WEL 400
Using the last two numbers of the SAE system, what would 1018 represent?
.18% C
The range of carbon in medium carbon steels is:
0.3% - 0.5%C
With a 4340 steel, there will be what % of carbon?
0.40%
What is maximum permissible limit of Si in carbon steels?
0.60%
This series is generally utilized in filler metal form.
4000
If a weldment made from 1" 6061T-6 needs to respond to heat treatment, the best filler metal selection would be:
4643
The 4 in E7018-H4R represents:
4ml of diffusible hydrogen per 100 grams of weld
When a 6061 is welded with a dissimilar filler, the composition of the admixture should be:
50% 4043 70% 5356
This aluminum alloy has good weldability, is non-heat treatable and is primarily used for structural applications.
5000
Which of the following aluminum alloys would be considered non heat-treatable?
5000
If a 6061 alloy is going to be anodized, which filler would provide the best color match?
5356 5556
How much does the volume of material decrease when an Al changes state from a liquid to a solid?
6%
Due to the potential of creating alpha case, the percentage of Al contained in Ti is kept at:
6-8%
Due to the potential of creating brittle phases, the percentage of Al contained in Ti is kept at:
6-8%
This aluminum alloys series would be considered the most versatile of the heat treatable alloys.
6000
This aluminum series should never be autogenously welded.
6000
Which of the following aluminum alloys would be considered heat-treatable?
6000
This type of aluminum alloy series can be heat treated to close to 100,000psi.
7000
Ti must be shielded until it reaches below this temperature, otherwise the oxide layer will grow too thick, and contamination of the weld zone will have occured.
800F
When exposed to temperatures above , unshielded Ti can pick up oxygen, nitrogen, carbon, and hydrogen.
800F
This heat treatment process will precipitate fine alpha particles from the unstable beta phase produced by solution treatment
Aging
This heat treatment process will precipitate fine alpha particles from the unstable beta phase produced by solution treatment.
Aging
The main alloying element in the 1000 series is:
Al
This element has the second most pronounced effect on the interstitial strengthening of unalloyed Ti.
Al
A stainless steel is said to be stabilized if there are alloys added to it to react with the oxygen before the chromium does.
False
As carbon content increases below the eutectoid point, it is harder (requires more temperature) to create austenite.
False
As long as the oxide layer color is acceptable, the weld is deemed 100% acceptable.
False
Because of the austenite stabilization in dss and sdss steels, they can be used at cryogenic temps.
False
Because of their high thermal conductivity, stainless steels are able to avoid distortion quite readily.
False
Chromium is a more effective at stabilizing ferrite, than nickel is at stabilizing austenite.
False
Diluted weld metal will have a lower FN than undiliuted because the ferrite level of the base metal is purposely kept high and unbalanced.
False
Distortion is a major concern when welding Ti due to the low thermal conductivity and high coefficient of thermal expansion.
False
FN and %ferrite are essentially the same. That means if you have an FN of 45, you have about 45% ferrite in the material.
False
Generally speaking, ferritic steels are usually susceptible to solidification cracking because the ferritic phase is so brittle.
False
HSLA steels always require a PWHT.
False
HSLA steels are generally classified by their chemical compositions, as opposed to their mechanical properties.
False
HSLA steels are known to have more carbon than mild carbon steels.
False
If a high carbon steel is welded with a nickel based electrode, the weld will have the same hardness values as the base material.
False
In order to ensure complete color match, a material that is to be anodized should be welded with a 4xxx series filler material.
False
It is a good idea to use the Schaeffler and DeLong diagrams to predict the FN number of sdss and dss.
False
It is possible to accurately (with all confidence) predict the FN of a weld.
False
Martensite is an iron-carbide with zero tensile ductility.
False
Martensitic stainless steels should be used when you need excellent corrosion resistance and high strength, as compared to the other stainless steel types.
False
Once created, it is impossible to dissolve chromium carbides in the material.
False
Q&T steels are sometimes furnished in the as rolled condition.
