1st Year Welder Flashcards
Which grain structure usually provides stronger mechanical properties?
Fine grain structure
A British Thermal Unit (BTU) is defined as :
The volume of heat required to raise one pound of water one degree Fahrenheit.
The heat treatment most likely to reduce Hydrogen cracking is:
Post heat
What type of grain structure is needle like and is very hard and brittle?
Martensite
Which heat treatment will bring steel to its softest, toughest, weakest state?
Annealing
What is the soaking time required to PWHT a steel weldment that is one inch thick?
1 hour
The process used to create a hard surface with a soft core is called?
Case hardening
Heating to a dull red temperature followed by controlled slow cool describes:
Stress relieving
What temperature is required to stress relieve irons and steels?
~1150°F (625°C)
Temperatures of 220°- 315°C (425°-600°F) would most likely be used for:
Tempering
The most common temperature indicating device used by welders is a:
Temp stick
The temperature sensing device that can provide a permanent record of a post weld heat treatment is:
A thermocouple
HAZ stands for?
Heat Affected Zone
HAZ consists of what zones?
- Solid/Liquid transition zone
- Grain growth zone
- Recrystallized zone
- Partially transformed zone
Which metal below has the highest thermal conductivity? Steel, aluminum, brass or copper
Copper
What type of welding power source is most often used for GMAW?
Constant Voltage (CV)
Restraining expansion during heating will produce which of the following, after cooling?
upsetting
Why is it important to pre-set the material when preparing to do a 2G weld?
to counteract distortion
Which of the following is a distortion control method producing low stress in the “as welded” condition?
presetting the parts to be welded
The use of rigid clamping and fixturing can cause:
residual stresses to increase.
One advantage of a “jig” is to:
ensures accuracy of dimensions
Pieces of metal placed on either side of the joint to absorb the heat of the weld and help prevent distortion are called:
chill strips
When a number of large sheets of plate are butt welded together, the distortion technique used is to weld from the:
center toward the outsides
Which of the following is not a method of distortion control?
Using high amperage
Which of the following would help to minimize distortion?
preheat for uniform heat distribution
Which welding process produces high quality deposits with minimum dilution and low distortion?
GTAW
If hardfacing with the SAW welding process, how many layers are recommended to obtain the full properties of the surfacing material?
Two or more layers
Which statement is false. Hard surfacing:
Assists in the corrosion of metal parts
Define the term “spalling”
The breaking away of weld metal from base metal
Which hardsurfacing process is popular for its low cost and convenience:
SMAW
This type of wear removes metal by gouging or grinding.
Abrasion
Hardfacing can only be applied using the GMAW welding process.
False
This type of wear washes away or grooves out the metal surface.
Erosion
Metal to metal wear is:
Seizing or galling type of wear
This type of wear pits and dissolves metal parts.
Corrosion
This type of wear causes the metal to crumble or flake on the surface.
Oxidation
This type of wear is caused by heavy static loads or loads that increase in pressure.
Compression
Rapid heating and cooling cycles may cause:
Thermal shock
Which type of hardfacing material has the most resistance to abrasion?
Tungsten carbide
Which of the following is a method to reduce dilution:
Use low current settings
What can be done to prevent spalling?
Slow the cooling rate down
Pre-setting parts and balancing stresses is a way to minimize?
Distortion
Which type of hardfacing pattern works well for earth moving equipment?
Waffle pattern
Which is true of the oxy-fuel hardsurfacing process:
Low base metal dilution
What type of gas is used for non ferrous metals?
inert gas (non reactive)
What is a reactive gas?
compounds of different gases that dissociate molecularly and recombine under certain conditions
What is C02?
A reactive, odorless, colorless and non flammable gas. Acts as an asphyxiant. Elements are carbon and oxygen. A multi atom molecule that is 53% heavier than air.
What transfer mode is C02 mainly used with?
Short circuit and globular transfer. Spatter loss is high in short circuit mode, and post weld cleanup costs may be a concern.
What is “Buried Arc”
When you have an extremely short arc, and are burying it below the surface of the metal reducing spatter.
Why is it not recommended to use spray transfer with C02?
A true spray arc cannot be obtained with gas mixes that contain more than 15%.
What is C02 gas most commonly used for?
welding mild and low alloy steels
What is O2 Gas?
Oxygen; which is a colorless, odorless, oxidizing gas. High concentrations may effect the pulmonary and nervous system. Oxygen combines with nearly all elements, and supports combustion
What is the advantage of adding small amounts of oxygen to gas mixtures?
Improves arc stability characteristics. Lowers transition current, and increases range over which the welding doesn’t spatter.
