dc2 welding Flashcards
List three frequent causes of porosity in welds
Leaks in gas lines
TOO HIGH GAS FLOW
DRAFTS AND EXCESSIVE TURBULENC IN WELD POOL
What are the four main causes of lack of fusion/penetration in a weld
Welder parameters
Welder technique
magnetic arc blow
Joint prep
An irregular groove at the toe of a run in the base metal is what type of welding imperfection
undercut
An overlap is a welding imperfection that is form when excessive ____ is added to the joint
weld metal
What type of inspection is used to check a welds quality without destroying the weld?
NDT
What is the most common and coast effective weld inspection?
Visual
What is the best way to check fillet weld size?
Fillet weld size
Gas Free Engineering Personnel are defined as what three positions?
Gas free engineer
Gas free engineer assistant
gas free engineering petty officers
The GFE afloat shall be of what pay grade?
E7 or above
GFE shall complete how many hours of practical on the job training
40 hours
The GFEA shall be of what paygrade and completed what formal course?
E6 or above
complete GFE course
GFEPO shall be what paygrade and completed what training?
E4 or above and have completed NAVEDTRA 43704 gfepo
Conditions for classifying a confined space as an IDLH?
Flam limit is of ten or more percent of the LEL- Oxygen content less than 19.5% and greater than 22%
Hot work includes any operation producing temperatures of what or higher?
400F or 204.4C
Keep welding or cutting operations which produce high levels of ultra violet radiation at least how many feet away from chlorinated solvents?
200 feet
The four gas analyzer is water, shock and ____ resistant?
EMI
Remote sampling tubes for the four gas analyzer are 19 and ___ feet long?
33
Four gas analyzer is charger is powered by a ___ VAC adaptor?
110
is the difference between ferrous and non ferrous metals?
Ferrous contain iron
non ferrous do not contain appreciable amount of iron
Stainless steel is classified by the american iron and steel institue into what categories?
Stainless steel 200-300 series
&
Stainless steel 400 series
Stainless steel 200-300 series are known as what?
Austentic- tough and ductile. ideal for welding and requires no annealing.
Stainless steel 400 series are subdivied into what two groups?
Ferritic chromium
Martensitic chromium
Used in the manufacture of aircraft parts such as propellers?
Nickel steel
Used for the races and balls in anti friction bearings; highly resistant to corrosion and to scale
Chromium steels
Expensive to produce, its use is largely restricted to drills, lathe tools, milling cutters
Tungesten steel
Are non ferrous metals magnetic?
NO
Zinc is used on iron or steel in a form of protective coating called what?
Galvanizing
What is the texture of unfinished stainless steel?
slightly rough
A grinder used for a metal spark test should spin no less than _____ feet per minute?
4500
Test used to determine the various effects of discontinuities in welding are called?
Destructive testing
Which type of iron is one of the main raw materials used to make steel?
Pig iron
Which stainless steel is normally non magnetic?
Austentic chromium nickel of the 300 series
Joins metals by heating and hammering until the metals are fused together?
Forged welding
Process that fuses metal by heating it to a melting temperature with an electric arc created between an electrode and the metals being joined?
Arc welding
No shielding is used in what type of arc welding?
Carbon arc welding (CAW)
The most common types of welding include ARC welding (AW), _______ and _______?
Resistance welding (RW) Oxyfuel gas welding (OFW)
When burned with oxygen, acetylene produces a hot flame with temperatures ranging at what degree?
5700F-6300F
Up to what pressure can acetylene be compressed to?
275 psi
Acetone can be drawn from an acetylene cylinder when the cylinder is not in which postion?
Upright
After laying an acetylene cylinder on its side it must sit upright for how long before use?
2 hours
In what unit is acetylene measured in?
Cubic feet with the most common cylinder size being 130, 290 and 330 cubic feet. Most common standard size holds 225 cuft of acetylene.
MAPP (methylacetylene-propadiene) is measured in what unit?
Pounds
MAPP gas at 70lbs can do the same amount of work as six and half _____ cubic foot acetylene cylinders
225
The total weight for a MAPP gas cylinder is ____ pounds. ___ pounds is MAPP gas.
120lbs
70lbs
You can store MAPP gas in what postions?
Any position.
Molten metal from the tip of the electrode flows together with the molten metal from the base metal to form a sound joint is called?
Fusion
GTAW( gas tungsten arc welding) or TIG uses a number os sheilding gases including HE and AR. what are HE and AR?
Helium and Argon
GMAW(Gas metal arc welding) or MIG uses a shielding gas, usually argon with 1 to 5% oxygen or argon with CO2 with what percentages?
3-25%
FCAW(Flux core arc welding) is a gas shielding process that uses a continuously fed consumable tubular electrode containing a ___
flux
Four factors for choosing a welding method are?
Types of metal
Nature of products you are fabricating
Techniques you use to fabricate them
Cost involved
Electrodes are grouped into these two categories?
Consumable and non consumable
Primary purpose of flux is what?
To prevent oxidation of the base and filler materials
Flux is thought of as a ____ agent
cleaning
Joint used to join two members aligned in the same plane?
Butt Joint
Used to join two members located at right angles?
Corner and tee joints
Most nonferrous metals can be annealed but never what?
Tempered
How many major stages are there for heat treating metals?
three
What are the four basic types of heat treatment in use today?
Annealing
Normalizing
Hardening
Tempering
when performing a lap or corner joint, you should overlap the metals a minimum of how many times the thickness of the thinnest member you are joining?
3 times the thickness
Used to join the edges of two or more members laying in the same plane? in most cases one of the members is flanged
Edge joint
An edge joint should only be used for joining metals ___ thick or less that are not subject to heavy loads?
1/4”
Portion of the joint where metals are closest to each other?
Root
Opening or space provided between the edges of the metal parts to be welded?
Groove
Angle formed between the prepared edge of a member and a plane perpendicular to the surface of the member?
Bevel angle
The total angle of the groove between the parts to be joined?
Groove angle
To determine the bevel, groove and root opening for a joint, you must consider what factors?
Thickness of the weld material
Type of joint to be made
Welding process to be used