False
Q&T steels rely on upper bainite, ferrite, and pearlite to get their elevated strengths.
False
Sensitization occurs when chromium gets tied up with another element other than carbon.
False
Since there are no commercially available filler materials, it is advisable to weld 6xxx base material autogenously.
False
Stainless steels are able to efficiently transfer electricity.
False
Stainless steels have a lower coefficient of thermal expansion as compared to carbon steel.
False
The 4xxx filler material should be stored in a controlled-environment cabinet when not in use because it is so susceptible to developing a hydrated surface.
False
The FCC structure is particularly susceptible to cracking if there are impurities present.
False
The FN number is determined by image analsis or point grid measurements, while the %F is a measurement of the magnetism of the material.
False
The ability of the passive layer to repair itself is contingent upon there being both Cr and Ni available.
False
The biggest challenge when welding ferritic stainless steels is grain growth in the HAZ, so you should be sure to preheat the material to prevent this.
False
The dss and sdss filler materials are usually over-alloyed with Cr in order to promote the ferrite phase upon cooling.
False
The effect of carbon on the A3 line is negligable.
False
The martensite phase will have the highest level of hydrogen embrittlement potential, but a bainitic structure will not be at risk at all.
False
The only 7xxx series base materials that are weldable are those with higher Cu values.
False
The strengthening effect from heat treatmnet in beta alloys occurs as a result of an increase in the beta grain size.
False
The thicker the material, the higher the tensile strength per square inch. This is known as the Effect of Mass.
False
There is no need to preheat aluminum because hydrogen isn't very soluble in aluminum.
False
Ti does not experience grain coarsening.
False
Usually Q&T steels are welded in the as-rolled condition.
False
Vanadium determines the maximum hardness that a steel can achieve.
False
Weld metal is generally less susceptible to hydrogen embrittlement due to it containing a higher amount of carbon.
False
This process is considered to be the lowest low hydrogen process:
GTAW
At 1700oF and above, ferritic stainless steels experience:
Grain Growth
The microstructure of the Ti alpha phase is:
HCP
What type of steel is generally classified by its mechanical properties, as opposed to its chemical composition?
HSLA
If you add this gas to your shielding gas mix when welding aluminum, it will increase your penetration due to the increase in ionization energy.
He
You can increase the temperature of the GMAW arc by adding this high ionization potential gas, which should allow the weld to stay fluid long enough to prevent trapping of porosity when welding aluminum.
He
An austenitic stainless steel may have elements added to it to prevent loss of ductility and loss of corrosion resistance at elevated temps. An example of such an element would be:
Tantalum Niobium Titanium
This color is generally widely accepted as being the limit for oxide layer thickness when visually inspecting welds in Ti:
Strae
If an aluminum classification has an H suffix, what does that tell you about the material?
Strain Hardened
This type of stainless steel would be high in levels of Cr and extremely low in the levels of interstitial elements:
Super Ferritic
This temper is a product of a solution heat treatment and natural ageing.
T4
This temper is a product of a solution heat treatment and artificial aging:
T6
If an aluminum classification has an T suffix, what does that tell you about the material?
Tempered
Q&T steels rely on the transformation products of:
Tempered martensite and lower bainite
The difference between CP1 - CP4 is:
The amount of O2 and Fe
A Q&T steel will always require a PWHT.
False
A rimmed steel is completely deoxidized during the steel making process.
False
Shielding gas purity is very important when welding Ti, and the dew point measurement of the gas indicates how pure the shielding gas is. Most Ar shielding is provided at this level:
-60F
After welding on an alloy with a -T6 temper, with no PWHT it can only attain a temper.
-T4
At what carbon level do we generally consider the steel to be unweldable?
1.0%
What is the maximum permissible limit of Mn in carbon steels?
1.65%
Generally speaking, in order to be a stainless steel, there should be at least what percentage of Cr?
10.5-12%
This aluminum series would be used when thermal/electrical conductivity or corrosion resistance are paramount.
