Welding Processes Handbook
This explanatory guide to the commercially significant and commonly-used welding processes covers the design of welded joints, quality assurance and costing, and can be applied to all instruction levels.
TABLE OF CONTENTS Welding Processes Handbook
Chapter 10: Cutting Methods
In the literature, thermal cutting processes by gas, plasma or laser are often covered in conjunction with the corresponding welding methods. This is because almost the same equipment is used for both processes, and because the methods are often also utilised together. It is then also appropriate to take the opportunity to cover competing methods, such as water jet cutting.
This chapter also describes air carbon arc gouging and oxy-fuel gas flame gouging; methods which are often closely associated with corresponding welding processes.
10.1 Thermal Cutting
Thermal cutting is used considerably in connection with the preparation of parts for welding. In addition to cutting plates etc., it may also be necessary to prepare the joints by bevel-edging them. The quality and smoothness of the resulting cut surface are generally satisfactory for the purpose, and the methods are easy to mechanise.
Oxy-Fuel Cutting
Oxy-fuel cutting uses a flammable gas, generally acetylene or propane. Burning the gas in oxygen, rather than just air, produces a flame with a high temperature. The flame first preheats the workpiece: when a sufficiently high temperature has been reached, a jet of oxygen produces the cut by actually burning the metal. This produces a metal oxide in the form of liquid slag, which is blown out of the joint by the jet of gas.
The flame also helps to maintain the upper surface of the plate above the ignition temperature of the metal while cutting is in progress, although most of the necessary heat required for the...
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