headsUP: Experience suggests more rigorous QA/QC for Asian supply-chain partners

On a recent tour of a new US combined-cycle unit close to commissioning, CCJ editors learned that project management was “not impressed” by the quality of components originating in Asian manufacturing shops during construction. As a result, the owner/operator had to revamp internal quality assurance (QA) and control (QC) processes.

“We found problems with pumps, valves, and HRSG components, including basic welding issues—such as boiler tubes being installed without post-weld heat treatment,” the engineer reported, “some valves literally came apart in our hands.” Fortunately, this utility owner/operator had experienced professionals available for beefing up QA/QC and verifying that contractors were following procedures.

The team developed checklists of items for specific critical components during construction and went as far as to install a professional in-country (Korea) to witness manufacturing 24/7. “We could have spent double what we did on QA/QC, but as it is, we feel we saved millions of dollars in rework,” the manager said.

It turns out this isn’t an isolated experience. CCJ checked in with others familiar with recent combined-cycle installations. One representative of a global power company said his firm had procured two main steam stop valves from Chinese firms and both had to be replaced because of casting issues.

Referring to his company’s bidding effort for a non-US project, he went on to say that for manufacturing being conducted in China, research showed that resident engineers should be appointed and installed in the fabrication sites with full authority to stop, inspect, and rework written into the contract. He had come across one company which he said had started with three engineers assigned to the fabrication sites. Eventually, the number maxed out at 17. Even then, they were only able to reduce reject rates to acceptable levels.

A director for a major non-utility owner/operator responded that they were “having some serious problems with HRSGs manufactured in Asia,” including:

      • Cracking of drum plates caused by low preheat temperatures, non-certified welders, and non-compliance with welding process specifications (WPS).

      • Tube materials: Lack of minimum temperature and temperature range listed in material test reports (MTR) for normalizing and tempering of SA 213-T11, and incorrect manganese temperature range listed in the MTR for SA210C.

      • Header nozzle ends machined out of accordance with approved drawings.

      • Incompatible material (inconsistent P number) used for temporary welded lugs.

      • Use of weld filler material, which was not identified.

      • Violations of supplier’s in-house nondestructive examination (NDE) and welding procedures.

At a recent user-group meeting, one attendee lamented failures of large spiral-wound gaskets manufactured in China.

It helps if the engineers speak the language, although having representatives onsite at least solves the time-zone problem. Another US project manager assailed the language, cultural, and time-zone barriers which make conference calls and email exchanges difficult, even for companies with high-quality products.

While such barriers have always been an issue with global supply-chain partners, it is even more paramount today because, according to more than expert, most HRSGs for combined cycles are manufactured in Asia today. Also, many owner/operators leave procurement to their EPC contractors, possibly at their peril if their own representatives aren’t following a “trust but verify” strategy with appropriate surveillance included.

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