120101i Flashcards
Describe the oxy fuel cutting process
Oxy cutting is a controlled process of rapid oxidation in which steel is heated to its kindling temperature and a high-pressure jet of pure oxygen is directed to the heated area metal exposed to the oxygen oxidizes and is blown away by the oxygen jet stream
What two Ferris base metals cannot be cut satisfactorily with an oxy fuel cutting torch
Cast irons and stainless steals
When a piece of metal is cut, it creates a cut gap called the
A) groove
B) bead
C) kerf
D) crater
C) kerf
On a combination cutting torch, the oxygen valve on the torch handle must be
A) close tightly
B) partially open
C) fully open
D) used to adjust to a neutral flame
C) fully open
The rivet cutting tip is designed to
A) make suitable holes for riveted construction
B) facilitate right angle square hole cutting
C) facilitate cutting in confined spaces
D) cut off rivet and bolt heads without disturbing the parent metal
D) cut off rivet and bolt heads without disturbing the parent metal
Which cutting tip has preheat orifices in a smaller pitch circle around the cutting orifice
A) standard cutting tip
B) high speed cutting tip
C) gouging tip
D) rivet cutting tip
B) high speed cutting tip
The larger the orifices on a cutting tip:
A) less gas you burn
B) greater the heat loss
C) faster you cut
D) thicker the plate that you can cut
D) thicker the plate that you can cut
Which metals can you cut easily using the oxy fuel cutting process?
A) cast irons
B) mild steels
C) stainless steel
D) nickel alloys
B) mild steels
Which oxy fuel torch design has the mixer chamber inside one of the tubes leading to the torch head
A) tip mixing
B) high-speed
C) pre-mixing
D) oxygen lance
C) pre-mixing
Explain why you cannot cut non-Ferris metals using an oxy fuel torch
Unlike steel non-Ferris metals will not oxidize or burn progressively
List three methods used for starting a cut on round stock
- Use a chisel to make the surface.
- Drill into the surface.
- Apply a bead of arc weld
List three types of control systems use for mechanized oxyfuel cutting
- Machine tracer guided.
- Magnetic tracer guided.
- Electronic tracer guided.
Templates for magnetic tracers are made of
Steel
Photo electric cells and computer controls are used with ______ tracer guided cutting machines
A) manual
B) machine
C) magnetic
D) electronic
D) electronic
When preheating for flame cutting the metal should be heated until it reaches its
A) liquid state
B) bright yellow colour
C) kindling point
D) transition temperature
C) kindling point
When the cut is rough and the slag accumulates on the bottom edge, the likely cause is
A) using propane fuel gas
B) using oxygen that is only 99.5% pure
C) using a dirty tip
D) using a cutting attachment type torch
C) using a dirty tip
When piercing holes in a plate you should
A) press, the cutting lever sharply to start the cut
B) allow the preheat cones to touch the material surface
C) raise the oxygen pressure by 25%
D) raise the tip when the cutting lever is depressed
D) raise the tip when the cutting lever is depressed
What is likely to happen if the cutting travel speed is too fast
A) productivity increases in your employer is very impressed
B) slag bubbles to the surface and the cutting action eventually stops
C) the tip overheats and begins to backfire
D) clean slag free cut is produced
B) slag bubbles to the surface and the cutting action eventually stops
What is likely the problem if the curve edges are melting back together behind the cut
A) the tip is too large for the material thickness
B) impurities are in the fuel gas
C) the steel has too high carbon content
D) you are running low on fuel gas
A) the tip is too large for the material thickness
If a shop were to switch from acetylene to propane gas for cutting, it would be necessary to
A) purchase all new torches
B) install special fuel, gas regulators
C) check with the manufacturer to determine if the equipment is compatible
D) change to larger size hoses
C) check with the manufacturer to determine if the equipment is compatible
You can determine a good quality cut by
A) inspecting the kerf lines
B) asking the foreman
C) the amount of welding experience the operator has
D) the amount of oxygen and acetylene consumed
A) inspecting the kerf lines
Kerf drag lines on a properly performed shape cut should be
A) irregular in profile
B) curved to match the shape
C) perpendicular to the plate surface
D) horizontally inclined
C) perpendicular to the plate surface
If you noticed the preheat flames changing from neutral to carbonizing during the cutting process, the most most likely caused would be that the
A) oxygen cylinder is nearly empty
B) acetylene consumption is too high
C) acetylene cylinder is nearly empty
D) tip is dirty and requires cleaning
A) oxygen cylinder is nearly empty
What tools can you use to lay out a structural shape?
A) contour marker
B) hammer and centre punch
C) square and level
D) combination square
E) all of the above
E) all of the above
A skid unit requires 2S shapes to be welded together to create a 90° angle. How can you cut the S shapes to create the required fit up?
A) but the flanges together and weld the gaps
B) cope, one beam to fit inside the other
C) an angle of 45° on each shape and fit together
D) both B&C
E) all of the above
D) both B&C
When cutting structural shapes, it is important to remember to watch your torch angle a torch angle that is off, can cause a structural shape to be cut incorrectly, which could result in a scrapped piece
True or false
True
Describe the term drag
(Lag) the amount the bottom of the kerf line drags behind the top of the kerf line.
