SMAW: Mild Steel Electrodes Flashcards

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1
Q

The ability of a metal to permanently deform under load without breaking is known as

A

Ductility

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2
Q

The ultimate pull that a material can withstand is called

A

Tensile strength

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3
Q

Impact tests such as izod or charpy are designed to measure

A

The welds impact strength

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4
Q

The point at which a material begins to deform permanently under load is called it’s

A

Yield point

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5
Q

Dynamically loaded structures are subject to

A

Reversals of stress

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6
Q

Which is the best example of dynamically loaded structure

A

The boom on a crane making a lift and then swinging the load

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7
Q

A static load means that the load

A

Is steady and relatively unchanged

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8
Q

Which is the best example of statically loaded structure

A

The column supporting the wall in a building

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9
Q

Electrodes used in SMAW are often called

A

Consumable electrodes

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10
Q

Electrode specifications are written by

A

CSA and AWS

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11
Q

In AWS classification for SMAW mild steel electrodes what does the last digit represent

A

The major ingredient in the coating and the recommended current for best results

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12
Q

What do the first two digits in the AWS classification for carbon steel SMAW electrodes represent

A

As welded min tensile strength

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13
Q

In the CSS numbering system for welding electrodes what does the prefix letter E represent

A

Electrode

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14
Q

According to AWS which number indicates the position an R7024 can be used in

A

Third number

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15
Q

The CSA system used what term to measure tensile strength

A

Megapascals MPa

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16
Q

Which set of characteristics best describes the electrode E4914 / 7014

A

Rutile coating, 30% metallic powder, AC or DC either polarity

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17
Q

E7024 electrodes are designed to be used in which positions

A

Flat and horizontal

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18
Q

What is the difference between an E7018 and an E7028 electrode

A

E7018 can be used in all positions
E7028 cannot

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19
Q

True or false
E7038 can only be welded in the flat position

A

True

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20
Q

True or false
E6010 has the least amount of metallic iron powder in its coating

A

True

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21
Q

What is one difference between an E7010 electrode and an E7018 electrode

A

Coating

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22
Q

What is one characteristic of an E6010 electrode

A

Deep penetration into the base metal

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23
Q

What is the major difference between the coatings of an E4310 and an E4311 electrode (6010 and 6011)

A

An E4311 has potassium added as an arc stabilizer for AC welding

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24
Q

Why is iron powder added to the coatings of some electrodes

A

To increase the rate of weld deposits

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25
Q

Which electrode has a cellulose coating

A

E6010

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26
Q

Which electode contains the highest amount of iron powder in its coating

A

E7014

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27
Q

What is one purpose of the slag produced from the flux coating on a welding electrode

A

To protect the molten weld puddle from atmospheric contamination

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28
Q

Which last digit in the classification of a smaw mild steel electrode describes a flux that is lime based

A

8

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29
Q

Adding large amounts of iron powder to electrode coatings would limit welding to which positions

A

Flat and horizontal

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30
Q

What is one function of the slag produced from electrode coatings

A

To prevent the weld from cooling too rapidly

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31
Q

Which statement is true about the slag produced when welding with a coated electrode

A

It helps prevent oxygen and nitrogen from contaminating the weld

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32
Q

What is the likely effect of using low hydrogen electrodes with a moisture content that exceeds the acceptable limits

A

The weld metal will probably have porosity and may develop hydrogen induced cracking

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33
Q

What is the main purpose for keeping low hydrogen electrodes dry

A

To minimize the possibility of hydrogen induced cracking

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34
Q

What is the recommended moisture content for E6010 electrode coatings

A

3% - 7%

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35
Q

Proper handling of electrodes includes following the manufacturer’s recommendations regarding

A

Storage and reconditioning procedures

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36
Q

To weld thin materials you would likely select a electrode with

A

A small diameter core wire

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37
Q

Which electrode works best for the root bead on groove welds with an open gap

A

E4310 / 6010

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38
Q

What is the major advantage of using an E4310 for the root bead and E4918 electrodes for fill passes on one welded joint

A

It takes advantage of the penetration qualities of the E4310 and the mechanical properties of the E4918

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39
Q

It is important to know the chemical and mechanical properties of the base metal so you can select an electrode with the correct

A

Flux coating

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40
Q

Which electrode would be best choice if the base metal properties were unknown

A

E7018

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41
Q

High impact strength (lack of brittleness) is a good indication of ….

A

Toughness

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42
Q

A leaf spring is a good example of a steel that has been _______ to a high degree of toughness.

