Question about weld line and hole near or on the weld line

By s_ramezani Date 04-12-2007 08:13

I have two questions about "weld lines" and "holes" near or on the weld lines. Assume that two pieces have been jointed together by a fillet or grooved welding process.

1) We want to make a hole on one of the pieces near the weld line. It is evident that welding line makes a Heat Affected Zone (HAZ) around itself in the work pieces. My question is that whether there is any restriction on the distance "L" between weld line and center of hole or not? Is there any reference "standard" for this subject? Please if you have seen this subject in any standard, inform me. Would you please if it is possible for you, send me a copy of the page of the "standard" corresponding to this subject.
You know that in some standards or handbooks (e.g. Die Design Handbook), there is restriction on the distances between center of hole and edges of the work piece must be at least 1.5D (D is the hole diameter)

2) Can one make a "bolt hole" exactly on a butt weld line (a hole with diameter "d" )? I saw this in two flanges which were bolted together. One of the flanges was made of some pieces welded together. Some of the bolt holes were exactly on the butt welded lines! I don't have a good sense about this design.

My email address: s_ramezani@mech.sharif.edu

By js55

Date 04-12-2007 13:52

The only thing that I can think of off hand that addresses this would be a PFI standard pertaining to RT holes. Holes at some short distance from welds are common in the power industry for running RT pills inot the pipe for radiography, and then sealing the hole once the RT is completed.
Other than that, I'm not sure there is any specific prohibition but it must be engineered.

By Bill M

Date 04-13-2007 13:32

Sometimes if a weld approaches a fillet weld, we are required to spot face the surface of the hole that ends up near a fillet weld to provide a flat seat for the fastener washer, nut, or bolt head. Sometimes this spotface cuts into the fillet weld. I have seen where some full pen. welds have been drilled through after surface milling operations. Obviously, if a bolted connection happens over a butt seam, one would think that the butt weld would have to be machined, milled, or ground flush to provide proper bearing for the mating parts. It would be hard to layout acurately and drill a hole if the weld was not ground flush.
I do not know of any code restriction prohibiting locating a thru hole over a butt weld, I do not think it is a common engineering practice though. You might have some problem tapping such a hole in some materials if there are some harder to softer heat effect zone issues.