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1. Concept of welding procedure qualification
Welding procedure qualification is the preliminary preparation for the entire welding work. The welding procedure qualification work is the test process and result evaluation carried out to verify the correctness of the welding procedure of the proposed weldment and related products.
It includes the process of pre-welding preparation, welding, testing and result evaluation. Welding procedure qualification is also an important process in production practice. This process has a premise, a purpose, a result, and a limited scope. Therefore, the welding process qualification should be based on the proposed welding process plan, including pre-welding preparation, welding test pieces, inspection test pieces, and determining whether the welded joints of the test pieces have various technical indicators of the required performance. Finally, the accumulated experience of the whole process Various welding process factors, welding data and test results are compiled into conclusive and recommended information to form a "welding process assessment report".
2. The significance of welding process qualification
Welding procedure assessment is an important link in ensuring the welding quality of boilers, pressure vessels and pressure pipes. Welding process assessment is an indispensable and important content in the technical preparation work before welding of boilers, pressure vessels and pressure pipelines. It is a must-inspection item in the engineering inspection carried out by the national quality and technical supervision agency. It is a must-have to ensure that the welding process is correct and reasonable. The approach is an important guarantee to ensure the quality of the welded parts and that the various properties of the welded joints must comply with the product technical conditions and corresponding standard requirements.
Therefore, the correctness and rationality of the welding process must be verified through corresponding experiments, that is, welding process qualification. Welding process qualification can also improve welding production efficiency and minimize production costs while ensuring the quality of welded joints, and obtain Maximum economic benefits.
3. Purpose of welding process qualification
1 is a technical document that should be followed in the manufacturing, installation, maintenance and other production processes of boilers, pressure vessels, pressure pipes and equipment, as well as in welder training and teaching.
2 is a key link or important measure to be implemented in welding quality management.
3 is an important symbol reflecting the welding ability and technical level of a unit.
4 It is a must-perform item stipulated by relevant industry and national regulations.
4. Scope of application of welding procedure qualification
1 Welding procedure qualification is applicable to the welding work of the production, installation and maintenance of steel equipment such as boilers, pipelines, pressure vessels and load-bearing steel structures, as well as welder training and welder technical assessment. Welding procedure qualification must be carried out before the implementation of these tasks. to determine the correctness of the proposed welding process.
2 Welding process qualification is applicable to welding methods such as electrode arc welding, tungsten arc welding, gas metal arc welding, flux-cored wire arc welding, gas welding, and submerged arc welding.
3 Enterprises engaged in manufacturing, installation or maintenance work.
4 The welding process qualification is targeted, and the technical condition requirements of various products are different. If the product is a pressure vessel, the test results of the process qualification should meet the requirements of the technical condition standards of the pressure vessel; if the product is load-bearing steel structure, the process qualification test results should meet the standard requirements of the technical conditions of the load-bearing steel structure, etc. The welding process qualification work is to meet the technical conditions of the product as the primary requirement of the welding process qualification test qualification standard.
5. Characteristics of welding process qualification
1 Welding process qualification is to solve the welding process problems of any steel under specific conditions, rather than selecting the best process parameters. It has a certain range and is acceptable to most people.
2 Welding process evaluation is to solve the performance problems under specific process conditions, but it cannot solve the overall quality problems involved in eliminating stress, reducing deformation, preventing welding defects, etc.
3. The welding process evaluation should be based on the welding performance of the raw materials and guide production through reliable technical condition tests for welding process evaluation, avoiding the disadvantage of using actual products as test pieces.
4 Human factors should be eliminated during the welding procedure qualification test process, and welding procedure qualification and welder skill qualification should not be confused. The person in charge of the welding procedure qualification should be able to distinguish whether the cause of the defect is a welding process problem or a welder's skill problem. If it is a skill problem, it should be solved through welder training.
5 The tests required by the existing welding procedure qualification regulations are mainly normal temperature mechanical tests of welded joints. That is, if it has passed the appearance inspection, non-destructive testing and normal temperature mechanical test, it is generally considered to have passed the welding process test. For new steel types for high-temperature and high-pressure pipelines in the power industry, this result is not completely reliable, and high-temperature endurance tests, creep tests, stress corrosion and other tests of joints must also be considered.
Post time: Feb-27-2024