A

Tempered

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43
Q

Non consumable electrodes

A

GTAW - Tig
Not intended to be consumed into the weld puddle. An electric arc is drawn between a non consumable tungsten electrode and the work

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44
Q

Consumable electrodes

A

SMAW
The electrode is melted into the weld puddle (consumed) a consumable electrode = filler metal bc the metal from the electrode is melted into the weld

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45
Q

Mechanical properties of metal

A

Ductility, tensile strength, brittleness, hardness, toughness, elasticity, malleability, yield strength, impact strength

46
Q

Physical properties

A

Colour, shine, density/weight, thermal conductivity, electro conductivity

47
Q

The ability of a material to stretch or deform under load without breaking
- expressed as a percentage of elongation

A

Ductility

48
Q

The ultimate pull that a material can stand
PSI or MPas

A

Tensile strength

49
Q

Necking

A

Where the metal pulls in and ultimately breaks

50
Q

Ultimate tensile strength

A

The peak of the strength not when it breaks

51
Q

The point that permanent deformation takes place

A

Yield or Elastic Limit

52
Q

When you pull and it keeps that new shape

A

Plastic

53
Q

You pull and it goes back to original form

A

Elastic

54
Q

Defined as it’s ability to resist penetration or indentation resist scratching or abrasions

A

Hardness

55
Q

Uses a diamond to test hardness
The hardness number is read directly from a gauge that measures the depth of the indentation
Used on harder material

A

The Rockwell system

56
Q

Measures the diameter of the steel ball impression made
Used on softer material

A

The Brinell hardness tester

57
Q

The ability of metal to withstand rapidly applied load without breaking

A

Toughness

58
Q

Controlled heating to draw some of the hardness out of a metal to promote toughness
(A leaf spring is a good ex of a steel that has been tempered to a high degree of toughness)

A

Tempering

59
Q

Ability of a metal to return to its original shape and dimensions once the load has been removed
(Tungsten filler rod)

A

Elasticity

60
Q

Ability to be cold worked with out a great deal of resistance.
Bends slightly or shows some distortion before breaking, doesn’t snap back

A

Malleability

61
Q

Ability of a metal to withstand a sharp high velocity blow
Measured in foot, pounds or joules

A

Impact strength/ fracture toughness

62
Q

Impact strength/ fracture toughness tests

A

Izod and charpy tests
Uses a weighted swinging pendulum to break a botched specimen at dif temps

63
Q

Crane booms, truck frames, farm tillage are an example of what loading

A

Dynamic loading
Occurs when a structure is subject to rapidly changing loads
Reversal of stress

64
Q

Stationary or relatively unchanging
Ex base plates, metal storage racks or beams that support building roofs
Less ductile, harder rod

A

Static loading

65
Q

Filler wire classified by

A

AWS and CSA

66
Q

Welding positions
1, 2, 3, 4

A

1: all postition
2: flat and horizontal
3: flat only
4: flat, overhead, horizontal and vertical down

67
Q

7048

A

Bohler rod
Down hand rod

68
Q

0: paper flux: DCRP
6010, 7010, 8010

A

Cellulose

AIT: 6010 is a good polarity checking rod bc it only works on DCRP

69
Q

2, 3, 4: mineral titanium : titanium dioxide : arc stabilizer and slag former
6012, 6013, 7014, 7024

A

Rutile

70
Q

5, 6, 8: Thick heavy slag/ductile
7015, 7016, 7018m, 7028, 7048

A

Lime (limestone) / calcium carbonate
Low hydrogen

71
Q

7: rust, good for welding on dirty/rusty material
6027, 7027

A

Iron oxide

Exceptions
6020: used on thicker base metals
6022: high speed, high current welding

Bc of the 2 in the third placement assume iron oxide. Amount of filler metal added to the flux can only be welded in the flat and horizontal

72
Q

Hydrogen

A

Causes hydrogen cracking, keep hydrogen as low as possible.

The suffix 1H4 shows hydrogen levels

H4 meets requirements of H8 and H16
The lower the number the better

1 means electrode meets optimal supplemental impact strength requirements at low temp

73
Q

R in the suffix means

A

Resistant to moisture absorption
(Why we use rod ovens)

74
Q

E4310

A

E6010

75
Q

E4918

A

E7018

76
Q

E5518

A

E8018

77
Q

AWS suffix
H2, H4, H8

A

H2: meets requirements of H4, H8 and H16

H4 meets requirements of H8 and H16

H8 meets requirements of H16

78
Q

Can be burned out by other passes
Ex 6010/ 4310

A

Friable

79
Q

6010/ 4310
Penetration, slag, bead, qualities

A

Flux: cellulose
Penetration: deep
Slag: thin, friable, easy to remove
Bead: flat weld face, coarse ripples
Qualities: dynamic loading, fast freeze
All position, DCRP only
Stored beside oven
Moisture content should range between 3-7%

80
Q

7018 / 4918
Penetration, Slag, bead, qualities

A

Lime
All positions
Penetration: medium
Slag: heavy, friable, easy to remove
Bead: smooth concave, fine ripples
Qualities: dynamic loading, low hydrogen weld deposit

81
Q

6013
Penetration, slag, bead, qualities

A

Rutile
All position
Penetration: low
Slag: easily removed slag
Bead: flat fillet, smooth, fine ripples
Qualities: static loading, light sheet metal

