Rail Tolerances and Coating System 1

[farhanjnawab]

Dear Sirs,

We have rails laid 20 years ago and were in service lifting ship-lift trolleys in a Naval Dock Yard Project. In the due course of its service the coating of the rails is removed with the top surface being rusted and corroded bottom in some rails, so the rails are now subject to assessment and refurbishment.

My queries is relation to the following are,

Assessment:

a. After sandblasting the rails, special profile check templates are being used by the third-party inspection agency to check the correctness of the profile and rail dimensions. Is there any standard for acceptance and rejection criteria for existing rails based on the actual dimensional checks?
b. The new specs for T rails i,e ASTM A 1, is very hard on the dimensions. If we go and compare the existing rail dimensions after sandblasting with ASTM A1 tolerances, I think we'll end-up rejecting all these rails. Pls Help....

Protection (Coating):

a. Pls recommend specific type of coating to be applied on these rails after sandblasting for re-use. should be hard-wearing, and anti-corrosive..

Thanks

 

[bimr]

Contact the manufacturer/supplier of the lifting system for technical assistance.

You should also make a comparison of the technical specification of the system as built versus the new specification.

 

[Ron]

Rails are usually not coated. What you are seeing is the corrosion resulting from wear and exposure.

You need to check tolerances against the equipment you are using. If the equipment requires a certain tolerance then use that as compared to a new rail. You can't expect a 20 year old rail to meet new tolerances.

 

[farhanjnawab]

Thanks.

What should be the Acceptance and Rejection Criteria while assessing such old rails. The rails visually have some rust only without any reduction in the section due to corrosion. How to prove to the Clients that we can re-use them with some refurbishment?

 

[Ron]

If there is no section loss from corrosion, and only the wearing surface is affected, then check the equipment that the rails support and see if the mating tolerances are OK...if so, move on. If not, consider replacement.

 

[bimr]

Take a section of rail out and measure the physical properties such as weight/meter of length. Compare that to new material. That would tell you the extent of the corrosion