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

Stud welding: φ13, φ16, φ19, φ22
②Welding posture: downward
*Deformed studs with the same diameter, threaded studs are also applicable. Please contact us for details.

(2) Range of applications with a particularly high effect

A point of high shear force acting on a headed stud in the main girder section of a bridge.

(3) Non-applicable range

①Headed stud diameter of less than φ13 or larger than φ22
②Horizontal welding method, overhead welding points

(4) Required qualification

Stud welding technical certificate Holders of Class A or above

Range of applications


Tokyo branch office: 81-(0)44-333-6500

Chubu branch office: 81-(0)566-45-5241

Osaka branch office: 81-(0)6-6385-2332

Chugoku branch office: 81-(0)82-532-1785