Mississippi Welding Examination

On oxyacetylene equipment, fuel-gas (acetylene) hose and torch fittings are made with which thread to keep them from being connected to the oxygen side?

• ALeft-hand (reverse) threads, often with a notched nut
• BRight-hand threads identical to oxygen fittings
• CMetric fine threads with no handedness convention
• DPipe threads that seal only with Teflon tape

Under OSHA 29 CFR 1910.253, acetylene shall not be generated, piped (except in approved cylinder manifolds), or utilized at a pressure in excess of:

• A15 psig (103 kPa gauge)
• B50 psig
• C200 psig cylinder pressure
• D5 psig

When oxygen cylinders are in storage, OSHA 1910.253 requires them to be separated from fuel-gas cylinders by:

• AA minimum of 20 feet, or a noncombustible barrier at least 5 feet high with at least a on…
• BA cardboard partition if both cylinder valves are closed
• CThree feet of open space and a painted stripe on the floor
• DAny convenient aisle, regardless of distance

A correctly adjusted neutral oxyacetylene flame is recognized by:

• AA long white acetylene feather extending well beyond the inner cone
• BA short, pointed inner cone and a loud hissing sound from excess oxygen
• CA well-defined bluish-white inner cone and a light-blue outer envelope, with the acetylen…
• DA yellow sooty flame produced with the oxygen valve closed

In standard US oxyfuel color coding, the acetylene hose is typically which color?

• ARed
• BBlack only, with no fuel identification
• CYellow with an oxygen stripe
• DGreen

A carburizing (reducing) oxyacetylene flame is produced by excess acetylene. Its distinctive appearance is:

• AThree zones, including a white acetylene feather between the inner cone and the outer env…
• BA short purple inner cone and a sharp hiss
• CNo inner cone at all
• DTwo zones only, with no acetylene feather

Compressed-gas welding cylinders in the shop should be stored and used:

• AUpright and secured (for example, chained) so they cannot tip over
• BLoose on a hand truck with the caps off at all times
• CInside an unventilated locker to hide them from traffic
• DOn their sides so the valve is easier to reach

What is the primary difference between a check valve and a flashback arrestor on an oxyacetylene outfit?

• ACheck valves are used only on oxygen; flashback arrestors are used only on acetylene
• BThey are identical devices with two trade names
• CA check valve only stops reverse gas flow; a flashback arrestor is built to stop or quenc…
• DA flashback arrestor only measures pressure; a check valve extinguishes flame

In oxyacetylene cutting of mild steel, the cutting oxygen jet removes metal primarily by:

• AElectric arc erosion from the torch tip
• BMelting the steel and blowing liquid metal out of the kerf with no chemical reaction
• CRapid oxidation (burning) of iron that has been preheated to kindling temperature, with t…
• DDissolving the steel in acetylene

Why must oil, grease, and oily gloves be kept off oxygen cylinders, regulators, and fittings?

• AGrease is required to seal CGA 540 oxygen connections
• BOil only stains the brass and has no safety effect
• COxygen can cause hydrocarbons to ignite violently, even without an open flame
• DOil improves regulator diaphragm life and should be applied lightly

An oxidizing oxyacetylene flame is identified by which combination of appearance and typical use?

• ANo inner cone; used only for brazing aluminum
• BA long acetylene feather; preferred for all mild-steel fusion welds
• CA short, pointed inner cone and often a hiss; hotter than neutral and used on some brasse…
• DA sooty yellow flame; used to preheat thick plate only

Acetylene is stored in a welding cylinder as:

• AA free compressed gas at several thousand psig, like oxygen
• BA liquid acetylene layer with no solvent
• CA gas dissolved in a solvent (commonly acetone) held in a porous filler mass
• DCalcium carbide pellets that generate gas when the valve is opened

The correct way to clean a clogged oxyacetylene welding or cutting tip is to:

• ASoak the tip in oil and blow it out with oxygen
• BReam the orifices with any steel drill larger than the hole to restore flow
• CUse a tip cleaner of the matching orifice size, inserted straight, without enlarging the…
• DBurn the slag out with an oxidizing flame for several minutes

A welder makes a straight 6-inch oxyfuel cut in 24 seconds. What is the travel speed in inches per minute?