How much oxygen is needed to increase puddle fluidity?
less than 10% (1-9%)
Describe H2, and what it is used for
Hydrogen is the lightest known element, and highly combustible in air or oxygen. burns with an almost invisible flame. Increase the heat input to the base metal.
Generally used for special applications like joining stainless steel.
What type of materials is H2 not used for?
Materials that are sensitive to Hydrogen enbrittlement.
Why is Oxygen added to Argon?
The oxygen improves the puddles wetting action and reduces the tendency to undercut. It permits controlled oxidation and increases the temperature of the molten metal as it travels across the arc.
What are Argon-Oxygen gas mixtures normally used for?
Low alloy and stainless steels.
What gas flow rates are generally required for spray transfer application?
11.8L/min to 18.9L/min (25 cfh to 49 cfh)
What is N2 what applications is it used for?
Nitrogen is a colorless, odorless, and non flammable gas that acts as an asphyxiant. Nitrogen is considered inert, but reacts with some elements at certain temperatures. Sometimes mixed with H2 and used as purging, back-shielding, or trailing shield for GMAW of 300 series austenetic stainless steels. Less cost for purging compared to Argon and brighter weld appearance.
Why is any gas mixture containing O2 not recommended for welding non-ferrous metals?
These metals typically react with oxygen
When oxygen and nitrogen from the atmosphere become mixed in the molten weld metal, what happens?
Forms harmful oxides and nitrites in the weld metal
Argon and Helium are what type of gases?
Inert
Which gas is the lightest?
Hydrogen
Where would you use pure Argon shielding gas with GMAW?
Welding non-ferrous metals
What is carbon dioxide gas primarily used for?
Welding mild and low alloy steels
What are 3 factors to consider when selecting a gas for GMAW?
Base metal type and thickness, welding process, and filler metal type
Is Carbon Dioxide a monatomic gas or a compound gas?
Compound gas
What is a characteristic of CO2 gas used with short-circuiting metal transfer?
High weld metal loss in the form of spatter
Which modes of metal transfer are possible with GMAW using 0.35 mild steel wire and C02 gas?
Short circuit and globular
When oxygen is added to Argon, this causes the temperature of the molten weld metal to
Increase
Compared to C02, Argon is an excellent gas for GMAW because it promotes the use of?
Spray metal transfer
When 1-9% oxygen is added to Argon it is to?
Improve wetting action of the weld puddle
Which gas mix tends to produce low crowned weld beads on stainless steels?
Ar-He-C02
What is an advantage of using 75% Ar and 25% co2 gas mix on carbon steel?
Improved arc characteristics
What are 4 factors that can influence gas flow rates?
Type and thickness of the metal, nozzle to work distance, inclination, type of shielding gas used
Which gas in generally used for shielding when using MCAW?
A mixture of Ar and Co2
The purpose of a flow meter is to?
Maintain a constant flow rate of gas
The preferred method of measuring gas supply is what?
Litres per min/ Cubic ft per hr
Flowmeters are calibrated to to indicate what?
Volume of shielding gas supplied
What can be done to prevent regulator freeze up when using Co2 gas?
Install a line heater, or manifold system
What must be considered before using a mini bulk system?
Frequency of use
What is the most accurate way to determine the amount of acetylene gas left in a cylinder?
Weigh the cylinder
What applications would a two stage regulator be used in?
Feeding to sensitive instrumentation
What gas introduced in an excessive amount into a weld zone can result in cold cracking?
Hydrogen
Which describes steels and cast irons?
It is usually a silver-gray to gray color.
What type of gas cylinder value connections use a right hand thread?
Shielding gas
Depending on the manufacture, push pull systems can reach distances of how many meters?
15m
Which gas is reactive, colorless, odorless, and non-flammable?
Carbon dioxide
Which shielding gas is primarily used on mild Steel?
CO2
What is the specific gravity of Argon?
1.38
What is the specific gravity of Oxygen?
1.113
What is specific gravity?
It is the ratio of weight of one substance compared to another.
How can heat be defined?
A volume or quantity and is measured in joules.
What unit is used to express heat?
BTU (British Thermal Unit)
Which term refers to the ability of a gas to conduct heat with shielding gases?
Thermal conductivity.
Which metal is lighter than aluminum?
Magnesium
Aluminum is a very reactive metal. What is meant by “reactive?”
A metal that readily reacts with other elements. Aluminum reacts very quickly with oxygen to form aluminum oxides.
Aluminum has a refractory oxide l. What is a refractory oxide?
