The wear of WC-Co drill bits during rotary-percussive drilling of reinforced concrete

Factors on vibrational harm during hammer drilling – Influences of lateral force, feed force, hammer drill and drill bit type

“…Uhl et al (2021;2019) further demonstrated that in addition to the feed forces of the user, lateral forces are also applied unintentionally. In the aforementioned studies, the forces were in the range between 4.7 N and 73.1 N. This finding is confirmed by the description of occurring transverse motion of the drill bit due to the human behavior, by Momeni et al (2017). The influence of these lateral forces have not been investigated to date in the current state of research.…”

Does the user behavior effect the productivity of hammer drilling? – Analysis of the influences of feed and lateral force

“…Whereas lateral forces in manual hammer drilling have been demonstrated, but their influence on productivity and possible interactions with other influencing factors have not yet been researched. Momeni et al (2017) wrote that small lateral motions exerted by skilled operators and varying the feed force can reduce borehole friction. If the detailed relationship between user forces, consisting of feed and lateral forces, on productivity were known, optimal operating points between user forces, productivity and user load could be identified.…”

Drilling performances and wear characteristics of coated drill bits during drilling reinforced concrete

“…High speed steel soldered with tungsten carbide tip has been widely used for drilling concrete as the drill bit has to withstand the high heat generated by the friction of drilling into a hard surface. Nonetheless, the tungsten carbide tip may undergo wear owing to a very high loading level transmitted from tools to drill bits resulting in a complex stress distribution between the drill head and the steel . Furthermore, tungsten carbide tip may chip off due its persistent usage as it is brittle in nature.…”

“…Yang et al have reported that there has been a substantial improvement in the wear resistance of WC‐12 wt% Co at elevated temperatures when they are allowed to slide against the alumina ball. Recent work carried out by Siavash Momeni et al demonstrate that the wear resistance of the WC‐Co drill bits increases with increase in the percentages of the cobalt content and the size of WC grains. Several surface modification techniques such as detonation gun spraying, electro spark coating, plasma spraying, etc, are available to protect the drill bits against wear and erosion .…”