Table of Contents
F Koons,. Mostafa and R. S Parmar. II, pp. Benyounis, et al. S Kim. Kim, et al. C Juang. Gunaraj and N.
J Yang. A Alfaro.
Hill, and J. Box, W. G Hunter, J. S and Hunter. Cochran, and G. Oxy-fuel welding oxy welding that uses fuel gases and oxygen to weld and cut metals. Shielded metal arc welding electric welding that uses an electrode that is coated in flux to protect the weld puddle. The electrode holder holds the wire as it slowly melts away. Gas tungsten arc welding inert gas that uses a non-consumable tungsten electrode for producing the weld. However, the weld area has to be protected from atmospheric contamination by an inert shielding gas such as argon or helium.
Peter Houldcroft and Robert John
Gas metal arc welding inert gas that uses a wire feeding gun that feeds wire at an adjustable speed and flows an argon-based shielding gas or a mix of argon and carbon dioxide CO2 over the weld puddle to protect it from atmospheric contamination. Metal casting is a metalworking process that is known to have started in ancient times, and it is still widely used for making sculptures, tools, and jewelry.
Most popular methods include lost-wax casting and sand casting.
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Guides Menu. What is metalworking: forming, cutting and joining 0 comments. Share with friends:. Facebook Send. Forming metal Metal bending Forging Cutting metal Joining metal Metal casting What type of metalworking should be used? Forming metal Forming is the process of fashioning metal objects through deformation, without adding or removing any material.
Metal bending Metal bending is a manufacturing process that uses ductile materials, most commonly sheet metal, as is generally used for equipment such as specialized machine presses. Top guides Manufacturing Guide. The way in which metal is transferred from the electrode wire to the molten pool depends upon current, voltage and shielding gas composition. As the current is increased the form of the transfer changes abruptly to a stream of fine drops which are propelled across the arc gap by the electro-magnetic forces in the arc.
This is called spray transfer and it enables welding to be carried out against gravity. Changing the shielding gas to carbon dioxide assuming steel electrodes causes the transfer to become more globular and less well directed; however, the situation can be reversed by using a mixture of inert gas and carbon dioxide. When using steel electrodes, decreasing the arc voltage markedly and also reducing current by reducing the wire feed rate results in a form of transfer known as dip transfer or short-circuit transfer.
In this mode of transfer metal is fused directly into the pool without passing freely across the arc gap. At slightly higher voltages the transfer is across a gap but is in larger globules without the pronounced directionality of the spray transfer. The globular to spray change is less marked with steel than with certain other metals. Welds in steel are sometimes made in which this type of transfer predominates.
It is also possible to control the type of metal transfer at low to medium currents by using a special power source which delivers pulsed current to the arc. For 'positional' welding, i.
Welding and Cutting: A Guide to Fusion Welding and Associated Cutting Processes
Overall times for a joint, and hence productivity, are better since there is no need to deslag or change electrode. In the flat position, currents up to amp 'Spray Transfer' can be used to give high welding speeds. MAG welding is especially suitable for fillet welded joints, e. It is not easy to use on site because of problems of equipment movement and the need to provide screens to avoid loss of the gas shield in draughty conditions. This is a fully mechanised process in which the welding head travels along the joint automatically Figure 3.
The electrode is a bare wire which is advanced by a governed motor. The voltage and current are selected at the beginning of the weld and are maintained at the pre-selected values by feed-back systems which, in practice, vary in sophistication. The flux is in the form of particles and is placed on the surface of the joint. The arc operates below the surface of the flux, melting a proportion of it to form a slag.
Unfused flux is collected and may be re-used for the next weld.