Common hazards when installing or maintaining wear plates include spring-back hazards, lifting, welding and cutting hazards, including fumes, radiation and electric shock. Falls from height hazards may also be present.
In general, using multiple smaller wear plates instead of one large wear plate is recommended. This will help minimise risks, including reducing the amount of stored energy and spring-back potential.
Wear Plates Spring Back Hazards:
There have been instances where wear plates spring off and kill or injure workers during routine maintenance or replacement. According to Worksafe Queensland, there can be numerous causes of wear plate spring-back including:
Misshape: Where a wear plate profile has not been cut to fit correctly for the machine or intended application and it is forced into place during installation, stress can build up in the wear plate and be released with potentially devastating consequences.
Welding: If a wear plate is incorrectly welded into place it can apply forces which may build up and cause spring-back.
Wear: Wear plates are designed to undergo huge amounts of stress, however if stress is not distributed evenly across the wear plate, it can lead to spring-back. This highlights the importance of fit-for-purpose wear plate solutions and routine wear plate maintenance.
Dirt ingress: A wear plate that has worn through or with damaged welds is susceptible to dirt ingress between the wear plate and structural plate it is protecting, contributing to the amount of stress the plate suffers and potentially forcing the two apart, again highlighting the importance of routine wear plate maintenance.
Corrosion: Like dirt, if corrosion gets between the structural plate and the wear plate it can contribute to the stress the plate suffers including wedging the plates apart.
The level of risk associated with wear plate removal or installation will vary based on the above factors, along with the size of the wear plate. Larger wear plates carry greater spring-back (and other removal or installation) risks.
Managing Wear Plate Spring-back Risks:
As with any hazardous work, a risk assessment should be carried out to identify any hazards, and control them using the hierarchy of control.
Even if there are no visible signs of the outlined wear plate installation and removal hazards, the wear plate may have been installed incorrectly or with excessive force and appropriate care must be taken.
According to Worksafe Queensland, managing the risk of wear plate spring-back includes, but is not limited to:
- Ensuring there are strict, documented procedures for working with wear plate installation and maintenance.
- Ensuring there are strict procedures for the identification and management of “stored energy situations”.
- Removing wear plates systematically to provide controlled release, including bracing the plate or reinstating cracked welds.
- Ensuring “line of fire” is identified.
- Ensuring all machinery and wear plate history and maintenance is documented and assessed prior to work commencing.
- Consulting with the manufacturer or supplier about maintenance and repair procedures.
Lifting wear plates:
Wear plates should also be constructed with installation in mind, with lifting lugs welded onto the mild steel backing plate. If you are working with wear plates that have a chromium carbide overlay, consider that lifting lugs cannot be welded onto the chromium carbide.
PPE in wear plate removal and installation:
Standard personal protective equipment (PPE) should be worn during wear plate installation and maintenance, however PPE is the last line of defence and other controls should be implemented first as per the hierarchy of control.
PPE includes – but is not limited to – steel capped boots, a hard hat, adequate protective clothing, cut resistant gloves to protect against a wear plate’s sharp edges, hearing protection, eye protection and respiratory protection for when cutting or welding wear plates.
Wear Plate Installation and Removal:
Cutting Edges do not offer wear plate installation service, however can recommend the services of a certified third-party if this specific experience and knowledge is not available within a customer’s team.