Malaʻe ʻo e lelue

The railway is one of the most important inventions and means of transportation of mankind. For centuries, mankind has continued to innovate its technology, and the technology of railways and locomotives has not yet reached its peak.

Today, railways around the world have more transport responsibilities than ever before, and the demands placed on locomotive manufacturers and their suppliers are constantly changing. Shorter product cycles and technological innovation, the use of newer, more advanced, lighter, more energy-saving and environmentally friendly materials, and even the ever-changing division of labor require continuous innovation and adaptation.

Wire thread insert, self-tapping thread insert and key locking insert are widely used in railways and locomotives as new and innovative fastening technologies. High-speed railways are developing particularly rapidly in our country, and high-speed EMUs are operating in large numbers on all major railway lines across the country and exported to various countries. Aluminum alloy has become the main material of locomotive units due to its lightweight and good sealing properties. However, the soft nature of aluminum alloy materials results in weak shear resistance in threaded connections. Direct processing of threads on the base material cannot meet the safety requirements of railway vehicle assembly and operation. Aluminum alloys require the use of thread sheaths to ensure the stability and reliability of the connection.

In various types of domestic EMUs, threaded sheaths are used in various threaded connection structures such as vehicle interiors, exterior suspensions, and under-car hoisting. The main types include wire thread inserts, self-tapping thread inserts, and key locking thread inserts. The CRH1 EMU has a stainless steel body and does not require the use of threaded sheaths; the CRH2 EMU mainly uses steel wire threaded inserts; the CRH3 EMU mainly uses self-tapping threaded inserts, and is also used in some large-diameter pipe connections. Wire thread inserts are used in parts; key locking thread inserts are used in CRH5 EMUs.