flair-bevel weld callout
flair-bevel weld callout
(OP)
I am interested in the correct weld symbol for a flair-bevel weld where the weld is expected to be flush with the material when finished.

The question that has come up is if the throat dimension is needed if you indicate that the weld finish is flush. I have always added the weld size to my symbols but maybe that is not needed in this case? below I have added the dimension and a grind symbol, but if it is not necessary for the surface to be ground smooth is it acceptable to leave the dimension off and just expect the weld to be roughly flush to the material surface?

The question that has come up is if the throat dimension is needed if you indicate that the weld finish is flush. I have always added the weld size to my symbols but maybe that is not needed in this case? below I have added the dimension and a grind symbol, but if it is not necessary for the surface to be ground smooth is it acceptable to leave the dimension off and just expect the weld to be roughly flush to the material surface?





RE: flair-bevel weld callout
If one wants to specify weld correctly they need to have an up to date edition of AWS A2.4.
If you can't afford the tools, don't take the job.
If you refer to AWS D1.1, Table 2.1 lists the maximum weld size based on the radius of the round component and the welding process. For your purposes you can use (5/16)R based on the bevel being filled flush. The welding symbol, by convention, is to list the radius followed by the weld size enclosed within brackets. Example: 1 (5/16) where 1 is the radius and 5/16 is the weld size.
Best regards - Al
RE: flair-bevel weld callout
With all that said, This doesn't answer the question as to whether or not the weld size designation is necessary or if the surface finish designation is sufficient in a symbol. I have seen books that seem to indicate both cases.
RE: flair-bevel weld callout
As you pointed out, the detail being welded is a flare bevel. The welding symbol standard most often referenced in the US is AWS A2.4. As I noted in my response, the convention is to define the radius of the round edge followed by the weld size. There is no throat dimension associated with the flare bevel unless one is looking at a text or standard that is out of date by twenty years or more.
I referenced AWS D1.1 because it is one of the few welding standards that provides a rational approach to determining the size of the flare bevel and flare V-groove. Most codes simply side step the issue.
The AWS Structural Welding Code/Steel does have provisions whereby a contractor can demonstrate larger weld sizes can be deposited via mockups. Designers often time mistakenly assume the weld is fused to the point of tangency where the round surface contacts the flat surface of the bevel groove or the two round surfaces make contact (or come as close as practical). Experience indicates that isn't the case when a typical arc welding process is used.
The attached sketch is one that I included in a WPS involving a double flare bevel groove weld. Notice the weld does not penetrate and fuse to the point of tangency.
Best regards - Al
RE: flair-bevel weld callout
CSAW59 - 2013
RE: flair-bevel weld callout
As the sketch indicates, fusion to the root is not going to happen. that differentiates a fillet weld from a groove weld. Most designs assume the fillet weld is fused to the root. This assumption is needed in order to determine the dimension of the throat. If there is no fusion to the root, our strength calculations fall apart.
Best regards - Al
RE: flair-bevel weld callout
RE: flair-bevel weld callout
Side note: how do you field inspect an (E) weld for specified penetration??
RE: flair-bevel weld callout
AWS D1.1 has prequalified joint details that have been used for many years because they provide adequate access for the welder to deposit a sound weld if they have the skills necessary to pass the prescribed welder qualification tests. The details are conservative enough, that if one follows the rules good welds can be made.
AWS D1.1/D1.1M:2015 includes table 2.1 that provides the user with a means of determining the weld size of both flare bevel and flare V-groove as a function of the radius of the round edge and welding process. Like many of the details included in D1.1, the details tend to be on the conservative side, so most welders have no problem depositing welds with the required size.
If one needs to verify the joint penetration/weld size, it can be done using UT with a straight beam transducer. One may have to grind the surface of the weld smooth to provide a flat surface for the UT transducer.
Best regards - Al
RE: flair-bevel weld callout
However you now have me concerned, if there is little or no root penetration expected from a flair bevel does it do much more than look good? You mentioned the fillet weld expects better penetration but my understanding has been that the material geometry dictates the weld and the geometry here would call for the flair bevel. Would it be acceptable then to place a fillet weld in this location and specify a flat surface rather than a leg dimension? Guess I am going to have to investigate the cost of A2.4 I just know that when the company purchased the D1.1 it was far out of what I could afford.
RE: flair-bevel weld callout
RE: flair-bevel weld callout
Yes, I am 20 years out of date.
RE: flair-bevel weld callout
Fillet welds, when they fail, do so in shear. If both legs are of equal length, the failure will be along a plane 22 1/2 degrees off the leg, not through the throat. However, we use the throat dimension, i.e., the shortest failure path, for the purposes of calculating the strength of the weld. The design approach works if there is fusion to the root and one can determine or assume the throat dimension. If unequal weld legs are specified, one can still use the shortest failure path, usually the shorter leg dimension to determine the strength of the weld. One must check to verify the base metal isn't over loaded, so AISC uses the allowable stress of 0.4 times the YS of the base metal in shear and 0.6 times the YS of the base metal for the allowable tensile stress.
The strength of the PJP and bevel grooves can be determined if the joint penetration (weld size) is known. When a prequalified groove detail is selected, the joint penetration is assumed to be some minimum dimension based on the depth of bevel and groove angle. If the groove angle is less than 60 degrees, one assumes the joint penetration is 1/8 inch less than the bevel depth. A conservative approach, but it hold true for a large percentage of welder.
Best regards - Al
RE: flair-bevel weld callout
RE: flair-bevel weld callout
Any reason the failure is at 22.5 degrees?
thanks, Dik
RE: flair-bevel weld callout
Best regards - Al