1000
This is the generally accepted minimum amount of Cr necessary in order for a material to be considered a stainless steel:
11%
At what point might the material thickness of a heat treatable aluminum be too thick to provide enough dilution for the weld metal to respond to heat treatment?
12.5mm
Generally speaking, what is the threshold temperature for Ti in a service application due to the excessive growth of the oxide layer?
1200F
This is the melting point of pure aluminum:
1200F
If a preheat is absolutely necessary, you should keep the temp below:
200F
This aluminum alloy is great for general purpose, and displays moderate strength with good workability. It is often used in the beverage industry.
3000
For the welding of dissimilar metals (eg. CS to SS), which filler metal would you recommend?
309L
Generally speaking, this filler metal classification would contian higher levels of alloying elements as compared to the other fillers that are listed.
316L 309/309L
This is the melting point of the aluminum oxide:
3700F
When welding Ti, the material must be shielded until it reaches below this temperature, otherwise it can dissolve discreet amounts of atmosphere into the solid base material.
800F
In this temperature range austenitic stainless steels may experience intergranular corrosion due to the creation of chromium-rich carbides forming at the austenitic grain boundaries.
840F to 1550F
This is the melting range of alloyed aluminum:
900F - 1200F
Generally speaking, SDSS have a PRE of:
>40
A nonheat-treatable weldment will experience a more ductile HAZ because:
A full anneal occcurs in the HAZ and the stress from cold-working will be lost due to recrystallization
The "L" in 309L is representative of:
A low level of C
Steel's fairly unique ability to transfrom between phases and exhibit multiple phases is known as:
Allotropic
If an aluminum alloy is non-heat treatable, the only increase in strength will be as a result of:
Alloying elements Cold working (strain hardening)
As a group, this Ti alloy generally has the highest creep strength.
Alpha
Considering all the types of Ti available, which would be the most susceptible to hydrogen embrittlement?
Alpha
This phase of Ti is particularly susceptible to contamination cracking because of its microstructure and how it is affected by interstitial elements.
Alpha
This category of Ti would most likely be used for cryogenic applciations
Alpha and Near Alpha
When using a hardness measurement to predict tensile, this could throw the results off:
Alpha case
This category of Ti is known for outstanding strength-to-weight ratios in the heat treated condition:
Alpha-Beta
This element is most widely used as a substitutional strengthener and alpha stabilizer for Ti due to its cost and availibility.
Aluminum
The factors that would best describe an increase in the likelihood of hydrogen embrittlement are:
Amount of Diffusible Hydrogen, Harder Microstructures, Tensile Stress
The factors that would best describe an increase the likelihood of hydrogen embrittlement are:
Amount of Diffusible Hydrogen, Harder Microstructures, Tensile Stress
Duplex stainless steels are known to be , which means they will exhibit different mechanical properties depending upon which way the grains are oriented.
Anisotropic
If an aluminum classification has an O suffix, what does that tell you about the material?
Annealed
If an austentic stainless is cold-worked, an increase in ferromagnetism can be remedied by:
Annealing
If an austentic stainless is sensitized, a decrease in corrosion resistance can be remedied by:
Annealing
Taking a material to a supersaturated solid solution condition, quenching it, then re-heating it to a lower temperature would be representative of what type of thermal treatment?
Artificial Ageing Precipitation Hardening
If an aluminum classification has an F suffix, what does that tell you about the material?
As fabricated
Stress in a weld will tend to concentrate:
At the Toe At the Root At any Notches
Carbon will stabilize this phase:
Austenite
In order to create martensite, you must first have:
Austenite
Nickel will stabilize this phase:
Austenite
It is generally accepted that this PH steel is the most difficult to weld due to the creation of liquid films along the grain boundaries, and some of the alloying elements being lost to oxide creation.
Austenitic
Of the PH stainless steels, this grade can only be hardened through an ageing heat treatment.
