Hardbanding Inspection
There are numerous items that are included in the process of inspecting drill pipe, such as thread condition, tool joint length, minimum and maximum OD’s, etc. One often misunderstood item is the condition of the hardbands.
Questions frequently arise when inspecting hardbanding. It’s usually clear as to what needs to be done when looking at the dimensions of the old bands. However, when looking at the condition of the hardbands, there can be questions and confusion on what should be done. In this bulletin we will try to make the process of inspecting the condition of hardbands a little clearer.
Hardbands can be put into three different classifications.
1. Pipe that can go back into service.
If there is still sufficient hardband height, and the material is in a good, stable condition, no repairs or re-hardbanding should be required. This would normally mean that they are at least 1/32” proud, and not cracked or spalled. If they are badly cracked or have any spalling they should be repaired (see classification 3 below). The severity of the drilling operation should also be kept in mind. In extreme, harsh conditions, the hardbands should be rebuilt earlier to ensure they aren’t completely worn away prior to the next inspection. Once the hardbands are worn flush, tool joint OD wear starts. It’s important to re-apply before the tool joints are worn flush.
2. Worn hardbands that can be rebuilt without additional repairs.
Hardbands that are not cracked, spalled, or that contain a lot of porosity can usually be re-hardbanded without additional repairs. If the hardbands are worn sufficiently, and are in stable condition, they are candidates for re-hardbanding. Any bands less than 1/32” certainly must be re-banded. For bands prouder than 1/16”, care should be taken to ensure the new hardbands are not excessively proud. Hardbands that are too high could create clearance issues when going back into the hole.
In the case of eccentric wear, partial banding can be done if it’s Duraband NC being applied over Duraband. Not all materials can be successfully partial banded. It’s best to check with the pipe owner to confirm partial banding is allowed. If it is not allowed, the solution is to remove the used hardbands to concentric, and then new hardbanding can be applied. It’s important to understand that some materials, even without cracks and spalling, cannot be easily reapplied.
3. Hardbanding that must be removed and rebuilt.
Bands less than 1/32” are dimensionally ready for re-hardbanding, however the type and condition of these old bands will determine what needs to be done. Bands that are cracked, spalled, and have a lot of porosity must be removed and rebuilt prior to re-hardbanding. After complete removal, the tool joints should be built back up using a buildup wire to get back to the original tool joint OD. Once the tool joint is rebuilt, it can be re-hardbanded.
The removal and rebuilding process is expensive and time consuming. It is an expense that can be avoided by using Duraband, which never has to be removed and rebuilt. Duraband can
