Chapter 17 Welding Theory Flashcards
A(n) … flame has a balance of fuel gas and oxygen. It is the most commonly used flame because it adds nothing to the weld metal.
neutral
Gauges that read “0” (zero) pressure when the pressure is released, or those that have a damaged glass or case, must be repaired or replaced.
True
A () works by holding the forces on both sides of a diaphragm in balance.
regulator
A () will stop both reverse gas flow and the flame of a flashback.
flashback arrestor
The regulator pressure-adjusting screw should be backed off each time the oxyfuel system is being shut down.
true
The purpose of the () valve is to prevent gases from accidentally flowing out of one hose through the torch body and then into the other hose.
reverse flow
High-pressure valve seats that leak result in a(n) () or rising pressure on the working side of the regulator
creep
A regulator that is left pressurized causes the diaphragm to stretch, the () to straighten, and the adjusting spring to compress
bourdon
A(n) () flame has an excess of oxygen. This flame has the highest temperature and may put oxides in the weld metal.
oxidizing
Rupture disk safety devices are one-time-use devices
true
A(n) () occurs when the flame burns back inside the tip, torch, hose or regulator.
flashback
The working pressure of a gauge is always a little less than the torch tip pressure due to some line drop
True
Internal and external moving parts on a regulator or a gauge DO NOT require oiling
True
A flashback that reaches the cylinder may cause a fire or an explosion
True
The () pressure gauge shows the regulated pressure being controlled for the torch
Working
Leak-detecting solution must be free flowing so that it can seep into small joints, cracks and other areas that may have a leak.
True
All oxyfuel processes use a high-heat, high-temperature flame produced by burning a fuel gas mixed with carbon dioxide
False
Acetylene is the most widely used fuel gas because of its high temperature and concentrated flame.
True
A(n) () is made up of a small ball held tightly against a seat by a spring
safety release valve
A(n) () occurs when a flame goes out with a loud snap or pop
backfire
The () hand torch is the most common type of oxyfuel gas torch used for welding and cutting
oxyacetylene
A(n) () is the only safe device to use when lighting any torch.
Spark lighter
Dedicated cutting torches are usually shorter than combination torches.
False
A(n) () is a thin piece of metal held between two seals
safety disc
A(n) () flame has an excess of fuel gas. This flame has the lowest temperature and may put extra carbon in the weld metal
carburizing
Why is acetylene the most popular fuel gas used for oxyfuel welding
Acetylene is the most widely used fuel gas because of its high temperature and concentrated flame.
What do pressure regulators do?
All pressure regulators reduce the high cylinder or system pressure to the proper lower working pressure.
List 5 various types of pressure regulators.
low-pressure regulators, high-pressure regulators, single-stage regulators, dual-stage regulators, cylinder regulators
Why are two-stage regulators used sometimes and not a single-stage regulator.
Because some small single-stage pressure regulators have difficulty maintaining the proper working pressure under high flow rates. Two-stage regulators have two sets of springs, diaphragms, and valves. A two-stage regulator does not require periodic readjustments and offers consistent supply pressure.
Why is the pressure at the torch tip always lower than the pressure shown on the working pressure gauge?
The torch tip pressure is always a little less than the working pressure due to some line drop.
Why should the regulator pressure adjusting screw be backed off each time the oxyfuel system is being shouting shut down?
This is done to release the spring and diaphragm pressures, which, over time, may cause damage.
Why do gas cylinders have different designs fittings?
A gas cylinder has fittings because there is a variety of different designs for various types of gases to ensure that regulators cannot be connected to the wrong gas or pressure,
Why is it unsafe to use oil on a regulator?
Oiling a regulator is unsafe and may cause a fire or an explosion.
What is the advantage of using a combination welding and cutting torch?
The combination welding and cutting torch offers more flexibility because a cutting head, welding tip, brazing tip, or heating tips can be attached to the same torch body