The oxide is difficult to melt, reduce, or work. The oxide of aluminum melts at a much higher temperature (3700°) than that of a parent metal (1220°)
How does the electrical and thermal conductivity of aluminum compare with that of mild steel?
The electrical and thermal conductivity of aluminum is approximately 4X that of steel.
What is the melting point of aluminum?
660°C (1220°F)
What is the melting point of the aluminum oxide?
2037°C (3700°F)
Under the same conditions, a section of aluminum would deflect how many more times as a similar section of mild steel?
3 times.
What process may be used to enhance the aluminum oxide film for increased corrosion resistance?
Anodizing. It increases the thickness of the oxide layer.
The coefficient of linear expansion of aluminum is approximately:
Twice that of steel.
In the Aluminum Association wrought aluminum alloy numbering system, the first digit indicates what?
The alloy group.
In the Aluminum Association wrought aluminum alloy number system, the second digit indicates what?
Modifications to the original alloy.
What is the purity of a 1050 aluminum alloy?
99.50 pure.
In the Aluminum Association wrought aluminum alloy number system for 1XXX series, the last 2 digits indicate?
The aluminum purity is over 99.00%
What does the number 43 indicate in the filler wire designation ER4043?
The alloys added
Which aluminum alloy contains substantial amounts of magnesium?
AA 5356
What does the fourth digit indicate for an aluminum alloy casting?
Product form.
The aluminum wrought alloy in the groups 1XXX, 3XXX, and 5XXX series are?
Non-heat treatable.
The aluminum wrought alloys in the groups 2XXX, 6XXX, and 7XXX series are?
Heat treatable.
How can the mechanical properties of heat treated aluminum alloys be restored after welding?
Heat treating again.
Heating an aluminum alloy to a temperature below its melting point for a specified period of time and then quenching from this temperature is called?
Solution heat treating.
Non-heat treatable wrought alloys are designated with several levels of mechanical properties. Which does NOT indicate a mechanical property designation?
A (anodized).
What does H1 stand for?
Work hardened only.
What does O represent?
Fully annealed.
What does F mean?
As fabricated
How are mechanical properties of non-heat treatable aluminum alloys improved?
Cold working and drawing.
Which two filler metals may be used to weld most weldable aluminum alloys?
ER4030 and ER5356
When welding a 6061-T6 alloy, which filler metal alloy is generally the best choice?
ER4043
What is the primary consideration when selecting a filler metal when using GMAW on aluminum?
Matching base metal and filler metal chemistry and mechanical properties.
Which is true about ER5356 aluminum alloy?
Magnesium is the major alloying element.
Where are the drive rolls located at on a pull type drive system?
In the gun itself, close to the contact tip.
A pull type welding gun is designed to be used with?
Soft wires.
What type of wire drive system allows greater machine-to-work distances?
Push-pull system.
Push-pull guns are an advantage when?
Soft wires are taken through long liners.
What type of metal transfer occurs with aluminum on GMAW and 100% Argon shielding?
Spray.
What is the most likely cause of a porous, dirty weld bead?
Drag technique.
What is the most likely cause of the wire melting back onto the contact tip?
Wire feed speed too low.
Where does Aluminum come from?
An ore called Bauxite.
Whu is aluminum added to molten steel during the steel making process?
To deoxidize and control grain growth.
Define non-ferrous metal
Metals that do not contain iron in sufficient quantities to have a dominating influence on the properties of metal.
Define thermal conductivity:
A measure of the speed at which heat flows through an object.
What is hot shortness?
The tendency towards brittleness and cracking while hot.
What is the specific gravity of aluminum?
2.7
What is Aluminums coefficient of linear expansion?
Twice that of steel, aluminum expands twice as much as an identical piece of steel for the same rise in temperature.
Define tensile strength
The resistance of a material to a force that is acting to pull it apart.
What is the tensile strength of aluminum?
48.3Mpa (7000psi)
What is yield strength?
Yield strength or (yield point) is the measure of a load that causes permanent deformation.
What is the yield strength of some aluminum alloys?
490Mpa (70,000psi)
What is modulus of elasticity?
The ratio of stress to the strain. It is determined using the force required to produce a non-permanent deflection in material.
What is the modulus of elasticity of aluminum?
About 1/3 that of steel.
Define ductility
The ability of a material to deform permanently without fracture.
What does HAZ stand for?
Heat affected zone.
What does the term “alloy” refer to?
A mixture of two or more elements.
What would be an example of an internal weld fault?
Oxidation.
Define chill strips?
Heavy strips of metal that are placed on either side of the weld shoulders.
What does the letter “F” refer to with non-heat treatable wrought alloys?
