Choosing between butt welding and fillet welding?
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When planning the piping, flat welding was chosen as the welding method. However, a colleague said that in actual construction, flat welding requires two weld passes, which is rather troublesome; therefore, they asked me to change all flat welds to butt welds instead. Looking at the standards as well, it can be seen that the scope of application for butt welding essentially covers all types of flat welding. So when installing pipes, can one always use butt welding instead of flat welding?
This post was last edited by Yimi on 2017-2-8 at 17:15. There is no absolute rule, unless it is the case of restrictions on the use of butt-welded flanges. At the very least, butt-weld flanges have a price advantage, which becomes more apparent for larger diameters and larger quantities. “A colleague said... “Will the owner agree?” Will the management approve it for EPC? If only convenience in construction is considered, threaded flanges don’t even need to be welded! ;P
But my colleague said that in actual construction, two welds are required for butt welding, which is rather troublesome; therefore, he asked me to change all the butt welds to fillet welds. I chuckled. Flat welding – are those two fillet welds? Don’t pipes need to have bevels cut? For work in South Korea, penetration welding with grooves is generally used; does preparing grooves for pipes count as a hassle? It’s impossible to use a whole tube all the time; there must be some point where it gets cut, right?
It is better to perform butt welding for one-time formation; this process involves one additional step compared to fillet welding. Fillet welding is a good option for thin-walled pipes, but it cannot be used for thick-walled pipes. It depends on the actual situation on site; choosing welding just to save trouble is not a good idea.
I think what you say makes sense. I’m also just starting out with piping work and learn by following my colleagues. We usually use the EPC method, and my colleagues say that the construction cost for butt welding is higher than that for fillet welding. Is that true?
We haven’t considered the economical option for now; thank you for your guidance
When I was on site, I noticed that the workers were very reluctant to weld a ring around it; they preferred to break it instead. Of course, the skill level of our construction team is relatively low, and their work isn’t very professional
Thank you for the reply; it’s just that the butt welding process has one extra step compared to fillet welding
This is a traditional* habitual issue that is not easy to change.
The team is not organized, its skill level is low, and there’s no sense of discipline; they just do things however is convenient for them – purely by brute force! This is the real reason. Following the standard specifications is perfectly fine!
There’s nothing absolute; I think as long as it looks good, is usable, and meets the standards, it’s fine