Welding quality control method for electric resistance welded pipe

ERW (Electric Resistance Welded) pipes utilize electric resistance welding technology, making the control of welding quality crucial throughout the process. The general method for quality control in electric resistance welded pipe welding includes the following procedures.

1. Product Damage Inspection Procedures

Destructive inspection involves using a tool or device to insert between the welded part and the adjacent section until the components are completely separated. The diameter of the weld joint is measured from two perpendicular directions, taking the smallest measurement. For welds between more than two components, inspection must be conducted between each pair of adjacent components.

a. Process Debugging Period: During this phase, conduct destructive inspections at each sub-assembly station to ensure weld quality meets process requirements and identify any potential problem areas.

b. Suspicious Areas: Continue destructive inspections on suspicious areas until all welds meet process standards.

c. Trial Production Stage: Perform thorough destructive inspections of assembly welds in each area to ensure weld quality under normal production conditions. During pre-production, re-inspect suspicious areas to confirm weld quality meets process requirements.

d. Mass Production Process: Conduct destructive inspections of all on-site welds according to the inspection cycle. If necessary, inspect sub-assemblies along with the main body to ensure all welds comply with the inspection cycle.

e. Continuous Analysis: Continuously analyze inspection results and inspect potential suspicious welds until they are fully controlled, ensuring corrective measures are effectively implemented in the production process.

f. Audit Procedure: Destructive inspection audits the entire welding strength assurance system. If unqualified welds are found, immediately identify and isolate all suspicious workpieces until corrective measures are taken.

2. Daily Inspection Method

Operators must use the following inspection methods to ensure the number and position of welds are correct and continuously monitor all welded joints. Notify the quality department if any welds of questionable quality are found:

a. Visual Inspection: Regularly check the welds to confirm their integrity and adherence to specifications.

b. Non-Destructive Testing (NDT): Utilize methods such as ultrasonic testing, radiographic testing, or magnetic particle inspection to detect internal defects without damaging the weld.

c. Dimensional Inspection: Measure the dimensions of welds to ensure they meet the specified criteria.

d. Documentation and Reporting: Record inspection results and report any discrepancies or defects to the quality department for further action.

By following these procedures, the welding quality of ERW pipes can be effectively controlled, ensuring the reliability and performance of the final product.