As fabricated.
What does the letter “O” refer to with non-heat treatable wrought alloys?
Fully annealed.
What type of electrons do the electrode and weld metal emit when using GTAW with AC current.
Unequal.
What is a major effect that zinc will have on aluminum when they are alloyed?
It is excellent for welding.
What is aluminums electrical conductivity rating compared to copper?
0.6
Why is Aluminum added to molten metal in the steel making process.
It is added to deoxidize and control grain growth
Aluminum is obtained from what ore?
Bauxite ore, a sedimentary rock.
What is the conductivity of aluminum compared to steel
x4 more
What is the coefficient of linear expansion of aluminum compared to steel?
Almost x2 more
What is the melting temperature of aluminum?
660C / 1220F
What is the melting temperature of aluminum oxides?
2037 C / 3700 F
What can happen to aluminum when in contact with dissimilar metals in a moist environment?
Galvanic corrosion. It’s an electrochemical process that causes one metal to corrode when it touches another metal in a conductive solution. It’s also known as bimetallic corrosion.
What is the process called of making the oxide layer thicker on aluminum?
Anodizing, an electrical current is passes through an acid electrolyte with the aluminum as the anode
What would be some advantages of increasing the oxide layer on aluminum?
Increases hardness, wear resistance, electrical insulation and corrosion resistance.
Why must you remove the oxide layer on aluminum prior to welding?
The oxide layer acts as an insulator
What is the primary cause of porosity in aluminum?
Hydrogen
How is the heat affected zone affected when welding aluminum?
It becomes softer and can take on a smaller bend radius
What is the minimum purity of aluminum in the 1xxx series
99% minimum content
What is the difference between a cast aluminum and a wrought aluminum designation?
Cast aluminum and wrought have a four number designation but the cast has a decimal point before the last number
What is the alloying element in the 4xxx series?
Silicon
What is the alloying element in the 5xxx series?
Magnesium
Name the wrought aluminum alloys series that are non-heat treatable.
1, 3 and 5xxx series
Name the wrought aluminum alloy series that are heat treatable.
2, 6 and 7xxx series
Which aluminum series is both heat treatable and non-heat treatable?
4xxx series
Name two categories of precipitation hardening.
Natural & Artificial aging. Natural aging occurs at room temperature. Artificial aging is at elevated temperature, The required temperature is determined by the alloy.
Should you use a push or pull technique when welding aluminum?
Push.
Pull produces porous, dirty welds because of lack of gas coverage
What is the desired mode of metal transfer with Gmaw aluminum welding?
Spray transfer with 100% argon shielding
Why would a push drive assembly not be well suited for aluminum?
The soft aluminum wire cannot be pushed through long liners. The pull system is favored
What type of liner would you use when welding aluminum?
Nylon, Teflon or plastic. They help the wire feed smoothly
What kind of wire brush would you use for cleaning the base metal for aluminum?
A stainless steel wire brush. It will prevent cross contamination
What type of power source would you use for stud welding aluminum?
A constant current power source
What temperature does aluminum oxide melt at?
TBD
Is cast aluminum machined to create its final shape? True/False
False.
In the aluminum wrought alloy designation system, the last two numbers in the 1xxx series, for example 1030, indicate a minimum aluminum purity of:
0.993
In the aluminum wrought alloy designation system 2xxx-8xxx series, what does the second number represent?
Modifications to the alloy.
What is the acronym to remember the aluminum alloy series
Alice - Aluminum (99%)
Cooper - Copper
Makes - Manganese
Silly - Silicone
Music - Magnesium
The letter “H” in non-heat treatable wrought aluminum alloy designations indicates the material has been
Tempered
Which two aluminum filler wires are the most widely used?
4043 & 5356
What is hot shortness?
Hot shortness is tendency towards brittleness and cracking while hot.
What is Refractory?
Heat resistant. A substance especially resistant to heat. Having a high melting point.
What is Thermal conductivity
Thermal conductivity is the SPEED at which heat travels through an object
What is Wrought
Wrought metals are metals that have been worked/shaped by mechanical means with care, not rough.
What is thermite welding and at what temperatures are obtained while welding?
Thermite welding is a chemical welding process that reacts between powdered aluminum and iron oxide. Temperatures of 4000F can be obtained. Used to join railroad rails.
Affinity
A natural liking for, the tendency for certain substance to bind with others.
What is a way to minimise distortion?
Preheat. Distortion isn’t a problem with heat. It’s a problem with difference in heat.
Explain Dimensional upset
Dimensional upset is a change of dimensions from original form due to distortion
What is one method of distortion control?
