Welding Symbols. Faculty of Engineering Mechanical Dept.

Transcription

1 Welding Symbols Faculty of Engineering Mechanical Dept.

2 Objectives 1. Know the name of the AWS & ISO standards for welding symbols 2. List the eight elements that may be found on a welding symbol 3. List the basic weld symbols 4. List the supplementary symbols 5. Identify the applications of the different weld symbols

3 Weld symbols on drawings A method of transferring information from the design office to the workshop is: Please weld here The above information does not tell us much about the wishes of the designer. We obviously need some sort of code which would be understood by everyone. Most countries have their own standards for symbols. Some of them are AWS A2.4 & BS EN (ISO 2553)

4 AWS Standard Weld symbol Graphic symbol that indicates weld required Welding symbol Following eight elements: Reference line (required) Arrow (required) Basic weld symbols Dimensions and other data Supplementary symbols Finish symbols Tail Other specifications

5 Welding Symbol Components

6 Welding Symbol Components

7 Welding Symbol Components

8 Weld symbols on drawings Advantages 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 regarding the specific joint to be obtained Disadvantages of symbolic representation: used only for usual joints requires training for properly understanding of symbols

9 Dimensions Convention of dimensions In most standards the cross sectional dimensions are given to the left side of the symbol, and all linear dimensions are give on the right side BS EN ISO a = Design throat thickness s = Depth of Penetration, Throat thickness z = Leg length (min material thickness) AWS A2.4 In a fillet weld, the size of the weld is the leg length In a butt weld, the size of the weld is based on the depth of the joint preparation

10 Weld symbols on drawings Joints in drawings may be indicated: by detailed sketches, showing every dimension by symbolic representation

11 Elementary Weld Symbols Square Groove Weld Single V Groove Weld

12 Elementary Weld Symbols Single Bevel Groove Weld Single V Groove Weld with Broad Root Face

13 Elementary Weld Symbols Single Bevel Groove Weld with Broad Root Face Single U Groove Weld

14 Elementary Weld Symbols Single J Groove Weld Backing Weld

15 Elementary Weld Symbols Fillet Weld Plug / Slot Weld

16 Elementary Weld Symbols Spot Weld Seam Weld

17 Elementary Weld Symbols Edge Weld Surfacing

18 SUPPLEMENTARY SYMBOLS Weld Profile Flat Convex Concave

19 SUPPLEMENTARY SYMBOLS M MR Toes blended smoothly Permanent Backing Strip Removable Backing Strip

20 SUPPLEMENTARY SYMBOLS Peripheral Welds

21 Basic Weld Symbols AWS

22 Basic Weld Symbols AWS

23 Welding Symbols AWS

24 ISO 2553 / BS EN of 691 Plug weld Square Butt weld Resistance spot weld Steep flanked Single-V Butt Resistance seam weld Surfacing

25 ISO & AWS

26 Arrow Line (BS EN ISO & AWS A2.4): Convention of the arrow line: Shall touch the joint intersection Shall not be parallel to the drawing Shall point towards a single plate preparation (when only one plate has preparation)

27 Reference Line (AWS A2.4) Convention of the reference line: Shall touch the arrow line Shall be parallel to the bottom of the drawing

28 Reference Line (BS EN ISO 22553) Convention of the reference line: Shall touch the arrow line Shall be parallel to the bottom of the drawing There shall be a further broken identification line above or beneath the reference line (Not necessary where the weld is symmetrical!) or

29 Double side weld symbols (BS EN ISO & AWS A2.4) Convention of the double side weld symbols: Representation of welds done from both sides of the joint intersection, touched by the arrow head Fillet weld Double bevel Double J Double V Double U

30 ISO 2553 / BS EN of 691 M M R Single-V Butt with permanent backing strip Single-U Butt with removable backing strip Single-V Butt flush cap Single-U Butt with sealing run

31 ISO 2553 / BS EN of 691 Single-bevel butt Double-bevel butt Single-bevel butt Single-J butt

32 ISO 2553 / BS EN s Partial penetration single-v butt S indicates the depth of penetration

33 ISO 2553 / BS EN of 691 a = Design throat thickness s = Depth of Penetration, Throat thickness z = Leg length(min material thickness) a = (0.7 x z) z 6 z a s a 4 4mm Design throat s 6 6mm leg 6mm Actual throat