Determined by examining the kerf lines on the cross-section of the cut
Describe the term kerf
The cut gap or width of the cut
Describe the term kerf lines:
Viewable with cross-section of the cut kerf lines are a result of the way iron oxidizes during oxy fuel cutting.
Describe the term heat energy and what units it is calculated with.
(heat value, heat of combustion)
The heat, the overall flame generates
Calculated as MJ/m^3 or BTU/ft^3
What cutting process is the: controlled process of rapid oxidation?
a) kindling action
b) plasma cutting
c) oxyfuel cutting
d) gouging
c) oxyfuel cutting
a metals __________ temp, occurs when steels and most ferrous metals are heated to their kindling point.
Ignition temperature
What is the average ignition temp of most steels?
a) 1200°F - 1800°F
b) 1400°F - 1600°F
c) 1600°F - 1800°F
d) 1600°F - 1900°F
b) 1400°F - 1600°F
The O2 ____ _____ blows aside the formed oxides which exposes the metal below until the cut has progressed through the thickness of the steel.
O2 jet stream
How do you determine drag?
by looking at the kerf lines on a cross section of a cut
______ is a term used to describe the cut gap or width of a cut
kerf
State whether the following can be used for manual cutting, automatic cutting or both
- Combo welding and cutting torches
- Standard or heavy duty cutting torches
- Machine cutting touches
- Combo- manual cutting
- Standard & heavy - manual
- Machine cutting torches - automatic
What type of cutting torch is the most popular?
Combo cutting torch
When using a combo cutting torch, the O2 valve on the handle must be _____ ______ to assure a full flow of O2 to the cutting attachment.
fully open
The torch valves on a heavy cutting torch, control the passage of ______ O2 and acetylene so the cutting handle or trigger is the only control valve for the ______ O2 flow
preheat, cutting
A torch that has 3 tubes, where are the gasses mixed?
In the torch tip
What is another name for electronic tracer guided cutting machine?
CNC - computer numerical control
As the orifices increase in size on a cutting torch you can
a) cut thinner materials with more precision
b) cut thicker materials with better control
b) cut thicker materials with better control
When using a cutting torch, if the flame reverts to a carbonizing flame check that the _____ supply is not running low.
a) fuel gas
b) O2 gas
b) O2 gas
What is the standoff distance to maintain when preheating the plate?
a) 1/16” - 1/8”
b) 1/8” - 1/4”
c) 1/4” - 1/2”
a) 1/16” - 1/8”
Always try and start a cut on
a) round edge
b) smooth surface
c) sharp edge
d) you should always pierce your starting point
c) sharp edge
What do you use to assist you in determining if you are using correct travel speeds when cutting.
a) kerf lines
b) drag lines
c) slag on the back of the plate
d) condition of the final cut
b) drag lines
If when cutting the torch is angled towards side A of a plate and away from side B the slag would be:
a) slag build up would be on the A side
b) slag build up would be on the B side
c) there should be no slag built up with a slight angle
d) the slag would be pushed along the cut and expelled out at the end of the cut
a) slag build up would be on the A side
With the still torch cutting method, why would you raise the torch upwards as you depress the cutting lever?
It allows any slag to blow clear of the tip
Can you cut SS with an Oxygen-fuel method?
No- plasma cutting is used on SS
What cutting method is used to cut cast iron?
a) plasma cutting
b) oxygen fuel cutting
c) Oxygen lance cutting
c) Oxygen lance cutting
What cutting method is used to cut: copper, bronze, brass, nickel aluminum and their alloys?
a) plasma cutting
b) oxygen fuel cutting
c) Oxygen lance cutting
a) plasma cutting
What does PAC stand for in relation to cutting processes?
Plasma Arc Cutting
Chromium and Nickel promote the burning process T/F?
False - Chromium and Nickel slow down progressive burning
This makes cutting SS with an oxyfuel torch not possible except for demolition.
Below are all considerations when choosing the type of cutting tip, however what is the one you absolutely must know?
a) type of material to be cut
b) thickness of material to be cut
c) type of cut to be made
d) speed of the cutting required
a) type of material to be cut
however
d) speed of the cutting required
comes in as a close 2nd.
The larger the cutting tip orifices need more or less O2 pressure?
Larger holes = more pressure
provide the correct tip size for each row of info
Thickness of metal - O2 pressure - C2H2 pressure
1. 3/8” - 30psi - 3psi = tip size?
2. 1/2” - 40psi - 3psi = tip size?
3. 1” - 50psi - 3psi = tip size?
- size 1 tip
- size 1 tip
- size 2 tip
What are the 3 cutting methods
a) arc, push, pull
b) across, push, pull
c) push, drag, swing
d) arc, push, drag
b) across, push, pull
What angle must you hold the torch when making bevel cuts for 3G welding
30° angle from the vertical plane to the plate
What does a radiograph use to help produce straight line cuts with the oxyfuel cutting process?
a) magnets
b) CNC operations
c) tracks
d) self-centering jaws
c) tracks
