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153 Cards in this Set
- Front
- Back
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What is eye protection protecting from |
Light rays Heat Flying metal Slag Sparks |
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What 3 harmful rays do you encounter with oxyacetylene brazing cutting and welding |
Visible light UV light Infra red (heat rays) |
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How are the lenses for welding and cutting goggles identified |
By number and by colour Larger number is darker Colours are commonly amber or green. |
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What is the prefered material for welding protective clothing |
In order leather, wool, denim, and cotton because they repel sparks |
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What are some guidelines to follow for clothing safety |
Shirt/jacket pockets have cover flaps Pant legs should not have cuffs Pant legs should cover boots No disposable lighters/matches in pockets Beanie to protect hair Dry type leather gaunlet-style gloves Hard and coarse cotton is relatively safe for clothing |
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3 components necessary for fire to occur |
Heat Fuel Oxygen |
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Classes of fire extinguisher |
A - ash (wood/paper) B - barrel (oil) C - current (electrical) D - special use |
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What are some fire safety considerations when welding or cutting |
Check for explosive atmosphere Check for nearby extinguishers Move combustibles to a safe place Be aware of blind spots and use a fire watch Protect concrete from hot slag/sparks Don't point the hot part at the hoses when using a torch Use screens to stop sparks, slag, and light to protect people/machines |
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What are the signs you should already be wearing hearing protection |
Ringing/buzzing sound, You have to raise your voice to a person 3 feet away |
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When is normal shop ventilation adequate |
Heating or cutting ferrous metals without coatings |
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When should you have a blower fan |
When in confined spaces or anywhere ventilation is inadequate |
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What do you need when heating or cutting material containing zinc cadmium or lead |
An approved air line respirator |
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What are properties of oxygen |
Colourless odourless and tasteless has that supports combustion |
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How much oxygen is in gas used for oxyacetylene equipment |
99.5% |
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How much oxygen is in the atmosphere |
Approximately 21% |
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How are oxygen tanks made |
Hot drawn from a single piece of steel |
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How thick are oxygen tanks |
.260"(7.4mm) |
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How big is a full sized oxygen cylinder |
21.5cm ID(8.5") 23cm OD (9") 129.5cm tall (51") |
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What is the volume of a full sized oxygen cylinder |
244ft² or 9.7m³ |
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What is the volume of a half oxygen cylinder |
122ft³ or 3.45m³ |
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What pressure is a new oxygen cylinder filled to |
2200psi at 70°f |
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What pressure are oxygen cylinders factory tested at |
3360psi |
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How often are oxygen tanks tested |
First retest 10 years Every other retest 5 years |
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Where should the valve position be on an oxygen cylinder |
Fully open or fully closed. |
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Is there a fixed draw limit on oxygen cylinders |
No it can empty as fast or slowly as required |
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What temperature should gauge readings be taken at to ensure accuracy |
70°f / 21°c |
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What thread do all oxygen cylinders have |
Right hand |
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What are the properties of acetylene |
Colourless Strong pungent odor Acts as anaesthetic in pure form |
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What % of acetylene is detectable by smell |
1% |
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What is the explosive mixture of acetylene in air |
2.5% to 80% |
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How should you check for acetylene leaks? |
Approved oil free detection liquid |
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What is the critical point of acetylene |
28psi at 70°f Lower pressure at higher temperature |
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When is unstabilized acetylene is not safe compressed beyond what psi |
The maximum safe working pressure (MWSP) is 15psi |
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What is commonly used as filler in modern acetylene cylinders |
Calcium silicate |
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Why is acetone used in acetylene cylinders |
Acetone has the ability to absorb acetylene under pressure and release it when pressure is dropped |
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After filler is added how much of the volume is filled with acetone |
40% |
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Why must acetylene cylinders be used upright |
The acetone stays liquid and will be drawn out if used at an angle |
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What is draw limit |
The maximum amount of acetylene that can be taken from the cylinder before acetone is drawn out |
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What is the draw limit of acetylene |
1/7 of the cylinder capacity per hour (no faster than 7 hours per cylinder) |
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When are manifold systems used |
When large volumes of acetylene oxygen or other gasses are needed |
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How do manifold systems work |
Connecting multiple cylinders together to draw from all tanks at once |
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What are fusible metal plugs? |
Safety valve that operates with dangerous temperature rather than pressure |
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What is the melting point of fusible plugs |
212°f |
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What is the purpose of fusible plugs |
To melt out and release gas in a controlled manner in case of fire |
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Where is it common to see fusible plugs |
Concave bottom Reinforcing collar or neck ring The shoulders of the cylinder |
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What thread does acetylene cylinder valve have |
Left hand |
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How far open should acetylene valves be during operation and why |
1.5-2 full turns to make it easy to close in case of fire |
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How should cylinders supported when in use |
Secured to a cart with a chain |
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When can the protective caps be removed? |
Once the cylinder has been secured to a cart or stationary object |
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What are the 2 categories of shielding gas |
Inert Semi inert |
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What is argon gas |
Colourless Odourless Inert |
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What is argon used for |
Shielding gas for welding primarily non ferrous metals It is also used for purging |
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What is argon mixed with for welding mild steel low alloy steel and stainless? |
Carbon dioxide |