Chill strips. Act as heat sink, lowering potential stresses.
What is the second method of distortion control?
Welding around neutral axis.
What is the third method of distortion control?
Back stepping.
Why is oxy-fuel hardsurfacing better for minimizing base metal dilution?
Lower temperature melts the base metal less.
What is base metal dilution?
When the base metal and filler metal are different (Hardfacing) it’s important to prevent them mixing into the weld metal. It changes the composition and properties. This is caused generally by excessive heat and should be avoided.
Define spalling
Spalling is when weld material breaks away from base material. Too much heat and stress can contribute to this.
What’s the difference between abrasion, corrosion, erosion?
Abrasion - solid, Gouging or Grinding
Corrosion - Chemical, pitying and dissolving
Erosion - Fluid, washes away or grooves
Line showing alternate position of an object
Phantom line
A break line is used to:
Save space on drawing.
2 line types that are usually used together are
Dimension & extension lines.
A line that may be used for dimensioning or adding a note:
Leader line.
Lines showing shape & outline of an object.
Object & Hidden line
Cut surface is highlighted by using
Section lines
Cutting plane line is used to identify a:
Section view
Who is responsible for preparing a set of plans for a welded structure?
Engineer
Title block will include:
Engineer stamp, scale, drawn by, revision, company name, drawing #
In Orthographic drawing how many views are required.
2 required, usually has 3.
Auxiliary View
A helper view that contains more details/specs
Orthographic view
Taking a 3D view and making it 2D views.
Isometric drawing
3D drawing contains two angles
Oblique drawing
3D drawing demonstrating 1 angle
What Part and Selection of the OHS Code describes the membership of a joint work site health and safety committee?
Part 13, Section 197
What Part and Section of the OHS Code describes the requirements and options for protective footwear?
Part 18, Section 233
What Part and Section of the OHS Code describes the requirements for workers training about WHMIS?
Part 29, Section 397
What are the first aid requirements for high hazard work at a close work site with 5 to 9 workers at the work site per shift?
1 Emergency First Aider, 1 Standard First Aider, No. 2 First Aid Kit.
What is an employer’s responsibility with regard to hazard assessment at the work site?
To develop a plan to eliminate or control any hazard identified at the work site.
How is WCB of Alberta funded?
100% from employers in Alberta.
What are the four categories of workplace hazards?
Biological, chemical, ergonomic, physical
Who is responsible to have an emergency response plan in place at the work site?
Employers
What part of the OHS code covers first aid requirements at the work site?
Part 11
What number and what type of first aiders must your employer ensure are present at an isolated work site with low hazard assessment rating and 65 workers at the work site per shift?
2 Standard First Aiders, and 1 Emergency First Aider
Who is responsible to ensure work site emergency response plans remain up to date?
The employer and the employees
What is not an obligation your employer assumes when a hazard assessment indicates the need for PPE?
To post a duty To Use Personal Protective Equipment sign at all entrances to the work site
What is the characteristic of protective footwear with a yellow triangle on the outer side or tongue of the right shoe?
Sole puncture protection and Grade 2 protective toe (will withstand impact up to 90 Joules)
What does GMAW stand for?
Gas Metal Arc Welding
True or False: GMAW is commonly used for welding aluminum.
True
Fill in the blank: In GMAW, the welding wire serves as both the ______ and the ______.
electrode, filler material
What type of shielding gas is typically used in GMAW for aluminum?
Argon or a mixture of argon and helium
What is the primary advantage of using GMAW for aluminum welding?
High welding speed and ease of automation
Multiple Choice: Which of the following is not a common problem in GMAW aluminum? A) Porosity B) Cracking C) Under-cutting D) Spatter
C) Under-cutting
What is the recommended wire diameter range for GMAW aluminum?
0.030 to 0.045 inches
True or False: GMAW can only be performed in flat positions.
False
What is a key characteristic of aluminum that affects GMAW?
It has a low melting point and high thermal conductivity
Short Answer: What is the role of the contact tip in GMAW?
To conduct electrical current to the welding wire
Fill in the blank: The ______ technique is often used to minimize distortion in aluminum during GMAW.
weaving
What is the effect of using too much heat in GMAW aluminum?
It can lead to burn-through and warping
Multiple Choice: Which alloy is commonly used for GMAW aluminum? A) 6061 B) 1018 C) 304 D) 4130
A) 6061
True or False: A push technique is preferred for GMAW aluminum.
True
What is the purpose of using a spool gun in GMAW aluminum?
To improve feeding of softer aluminum wire
Short Answer: Why is it important to clean aluminum surfaces before GMAW?
