CWB level 3 Module 21 practice
questions
4. If a thermal stress relief is applied to a welded quenched and tempered steel, the
temperature
should not be greater than: (a) the temperature of transformation. (b) the original
temperature of tempering. (c) grain coarsening temperature. - ANS(b) original tempering
temperature.
After a post-weld stress relief of two hours, the weld metal had a strength of 500 MPa. If the
If the time were increased to four hours, would it still be likely that the weld metal would
exceed a predetermined minimum strength of 480 MPa? - ANSYes
Weld metal acicular ferrite is: (a) At the grain boundaries, proeutectoid ferrite was formed.
(b) a specific kind of martensite. (c) ferrite nucleated within the grains of austenite - ANS(c)
ferrite nucleated within the grains of austenite Bainite can only be made from plain,
hardenable carbon steel: (a) quick quench C
b) normalization (c) isothermal transformation.
(d) rapid quenching at a high austenite temperature; (c) isothermal transformation.
Determine the ideal critical diameter (hardenability) for a steel containing 0.25% Si, 1
percent C, and 0.2% .0%Mn,
0.5% Cr, 0.5% Mo, and 1.0% Ni (assuming an ASTM 8-sized initial grain size). Use section
2.5.3 and 2.5.4
as a reference. - ANS5.0
Can plain carbon steel typically be continuously cooled to produce bainite? - ANSNo. Does
a post-weld stress relief always improve the toughness of a weld metal? Do you say yes or
no? Steel's hardenability is influenced by: (a) carbon content and austenite grain size.
(b) the low mass and amount of carbon. (c) alloy content and austenite grain size.
(d) the component's mass and the rate of cooling; (c) the alloy content and austenite grain
size. During fabrication, if plates are deformed by more than 5%, simple heat treatment
frequently formulated to regain ductility is: (a) a full furnace anneal at 900°C.
B. normalization (c) relief from stress, typically at 635°C - ANS(c) relief from stress, typically
at 635°C You would use the if you wanted a deposit with very little silicon using SAW.
combination of a:
(a) low silicon wire that has a flux that is acidic (non-basic). (b) high silicon wire with a basic
flux.
(c) basic flux low silicon wire - ANS(c) basic flux low silicon wire Increasing the amount of
carbon: (a) lowers the M start temperature of martensite. (b) raises the M.
(c) has no effect on M. - ANS(a) lowers the martensite start temperature M.
Martensite is a phase produced in hardenable steels that are quenched rapidly because the:
(a) reduced diffusion causes the carbon atoms to distort the usual BCC crystal into a BCT
through a shear mechanism. (b) high thermal gradient produces high strains.
(c) the cool outer surface prevents steel from expanding during quenching. (d) carbon
atoms accumulate at the boundaries of austenite grains. - ANS(a) Carbon atoms distort the
typical BCC crystal into a BCT due to reduced diffusion. crystal by a shear mechanism.
questions
4. If a thermal stress relief is applied to a welded quenched and tempered steel, the
temperature
should not be greater than: (a) the temperature of transformation. (b) the original
temperature of tempering. (c) grain coarsening temperature. - ANS(b) original tempering
temperature.
After a post-weld stress relief of two hours, the weld metal had a strength of 500 MPa. If the
If the time were increased to four hours, would it still be likely that the weld metal would
exceed a predetermined minimum strength of 480 MPa? - ANSYes
Weld metal acicular ferrite is: (a) At the grain boundaries, proeutectoid ferrite was formed.
(b) a specific kind of martensite. (c) ferrite nucleated within the grains of austenite - ANS(c)
ferrite nucleated within the grains of austenite Bainite can only be made from plain,
hardenable carbon steel: (a) quick quench C
b) normalization (c) isothermal transformation.
(d) rapid quenching at a high austenite temperature; (c) isothermal transformation.
Determine the ideal critical diameter (hardenability) for a steel containing 0.25% Si, 1
percent C, and 0.2% .0%Mn,
0.5% Cr, 0.5% Mo, and 1.0% Ni (assuming an ASTM 8-sized initial grain size). Use section
2.5.3 and 2.5.4
as a reference. - ANS5.0
Can plain carbon steel typically be continuously cooled to produce bainite? - ANSNo. Does
a post-weld stress relief always improve the toughness of a weld metal? Do you say yes or
no? Steel's hardenability is influenced by: (a) carbon content and austenite grain size.
(b) the low mass and amount of carbon. (c) alloy content and austenite grain size.
(d) the component's mass and the rate of cooling; (c) the alloy content and austenite grain
size. During fabrication, if plates are deformed by more than 5%, simple heat treatment
frequently formulated to regain ductility is: (a) a full furnace anneal at 900°C.
B. normalization (c) relief from stress, typically at 635°C - ANS(c) relief from stress, typically
at 635°C You would use the if you wanted a deposit with very little silicon using SAW.
combination of a:
(a) low silicon wire that has a flux that is acidic (non-basic). (b) high silicon wire with a basic
flux.
(c) basic flux low silicon wire - ANS(c) basic flux low silicon wire Increasing the amount of
carbon: (a) lowers the M start temperature of martensite. (b) raises the M.
(c) has no effect on M. - ANS(a) lowers the martensite start temperature M.
Martensite is a phase produced in hardenable steels that are quenched rapidly because the:
(a) reduced diffusion causes the carbon atoms to distort the usual BCC crystal into a BCT
through a shear mechanism. (b) high thermal gradient produces high strains.
(c) the cool outer surface prevents steel from expanding during quenching. (d) carbon
atoms accumulate at the boundaries of austenite grains. - ANS(a) Carbon atoms distort the
typical BCC crystal into a BCT due to reduced diffusion. crystal by a shear mechanism.
