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Cold cracking—also known as delayed cracking, hydrogen-assisted cracking (HAC), or hydrogen-induced cracking (HIC)—is a type of defect that often develops after solidification of the weld when the temperature starts to drop from about 190 °C (375 °F); the phenomenon often arises at room temperature, and it can take up to 24 hours to appear even after complete cooling. [8]
Methods of weld testing and analysis are used to assure the quality and correctness of the weld after it is completed. This term generally refers to testing and analysis focused on the quality and strength of the weld but may refer to technological actions to check for the presence, position, and extent of welds.
In general, resistance welding methods are efficient and cause little pollution, but their applications are somewhat limited and the equipment cost can be high. [47] Spot welder. Resistance spot welding is a popular method used to join overlapping metal sheets of up to 3 mm thick. [47]
The Canadian Welding Bureau, through CSA Standards W47.1, [3] W47.2 [4] and W186, [5] specifies both a WPS and a Welding Procedure Data Sheet (WPDS) to provide direction to the welding supervisor, welders and welding operators. The WPS provides general information on the welding process and material grouping being welded, while the WPDS ...
While weldability can be generally defined for various materials, some welding processes work better for a given material than others. Even within a certain process the quality of the weld may vary greatly depending on parameters, such as the electrode material, shielding gases, welding speed, and cooling rate. [1]
In addition to welders and welding machine operators, there are also schemes to independently certify welding inspectors and related specialities. The duties of the welding inspector are described in ISO 14731; [12] however the requirement for inspector certification are not standardized, so there are differences in requirement between the various schemes.
Most weld purging is carried out on joints made by the TIG or GTAW arc welding process. [6] When the laser welding process is chosen, joints or welds being made on reactive materials will need to be carried out and in the case of electron beam welding, this is carried out in a vacuum, in which case purging takes place by complete evacuation of all gas.
This is a list of welding processes, separated into their respective categories. The associated N reference numbers (second column) are specified in ISO 4063 (in the European Union published as EN ISO 4063 ). [ 1 ]