Single V bevel designs V/s Single Bevel

Date 01-16-2018 22:49 Edited 01-16-2018 23:09

There is a difference in heat transfer. The beveled side dissipates the heat more slowly because it is for all practical purposes thin. Less heat is required to penetrate and fuse the thinner metal in the root. The square edge is thick in comparison and requires more heat to penetrate and get proper fusion in the root. Two opposing conditions that the welder must contended with.

You didn't mention whether this is open root; more difficult, or welded with backing; less difficult. The red arrows represent the different paths by which the heat can dissipate.

Best regards - Al

By Lawrence (*****)

Date 01-17-2018 14:01

Great representation Al.

Here is another discussion on this subject that Al spoke to https://app.aws.org/forum/topic_show.pl?tid=34211

The other side of the coin (in general terms) is that single bevel joints can reduce weld volume, deposition, and time.

The inherent increase in difficulty in a single bevel vs a V-groove (even with backing) means that thought should be put into training of operators. This is especially relevant in the structural steel world where single bevels are very commonly detailed.

This is one of the scenarios where I really appreciate the CWB (Canadian Welding Bureau). Their standard performance qualification test (with backing) for structural steel is detailed as a single bevel and requires a split root with a start and stop on the non-beveled (fillet) side. In essence this exam performs a destructive test on a groove and fillet in the same assembly.

I know I strayed slightly off topic from girth welds... Sorry

By 803056

Date 01-17-2018 15:00

In one of the articles I wrote for Inspection Trends I proposed using a bevel groove instead of the standard V-groove. I may have mentioned CWB's test.

I believe it more closely represents the majority of welding performed in the shop, i.e., it requires proficiency in depositing a fillet weld and once the fillet is deposited in the corner, the remaining groove closely resembles a V-groove.

I think the CWB is ahead of the curve while the AWS lags the curve when it comes to welding and welder qualification.

Lawrence, you mentioned training, the sad truth is the majority of manufacturers provide little if any training once an individual is on the payroll and on the production line. Most of my clients do, but only because they are forced to in order to meet the requirements of the military standard. Even that training is primarily a familiarization of the military standards. There is no hands-on skill development other than what may be necessary to pass the skills, i.e., performance, test.

It amazes me how many people in management positions believe genetics plays a roll in welding. I hate to say how many times I've heard, "Well, his father was a great welder." Translation; dad could deposit a weld be that was consistent from one to the next. I always ask the question, "But what if dad had a bad cold the night Junior was conceived?" That usually sets them back in their chair as they begin to ponder the question. I usually get myself a tea while they mull over the concept.

Just my thoughts - Al