3.2 Certificate, TPI inspection and delivery process description
Product Information
ASME SA179 Seamless U-tubes ∅19.05 × 2.11min × L12210.9~13617.8mm, Total: 1,352 pcs
Project Background
The end user is a large energy and chemical company. Due to severe quality issues with previously sourced ASME SA179 tubes from India—leading to equipment shutdown and project suspension—the customer urgently needed to procure new tubes for heat exchanger remanufacturing and project restart.
As the core components of the heat exchanger, the quality of the tubes is critically important. The customer places great emphasis on this project. To ensure 100% compliance with standards and full inspection conformity, this order follows the EN10204-3.2 certification standard, with all inspection items witnessed on-site by the authoritative third-party agency Bureau Veritas (BV).
Below are the key inspection highlights and process optimizations. The entire process is traceable and fully transparent.
Inspection Highlights & Technical Enhancements
1) Sufficient Stock Prepared to Ensure Safe Project Delivery
To account for sampling inspections and potential losses during on-site installation, we produced an additional quantity of tubes as buffer for third-party sampling and customer backup. In the final delivery, we provided 10 extra tubes FREE OF CHARGE as SUPPORT to help ensure smooth project progress.
2) Upgraded Heat Treatment Process to Enhance Product Performance
To meet the customer’s higher performance demands in actual application, the standard annealing process (Annealing at 650°C) was upgraded to normalizing treatment (Normalizing at 870°C ~ 920°C). This significantly improved the uniformity of the tube structure and mechanical properties, ensuring reliable operation under the high-temperature, high-pressure conditions of heat exchangers.
3) Stricter Chemical Composition Control – Beyond Standard Requirements
In addition to fulfilling ASME SA179 standard requirements for C, Mn, P, S, etc., the customer imposed additional limits: Cu+Ni+Cr ≤ 0.15 and CE ≤ 0.43. These special requirements were communicated to BV in advance. All samples were witnessed, collected, and tested on-site by BV. All test results fully met the customer’s stringent requirements, reinforcing their confidence in our quality control capabilities.
4) Comprehensive U-Bend Tube Quality Verification – Highly Recognized by Customer
The smaller the U-bend radius, the greater the manufacturing difficulty and risk of wall thinning or structural damage. This order includes U-bends with a minimum radius of R = 30.52 mm. To ensure quality, we implemented the following special inspections:
100% Dye Penetrant Testing (DPT) – witnessed by BV on-site for all tubes
Destructive Testing – cutting through the midpoint of the smallest U-bend to assess wall thinning
Test Results – The maximum wall thinning rate was well below the customer’s allowable limit of 17%, earning high customer satisfaction
Conclusion
Through the rigorous quality control and inspection measures above, we ensured the full compliance, traceability, and superior quality of this batch of ASME SA179 Seamless U-tubes. This demonstrates DLSS’s technical expertise and delivery capabilities as a professional manufacturer supporting high-end projects.