82
Q

7024 / 4924 jet rod
Penetration, slag, bead, qualities

A

(Puts down all the metal fast)
Iron oxide
Flat and horizontal position only
Penetration: low penetration
Slag: easy to remove, sometimes removes itself
Bead: smooth, fine ripples
Qualities: static loading, high deposit rate

83
Q

6011
Penetration, slag, bead, qualities

A

Cellulose
All position
Penetration: deep
Slag: thin friable, easy to remove
Bead: flat weld face, coarse ripples
Qualities: dynamic loading, fast freeze
Can run AC and DCRP it’s similar to 6010
Has added potassium silicate which is an arc stabilizer

84
Q

1 inch = ______ mm

A

25.4 mm

85
Q

Core wire is made of what steel

A

Rimmed / cheapest

86
Q

Flux v slag

A

Flux when it’s on the rod
Slag on the weld

87
Q

Increases deposition rate by 50% or more

A

Iron powder
- High current: more current is needed to melt the iron powder in the coating
- a deep cup (crucible cup) is formed on the end of the electrode the core wire melts slightly ahead of the flux
- drag technique: arc length becomes self regulating with electrode that form a crucible cup if you use the drag technique

88
Q

3 electrode operating characteristics can be controlled by

A
  1. Fast freeze: speed at which weld puddle solidifies
  2. Fast fill: amount of filler metal produced
  3. Fill freeze: speed at which filler metal deposited
89
Q

Fast freeze electrode

A

Ability to solidify quickly
Penetrates deep
Little slag
Vertical or overhead
E4310 (E6010)

90
Q

Fast fill electrode

A

Deposit a weld with a substantial amount of filler metal at a fairly fast rate
Production welding
Jet rod E4924/ E7024
Flat and horizontal positions

91
Q

Fill freeze electrodes

A

Rapid deposit of narrow, shallow penetrating weld bead with crater following rapidly behind arc
- little filler metal is needed
- light gauge sheet metal
- straight polarity = less penetration
- E4913 / E7013

92
Q

Slag functions

A

Excludes oxygen and nitrogen from weld until cool
Prevent hard, brittle weld
Dissolves impurities in molten weld pool/ floats them to surface
Controls shape and smoothness of bead
Slow down cooling rate

93
Q

Reasons for slag to be difficult to remove

A

Improper weld technique
Incorrect current setting
Wrong current type
Incorrect travel speed
Wrong welding position

94
Q

Lime coated electrons should be packaged

A

Hermetically sealed (air tight) containers and placed in an electrode holding oven
30-140 C (50-250 F)

95
Q

Which polarity tends to cause arc blow

A

Direct current DC

96
Q

Describe the difference between a constant current machine volt amp curve and a constant potential volt amp curve

A

Constant current: SMAW GTAW
Drooping volt amp curve

Constant potential/ constant voltage:
Wire feed
Relatively flat volt amp curve

97
Q

What electrical factor influences the metal deposition rate? What happens when this factor increases or decrease

A

An increase in amperage = increase in metal deposition and vice versa

98
Q

What does NEMA stand for and what is their role when it comes to welding

A

National electrical manufacturers association

Rates all welding machines, max rated output in 10 min before it has to cool down

99
Q

What is the purpose of a rectifier

A

Changes an AC machine to a DC machine with use of a diode

100
Q

When SMAW welding with reverse polarity where is 2/3 of the energy located

A

2/3 of the arc energy is with the base metal (negative terminal)

101
Q

When SMAW welding with straight polarity what happens to metal flow and penetration

A

Electrode melts faster
Less heat in baseplate
Wide puddle
Shallow penetration
Think metals, cladding, hardfacing
(Electrode negative, clamp/work piece positive)

102
Q

What does electromotive force (EMF) influence while welding?

A

EMF is the voltage
- starting the arc
- maintaining the arc
- puddle fluidity
- puddle flow

103
Q

When blowing dust and debris out of a welding machine what type of air should u use

A

Low pressure air

104
Q

Name the welding cables in order from least resistance to most resistant

A

(Least) 4/0, 3/0, 2/0, 1/0, #1, #2, #3, #4 (most)

105
Q

Why it is important to ensure your work lead has a tight clean connection

A

Poor connection can cause accidental arcing at the work lead, cause extreme hard and brittle spots to form on workpiece

Resistance to current flow, creates unstable arc, overheating welding cables

106
Q

Describe how arc length can influence your weld puddle

A

Short: more narrow and deeper penetration

Normal: larger puddle and less penetration

Long arc: bigger puddle, shallow penetration, well on thin metals

107
Q

F1

A

Iron

108
Q

F2

A

Rutile

109
Q

F3

A

Cellulose

110
Q

F4

A

Lime

111
Q

Holding oven temp

A

50F - 250F

112
Q

Re bake oven temp

A

500F - 800F