34 ISO 2553 / BS EN of 691 Arrow side Arrow side

35 ISO 2553 / BS EN of 691 s6 6mm fillet weld Other side s6 Other side

36 ISO 2553 / BS EN of 691 n = number of weld elements l = length of each weld element (e) = distance between each weld element n x l (e) 2 x 40 (50) 3 x 40 (50) 111 Welds to be staggered Process

37 ISO 2553 / BS EN All dimensions in mm z5 z6 3 x 80 (90) 3 x 80 (90)

38 ISO 2553 / BS EN All dimensions in mm z8 z6 3 x 80 (90) 3 x 80 (90)

39 Supplementary symbols (BS EN ISO & AWS A2.4) Convention of supplementary symbols Supplementary information such as welding process, weld profile, NDT and any special instructions Site Weld Toes to be ground smoothly (BS EN only) Concave or Convex Weld all round

40 Supplementary symbols (BS EN ISO & AWS A2.4) Convention of supplementary symbols Supplementary information such as welding process, weld profile, NDT and any special instructions Ground flush MR Removable backing strip M Permanent backing strip 111 Welding process numerical BS EN Further supplementary information, such as WPS number, or NDT may be placed in the fish tail

41 ISO 2553 / BS EN of 691 a b c d

42 ISO 2553 / BS EN Mitre Convex Concave Toes shall be blended

43 ISO 2553 / BS EN Complimentary Symbols Field weld (site weld) Welding to be carried out all round component (peripheral weld) NDT WPS The component requires NDT inspection Additional information, the reference document is included in the box

44 ISO 2553 / BS EN of 691 Numerical Values for Welding Processes: 111: MMA welding with covered electrode 121: Sub-arc welding with wire electrode 131: MIG welding with inert gas shield 135: MAG welding with non-inert gas shield 136: Flux core arc welding 141: TIG welding 311: Oxy-acetylene welding 72: Electro-slag welding 15: Plasma arc welding

45 AWS A2.4 Welding Symbols

46 AWS Welding Symbols Depth of Bevel Root Opening 1 (1-1/8) 1/8 60 o Effective Throat Groove Angle

47 AWS Welding Symbols Welding Process 1 (1-1/8) 1/8 60 o GSFCAW GMAW GTAW SAW

48 AWS Welding Symbols Welds to be staggered SMAW Process

49 AWS Welding Symbols Sequence of Operations 3rd Operation 2nd Operation 1 (1-1/8) 1st Operation 1/8 60 o FCAW

50 AWS Welding Symbols Sequence of Operations MT MT RT 1 (1-1/8) 1/8 60 o FCAW

51 Fillet Welds and Symbol Fillet weld triangular-shaped weld placed on the joint Fillet weld symbol triangular in shape Vertical line of fillet weld symbol always drawn to left of symbol Size always shown to left of symbol and length to right of symbol No length given, then weld should run full length of joint

52 AWS Welding Symbols 52 of 691 Dimensions- Leg Length 6/8 6 leg on member A Member A 6 8 Member B

53 AWS A 2.4 rules-example 10 3 x 50 (70)

54 Fillet welds Fillet weld dimensions according AWS A x 8 5 leg on vertical member

55 Intermittent fillet welds Chain intermittent fillet weld pitch (e) length (l) z z z l - e l - e Symbol to AWS A2.4

56 Intermittent fillet welds Staggered intermittent fillet weld pitch (e) e/2 length (l) z Symbol to AWS A2.4 z z l - e l - e

57 Examples: Fillet Welds on T-Joints

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59 Example: Fillet Weld Length and Pitch Indications

60 Weld-All-Around Symbol Used when weld is to extend all way around joint or series of connected joints Symbol: circle viewable at junction of reference line and arrow

61 Groove Welds Seven types of groove welds and symbols to represent them Square V Bevel U J Flare-V Flare-bevel Symbols take the shape of the groove the weld is to be placed in.

62 Groove Welds Place in a joint Used to make butt joints, but can be used to make other types of joints Double bevel One of joint members has bevel on both sides and joint is to be welded from both sides V shape

63 V-groove Weld on Butt Joint

64 Double V-groove Weld on Butt Joint

65 Contour Symbol and Letters Which Indicate Finishing Method

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