Austenitic
When welding martensitic stainless steels, if you need ductility of the weld you should pick a filler made of:
Austenitic
Genearally speaking, duplex is primarily composed of these phases:
Austenitic / Ferritic
The ability of a stainless steel to regenerate the chromium oxide layer if it is removed is dependant upon:
Available Cr Available O2
Ferrite has a microstructure of:
BCC
The microstructure of the Ti beta phase is:
BCC
Martensite has a microstructure of:
BCT
When a 300 series is cold-worked, the FCC microstructure breaks down into a(n) structure, and may cause an increase in ferromagnetism.
BCT
Cr-Mo steels rely upon the microstructures of:
Bainite and martensite
Generally speaking, Ti will first solidify as this phase, then depending upon the level of alloying elements, it will allotropically change or remain metastable.
Beta
This phase of Ti is known to have the ability to dissolve higher amounts of H:
Beta
Which of the following Ti alloys would benefit the most from heat treatment?
Beta
Which phase of Ti has the highest amount of stabilizing elements?
Beta
This is the temperature in which Ti has an allotropic transformation, and when it occurs is dependent upon the alloying elements.
Beta Transus
Why would it be beneficial to have an FN number between 3 and 20 in austenitic weld metal?
Better resistance to cracking
If an HSLA requires a preheat, it will depend upon
Pcm Thickness of material Filler metal
This group of Ti would be utilized for corrosion resistance, but not usually for high strength.
CP
This formula allows us to predict and quantify the effect of the alloying elements in relation to the hardness they could produce or the liklihood of martensite formation.
Carbon Equivalent
What three things should be known in order to determine the weldability of a material?
Chemical, Mechanical, Thermal History
This alloy is a potent ferrite stabilizer, and is also added to improve strength at elevated temps and increase the materials resistance to corrosion.
Chromium
A PWHT on Cr-Mo material will be required if there is 2.25% Cr or less, and a low C filler metal is used.
False
The main alloying element in the 2000 series is:
Cu
The only way to refine the grain size of Ti is to:
Deformation processing and heat treatment
If an austenitic filler is chosen to weld martensitic stainless steels, you should first consider:
Differences in mechanical properties of the base metal and weld metal. Possible adverse effects of the pwht on the weld metal Environmental factors such as corrosion
Creep Resistance is defined by three characteristics of:
Elevated Temp, Pressure, Time
The alloy concentration where, when temperature increases, the material has a phase change from many microstructures to a single microstructure is known as:
Eutectoid Point
Generally speaking, 4xxx filler should not be used to weld 5xxx base materail because:
Excessive creation of magnesium silicide eutectics
The main alloying element in the 8000 series is:
Expiremental
Austenite has a microstructure of:
FCC
Before a BCT structure can be created, what structure must first be present?
FCC
This microstructure is much more accepting of carbon
FCC
What microstructure does Al exhibit?
FCC
When autogenously welding a carbon steel and you need some deoxidization to prevent porosity in the weld, you could select an E70s-2 to help clean the weld.
False
When autogenously welding a carbon steel and you need some deoxidization to prevent porosity in the weld, you could select an ER70S-2 to help clean the weld.
False
When iron atoms rearrange from ferrite to austenite there is a volumetric expansion. This is why carbon is more soluble in austenite than ferrite.
False
When welding high carbon steels, concave is better than convex.
False
This type of cracking is primarily a design issue, but can be increased by stress concentrations.
Fatique Cracking
Chromium will stabilize this phase:
Ferrite
Silicon will stabilize this phase:
Ferrite
Between the temperatures of 1341F and 1674F, the iron atoms may be arranged in what phase, depending on the carbon content?
Ferrite and Austenite
Below the temperature of 1341F, the iron atoms may be arranged in what phase, depending on the carbon content?
