Residual stress and distortion

Question 1

When heated metals expand;
a. In area
b. In thickness
c. In volume
d. In width

Answer 1

c. In volume

Question 2

Why does welding cause distortion?
a. The weld expands during cooling
b. The joint edges contract when heated
c. The area next to the joint changes
shape

Answer 2

c. The area next to the joint changes
shape

Question 3

Residual stresses;
a. Can equal the yield strength
b. Can be seen at an angle
c. Can be balanced by stretching
d. Can usually be ignored in pr,.actice

Answer 3

a. Can equal the yield strength

Question 4

What causes distortion (deformation)?
a. Free expansion
b. Free contraction
c. Restricted expansion
d. Restricted contraction

Answer 4

c. Restricted expansion

Question 5

Restricted contraction after welding;
a. Causes softening the weld area
b. May set up sufficient stress to cause failure
c. Creates l~calized thickening of the ·oin
d. Stress relieves the final passes

Answer 5

b. May set up sufficient stress to cause failure

Question 6

How does welding speed affect the root opening
of butt joint?
a. At slow speed the root closes
b. At slow speed the root opens
c. At high speed the root closes
d. At any speed the root closes

Answer 6

a. At slow speed the root closes

Question 7

Applying heat (either cutting or welding) to the
edge of an object promotes distortion by;
a. Thinning the edge
b. Shortening the edge
c. Flattening the edge
d. Trimming the edge

Answer 7

b. Shortening the edge

Question 8

What is the maximum temperature used in heat
straightening or forming of low-alloy steels?
a. 450 ·c
b. 650 *c
c. 123 ·c
d. 910 *c

Answer 8

b. 650 *c

Question 9

In flame straightening or forming of low-alloy steel members, what colour should be watched for?
a. Dark Brown
b. Light Blue
c. Dull Red
d. Bright yellow

Answer 9

c. Dull Red