Sbarclay Mig Welding

Front 1

How are weld sizes indicated?

Back 1

Throat Thickness - represented by the letter 'a'

Leg Length - represented by the letter 'z'

Deep Penetration Throat Thickness - represented by the letter 's'

Front 2

What is the numerical representation for MIG welding?

Back 2

131

Front 3

What is the numerical representation for MIG welding?

Back 3

MAG welding

Front 4

Describe 'Ohm's Law'

Back 4

V = I x R (voltage = current x resistance)
or
I = V/ R (current = voltage / resistance)
or
R= V/I (resistance = voltage / current)

Resistance is measured in Ohms

Front 5

Describe the formula for calculating electrical power

Back 5

P = V x I (power = voltage x current)
or
V + P / I (voltage + power / current)
or
I = P / V (current = power / voltage)

Front 6

What is Coefficient of linear expansion

Back 6

The term for when a length of material expands due to it's temperature being raise by 1º

Front 7

How can heat distortion be controlled?

Back 7

Reduce the amount of welded joints

Reduce the amount of weld - stitch joints

Use correct cross- sectional weld sizes for the strength required

Use smallest suitable angle of preparation (U rather than V, double U rather than single U)

Use MIG or MAG

Balance heat during welding

Increase welding speed

Preset component to an angle which allows for distortion

Restrain components with clamps (can increase residual stress)

Restrain components with welded supports (can increase residual stress)

Tack Weld

Use Chills - strips of metal that conduct heat away

Welding sequencing

Pre-heat the structure to 150ºc - 200ºc

Front 8

Identify the welding position PA

Back 8

Flat position

Front 9

Identify the welding position PB

Back 9

Horizontal Vertical position

Front 10

Identify the welding position PC

Back 10

Horizontal position

Front 11

Identify the welding position PD

Back 11

Horizontal Overhead position

Front 12

Identify the welding position PE

Back 12

Overhead position

Front 13

Identify the welding position PF

Back 13

Vertical Upwards position

Front 14

Identify the welding position PG

Back 14

Vertical Downwards position

Front 15

How can heat distortion be corrected mechanically?

Back 15

Large sections with a press

Small parts with hammering, drifting or jacking

Sheet metal with planishing

Front 16

How can heat distortion be corrected using heat?

Back 16

Heat uniformly to 650ºc then cooling normally

Heating the opposing side of the weld (bright red heat should not be exceeded)

Heat small areas one at a time (bright red heat should not be exceeded)

Front 17

Which standards cover welding symbols?

Back 17

BS EN 22553 welded, brazed and soldered joints - symbolic representation on drawings

Front 18

Name the different types of heat distortion from welding

Back 18

Angular

Longitudinal

Transverse

Front 19

Shielding gas is usually made up from what gases?

Back 19

Argon

Carbon Dioxide - CO2

Helium

Oxygen

Front 20

What is a rectifier?

Back 20

An electrical device that converts alternating current (AC) into direct current (DC)

Front 21

What is a solenoid?

Back 21

An electromagnet

Made from a soft iron shaft with insulated wire coiled around it

When a current is passed through the wire the solenoid becomes magnetic

The more wire coiled, the greater the magnetism created

Clockwise wire direction is north polarity - negative

Anti-clockwise wire direction is south polarity - positive

Front 22

Describe an AC/DC inverter

Back 22

Silicon controlled rectifiers convert and reduce current

Power semiconductor unit inverts current back to AC at a higher frequency - 5,000-10,000 Hz

Has a solid ferritic core transformer

Up to 75% lighter and smaller than conventional power sources

Experiences much less power loss, which increases duty cycle

Improves arc and penetration

Synergic pulse allows welding of thinner material with no spatter

Can be used for AC or DC MMA, MIG/MAG, TIG and resistance welding

Front 23

Describe a DC welder generator

Back 23

Powered by petrol or diesel

Used mainly onsite, where power is dangerous or unavailable

Uses lower voltage, 20V - 40V

Safer to use, especially outdoors

Needs more maintenance due to moving parts

Can cause the weld pool to pull to one side (arc blow) due to the magnetic current

Front 24

What are the three most common colour coded plugs and sockets?

Back 24

Yellow 100V - 130V

Blue 200V - 250V

Red 380V - 480V

Front 25

Describe an AC/DC transformer rectifier

Back 25

Steps down the voltage

Increases the current

Converts AC current to DC current

Can be used for a variety of processes including MMA, MIG/MAG and TIG

Front 26

How much carbon does steel need to contain for it to be heat treatable?

Back 26

0.3% or more

Front 27

How does heat treatment change the crystalline structure of metal?

Back 27

Structure changes from body centre cubic (ferrite) to face centre cubic (austenite)

Front 28

What power control characteristics are used for MIG/MAG welding?

Back 28

Constant voltage (flat characteristic, constant potential) -

As the arc gets shorter, the current increases ensuring the same burn rate

Most MIG/MAG welders have the current balanced with the wire feed speed, but some allow for manual adjustment

Front 29

Describe Dip Transfer

Back 29

The electrode intermittently short-circuits, causing it to dip into the weld pool and transfer metal

Occurs when volts and current are at low settings

It is used when welding thin material

Front 30

Describe Spray Transfer

Back 30

Metal from the electrode is sprayed by electromagnetic force, in a continuous stream onto the material

A high voltage method of transfer

Causes a large weld pool and a lot of metal to be deposited

Suitable for thicker materials over 6mm

Front 31

Describe Pulse Transfer

Back 31

A variation of spray transfer

The spray is controlled so the method can be used at lower settings and so can weld lighter material

Good for welding in all positions

Better penetration than dip transfer, but less metal is deposited than spray transfer

Front 32

What current and voltage range should be used when using 0.6mm diameter wire in dip transfer?

Back 32

30 - 80 A

15 - 18 V

Front 33

What current and voltage range should be used when using 0.8mm diameter wire in dip transfer?

Back 33

45 - 180 A

16 - 21 V

Front 34

What current and voltage range should be used when using 1.0mm diameter wire in dip transfer?

Back 34

70 - 180 A

17 - 22 V

Front 35

What current and voltage range should be used when using 0.8mm diameter wire in spray transfer?

Back 35

150 -250 A

25 - 33 V

Front 36

What current and voltage range should be used when using 1.0mm diameter wire in spray transfer?

Back 36

230 - 300 A

26 - 35 V

Front 37

Which process out of MIG or MAG creates the brightest arc?

Back 37

MIG

Front 38

Why are active gases mixed with Inert shielding gas?

Back 38

To increase arc temperature and improve fluidity of the weld pool