Describe the history of the development of plasma arc cutting.
What will be an ideal response?
The plasma process was originally developed in the mid-1950s as an attempt to create an arc, using argon, that would be as hot as the arc created when using helium gas. The early gas tungsten arc welding process used helium gas and was called "heliarc." This early GTA welding process worked well with helium, but helium was expensive. The gas manufacturing companies had argon as a by-product from the production of oxygen. There was no good commercial market for this waste argon gas, but gas manufacturers believed there would be a good market if they could find a way to make argon weld similar to helium.
Early experiments found that by restricting the arc in a fast-flowing column of argon a plasma was formed. The plasma was hot enough to rapidly melt any metal. The problem was that the fast-moving gas blew the molten metal away. They could not find a way to control this scattering of the molten metal, so they decided to introduce this as a cutting process, not a welding process.
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A. A only B. B only C. Both A and B D. Neither A nor B
Engines need a heavier oil when temperatures drop
Indicate whether the statement is true or false.
A boil is an example of:
What will be an ideal response?
What is the typical maximum air inlet restriction pressure on a boosted engines?
A. 5inH2O vacuum B. 50inH2O vacuum C. 15inH2O vacuum D. 25 inH2O vacuum