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Haiyan Tianqi Fastener Co., Ltd.
  • Add:Jiaxing Haiyan China NO.1-3 Jincheng South road, Qinshan Industrial Zone of Haiyan, Jiaxing
  • Tel:+86-573-86408971
  • Mobile Phone:+86-13606831322
  • Fax:+86-86408973
  • E-mail:472660558@qq.com
  • Post Code:314300
  • Skype:tianqi

Solution to the corrosion problem of non-standard screw connection


The most important corrosion at the connection of non-standard screws is contact corrosion. BST selects the surface treatment of the screws according to DIN25201-6 table 3, "the actual voltage level of the potential difference of 500mV" when designing the fit between the non-standard screw connection fasteners and the connectors, for example: aluminum-magnesium alloy connectors, the anode The index is 750mV, and the non-standard screw using austenitic stainless steel has an anode index of 350mV, and the potential difference between the two is 400mV; in addition, the non-standard screw using Dacromet treatment has an anode index of 1150mV. The potential difference is 400mV; all are within the allowable use range.
In addition, in certain parts of the train, due to daily maintenance, such as non-standard screws connected to the bottom cover plate of the car. Due to daily car washing, the cleaning fluid will stay on the two rows of bottom cover plates near the lower edges of the skirts on both sides. On the standard screw, the surrounding area of ​​the screw connection is often in a wet state; or due to the extremely harsh operating environment, such as the bolt connection on the train bogie. BST adopts the method of applying isolation grease. After the non-standard screw is installed to the specified pre-tightening force, the entire non-standard screw connection is coated with specific isolation grease around the exposed areas to protect the bolt connection from the environment and ensure driving safety.

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