To remove oxide layers and contaminants that hinder welding
Fill in the blank: The recommended travel speed for GMAW aluminum is typically ______ than that for steel.
faster
What is the impact of using a wrong gas mixture in GMAW aluminum?
It can lead to poor arc stability and increased defects
Multiple Choice: What is the typical voltage range for GMAW aluminum? A) 10-15V B) 15-25V C) 25-35V D) 35-45V
B) 15-25V
True or False: GMAW aluminum requires a different polarity than steel.
False
What is the significance of preheating aluminum before GMAW?
It reduces the risk of cracking and improves weld quality
Short Answer: What should be done to prevent contamination of the weld pool in GMAW aluminum?
Maintain a clean and stable arc and avoid excessive spatter
Fill in the blank: ______ is used to control the heat input in GMAW aluminum.
Voltage adjustment
What is a common defect associated with GMAW aluminum?
Porosity
Multiple Choice: Which of the following is a benefit of using a pulsed GMAW process for aluminum? A) Increased heat input B) Better control of weld bead C) Reduced spatter D) Both B and C
D) Both B and C
What is an advantage of GMAW regarding light gauge metals?
Excellent for light gauge metals
How does GMAW perform with poor fit ups?
Good arc control when working with poor fit ups.
What is the heat input comparison of GMAW to SMAW?
Less heat input means less distortion than SMAW.
What are the production rates like for GMAW?
High production rates
What is a cleanup advantage of GMAW?
No slag and little clean up
What is a disadvantage of GMAW related to equipment?
Special equipment required, higher initial cost.
What maintenance issue is associated with GMAW?
Equipment requires more maintenance and down time.
What is a potential issue with GMAW regarding weld quality?
Lack of fusion can be an issue.
In what conditions cannot GMAW be used?
Cannot be used in drafty conditions or outdoors.
What safety concern is associated with GMAW?
High radiant energy requires protection for the welder and others in the vicinity.
What is required for the wire feeder in GMAW?
Wire feeder must be in close proximity to the welding.
What is Cementite?
Cementite (Iron Carbide / Fe3C) is a hard, brittle and present in cast iron and most steels. By weight, it is 6.67% carbon and 93.3% iron.
What is recommended when attaching the hook to an eye-bolt?
always use a shackle when attaching the hook to the load
How heavy is steel?
7850kg/m3 or 490lb/ft3
What happens to load radius will when the crane operator lifts the load.
As the boom deflects from the weight. The horizontal distance between the centre of the load and the rotation centre of the crane will increase.
The two most common types of synthetic rope are?
nylon and polypropylene.
What advantage do synthetic slings have over wire rope or chain slings?
- They are non-sparking
- They do not rust
- They mould themselves to the shape of the object
Suppliers of controlled products are responsible to
Ensure labels are on product
Who is responsible for providing workers with WHMIS training?
The employer
The key elements of WHIMS are
employee education, MSDS and product labelling
Minimum air circulation requirements for the work site are found in the:
provincial and national building codes
How do you identify a portable gasoline container that is approved for use?
Approved by ULC or CSA
What type of fire extinguisher is versatile in fighting different types of fires?
multi-purpose dry chemical
Which of the following portable fire extinguishers should be used to fight a small fire burning in a pile of discarded oily rags?
Classes A, B and C
A Class C fire invloves:
electrical equipment
What is the temperature of a cutting tip with a neutral flame?
5600 degrees farenheit.
What is metal fume fever (MFF)
A short-term illness caused by inhaling metal fumes, especially zinc oxide. It’s an occupational disease that commonly occurs during welding, smelting, casting, brazing, and soldering.
What does bleeding the lines mean?
Reducing line pressures to atmospheric pressure
Drill bits are manufactured with an included angle of
118 Degrees
A screeching sound accompanied by black smoke and red sparks indicates that the tip has a:
Burnback
A steamed vessel is safest to weld on when it is cooled down to room temperature?
False.
Grossly unequal pressure of gases may cause a
Flashback.
After attaching regulators to cylinder valves, and before opening cylinders, make sure that:
pressure adjusting screws are disengaged
The critical pressure of C2H2 is?
28 psi
What is the explosive limit of acetylene in pure oxygen?
2.5-80%
What is the safety device on an oxygen cylinder?
Rupture disc
What is the bursting pressure an oxygen rupture disc?
3200 psi
In order to protect the regulator gauges:
Release the adjusting screw before you open the cylinder valve.
Why are the cylinder valves cracked before the regulators are attached?
Remove dust or dirt from the valve
What precaution should be taken when regulators are to be stored for extended periods of time?
