 Stops
Fatigue Cracking
Stress Cycle
Illustration of Before and After on NEW tooling.
MetaLL ifeÒ protects
drawing / forming / stamping tools from initial or subsequent fatigue stress
cracking by replacing detrimental residual tensile stresses with an encapsulating
subsurface region of
compressive stress. For comparative compressions curves, see sample X-ray diffraction Lambda Curves.
By having a compressive force in place, the initiation and propagation of
fatigue cracks is
prevented. Cracks cannot propagate into or through this layer of compressive stress unless the increased effective yield fatigue strength of the steel is exceeded which MetaLL ifeÒ increases by
30-40%.
MetaLL ifeÒ
is best applied to NEW tools, however, USED
tools can also be processed providing they are in a usable "ready for
production" condition. On softer steel hardness materials, such as
seen in Hot Work Steels, it is possible to close smaller existing cracks.
The range of hardness for D2, A2, and M steels prevents this from
occurring. As most metallurgists know, a crack can not propagate into or through a layer of compression unless the fatigue yield strength is exceeded.
See photos below and click here
to see illustration of stress cycle for unprocessed and processed punch.
Before - polish marks and inclusions
that cause initiation of cracking. |
After - MetaLL ifeÒ
crack initiators
are not longer present. |
|