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What is argon mixed with helium good for welding |
Non ferrous metals like copper aluminum and magnesium |
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What is argon oxygen used for |
Stainless steel and sometimes low alloy and mild steel |
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What are some rules for handling cylinders |
Store cool dark and dry Store and use vertical Do not transfer acetylene from one cylinder to the other Don't drop hit or bump tanks Do not use cylinders for anything but storing gas Separate oxygen cylinders from acetylene cylinders Do not use equipment from other gases Use the real names for gasses |
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What to do with a leaking cylinder |
Place outside away from ignition sources, tag, and notify supplier |
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Can you use oxygen like compressed air to blow away dust |
Never |
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What should you do when returning empty bottles |
Close valve and put on cap |
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Where can you find the chemical or trade name of the gas |
On the cylinder |
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Why can't we use colour to identify gas |
Many combination of gasses Damage may obscure colour Colour blind people exist Colours can appear different based on light Suppliers each have different colour ideas |
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Why are regulators required |
To reduce the pressure of the cylinder to working pressure |
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What are the 2 gauges on a regulator for |
High pressure is cylinder pressure Low pressure is output pressure |
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Are oxygen and acetylene regulates interchangeable? |
No Oxygen has right hand thread Acetylene has left hand thread |
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How can you identify acetylene regulators |
Annular groove cut into the outside of the fittings |
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What do single stage regulators do |
Change line or cylinder pressure in one step |
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What is a disadvantage of single stage regulator |
Does not provide fine control of delivery pressure |
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What is a 2 stage regulator |
A 2 stage regulator has 2 diaphragms and 2 meeting needles and seats The first reduces high pressure to intermediary pressure the second brings it down further to working pressure |
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What is regulator creep |
When one of the valves does not seat properly and gas can leak past |
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What remedies are suggested for regulator creep |
Sent it for repair Dismantle and recondition yourself Check for ruptured diaphragm Check and clean springs valve stems and regulator body Clean face and replace/flip the seat |
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What is the purpose of oxyacetylene hoses |
Carry gasses safely without leaks Minimum burst pressure 400psi Resistant to wear and tear Withstand strain of own weight Be resistant to liquids common to jobsites. |
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What are oxyacetylene hoses made of |
One of the following Rubber and filler with fabric or linen linen braid Natural rubber and linen braid Neoprene and nylon |
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Dual line hose sizes ID and OD |
ID 3/16" 1/4" 5/16" OD 7/16" 17/32" 19/32" |
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What colour are oxyacetylene hoses |
Red acetylene Green oxygen |
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What do you use to connect 2 hoses? |
Hose coupling |
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What do you use to splice a hose together |
Hose splicer with crimp type hose clamps |
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How do you test for leaks in oxyacetylene hoses |
Immerse the hose under water at operating pressure or spray with approved leak detection fluid and check for bubbles. |
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What types of fittings should you not use to splice oxyacetylene hoses |
Copper or red brass because copper reacts with acetylene |
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What materials should Oxyacetylene Jose fittings be made of |
Yellow brass Iron Steel |
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What should you do to your hoses if flashback occurs |
Discard hoses |
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What are flashback arrestors |
Reverse flow check valve |
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What are flashback arrestors for |
Prevent flames from traveling from the torch to the regulator |
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What do flashback arrestors do |
Prevent mixture of oxygen and acetylene in the hoses or regilators |
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How do flashback arrestors work |
Allow the flow of gas in one direction only |
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Where are flashback arrestors located commonly |
The torch |
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What is a torch |
Device that mixes oxygen and acetylene in the correct proportions for Oxyacetylene welding and cutting |
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Where is the mixing chamber on a torch? |
Near the tip |
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How does the tip size correlate to the pressure needed in a balance pressure torch |
Tip size is equal to psi. #3 is 3 pounds of pressure(of each has |
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What are welding tips made of |
Copper |
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What angle is the welding flame relative to handle |
75° |
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What are the 2 classes of welding tips |
Swedge tips Straight bore tips |
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What welding tip has a short thick bulbous flame |
Straight bore |
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What type of flame does a swedge tip produce |
Long thin pointed flame |
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What is the size range of welding tips |
000-10 |
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What does a larger number tip mean |
Larger orifice |
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What are rosebuds |
Heating tips |
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What are rosebuds used for |
Produce large amounts of heat for bending preheating shrink fits bronze welding and hard surfacing of large areas |
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How do you determine pressure for a rosebud |
Recommended by manufacturer |
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When lighting the torch how do you prevent backfires and burnback |
Equal pressures the acetylene must be taken out of the smoke range before introducing oxygen |
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How do cutting and welding torches differ |
Design of the tip and by the addition of a passage for pure oxygen |
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What is the most popular torch and why |
Combination torch because it takes most welding and cutting tips and easily change between cutting and welding. |
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What tips are not recommended on a combination torch |
Tips over size 2 and gouging tips should not be used |
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Why is it essential to have the oxygen needle valve on the torch handle fully open |
To assure : a full flow of oxygen to the cutting jet Preheat oxygen is controlled by the preheat oxygen needle valve Cutting oxygen is controlled by the trigger Preheat acetylene is controlled by the torch handle needle valve |
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What is considered better for cutting in rough service applications |
