require offset

    offset

    ld i

  • 7/18/2019 Welding Symbols Weld Preparations

    43/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Type of joint impacts upon weld preparation

    Bevel angle = 30

    Included angle = 60Included angle = Bevel

    angle = 50

    lap and square edge butt joints do not requirepreparation

    ld i

  • 7/18/2019 Welding Symbols Weld Preparations

    44/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Type of parent material impacts upon weld

    preparation

    Steel Aluminium

    to reduce distortions on stainless steels welds,reduce included angle and increase root face

    to avoid lack of side wall fusion problems aluminiumrequire larger included angles than steel

    6030

    70-90

    35-45

    W ld i

  • 7/18/2019 Welding Symbols Weld Preparations

    45/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Thickness of parent material impacts upon weld

    preparationa single bevel groove requires a volume of weldmetal proportional to the square of plate thickness

    its lack of symmetry lead to distortions

    Reduce shrinkage by:

    reduce weld volume

    use single pass welding

    W ld i

  • 7/18/2019 Welding Symbols Weld Preparations

    46/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Reduce weld volume by:

    reduce included angle

    Thickness of parent material impacts upon weld

    preparation

    reduce root gap

    W ld ti

  • 7/18/2019 Welding Symbols Weld Preparations

    47/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Reduce weld volume by:

    increase root face

    Thickness of parent material impacts upon weld

    preparation

    use double bevel weld prep

    W ld ti

  • 7/18/2019 Welding Symbols Weld Preparations

    48/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Reduce weld volume by:

    use U prep instead V prep

    Thickness of parent material impacts upon weld

    preparation

    U prep better than V prepV prep better than U prep

    W ld ti

  • 7/18/2019 Welding Symbols Weld Preparations

    49/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparations

    Reduce distortions by using an asymmetric V prepinstead of a symmetric V prep

    Thickness of parent material impacts upon weld

    preparation

    t/3t

    weld first into deeper side

    after welding half of depth, root back gouging

    weld completely on backside

    complete welding on first side

    W ld ti

  • 7/18/2019 Welding Symbols Weld Preparations

    50/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    PF symmetric

    preparation

    Welding position impacts upon weld preparation

    PC asymmetricpreparation

    If symmetric preparation is used in the PC position theweld may spill out of the groove

    6030 60

    15

    W ld ti

  • 7/18/2019 Welding Symbols Weld Preparations

    51/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Type of loading impacts upon weld preparationStatic loads - prohibited application of one sidedfillet weld

    W ld ti

  • 7/18/2019 Welding Symbols Weld Preparations

    52/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Type of loading impacts upon weld preparationStatic loads - equal throat T joints

    13 mm

    weld area = 160 mm2 weld area = 90 mm2

    13 mm

    no preparation required

    danger of lamellar tearingpreparation required

    reduced distortions

    60

    W ld ti

  • 7/18/2019 Welding Symbols Weld Preparations

    53/54

    Copyright 2004, TWI Ltd World Centre for Materials Joining Technology

    Weld preparation

    Type of loading impacts upon weld preparationStatic loads - equal throat T beams in bending

    neutralaxis

    deep penetrationfillet weldsnormal filletwelds

    neutral

    axis

    Lower neutral axis is more advantageous (alsohelps to reduce residual distortions!)

    W ld ti

  • 7/18/2019 Welding Symbols Weld Preparations

    54/54

    Weld preparation

    Type of loading impacts upon weld preparationDynamic loads - full vs. partial penetration welds

    double bevel weldfillet weldsLack of penetration promotes cracking!

    cyclic load