Distortion - 120102G

Front 1

Angular distortion is

Back 1

A rotation around the wild line

Front 2

Transverse distortion is

Back 2

Perpendicular to the wild line

Front 3

Longitudinal distortion is

Back 3

Parallel to the weld line

Front 4

When using rigid clamping and fixturing to minimize distortion, What should you be careful of with regards to residual stress?

Back 4

The greater the restraint against contraction, the greater the residual stresses that are induced which can lead to cracking once the weld has cooled.

Front 5

Temperature refers to the measure of the _____ of energy

Back 5

Intensity

Front 6

The term heat expresses the _____ of energy

Back 6

Quantity

Front 7

Which is a common cause of distortion?

Back 7

Unequal heating and cooling of welds

Front 8

When heated evenly and without restraint, in which direction does metal expand?

Back 8

Volumetrically (in all directions)

Front 9

Transitional expansion occurs when metal changes from

Back 9

One crystalline structure to another

Front 10

Which type of distortion results from shrinkage across the weld that tends to pull a member of a t-joint towards the welded side?

Back 10

Angular distortion

Front 11

Which type of distortion results in an overall reduction in the length of the weld?

Back 11

Longitudinal distortion

Front 12

Which type of distortion refers to the tendency (in butt joints) for the plates to draw together down the length of the joint as you are welding?

Back 12

Transverse distortion

Front 13

What causes angular distortion in a v-groove weld if the plates are free to move?

Back 13

The non-uniform contraction of weld metal

Front 14

What is the primary cause of distortion created from longitudinal shrinkage?

Back 14

Weld beads contracting upon cooling

Front 15

What is one method you can use to correct angular distortion on butt joints?

Back 15

Weld on both sides

Front 16

How can you reduce longitudinal distortion?

Back 16

Keep well reinforcement to a minimum

Front 17

What is one method to reduce transverse distortion?

Back 17

Use a fast deposition rate

Front 18

What is a disadvantage to rigid, clamping and fixturing?

Back 18

Some distortion can occur after releasing the clamping

Front 19

What is one advantage of a jigging device?

Back 19

It's maintains accuracy of a finished product

Front 20

Pieces of metal placed on either side of the joint that absorb the heat of the weld and help prevent distortion are called?

Back 20

Chill strips

Front 21

What is the purpose of balancing welds around the neutral axis of a worn shaft?

Back 21

To equalize the contraction stresses of the welds

Front 22

How can you control distortion when welding light gauge metal?

Back 22

Increase the number of tacks

Front 23

Which fillet Weld application produces the greatest amount of distortion

Back 23

Multi pass fillet welds with a convex profile

Front 24

What is one characteristic of a good welding design?

Back 24

It's uses formed or rolled sections

Front 25

When several plates must be welded together with butt joints, what is the best weld sequence to control distortion?

Back 25

Weld from the center and toward the outside in both directions

Front 26

What is the advantage of using sub assemblies?

Back 26

They provide for more welds in the flat position

Front 27

The principal behind procedural methods is that _____ _____ set up by one weld are counteracted by the ____ ____ in subsequent welds

Back 27

Shrinkage forces

Front 28

List some of the procedural methods to reduce distortion? (11)

Back 28

Planning the welding sequence

Welding around the neutral axis

Staggering welding

Skip welding

Backstep welding

Tack welding

Presets and joint preparation

Using fewer weld passes

Welding at a fast and even rate of travel

Preheating the work

Specialized equipment

Front 29

List some of the welding sequences that can reduce distortion (8)

Back 29

*Decide on the direction of each weld. Generally, it is best to work from the center outwards in both directions. Weld short seems before longitudinal seams.

* Choose the type of distortion control. Welding around a neutral axis, back stepping, stagger welding or skip welding.

* Consider whether the joints are free to move or should be rigidly tacked

* Decide what the proper joint preparation should be

* Avoid an excessive number of weld passes

* Decide whether presetting, pre-bending or preheating is needed

* Weld but joints before lap joints

* The type of material may affect your decision

Front 30

Draw out staggered welding

Back 30

Front 31

Draw out back step welding

Back 31

Front 32

Draw skip welding

Back 32

Skip welding starts in the center, alternating side it welds toward the center from.

Front 33

How long should a weld be if using the SMAW process?

Back 33

As much as can be deposited with one electrode

Front 34

Which required more tacks, flat or cylindrical pieces?

Back 34

Flat objects

Front 35

Which pieces require more tacks. Narrow strips or wide strips of metal?

Back 35

Narrow strips

Front 36

One pass performed at higher current settings results in ____ distortion then depositing several passes.

The trade off with this is that it creates a more _____ grain structure.

Back 36

Less

Coarse

Front 37

What is a disadvantage of a coarse grain structure?

Back 37

It creates low strength and toughness

Front 38

Good design methods. Use smooth flowing lines and few or no rapid changes in ____ or _____-______

Back 38

Direction or cross section

Front 39

Five design methods that can reduce distortion are

Back 39

Minimizing the number of pieces

Welding in the flat position

Rounding corners

Not welding across carrying members

Not accumulating weld intersections (stop/starts)

Front 40

_____ corners prevents a rapid change in the direction of the stress flow lines, which causes a notching effect.

Back 40

Rounded