Screw connection establishing method for motor vehicle engine`s thermally loaded components, involves monitoring length variation of screw during tightening procedure by using ultrasonics

摘要

The method involves strongly pre tensioning or tightening screw of a screw connection, in a non-heating condition such that a stretching limit of the screw is not achieved and the length variation of the screw in an flexible area is remained. The length variation of the screw during the tightening procedure is monitored by using ultrasonics, where heat expansion coefficient of the screw is small or same as that of components to be connected.