Ferrite and Pearlite
HSLA steels are strengthened by:
Ferrite grain refinement Precipitation hardening Substructural strengthening
This type of stainless steel has a coefficient of thermal expansion similar to carbon steels:
Ferritic
This type of stainless steel would be high in levels of Cr and lower in the levels of other alloys:
Ferritic
This type of stainless steel would have ferromagnetic properties
Ferritic Martensitic
Austenitic stainless steels may be prone to cracking. This may be partially due to:
High thermal expansion Low thermal conductivity Distortion stresses
An HSLA will require a PWHT under the following circumstances:
If it will be in a stress-corrosion cracking environment. Dimensional stability for machining
Sometimes there is an increase in the amount of C in a stainless steel filler metal. If so, it is added in order to:
Increase strength at elevated temps
The creation of chromium carbides promotes:
Intergranular corrosion
This type of cracking occurs as a result of a discontinuity in the material that occurred in the steel making process during the flattening of the material, and isn't usually noticed until after welding.
Lamellar Tear
To prevent excessive softening of the base metal in a high carbon steel, which of the following would not help?
Larger electrode
The "L" in 308L is representative of:
Low amounts of C
Hot cracking is a form of solidification cracking that results due to:
Low melting temp compounds (sulfur, lead, tin, etc.)
This phase is a feathery composition of ferrite and cementite?
Lower Bainite
Sometimes a 4047 series will prevent cracking better than a 4043. Why?
Lower melting range
In order to prevent iron sulfide inclusions, this element is added during the production of steel:
Manganese
This type of stainless steel can be heat hardened:
Martensitic
This type of stainless steel would be high in levels of Cr and C (relatively speaking).
Martensitic
Of the PH stainless steels, this grade can be hardened through martensite creation and an ageing heat treatment.
Martensitic Semi-Austenitic
PH stainless steels have strengths comparable to , but corrosion resistance comparable to .
Martensitic, Austenitic
This category of Ti is known for excellent formability, with high strength-to-weight ratios making them excellent for fasteners and springs.
Metastable Beta
The main alloying element in the 5000 series is:
Mg
The main alloying element in the 3000 series is:
Mn
This element has the most pronounced effect on the interstitial strengthening of unalloyed Ti.
N
Which of the following is an important alloying element in DSS and SDSS steels, but can be difficult to contain as it wants to escape at atmospheric pressure and below.
N
can be used as an effective and potent FCC stabilizer, but won't provide the same mechanical and physical properties that Ni provides.
N
This element is responsible for making the 300 series austenitic:
Ni
This element increases hardenability, is a strong austenite stabilizer and is resistant to the creation of oxides and carbides.
Nickel
The protective layer of stainless steel is said to be , which means that once it is created it does not react with anything else.
Passive
This formula allows us to predict and quantify the effect of the alloying elements in relation to the hardness they could produce or the liklihood of martensite formation in HSLA steels.
Pcm
High carbon steels can be successfully welded with:
Nickel filler Austenitic stainless filler Under-matched filler (dilution)
A preheat is necessary with this stainless steel to prevent hydrogen embrittlement :
None of the above
Between the temperatures of 1418F and 1675F iron exhibits this property:
Paramagnetic
This is the act of creating the protective layer in stainless steels:
Passivation
Generally speaking the goal is to keep carbon content low in filler materials to prevent opportunity for chromium-carbide creation, and is designated by an "L" suffix. When would an "H" suffix be utilized.
Possibly for high temperature applications
Generally speaking the goal is to keep carbon content low in filler materials to prevent opportunity for chromium-carbide creation, and is designated by an "L" suffix. When would an "H" suffix be utilized?
Possibly for high temperature applications
What element is frequently added to the flux coating in order to aid in arc stability?
Potassium
The AISI designation for steel is much like the SAE, with the exception of a:
Prefix that denotes which steel making process
What is the main difference between HSLA and Q&T steel?
Q&T is furnished in the heat treated condition
After a PH steel has been heated to create a homogeneous dispersal of the alloying elements, it must then be in order to lock those alloys in place.
Quenched
Which one of the following will not aid in preventing hardening of the base metal when welding high carbon steel?
