1 Sampling ratio of acceptance inspection:inadequate tension inspection shall take 20% sampling of flange anchor bolts, if once test fails, sampling rate shall be expanded to 50% . If more than 5% of these 50% tests fail, all flange anchor bolts shall be re-tensioned and re-tightened. exceeding tension inspection takes 1 sampling from all flange anchor bolts, if fails, sampling rate shall be expanded to 10%. If one of 10% sampling fails, all flange anchor bolts shall be re-tested by exceeding tension inspection.
2 inadequate tension inspection: tension anchor bolt to target oil pressure of inadequate tension inspection. If no gap between nut and flange, and the nut cannot be turned by the torque with a wrench of 50N·m～100N·m, that indicates the anchor bolts pass acceptance inspection.
3 Exceeding tension inspection: tension anchor bolt to target oil pressure of exceeding tension inspection. If no gap between nut and flange, and the nut cannot be turned by the torque with a wrench of 50N·m～100N·m, that indicates the anchor bolts exceed tension. Continue to slowly pressurize until the nut can be twisted. At this time the oil pressure shall not exceed 1.3 times of the design pre-tension. If exceed 1.3 times of the design pre-tension, this anchor bolts shall be unload and re-tightened. If oil pressure of exceeding tension is larger than 1.4 times the design pre-tension force, this anchor bolt shall be replaced.
4.When a whole set of wind turbine foundation anchor bolt tension acceptance inspection complete, nuts and external threaded parts shall be coated with corrosion protective grease and dust-proof caps(as shown in Figure 24)
Our manufacture have the most advanced facility of heat treatment, with experienced experts and service teams. Main products are Wind turbine foundation cage, anchor bolts, studs, nuts, washers, rock bolts, heat treating round bars, heat treated stirrup, seamless tubes.
Anyang Longteng Heat Treatment Material Co.,Ltd
Add: Industrial Park, Indu District, Anyang City, Henan Province, P.R.C.
TEL: +86-372-2256782
Email: [email protected]
Post time: Nov-04-2019