Welding Chapter 14 Questions And Answers
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What is the ignition temperature of a metal? - Answer✔About 1300°F to 1400°F
The lowest temperature in a normal atmosphere at which a given material will ignite
spontaneously without any external spark or flame
Is an oxyfuel gas cut smooth or rough when complete? - Answer✔It depends on how skilled the
operator is
Are the preheat flames used after the cutting has begun? Why? - Answer✔Yes, to ensure the
preheat metal in front never goes below cutting temperature
So you can cut through the whole thing
What is the purpose of the preheating jets or orifices in a cutting torch tip? When is the cutting
oxygen valve open? - Answer✔Preheating flames heat the metal to a cherry red color the oxygen
oxidizes the metal await forming the curve, Oxygen blows it through
When the ignition temperature is reached
What are the two types of flame-cutting torches called? - Answer✔Positive-pressure torch
Injector-type torch
When adjusting pressures before lighting a cutting torch, why is it necessary to check the
pressures with the torch cutting lever in the fully open position? - Answer✔The oxygen pressure
will be too low because you won't have have enough pressure if it is not correctly working
What oxygen and acetylene pressures are used when cutting 1/2" (12.7mm) plate steel with a
positive-pressure torch? - Answer✔Oxygen: 25
Acetylene: 3
List two conditions that may cause the slag stream to lag behind the torch tip (drag). -
Answer✔The flame adjustment may be incorrect
The cutting oxygen pressure adjustment may be too low
The tip travel is too fast and the metal is not being preheated enough
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