first and foremost used procedures in the production process of a screw
are heat treatment processes for case hardening, tempering and
annealing. The structure of the alloy is converted to ensure the
required mechanical features.
Depending on the carbon content
the screw is heated up to a certain temperature which is kept for an
extended period of time. Thereby the microstructure is converted and an
increase of hardness is achieved through a subsequent quenching in oil.
The now glass-hard (brittle) screw cannot be used in
the field yet. In a second process called annealing it is heated up
once more. During this process the high hardness decreases and the
tenacity improves considerably.
A wood-concrete-composite is a connection between supporting timber beams and a concrete slab mounted on them. A rigid connection is achieved with shear connectors or screws which transfer shear forces between beams and slab. Wood-concrete-composite floors are utilized when large beam spacing’s or spans must be bridged and high pay loads must be carried after retrofitting the ceiling. This bonding is deemed to be the ideal solution for increasing the load-carrying capacity and stiffness of ceiling systems.