(Introduction, results, summary) (PDF, 69 kB) - Queensland Mining ...

einflated in situ. The ranges of pressure suggested for doing this was from
80% to 60%.
4) A repair standard that allows quick and easy identification of the extent of
the repair made to a tyre from visual observation of the tyre when in position
on truck, loader etc is recommended. Consideration to be given to
suggestion by Giant Tyre Vulcanisers draft standard to include as a standard
for tyre repair identification in AS4457.
5) AS 4457 calls for identification/inspection of wheels and rims and gives
instructions regarding repairs required but does not give serviceability limits
for components. A general serviceability limit for wheels and rims is
required. This includes hours of operation before removal for testing and a
standard to compare against for when is a rim non serviceable. When should
a rim be designated as unserviceable etc? How many times should a rim be
serviced before being replaced? How much material can be machined off the
back section of the rim. Wheel and rim manufacturers to assist in the
provision of information for AS4457 committee. RIMEX has provided the
following comments with respect to this point.
i. General Serviceability Limits: Hours of Operation
Currently the industry standard is around 15000hrs for all rims and has
worked thus far. Some sites have different hours for different
machines. RIMEX are currently running a program in Queensland and
NSW where snapshots are taken. This involves sending in batches of
rims at increasing hours to find out at what hourly service interval
problems begin to arise. Once problems start to surface at a certain
service interval RIMEX will reduce the hourly service interval by 10%
and designate that interval as the testing point. Currently on 930E
TSR’s (63”) RIMEX have increased the hours of testing to 20000hrs.
This is an ongoing program.
ii. When should a rim be designated as unserviceable etc
RIMEX have suggested that an objective measure maybe to check the
the pitting on centre bands and sections. The Australian Standard for
pressure vessels identifies a maximum of 15% of depth of parent
metal. RIMEX have seen pitting over 20% and fail these rims, even if
test shows no cracking in sections.
iii. How many times should a rim be serviced before being
replaced?
RIMEX suggest that after one back section and or one gutter section is
replaced. The amount a wheel diameter shrinks when cut or welded is
surprisingly large and leads to a fair amount of heat stress-weakening
the rim.
Tyre Fitters Workshop Townsville 2 Sep 2004: Minutes and Report. Author: Peter Power Page 10