Turn the working pressure adjusting screw in to take the valve off of the valve seat
How would you safely repair an acetylene hose?
Use approved fittings of yellow brass, iron or steel
Which type of welding tip gives you a long pointed flame?
Swedge bore
What tool would be used to properly clean a dirty oxy-fuel welding tip?
Tip drill
The reason for purging each line individually before lighting a welding or cutting torch is to:
Prevent a possible flashback from occurring.
Grossly unequal pressure of gases may cause a:
Flashback
A burnback is when the fire:
Stays steadily in the tip and mixer.
What is meant by the term 2X flame?
The cone and the feather are both the same length
Changing the tip size to a smaller size when oxy-acetylene welding with a neutral flame will produce a flame temperature that:
It’s the same
A screeching sound accompanied by black smoke and red sparks indicates that the tip has a:
Burnback
A popping flame, at the mixer nut, would indicate that the:
small “0” ring is damaged.
When balancing a No. 2 welding tip and the acetylene torch needle valve is fully open, the acetylene regulator should be adjusted so that the flame blows away from the tip _______ inch. (Oxygen needle valve is closed)
1/4”
What is SMAW
Shielded Metal Arc Welding (Stick welding)
Who is responsible for the personal safety of everyone in the shop?
Each individual
Exposure to infrared light while cutting without proper eye protection can cause:
Retina damage
Temporary blindness is caused by the eyes being exposed to high concentrations of:
Visible light
Permanent eye damage in the form of cataracts may result from over exposure to which harmful light ray?
Infrared
What shade of filter plate is recommended for most low to medium amperage SMAW operations?
37175
Why should you place a gasket between the outside clear plate and the filter plate in your welding helmet?
To help prevent heat cracking of the filter plate.
A carbon dioxide fire extinguisher is best suited for:
Class B or C
Poisonous phosgene gas can be created by vapours of chlorinated hydrocarbon degreasers when the vapours are acted upon by:
ultraviolet radiation from the welding arc.
When oxygen reacts with ultraviolet light from welding, the gas produced is:
Ozone
Which supplied air respirator maintains positive pressure in the face piece upon inhalation?
Pressure demand respirator
Files are classified by the:
length, shape and cut.
The cutting edge of a cold chisel should be prepared to a _____ degree angle for softer materials and up to _____ degrees for very hard materials.
60 & 90 degrees
Guards on bench grinders should cover:
2/3rd of wheel.
The web of a drill bit:
1) Separates the flutes.
2) Is the supporting section of the bit.
3) Gradually increases in thickness throughout its length.
The power tool that is best suited for creating intricate shapes and multiple bends is the:
Power bender
When using CO2, dry ice may form in the control openings. One way to remedy this is to install a:
Line heater
The safety device located on the back of a gas cylinder valve used to control the release of the gas in the event of excessive pressure, is called a
Metal rupture disc
What is porosity?
Small cavities that form within the weld metal due to trapped gas bubbles that are released as the molten metal solidifies. Caused from contaminants like O2, H, or N absorbed into the weld pool.
What is dry ice?
CO2 pressurized and cooled into a solid state
Metal rupture disc vs fusible plug?
MRD: is affected by excessive pressure
FP: is affected by excessive temperature
Adding small amounts of oxygen (less than 10%) to argon, causes the weld metal to have less:
Undercut
Why should rubber hoses not be used when using Helium as a shielding gas?
He atoms are tiny and will penetrate through the hose above 20psi.
What is the minimum amount of Argon needed to promote spray transfer?
85%+
Flowmeters indicate:
The volume of gas in liters per minute. The flow rate.
GMAW shielding gas flow rates vary from: (L/min)
7 to 23 L/min
The preferred method of measuring shielding gas supply is:
litres per minute (cubic feet per hour)
What is the ‘Specific Gravity’ of a shielding gas?
Ratio of its mass compared to ATMOSPHERIC AIR
What pressure are cylinders?
40-104 psi - Gas
+40psi - flammable liquid
Cryogenic Liquid
A liquid with a normal boiling point below 150℃
Dewar
A vessel that contains cryogenic liquid gases
Liquefied Compressed Gas
A gas that becomes a liquid at ambient temperatures when compressed in a container
Shielding gas’s primary purpose.
To prevent weld metal from oxidizing and nitriding. Failure to do this may cause harmful fusion defects, porosity, lower ductility, yield strength & tensile strength
Additional effects of welding gas.
Arc characteristics
Mode of metal transfer
Penetration
Weld metal profile
Tendency to undercut
Cleaning action
Speed of welding
Mechanical & chemical properties of weld metal
Factors when choosing a gas.
