Heat treatment technique of high strength anchor bolt for extra-high voltage transmission line rod tower
A technology for transmission lines and anchor bolts, applied in heat treatment furnaces, heat treatment equipment, manufacturing tools, etc., can solve problems such as splitting concrete, increasing the number of bolts, increasing the size of the bolts, etc.
Active Publication Date: 2008-05-28
CHINA ELECTRIC POWER RES INST
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Problems solved by technology
The above is a 1000KV single circuit, if it is a 1000KV double circuit, the pulling force may increase exponentially, if the number of bolts is not increased, the diameter of the bolt will be greatly increased), the current number of bolts is generally 4, 6, 8, 12, the load increases. If ordinary anchor bolts are used, the number of bolts is increased, the size is increased, and the concrete foundation is split. At the same time, the structure of the tower foot plate of the tower is complicated, the size is enlarged, the bolt arrangement is difficult, and the strength is low. Anchor bolts can no longer meet the needs of actual engineering
Method used
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Experimental program
Comparison scheme
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Embodiment Construction
[0010] The specifications are M48×1800, M64×2400 and M100×2700 respectively. The material composition is shown in Table 2, the heat treatment process is shown in Table 3, and the bolt mechanical properties are shown in Table 4.
[0011] Chemical composition analysis (Wt%) of table 2 material
[0012] Numbering
[0013] Table 3 heat treatment process
[0014] heat treatment process
[0015] Table 4 Mechanical properties of bolt samples
[0016] mechanics project
[0017] The strength level of the high-strength anchor bolts of the present invention is above 8.8, and the mechanical properties meet the requirements in Table 1.
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Abstract
Provided is a heat treatment process of anchor bolts with high intensity used for pole tower of ultrahigh voltage transmission lines, which belongs to the technical field of high-intensity fastening pieces. Past anchor bolts used for the connection of pole tower and base are manufactured by Q235, 35#, 45# and the like high-quality carbon steels and the like directly cut threads which are usually employed and are relatively low in extension strength. The invention is characterized in that the raw material is one of the 45# steel, 40Cr and 42CrMo, the processing temperature range of the heat treatment is 840-880 DEG C for heating, the heat preservation time is 120-270 minutes, and the quenching medium is natrii chloridum salt water of which the mass percentage concentration is 2.0-8%, the tempering temperature range is 540-650 DEG C with 120-300 minutes of insulation, then water-cooling and air cooling are proceeded. The bolts of the invention have the advantages of high intensity, high ductility and tenacity, and low crack sensitivity, and the intensity level satisfies 8.8 grade and upper intensity levels.
Description
technical field [0001] The utility model relates to a high-strength anchor bolt belonging to the technical field of high-strength fasteners, which is used for high-strength anchor bolts connecting towers and foundations of ultra-high voltage transmission lines. Background technique [0002] In the past, the anchor bolts used to connect the tower and the foundation were mostly made of high-quality carbon steel such as Q235, 35#, and 45#, which were directly turned and threaded, and their tensile strength was relatively low. [0003] UHV 1000kV transmission line foundation force and line horizontal load are relatively large (the pullout force of J1 tower is 290 tons, 12×Φ60; the pullout force of J4 tower is 615 tons, 12×Φ72. The above is 1000KV single circuit, if it is 1000KV double circuit , the tension may increase exponentially, if the number of bolts is not increased, the diameter of the bolts will be greatly increased), the current number of bolts is generally 4, 6, 8, 12...
Claims
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IPC IPC(8): C21D9/00C21D1/18
Inventor 徐德录李现兵韩钰陈玉成王立全
Owner CHINA ELECTRIC POWER RES INST