Heavy duty hand cutting torch |
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What torch is heavier and longer than a combination torch |
Heavy duty hand cutting torch |
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what are backfires |
when the flame goes back up the tip into the mixer |
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what gas do you turn on first |
acetylene |
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what gas do you turn off first |
acetylene |
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what are causes of backfires |
to little gas speed obstruction of the gas flow loose or faulty seat connections dirty or hot tip |
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what is a flashback |
explosion in the line causing damage to the euipment |
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what causes flashbacks |
grossly unequal pressures mildly unequal pressures and an obstruction failure to purge each line faulty manipulation of the valves |
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what is burnback |
when the fire is inside the tip or mixer and stays lit continuously |
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causes of burnback |
hot tip orifices enlarged too much faulty mixer and torch body seats |
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what materials are suitable for cutting with oxyacetylene |
ferrous metals with some exceptions |
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what metals cant be cut with oxyacetylene |
non ferrous metals like brass copper aluminum and bronze stainless steel cutting is retarded |
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what should you consider when selecting a tip for oxyacetylene cutting |
how deep the cut will be material condition of the material type of cut quality of cut speed of cut |
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why is a clean tip important |
prevent flashback backfire and burnback tip can cut at odd/undesired angles |
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what is the procedure for lighting a torch |
set gas pressures at regulators purge oxygen and turn needle valve off purge acetylene and light torch increase oxygen to neutral flame press oxygen lever and make sure preheat stays neutral |
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what do you do if preheat flames are not even |
clean/replace tip |
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what should you do if oxygen stream is not aligned with preheat flames |
clean oxygen orifice or replace tip |
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how far should the preheat cones be from the surface of the work material |
1/16 of an inch |
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when should you increase the torch inclination |
thinner materials |
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how much torch inclination for contour cutting |
very little or none at all |
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what are drag or lag lines |
the lines on the side of the workpiece caused by the oxygen jet |
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how can you tell if you are cutting at the right speed |
inspecting the drag lines for excessive lag |
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what are the 2 ways for piercing a hole |
traveling torch still torch |
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what must you do before oxyacetylene equipment is used for welding that is not as important for cutting |
balance the pressures |
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why do you need to balance pressures |
regulators vary as much as 5psi and get abused |
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what are the 3 types of flames |
carbonizing neutral oxidizing |
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what is a carbonizing flame used for |
fusion welding of alloy steel or mild steel using low alloy, high strength filler rod fusion welding of medium and high carbon steel for repair hard surfacing aluminum and silver brazing |
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what are the reactions of mild steel to a oxidizing flame |
tensile strength is lowered if inclusions are caused by the steel ductility and shock resistance is lowered |
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what are the uses of an oxidizing flame |
fusion welding of brass and bronze braze welding of copper and galvanized iron searing of ground surfaces on cast iron in preparation to brazing braze welding of cast iron |
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what are the uses of a neutral flame |
fusion welding of low carbon steel aluminum and cast iron brazing of copper and its alloys flame cutting and heating |
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what is the flame type used by millwrights the most |
neutral flame |
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what is brazing |
brazing is not braze welding brazing uses dissimilar filler to join two base metals filler metal is spread by capillary action |
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what is braze welding |
braze welding is using filler rod and dissimilar metals with a larger amount of filler rod used |
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what is solidus |
highest temperature that the metal is completely solid |
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what is liquidus |
lowest temperature a metal is completely liquid |
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what is capillary attraction |
the action by which liquid is drawn and spread trough a very small space between two surfaces it an sometimes work against gravity |
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what are some advantages of brazing |
less heat distortion dissimilar metals and a wide variety of metals good strength (weld can have higher tensile strength) ductile joints withstand severe reversal of stress little prep is required quick and cheap minimal base metal interaction conductive electrically and corrosion resistant |
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how do you now you are brazing |
base metal not melted closely fitted surfaces for capillary attraction filler metal liquidus temperature above 840 degrees fahrenheit |
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types of brazing joints |
butt lap scarf shaft |
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how big are the joints of a braze |
0.001-0.010 inch 0.001-0.005 inch for high strength tubular telescopic joints can be slip fit |
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what should be considered in regards to the fit-up of dissimilar metals |
rate of expansion |
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what shapes and forms can filler meals come in |
wire or rod powder paste washers rings and inserts |
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what must be considered when selecting filler material |
method of heating joint temperature is the metal compatible with base material and joint type |
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what are some filler materials |
silver aluminum-silicone nickle copper-phosphorous copper copper zinc gold cobalt magnesium |
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what does wetting mean |
the ability of solder to spread |
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what is flux |
compound used to protect the joint from oxidization |
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what are the principal functions of flux |
prevent oxidization during heating absorb and remove oxides assist in flow of the filler material act as a temperature indicator |
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what must you do to the materials before brazing |
clean and check the fit of the joints |
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why should spent flux be removed |
it is chemically corrosive |
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what type of welding is used for cast iron |
braze welding |
