High-frequency impact treatment

The HiFIT (High-Frequency Impact Treatment (also called HFMI (High Frequency Mechanical Impact))) process is such a hammering method that is universally applicable, requires only a low tech equipment and still offers high reproducibility and the possibility for quality control.

The HiFIT hammer operates with a hardened pin with a ball resting on the workpiece with a diameter D of 3 mm.

The International Institute of Welding Technology IIW published the Guideline "Recommendations for the HFMI Treatment"[3] in October 2016.

An overview of higher frequency hammers (HFMI) is presented, and recommendations for the correct application of the method and quantitative measurements for quality assurance the guideline provides the basis for measurements of HFMI improved welded joints on the basis of all known stress calculation concepts.

For a targeted treatment, the visibility and accessibility of the transition in the welded areas are required.

With timely remediation of existing structures there is practically no difference to the life of new treated welds.

The HiFIT-method is used very efficient e.g. at highway bridges in steel hollow box-section design on the fly.

In case of new constructions and for some existing structures the load level for treated welds can be increased.

Taking into account the HiFIT process during development, on same load level and same lifetime, the construction can be slimmed down specifically.