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Welding Processes. HH elps spot problems LL eads to better inspection GG ains respect of welders GG ains cooperation Welding Process Knowledge.

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Presentation on theme: "Welding Processes. HH elps spot problems LL eads to better inspection GG ains respect of welders GG ains cooperation Welding Process Knowledge."— Presentation transcript:

1 Welding Processes

2 HH elps spot problems LL eads to better inspection GG ains respect of welders GG ains cooperation Welding Process Knowledge - A Benefit to Inspectors

3  Source of energy  Source of shielding  Filler metal (optional) { autogenous or hetrogeneous} Common Features of Welding Processes

4 SMAW

5  To provide a gas to shield the arc  To produce a slag blanket to protect the hot weld metal from the air  To improve the smoothness and stability of the arc  Deoxidisers to cleanse the weld  Adding alloying elements Functions of the Electrode Coating

6 1- Cellulose - Organic compound cellulose - Limited amount of slag - used for all positions - E 6010, E 6011 Types of coating

7 2- Basic - Calcium carbonates - Low hydrogen content - E 7015, E Rutile - Titanium dioxides - Heavy slag - E 6013, E 6024 Types of coating

8 E X X X X-X E ELECTRODE XX Deposite weld metal tensile strength Ksi X the position SMAW Electrode Identification System

9 Welding Positions

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14 1 - used in all positions 2 - used in flat or horizontal fillets only 3 - not used at present time 4 - used for ‘downhill’ progression Position Description

15 E X X X X-X X Coating/Operating Characteristics X Alloying elements percent SMAW Electrode Identification System

16 Electrode Suffixes - 1 of 2

17 Electrode Suffixes - 2 of 2

18 E 7010 E 6013 Example of electrode classification

19  F1 - EXX20, EXX24, EXX27  F2 - EXXX2, EXXX3, EXXX4  F3 - EXX10, EXXX1  F4 - EXXX5, EXXX6, EXXX8 Electrode Coating Classification F #s

20  Types end in a ‘5’, ‘6’, or ‘8’  Purchase in sealed, metal containers  Store after opening in heated, vented oven  Limit atmospheric exposure Low Hydrogen Electrodes

21  E308, E308L - Weld 304 and 304L  E316, E316L - Weld 316 and 316L  E309 - Weld Stainless to Carbon Steel Stainless Steel Electrodes

22  Simple equipment  Inexpensive  Very portable  Welds most alloys  Less sensitive to wind & draft air  Not required shielding gas SMAW Advantages

23 SMAW Limitations  Relatively slow  Slag removal  Electrode storage considerations  Arc blow  It can not weld refractory materials ( tantalum, Mo, Cr, W ) or reactive materials ( Titanium,..

24  Porosity  Slag inclusions  Spatter  Incomplete joint penetration  Incomplete fusion SMAW Discontinuities

25 Gas Tungsten Arc Welding Equipment

26 GTAW Nomenclature

27 AWS Tungsten Electrode Classifications

28 Carbon Steels  ER70S-2, ER70S-3, etc. Stainless Steels  ER308, ER308L, ER316, etc. GTAW Filler Metals

29 Effect of DCEN Current on GTAW

30 Effect of DCEP Current on GTAW

31 Effect of AC Current on GTAW

32  ARGON - High density ( suitable in flat position ) - Weld all metal except reactive & refractory materials - High spatter - Recommended flow rate 7 : 16 L /min SHIELDING GASES

33  Helium - Low density ( suitable in overhead position position ) - Good penetration - Recommended flow rate 14 : 24 L /min SHIELDING GASES

34  Good for thin materials  High quality welds  Good appearance  Very clean  No slag  Autogeneous ( without filler metal )&heterogeneous GTAW Advantages

35  Relatively slow  Low tolerance for contamination  Shielding gas expensive  Purging gas expensive GTAW Limitations

36  Porosity  Incomplete fusion  Incomplete joint penetration  Tungsten inclusions GTAW Discontinuities

37  Contact between:  Tungsten and base metal  Tungsten and filler metal  Excess current  Excess tungsten extension  Improper tungsten tip grinding Causes of Tungsten Inclusions

38 Submerged Arc Welding (SAW)

39 SAW

40 F X X X - E X X X F Flux X Tensile strength X Heat Treatment X Impact Test Temperature SAW Filler Metal Identification System Flux

41 F X X X - E X X X E Electrode X (Low, Medium, High - Mn%) XX (8 through 16 for chemistry) SAW Filler Metal Identification System Flux

42 F7A6-EM12K SAW Filler Metal Example

43 SAW Equipment

44  High deposition rate  Deep penetration  Mechanized process  Not required black lenses  Good for overlay of large areas  Less smoke than SMAW SAW Advantages

45  Flat or horizontal fillets only  Extensive setup time  Needs positioning equipment  Arc not visible to operator  Slag removal SAW Limitations

46  Groove alignment  Slag inclusions  Porosity  Incomplete fusion  Cracking (W/D ratio) SAW Discontinuities

47 GMAW

48 GMAW Equipment

49 GMAW Nomenclature

50 E R X X S – X E Electrode R Rod S Solid XX Stregngth of deposite weld metal X Chemical Composition GMAW Electrode Identification System

51  Semiautomatic process  High productivity  No slag to remove  Clean process  Continuous filler metal feed  Welds most alloys GMAW Advantages

52  Unsuitable for windy conditions  Little tolerance for contamination  Usually limited to shop welding  Equipment is more complex GMAW Limitations

53  Porosity  Incomplete fusion  Incomplete joint penetration GMAW Discontinuities


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