Repair to Corroded Steel Guides

[dik]

We have a series of steel Corten guides that have been (and will be) submerged and exposed numerous times to flowing water. They have been in place over the last 40 years and subject to alternate wetting and drying and also water borne erosion of the oxide layer. The corrosion is generally limited to the area that is alternately wetted.

Corrosion cells have formed crater like pits approximately 1-1/2" diameter and approx 1/8" deep. There are a couple of areas where the 'pits' are overlapping and the material surface is relatively rough (lunar landscape comes to mind).

We are planning to clean the area and plate over areas with significant material that is corroded. This would be seal welded to reduce the likelihood of water.

Other than remove the existing oxide layer, is there a compelling reason to fill the existing craters with weld and grind smooth prior to plating?

With areas that have significant corrosion, it is intended that these be plated to restore the area of metal. With areas that have a few discrete pits it is intended that these be filled and ground flat.

What problems could be associated with the manner of remedy?

Dik

Could the welding of Corten cause corrosion problems in the weld boundaries? and accelerate the new corrosion?

 

[metengr]

dik;
My question back to you is why can't you mill the existing guides in the field smooth to remove the corrosion damage versus local weld repair and subsequent grinding? I would presume that having surface corrosion to a depth of 1/8" is not that significant in terms of wall loss. Weld overlay is an acceptable option with no adverse affects to the guide base material if the surface is treated to protect from exposure to moisture.

Leaving the surface as is with the local pitting corrosion damage will act as a trap for debris and could result in accelerated wear to the guides.

 

[dik]

thanks metengr, the section is an S type and the front part of the flange and web have been machined down (rotary cutter). The problem is on the back (sloped) part of the S section; it is not readily/easily accessible.

Dik