• A6 in/min
• B12 in/min
• C15 in/min
• D24 in/min

OSHA 1910.253 states that an acetylene cylinder valve must not be opened more than:

• AAs many turns as needed until the regulator reads 25 psig
• BOne-quarter turn only, because the cylinder has no shutoff
• COne and one-half turns of the spindle, and preferably no more than three-fourths of a turn
• DFully open against the backseat, like many oxygen valves

Which statement correctly distinguishes a backfire from a flashback?

• AA backfire is a momentary recession of the flame into the tip, often with a pop; a flashb…
• BA flashback is only a loud pop at the tip that immediately relights
• CA backfire always travels into the cylinder; a flashback stays at the tip
• DThe two terms describe identical events and need no different response

Which statement about acetylene working pressure at the torch is correct?

• AOnce the flame is lit, acetylene pressure may be raised above 15 psig to increase heat
• BRegulator delivery pressure may be set at 15 psig or higher if the hose is short
• CWorking pressure in the hose and torch must stay below 15 psig; typical welding-tip setti…
• DAcetylene should be used at the full cylinder pressure with no regulator

A shop cannot keep stored oxygen and acetylene cylinders 20 feet apart. Which OSHA-compliant alternative applies to storage?

• AStore oxygen on its side next to the acetylene to save floor space
• BStore them touching if both valves are closed
• CSeparate them with a noncombustible barrier at least 5 feet high having a fire-resistance…
• DDrape a welding blanket over both cylinders

On an AWS A2.4 welding symbol, the fillet weld is drawn as a right triangle. The fillet leg size is placed:

• ATo the left of the weld symbol, on the same side of the reference line as the triangle
• BTo the right of the weld symbol
• CIn the tail only
• DInside the all-around circle

Under AWS A2.4, a weld symbol placed below the reference line means the weld is made on the:

• AInterior of a pipe only
• BOther side of the joint
• CArrow side of the joint
• DField only, regardless of the flag

On an AWS A2.4 fillet weld symbol, the length of the weld is placed:

• AAbove the flag only
• BTo the left of the triangle
• CTo the right of the weld symbol
• DAlways in the tail as a note

A small flag at the junction of the arrow and the reference line on a welding symbol means the weld is:

• AA grind-flush requirement
• BA shop weld that must be made before shipping
• CA field weld, made after the assembly leaves the shop
• DA tack weld only

A circle at the junction of the arrow and the reference line is the AWS A2.4 symbol for:

• AWeld all around the joint
• BA spot weld
• CRadiographic inspection
• DA melt-through requirement

The tail of an AWS A2.4 welding symbol is used to:

• AReplace the reference line on field welds
• BShow fillet size
• CIdentify the welding process, specification, or other notes such as SMAW or a WPS number
• DIndicate arrow side versus other side

A fillet triangle drawn above the reference line specifies a fillet weld on the:

• AInterior root face only
• BArrow side only
• COther side of the joint
• DBoth sides automatically

An intermittent fillet symbol shows 3-6 to the right of the triangle. That means:

• AA 6-inch fillet broken into 3 equal parts
• BA 3-inch fillet size with a 6-inch leg
• C3-inch-long fillet segments on 6-inch centers (pitch)
• DA 3-pass weld with 6 seconds of travel per inch

A drawing shows fillet triangles both above and below the reference line, each with 1/4 to the left of the triangle and no length to the right. The required weld is:

• ATwo 1/8-inch fillets stacked to make 1/4 inch on one side
• BA 1/4-inch fillet on the arrow side only, shop welded
• CA 1/4-inch fillet on both the arrow side and the other side, extending for the length of…
• DA 1/4-inch groove weld with melt-through

For an equal-leg fillet weld with a 1/4-inch leg, the theoretical throat is closest to:

• A0.354 in
• B0.125 in
• C0.177 in
• D0.250 in

AWS defines brazing as a joining process that uses a filler metal with a liquidus:

• AAlways above the melting point of the base metal
• BExactly 212°F so water can be the flux
• CBelow 840°F (450°C)
• DAt or above 840°F (450°C) and below the melting temperature of the base metal

In true brazing, molten filler metal is drawn into the joint primarily by:

• AThe force of the welding arc
• BHammering the parts after the filler freezes
• CGravity filling a wide V-groove
• DCapillary action between closely fitted faying surfaces

The primary functions of brazing flux are to:

• ARaise the filler liquidus above the melting point of steel
• BAct as the only source of filler metal
• CReplace all precleaning and add carbon to the joint
• DDissolve or prevent oxides during heating and promote wetting of the base metal by the fi…

How does soldering differ from brazing in the AWS temperature definition?