Reduce rigidity of joint
This type of cracking occurs due to the HAZ grains being coarsened, and usually occurs during a PWHT.
Reheat Cracking
This diagram uses the chemistry of the material(s) to determine the resulting microstructure, and is usually used to determine the balance of ferrite and austenite.
Schaeffler Diagram DeLong Diagram WRC-1992 Diagram
Of the PH stainless steels, this grade is very complex and has an intermediate conditioning heat treatment to precipitate carbides in order to raise the Mf temp.
Semi-Austenitic
This term relates to the creation of chromium carbides:
Sensitization
If the 5XXX base material is high in Mg, care should be taken to ensure the 4XXX filler is low in , otherwise there will be a high propensity for cracking:
Si
The main alloying element in the 4000 series is:
Si
The main alloying element in the 6000 series is:
Si & Mg
This phase is a brittle phase that occurs in ferritic stainless steels when the temperature gets too high:
Sigma phase
This element promotes fluidity in the steel as a result of its low melting temp. It also acts as a deoxidizer.
Silicon
Which one of the following will not aid in preventing cracking of the weld metal when welding high carbon steel?
Slow travel speed
If a material is 6061-T6, then it has been:
Solution Heat Treated and Artificially Aged
In order for a PH steel to be hardened it must first be raised above the temperature in order to create a super-saturated solid solution.
Solvus
Some stainless steels can handle higher temperatures and delay the creation of chromium carbides due to the addition of certain reactive elements. These stainless steels are known as:
Stabilized
If you weld on a 6000 series aluminum with a 4000 series filler, the following is true:
The weld may respond to heat treatment depending upon the amount of dilution
In order to keep the FN number in balance when GMA welding, there may be an addition of N to the shielding gas.
True
Increasing the welding amperage and decreasing the travel speed may be an effective way to reduce the cooling rate for a welded material.
True
This is the most popular classification of Alpha-Beta Ti:
Ti-6Al-4V
A form of Ti used quite readily in the production of filler materials due to its refractive properties is:
TiO2 Rutile
This element is usually responsible for stabilizing stainless steels, and was very important before the advent of AOD.
Titanium
A higher solidification and cooling rate will produce a finer grained microstructure with greater strength and a decreased tendency for hot cracking.
True
Aluminum is able to increase in strength with no decrease in ductility with temps as low as -320F
True
An increase in % weight of Si or Mg will decrease the alloys crack sensitivity.
True
Austenitic stainless steel filler can be used on ferritic grade stainless, but can be cause for concern if the material is going to be placed in an SCC environment.
True
Austenitic stainless steels are usually limited in application over 1530oF due to heavy scaling issues.
True
Austenitic stainless steels have about a 50% greater thermal expansion as compared to carbon steels.
True
Austenitic stainless steels work well over a wide temperature range; from cyro temps to elevated service temps. They are able to do this because they don't have a sharp ductile-to-brittle transisiton like the other stainless steels.
True
Chromium is the main element responsible for the creation of the passive layer, in addition to oxygen.
True
Contamination is the most prevelant enabler of discontinuties in the welding of Ti.
True
Copper, titanium, niobium and aluminum are often used as precipitates in PH stainless steels.
True
Cracking as a result of hydrogen embrittlement can occur up to 48 hrs after fabrication.
True
Duplex stainless steels offer higher strength and better resistance to scc and pitting as compared to conventional stainless steels.
True
Filler metal selection for welding aluminum must be well thought out because while many fillers are acceptable, there is usually one selection that is most applicable.
True
First generation (430/434/442/446) ferritic stainless steels can produce a martensitic reaction upon cooling, so they will need to go through a pwht in order to dissolve any martensite and increase toughness.
True
Generally speaking, HSLA steels should require a low hydrogen welding process.
True
Generally speaking, for a material to be considered high alloy, it should have 8% or more of alloying elements.
True
Generally speaking, for a material to be considered low alloy it should have less than 4% of alloying elements.
