120102h Weld Faults

Question 1

For each term, answer whether it is a dimensional defect, a structural discontinuity or a defective property.

a) overlap
b) insufficient root opening
c) lack of fusion
d) warping
e) filler metal composition
f) excessive reinforcement
g) incorrect joint preparation
h) incorrect weld size
i) excessive hardness
j) undercut
k) cracking
1) porosity
m) insufficient tensile strength
n) slag inclusions
o) stray arc strikes
p) poor weld profile

Answer 1

a) dimensional defect
b) dimensional defect before welding
c) structural discontinuity
d) dimensional defect
e) defective property
f) dimensional defect
g) dimensional defect
h) dimensional defect
i) defective property
j) dimensional defect after welding
k) structural discontinuity
I) structural discontinuity
m) defective property
n) structural discontinuity
o) structural discontinuity
p) dimensional defect

Question 2

Of the weld faults in number 1, which is considered the most serious? Explain your answer.

Answer 2

Cracking is the most serious because cracks usually continue to spread and lead to
complete weld failure.

Question 3

Cutting a notch into both ends of a weld and applying force against one end is known as a:
a) stress flow test.
b) weld fault test.
c) weld press test.
d) nick break test.

Answer 3

d) nick break test.

Question 4

Notch effect in a weld has stress flow lines:
a) concentrated at one point.
b) flowing from left to right.
c) flowing smoothly through the welded joint.
d) stretched beyond the elastic limit.

Answer 4

a) concentrated at one point.

Question 5

A tapered transition ratio of 3:1 when joining plates of different thicknesses would:
a) waste time and energy.
b) decrease notch effect.
c) decrease cross-section strength.
d) create a point of high stress.

Answer 5

b) decrease notch effect.

Question 6

A high concentration of stress in a weld causes:
a) stress flow.
b) high strength.
c) a notch effect.
d) a nick break.

Answer 6

c) a notch effect.

Question 7

List three (3) weld faults that may be caused by each of the following:

a) inadequate heat input:
b) excessive heat input:
c) incorrect electrode angle:
d) travel speed too slow:
e) travel speed too fast:
f) contaminated joint area (rust, scale, oil or paint):

Answer 7

a) any of these: slag inclusions, porosity, lack of fusion, incomplete penetration
b) cracking, undercut, excess penetration
c) undercut, overlap, lack of fusion
d) overlap, excess convexity, excess penetration
e) any of these: cracking, lack of fusion, slag inclusions, incomplete penetration
f) any of these: porosity, slag inclusions, lack of fusion, cracking

Question 8

An insufficient root opening on a groove weld is likely to cause:
a) lack of penetration.
b) excessive penetration.
c) complete fusion.
d) stray arc strike.

Answer 8

a) lack of penetration.

Question 9

Which of the following variables would be effective in controlling excessive
penetration on a groove weld?
a) Reduce the land thickness.
b) Increase the bevel angle.
c) Decrease the root opening.
d) Pre-set the plates to widen the groove opening.

Answer 9

c) Decrease the root opening.

Question 10

Porosity in a weld can be reduced by:
a) cleaning the joint area before welding.
b) welding with stringer beads instead of weave beads.
c) maintaining a fast travel speed with the electrode.
d) avoiding the use of low hydrogen electrodes.

Answer 10

a) cleaning the joint area before welding.

Question 11

Undercut is most commonly caused by:
a) current setting too low.
b) travel speed too fast.
c) using high iron powder electrodes.
d) incorrect electrode angle.

Answer 11

d) incorrect electrode angle.

Question 12

Distortion can be controlled by:
a) making several passes using small electrodes at low current settings.
b) using a long arc length.
c) using low hydrogen electrodes.
d) maintaining an accurate joint fit-up.

Answer 12

d) maintaining an accurate joint fit-up.

Question 13

Which of the following can cause a quenched and brittle condition in metal?
a) a stray arc strike
b) welding current set too low
c) an inadequately filled crater
d) using a damp electrode

Answer 13

a) a stray arc strike

Question 14

Which situation would most likely produce slag inclusions in multi-pass welds?
a) high current setting with a short arc length
b) high current setting with a normal arc length
c) low current setting with a long arc length
d) removing the slag between passes

Answer 14

c) low current setting with a long arc length

Question 15

Longitudinal cracks in a weld can be caused by:
a) excessive travel speed.
b) excessive joint restraint.
c) arc length too long.
d) incorrect electrode inclination.

Answer 15

b) excessive joint restraint.

Question 16

Incomplete penetration would likely be caused by:
a) travel speed too slow.
b) the root opening too narrow.
c) electrode diameter too small.
d) welding with excessively high current settings.

Answer 16

b) the root opening too narrow.

Question 17

Excessive penetration on a root pass would likely be caused by:
a) current settings too low.
b) travel speeds too slow.
c) root opening too narrow.
d) arc length too short.

Answer 17

b) travel speeds too slow.

Question 18

From a welding standpoint, a crater is a term used to describe:
a) a person who puts tools in crates.
b) a pinhole at the beginning of a weld.
c) a depression at the end of a weld.
d) the cup-shaped cavity at the end of a used electrode.

Answer 18

c) a depression at the end of a weld.

Question 19

A weld is said to be concave when the:
a) surface of the weld has a slight reinforcement.
b) centreline of the weld is below the sides of the weld.
c) centreline of the weld is above the sides of the weld.
d) centreline of the weld is level with the sides of the weld.

Answer 19

b) centreline of the weld is below the sides of the weld.