【Haichuan’s Best Practices】Adjusting the shot blasting pressure through multiple tests to meet the requirements of the dual anti-corrosion process of \"galvanizing + painting\"

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On the shores of the Bohai Bay in August, a striking silver color caught everyone’s attention – the first batch of photovoltaic mounting structures for the Sanhang Dongying offshore photovoltaic project were already standing tall. However, the team members from the Business Department 1 of CCCC Third Harbor Engineering Co., Ltd.’s Materials Company still vividly remember their experience overcoming the challenges associated with the \"excessive anti-corrosion\" process during construction. “The anti-corrosion requirements for these galvanized pipe fittings indeed exceed industry standards, but we must ensure absolute reliability! ”Last summer, at the coordination meeting for the supply of materials for the Sanhang Dongying offshore photovoltaic project, in the face of the doubts expressed by representatives from the steel pipe factory, the processing plant, and the project team, Yao Yuhong, the manager of Department 1, spoke firmly and decisively. Faced with these new challenges, the team from Business Department 1 stepped up to the task, making full use of their professional coordination skills to complete the preparation of over 5,000 tons of steel pipes, purlins, and other materials five months ahead of schedule, thus securing valuable time for the smooth progress of the project. At the beginning of the project, the dual anti-corrosion method of \"galvanizing + painting\" proposed by the design institute posed a significant challenge to the team. This approach, which requires the pipe fittings to first undergo hot-dip galvanizing, then have their surfaces textured through shot blasting before being coated with an anti-corrosion paint, is very rare in the industry. “The galvanized layer peels off immediately after shot blasting; this process simply doesn’t work! ”In the workshop of Tianjin Youfa Steel Pipe Factory, technician Zhang pointed at the pipe fittings whose zinc coating had peeled off after sandblasting, looking helpless. It turns out that with the conventional high-pressure shot blasting process at 0.8 MPa, the sharp-edged iron shrapnel acts like a grinding wheel on thin ice; not only is it impossible to achieve a roughened surface, but the carefully applied zinc coating is also completely stripped off, resulting in a decrease rather than an improvement in the corrosion resistance of the pipes. The sudden change forced the team to rethink their plan. The team from Business Department 1 took immediate action, proactively coordinating with the design institute, manufacturers, processing firms, and contractors to hold a meeting among all parties, and worked through the night to address the technical challenges. Leveraging modern communication technologies, the team innovatively developed a \"cloud-based consultation\" platform, which enables multiple technical experts to be invited to conduct online analysis and discussions through video calls and real-time data sharing. “The key to this technique lies in controlling the force and the tools used with precision; it’s like polishing an eggshell with sandpaper, as the slightest carelessness can render all efforts futile. ”The on-site engineer explained, holding up the comparison samples. After in-depth discussions, the technical team proposed several solutions. However, to verify the feasibility of these ideas, they must still undergo rigorous practical testing. A technical battle focused on the anti-corrosion processes for galvanized pipe fittings promptly broke out in full force.