Improved Fatigue Strength Ferrules

• Patent No. 5606789
• Design registration: 1409671
• NETIS registration No. QS-170001-A

In a typical composite girder structure, just as described in various design standard documents such as for road bridges, there is a broad recognition that the studs near the end and intermediate supports (areas assumed to be more quickly damaged than the usual points) are the most susceptible to high loads (maximum shear force). These points are mainly where ferrules with improved fatigue strength are used to extend the service life of stud weld points.
In May 2017, we completed registration of the improved fatigue strength ferrule to the New Technology Information System (NETIS), and trial results demonstrated that when subjected to repeated one-way shear forces, the fatigue durability of stud welding points was 1.5 to 1.8 times greater than that of conventional ferrules.
Moreover, while current ferrule products are prone to post-weld spatter that adheres to the contact surface with the steel plate, leading to time-consuming removal work, the structure of the new ferrule eliminates almost all spatter adhesion on the steel plate. This gives rise to expectations for less of a burden on the welder, and increased efficiency.

Range of applications

(1) Applicable stud shaft diameter and welding posture

(2) Range of applications with a particularly high effect

(3) Non-applicable range

(4) Required qualification

Range of applications