The compatibility of the strength grade of track bolts with the load of the line
Which line scenarios are 8.8 grade bolts mainly suitable for?
Grade 8.8 bolts have moderate strength and are suitable for conventional railways, branch railways and non-heavy-load sections. Its cost is reasonable and it can meet the fastening requirements under normal loads. It is the most commonly used bolt grade.
What are the application advantages of 10.9 grade high-strength bolts?
10.9 grade bolts have higher strength and better toughness, and can resist the impact and vibration of trains. In high-speed and heavy-load lines, it can effectively prevent bolt loosening and enhance the stability of the track system.
What are the usage characteristics of 12.9 grade ultra-high strength bolts?
Grade 12.9 bolts are suitable for sections with extremely heavy loads and strong vibrations, such as heavy-haul railways and bridge connection parts. It has strong fatigue resistance, can maintain preload for a long time and reduce the risk of fracture.
What safety hazards can be brought about by the mismatch of bolt strength grades?
Insufficient strength can cause bolts to deform or break, leading to the failure of fasteners and the displacement of rails. In severe cases, it can cause the gauge to expand and the train to crawl, threatening the safety of train operation.
How to select the appropriate bolt strength grade based on the type of line?
For regular speed lines, choose grade 8.8. For high speed and heavy load, choose grade 10.9. For extremely large loads and Bridges, grade 12.9 is selected to ensure that the strength matches the load for a long time.