True
Generally speaking, the only way to refine the grains of a ferritic stainless steel is by cold-working and then annealing because they generally can't transition to austenite through thermal treatment.
True
HTLA generally has a higher carbon content as compared to HSLA and Q&T.
True
Hardness testing is an acceptable way to predict the tensile strength of Ti.
True
Hydrogen is readily absorbed by liquid iron.
True
It is very difficult to avoid martensite formation in HTLA steels no matter how slowly you cool them down, and impossible to prevent martensite if there is no preheat.
True
Low hydrogen practices are the most cost effective and easily attainable ways to control hydrogen embrittlement.
True
Martensitic stainless steel are most successfully welded in the annealed condition, followed by a pwht to bring about some better toughness properties.
True
Martensitic stainless steel is considered heat hardenable.
True
Martensitic stainless steels are magnetic.
True
Martensitic stainless steels have the highest level of carbon relative to the other stainless steel types.
True
Nickel based stainless steels perform better in a reducing environment.
True
Oftentimes fabricators of superferritic stainless steels use a strip of the base material as filler metal as commercial filler material is often limited.
True
PH stainless steels are less susceptible to solidification and liquation cracking as compared to conventional austenitic stainless steels.
True
Passivation is the process of re-creating the chromium oxide layer.
True
Q&T steels are similiar in composition to HSLA steels, but they usually have a higher level of C, Cr, and Mo.
True
Si would be a good example of a ferrite stablizer in a filler metal.
True
Sigma Phase creation is generally only an issue when the Cr levels are above 13%.
True
Stabilizing BCC in an FCC structure could help eliminate hot cracking or solidification cracking.
True
The 400 series is a combination of ferritic and martensitic stainless steels.
True
The effect of carbon on the A1 line is negligable.
True
The eutectoid point is the alloy mixture that provides the lowest possible melting temp of the material.
True
The martensite phase will have the highest level of hydrogen embrittlement potential, but a bainitic structure would be susceptible as well, just at a lower level.
True
The preheat for HSLA steels may be dependent upon the selected filler material.
True
The stress as a result of a phase transformation could be enough to enable cracking from hydrogen embrittlement.
True
The use of Ti is generally limited to temperatures below 1200oF due to excessive oxide creation.
True
Ti has a comparable percent of elongation to carbon steels.
True
Titanium has a passive, tenacious, and self-renewing oxide layer just like stainless steels.
True
Titanium is unique in the fact that as temperature decreases it will experience an increase in tensile properties with little reduction of ductility.
True
Too little Mn in a steel can be harmful due to the incease in the likelihood of hot shortness, or a reduction of ductility at elevated temps.
True
Two materials could have the same identical chemistry, go through different thermal treatments, and have completely different mechanical properties.
True
Underbead cracking is the most common type of hydrogen induced embrittlement.
True
Using a filler metal of matching composition for the ferritic stainless steels can produce a weld and HAZ that lacks toughness.
True
With some high energy, low themal input welding processes, the creation of martensite may be a concern.
True
The main alloying element in the 9000 series is:
Unused
How can embrittled phases be prevented when fabricating superferritic stainless steels?
Water Quenching & Full Annealing
Hydrogen cracking can be problematic in Ti as it is in steels. However, the delay time for a hydrogen crack to occur in Ti can be up to:
Weeks to months
Generally speaking the goal is to keep carbon content low in filler materials to prevent opportunity for chromium-carbide creation, and is designated by an "L" suffix. When would an "N" suffix be utilized.
When more nitrogen is needed to increse the yield strength without impairing ductility .
Sometimes a small amount of a BCC structure can help a largely FCC structure, but sometimes is can't. Those times that it can't would be:
When there are elevated temps When there are cryo temps When ferromagnetism can't be tolerated
The main alloying element in the 7000 series is:
Zn
Cementite is:
an iron carbide
5xxx filler material will only be good for prolonged high temp service if it has 3.5% Mg and above.
false
A PWHT may not be necessary for an HTLA because we want the formation of the hard and brittle martensite.
false