Base metal type & thickness
Filler metal type
Welding process
Cost of gas
Width & depth of penetration
Desired bead shape
Importance of spatter & post-weld cleanup
Joint design & positioning
Jigging & fixturing
Type of metal transfer
Speed of travel required
Basic properties of a shielding gas include:
Specific gravity
Ionization potential
Thermal conductivity
Dissociation & recombination characteristics
Reactivity/oxidation potential
What is specific gravity?
The ratio of its mass in comparison to the atmospheric air. Atmosphere is 1. Anything greater than 1 sinks. Less than 1 rises. Ie. Argon is heavier than air at 1.38, it therefore shields well for flat position. Conversely, Helium is lighter than air at 0.1368 would be better in overhead position.
Ionization potential
The amount of energy required to remove an electron from a gas atom, converting to gas ion. It influences arc starting and stability. Ie. Argon has low ionization potential meaning smooth & stable arc. Helium high potential making it more difficult to initiate & maintain a smooth arc. In addition, if a gas has a high ionization potential it requires more energy to ionize the gas. Argon would require less voltage than helium. This also plays into thermal conductivity of the metal.
Amperage is responsible for?
Metal deposition rate
What is puddle fluidity?
The viscosity of the puddle
The term “Buzz Box” refers to a:
A/C transformer welding machine
An inverter type welding machine changes:
DC to AC
Three phase equipment is cheaper than single phase equipment. T/F
True
An A/C transformer type welding machine converts:
High voltage and low amperage to low voltage and high amperage
When referring to a “Metal shunt adjustable coil”, the more open the more voltage flow is ______
Increased
A benefit to using an A/C-D/C transformer rectifier power source is _____
Full selection of electrodes
A benefit to using an A/C alternator power source is _____
It can run power tools
A benefit to using a D/C Generator power source is _____
Full choice of electrodes
A benefit to using an Inverter power source is _____
It’s small and compact
What type of welding power source is most often used for GMAW?
Constant Voltage (CV)
List some advantages of GMAW.
- Lower skill
- Excellent for light gauge metals
- Good arc control when working with poor fit ups.
- Less heat input means less distortion than SMAW
- High production rates
- No slag and little clean up
List 3 disadvantages of GMAW
- Special equipment required, higher initial cost.
- Equipment requires more maintenance and down time.
- Lack of fusion can be an issue.
- Cannot be used in drafty conditions or outdoors.
- High radiant energy requires protection for the welder and others in the vicinity.
- Wire feeder most be in close proximity to the welding.
When examining the fractured surface of white cast iron it is usually:
Coarse and silvery white
Which is the lightest: Nickel,
Aluminum, Magnesium, Zinc
Magnesium
Which of the following is incorrect. Parameters that should be considered when welding with FCAW or MCAW are:
Slope adjustment
What is the recommended electrical stickout when using 0.035” to 1/16” wire for FCAW and MCAW?
3/8” to 3/4”
What is the recommended electrode inclination when placing the root pass in a 2F weld using FCAW?
15-30 degrees backhand
When welding a 3F with MCAW, and you encounter undercut on the edges of your cap pass, what corrective measure should you use?
Pause longer on your sides
When performing a 1GF using FCAW, what is the gap between the bevelled plate and the square edge plate?
5/8”
When performing a 2GF using FCAW, what is the gap between the bevelled plate and the square edge plate?
5/16”
How much land is recommended for a 1G groove weld with a GMAW root?
0 - 1/16”
What type of current is used when welding aluminum with GMAW?
DCEP
Which aluminum filler metal is not recommended for sustained high temperature service?
5356
What are the two most commonly used filler metals for GMAW on aluminum?
4043 & 5356
What element causes porosity in an aluminum weld?
Hydrogen
What duty cycle rating is recommended for SAW power sources?
100%
What type of drive rolls are used with the SAW setup?
Knurled or smooth V groove
Amperage is responsible for:
Burn-off rate
Increasing amperage would have what effect on the weld puddle.
Narrow low bead
How can the operator increase the arc length while using SAW?
Increase voltage setting
A good starting point for electrode extension using the SAW process is:
8 times the diameter of the electrode
Which of the following is incorrect. When welding with DCEP:
Penetration is shallower
In the AWS filler metal designation F7A3-EL12K, What does the “L” stand for.
Low manganese content
Which type of SAW flux can be re-used?
Fused
Which type of flux contains deoxidizers to help improve resistance to porosity and weld cracking?
Active flux
Following the manufactures recommendations, how long can SAW consumables be stored for?
6 months
