The aim of the proposed project is development and
optimisation of technology for production and processing of
materials (in assortment of wires and rods) designed for
manufacture of high-strength pressed pieces in strength
class 800-1200 MPa (one strength degree 800-950 MPa and one
degree 950-1200 MPa) without final heat treatment.
The end-targeted technology of production and subsequent
processing of materials would ensure the required final
strength in the interval given above, together with
guaranteed cold formability (ductility A5 minimum 15% or
12% and contraction minimum 30 J/cm2 up to -30 degrees
Celcius and stability of the given parameters also at
elevated temperatures of up to 300 degrees Celcius.
In the course of the project solution there will be
analysed influence of structure and sub-structure character
of the input material. Impact of the size and character of
cold deformation will also be investigated. The influence
of individual parameters will be verified in pilot and in
industrial operation conditions and subsequent
determination of permissible interval for production of
individual strength degrees in the above mentioned range.
A programme will be developed for modelling of the cold
volume forming process, including development of individual
strength plastic characteristics and fatigue
characteristics. The aim of this programme is the computer
design of manufacturing technology on the basis of
knowledge of final construction with respect to the
required final parameters.
Considering the fact that in the course of manufacture of
most components there is uneven distribution of deformation
in material, the final material (product) is also
non-homogenous from the viewpoint of final strength-plastic
parameters after cold volume forming. In case of
conventional production technology, final properties in
volume of material are homogenised at final heat treatment.
Owing to the fact that the proposed technology does not
comprise thermal treatment it is necessary to propose, with
the use of mathematical modelling, optimal parameters of
input material and technology of its cold forming.
Technological processes obtained in this manner will be
experimentally verified both by pilot and industrial scale
testing. On the basis of experimental results the
production technology will be corrected and a mathematical
model developed to reflect given chemical composition and
dimension assortment of wires and rods. During all
experimental tests emphasis will be on research of service
non-standardised properties of the mentioned materials and
specific machine parts made from these materials.
Properties specific for individual products will also be
investigated. Knowledge of the whole complex of strength
plastic and service properties is absolutely necessary for
application of material for production of individual
machine parts, namely components for the automotive
industry. It is presumed that the developed material and
technology of its production would also be applied,in
certain cases, to the manufacture of safety components for
the automotive industry. In the course of solution,
resistance to fatigue, ageing of material, material brittle
fracture properties at temperatures to minus 30 degrees C
and stability of properties in the course of ageing will
also be investigated in detail.
Tests of basic strength plastic parameters will be
investigated in laboratory conditions. Service
characteristics will then be studied on testing machines in
manufacturing plants - always on specific machine
components. At the same time mutual links between strength
plastic and structural characteristics of hot-rolled wires
and rods and between cold ductility will be verified
At production of concrete fastening and joining parts and
other machine components it will be necessary for
successful implementation of the developed manufacturing
technology to process this material (and possibly the
technology) and to prepare relevant standards (corporate,
Czech, ESN, DIN, ISO).
Keywords: hot rolling, cold drawing, cold forming.