Related Topics
Related Topics covers many different aspects of welding engineering, metallurgy, and standards in industry. The main subject areas are listed above. Welding and cutting defects do happen even when care is taken to try and avoid them. Understanding what the main causes for these defects occurring are is fundamentally important in trying to ensure that they do not occur. It is a logical statement to say that we should know what the cost of completing a cut or weld is, but do you know how to work out the cost? Several factors must be taken into account to give an accurate cost, power consumed, consumable used, labour and gas cost. Should depreciation of equipment or purchase price be considered? Weld testing can be divided into two main areas destructive and non-destructive testing methods. In destructive testing the sample of material or weld is snapped, broken and pulled apart by numerous techniques to gather actual data on the strength, toughness and hardness of component. With non-destructive test as the name suggests no physical damage occur to the component being tested. Techniques such as visual inspection, x-ray and ultrasonic testing are some of the most common methods used. Welding engineering is a very broad topic area, which covers such topics as joint design, weld preparations and welding positions. Welding procedures are documents used by the welding engineer to guide the welder in the choice of consumable and welding conditions they also carry other valuable information such as when preheating is required. Many standards and classifications are used by the welding industry but are they easy to understand? MMA electrode manufactures and suppliers quote electrodes as being types E7018 but what does this mean? The numbers give an indication of the strength of the weld metal that will be deposited by the electrode and the type of coating the electrode has. When a weld is produced both the welding conditions used and the composition of the shielding gas can have a significant affect on the metallurgy. When welding stainless steels carbon can be added to the weld metal through the decomposition of carbon dioxide used in the shielding gas. If too much carbon is added then this can affect the corrosion properties of the stainless steel. There is a range of different heat treatment employed to materials both before, during and after welding takes place. Preheating is a method in steels used to prevent hydrogen cracking taking place. Heat treating a material can also be a method of reducing or removing stress, which may have built up in a component either through forming or welding. Other topics covered include basic electricity, which is fundamental in understanding how arc welding power sources operate. Hardfacing, surfacing and cladding are all surface treatments carried out on components to improve their operation. Hardfacing the teeth used in digger buckets is carried out to improve the wear resistance of these components. Cladding of the internal surfaces of a vessel with stainless steel panels can mean that the structural parts of the vessel can be made out of a material which is cheaper but the overall corrosion resistance and working life is not compromised.
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