Conceived in the USA by Meehan and Smalley in the early 1920's
Meehanite originated the very revolutionary concept that cast
iron would be treated as a quality material manufactured to
precise specifications
Previously grey cast iron with its coarse graphite structure
and phosphide eutectic had been regarded as unreliable by designers
The change in outlook was brought about by the fact that the
structure of iron, especially the graphite form, could be controlled
- Meehanite Metallurgy
This process became known as inoculation and produced
not only high strength irons, but ones which were less sensitive
to variations in casting thickness
The effect of inoculation is easily measured before pouring
any castings
Wedge testing, for process control, was originally developed
by Meehanite
The test indicates the tendency of the metal to chill and is
directly related to ruling casting section
Meehanite foundries make particular use of the information gained
from the wedge test with regard to the constitution of the metal
before and after inoculation
Process advanced through the development of a range of Meehanite
metal types with analytical compositions which correlate to
the castings being made
Control was extended to cover all foundry process parameters
and developed as an inseparable extension to Meehanite metallurgy
The Meehanite Process
employed in 1945 was the earliest form of foundry
statistical process control
More stringent control was exercised through the implementation
of standardised Meehanite gating and feeding practices
The Process incorporates a continuous system of inspection of
all process parameters recording and recognising deviations
and acting upon such events in time resulting in a
practical quality assurance system
In the interests of casting quality recommendations on the manufacturing
equipment suited to the production of the foundry's casting
range are made during the introduction of the Process
A structured programme of audit (service) visits are applied
to assess a foundry's quality level and reports detailing practical
remedial actions are provided
A scrap control system is introduced and monitored during audit
visits
Metallurgical principles developed in the production of Meehanite
flake irons were extended enabling the manufacture of nodular
irons even from the cupola
Many patented procedures were developed to overcome magnesium
recovery and fade
Ultrasonic determination of nodular iron structures was pioneered
as a control tool
Meehanite metallurgy was further expanded to create a family
of irons to withstand heat, wear and corrosion service conditions
More recently the Process has advanced to cover the manufacture
of high strength austenitic ductile irons -
Meehanite ADI
Following a number of years development 1996 saw
the introduction of the first Meehanite realtime
Casting Solidification Simulation and mould filling software,
providing:
- Mould filling sequences (single & multiple cavity)
- Casting solidification (time elapsed tomography)
- Defect risk analysis
- Nodularity evaluation
- Hardness profiles