456A Oxyfuel Welding & Cutting 2

Question 1

What minimum distance must separate oxygen and fuel gas cylinders in storage, unless a fire-resistant barrier is used?

Accepted Answer

6 m (20 ft)

Answer

1.5 m (5 ft)

Answer

3 m (10 ft)

Answer

9 m (30 ft)

Question 2

When cutting mild steel with an oxyfuel torch, what reaction actually performs the cut?

Accepted Answer

Rapid oxidation (burning) of the preheated steel by the cutting oxygen stream

Answer

Melting of the steel by the preheat flames alone

Answer

Mechanical action of the high-pressure oxygen blasting away molten metal

Answer

Plasma arc formation within the oxygen jet

Question 3

Why cannot aluminum be effectively cut using the standard oxyfuel cutting process?

Accepted Answer

Aluminum oxide (Al₂O₃) has a higher melting point than the base metal, blocking the oxidation cut

Answer

Aluminum ignites at too high a temperature for the preheat flames to reach

Answer

Aluminum reacts explosively with the high-pressure cutting oxygen stream

Answer

Aluminum requires a carburizing flame rather than a cutting oxygen jet

Question 4

What is the purpose of flux when performing oxyfuel welding on cast iron or bronze?

Accepted Answer

To prevent oxidation and chemically remove oxides from the weld pool

Answer

To rapidly cool the weld pool and refine grain structure

Answer

To increase the melting point of the filler rod

Answer

To add specific alloying elements to the weld deposit

Question 5

What is 'kerf' in the context of oxyfuel cutting?

Accepted Answer

The width of material removed by the cutting process

Answer

The heat-affected zone on either side of the cut

Answer

The angle of the cutting tip relative to the plate surface

Answer

The travel speed of the cutting torch along the cut line

Question 6

How should acetylene cylinder valves be opened during oxyfuel setup?

Accepted Answer

No more than 1.5 turns from the closed position

Answer

Fully open using a cylinder wrench, same as oxygen

Answer

Exactly 3 full turns open to ensure adequate flow

Answer

Cracked open only, about a quarter turn, for safety

Question 7

What does a zero reading on the cylinder pressure gauge indicate when the cylinder valve is fully open?

Accepted Answer

The cylinder is empty and must be replaced

Answer

The regulator delivery pressure is correctly set to zero for startup

Answer

The high-pressure gauge needs recalibration

Answer

The cylinder valve is opening in the wrong direction