Control of Weld Quality
Welding involves the use of energy in the form of arcs or flames to create structural bonds between different materials. The result of a well-executed welding process is a joint with superior strength, durability, and applied force/resistance when compared with the components as separate entities. In order for the welds to meet all the standards, the weld quality must be controlled.
The control of weld quality mainly focuses on the two aspects of working interface conditions and the quality of the weld. With regard to the working interface conditions, this entails measurements of the proximate and intermediate joint surfaces at the joint interface, structural completeness of the joint, pliability, and effects such as corrosion resistance. With regard to the quality of the weld, this involves measurements of the dimensions, surface condition, contamination and other issues associated with the actual welds.
A large number of factors are responsible for variations in weld quality that influence the performance of the finished product. First and foremost, the quality of workmanship is the most important contributing factor to ensuring good weld quality. Welders need to be adequately trained and certified for their respective welding processes and properly instructed to follow the relevant welding procedure and the applicable codes, standards, specifications and regulations to ensure that the welds meet the required integrity and quality internationally approved for such materials and processes.
Additionally, the welders need to follow specific precautionary measures and weld from clean surfaces as dirt, grease and oil have the potential to negatively affect the weld quality by providing insulating barriers to the weld area and preventing proper fusion. The welding process should also be designed in a manner that prevents the accumulation of moisture and other impurities in the weld and its surrounding environment.
Furthermore, welding technique and parameters also play a critical role in obtaining the desired weld quality. Factors such as selection of the right heat input and weld joint parameters, current and voltage settings, process changes, and post-weld washing and cleaning can drastically impact the weld quality. All of these steps should be closely monitored to ensure that each weld is made with precision and that the joints produced meet the requirements in terms of size and strength.
Inert gas backing and the use of fluxes may also be beneficial for specific welding processes, especially those which are run in complete shielding environments. Using backing and flux helps reduce porosity and other undesired defects from the welds and limits the amount of damage done to the process and its surrounding environment. In addition to welding technique and parameters, welding consumables must also be correctly selected and stored properly as these are significant factors in determining weld quality.
In summary, weld quality is a critical factor in the quality of any welded structures since the performance of the structure is closely linked to it. As such, it is highly important that adequate control measures are taken to ensure the weld joints are made to the best standards possible and meet the pre-defined requirements. This involves ensuring the right processes, techniques, and quality control systems are implemented during welding. For this, proper training and quality assurance systems should be put in place to guarantee that all personnel are competent enough to make quality welds and that the welds are made according to the required codes, standards, and specifications.