• ASoldering uses a filler with a liquidus below 840°F (450°C); brazing uses a filler with a…
• BSoldering always melts the base metal; brazing never uses flux
• CThere is no temperature distinction; the words are interchangeable
• DBrazing is only done with tin-lead, and soldering only with silver

For capillary brazing, joint clearance should be:

• ALeft random because clearance does not affect flow
• BPacked with steel wool to hold the filler
• CAs wide as a welding groove so filler can be stacked in passes
• DSmall and reasonably uniform so capillary action can fill the joint

Before brazing, the joint surfaces must be:

• APainted with oil to prevent oxidation in the torch flame
• BGalvanized immediately before heating to improve wetting
• CLeft covered with mill scale so the flux has something to attack
• DCleaned of oil, paint, dirt, and heavy oxides; flux then protects the clean metal during…

How does braze welding differ from capillary brazing?

• AThere is no difference; both terms mean soldering
• BBraze welding is defined as any process done below 840°F
• CBraze welding melts the base metal the same way SMAW does
• DBraze welding deposits filler into a groove or fillet much like a weld, relying less on c…

Which pairing of filler family and typical joint style is most accurate?

• ASilver-brazing (BAg) fillers are commonly used in close-clearance capillary joints; bronz…
• BSilver fillers are only for soldering below 400°F, and bronze cannot join steel
• CAny copper-zinc rod will capillary-braze a 1/4-inch open gap as reliably as a tight lap
• DStainless assemblies can be brazed only with unalloyed lead

In the 1G pipe welding position, the pipe is:

• AFixed at 45 degrees with no rotation
• BHorizontal and fixed so the welder must weld overhead, vertical, and flat
• CFixed vertically, and the weld is made horizontally around it
• DHorizontal and rotated so the welder stays in the flat position

The 6G pipe test position is best described as:

• APipe axis horizontal, pipe rotated under a stationary torch
• BPipe axis vertical and rotated
• CPipe fixed with its axis at approximately 45° to horizontal, not rotated
• DA plate test in the overhead position only

In the 2G pipe position, the pipe is:

• AHorizontal and fixed
• BInclined at 45° and rotated
• CHorizontal and rotated
• DVertical and fixed; the groove is welded in the horizontal position around the circumfere…

In the 5G pipe position, the pipe axis is horizontal and the pipe is not rotated. Completing the joint requires the welder to:

• AStay in the flat position only
• BWeld only from the 12 o'clock position
• CProgress through overhead, vertical, and flat portions of the circumference
• DRotate the pipe 90° after each pass

On a single-V pipe bevel, the root face (land) is:

• AThe extra reinforcement on top of the cap
• BThe distance from the torch to the work
• CThe included angle between the two beveled ends
• DThe un-beveled remaining edge at the root that helps control melt-through

A common US carbon-steel open-root pipe procedure uses which electrode combination?

• AE7018 root with no cleaning, then E6010 cap
• BOnly E7024 in all positions, including the root
• CE7024 root and E6013 fill and cap
• DE6010 (or a similar all-position cellulosic electrode) for the root, then E7018 for fill…

For open-root carbon-steel pipe of moderate to heavy wall, vertical progression is most often:

• AUphill (vertical-up) to maintain penetration and fusion at the root and sidewalls
• BDownhill only, because uphill is never used on pipe
• CHorizontal only, even on 5G
• DOverhead only, with no vertical travel

A 4-inch NPS Schedule 40 steel pipe has a 4.500-inch outside diameter and a 0.237-inch wall. What is the inside diameter?

• A4.500 in
• B4.263 in
• C4.026 in
• D3.500 in

ASME B16.25 buttwelding-end preparation for common pipe wall thicknesses uses a bevel of approximately:

• A90° square ends with no land on all wall thicknesses
• B60° on each end (120° included) as the only allowed bevel
• C10° on each end (20° included)
• D37.5° ± 2.5° on each end, giving an included angle of about 75°

Why is a 6G pipe test widely used for welder performance qualification?

• AIt qualifies only fillet welds on plate
• BIt eliminates the need for a written welding procedure
• CIt is the easiest position because the pipe rotates
• DThe 45° fixed orientation forces the welder through flat, horizontal, vertical, and overh…

Which common construction metal is generally the most readily fusion-welded with standard carbon-steel procedures?

• AFree-machining steel with high sulfur
• BUncleaned galvanized sheet in a confined space
• CGray cast iron with no preheat
• DLow-carbon (mild) steel