Hello, I'm a 4th year welding engineering student and I'm currently in a summer internship at a company that I will leave nameless. I've worked as a welder (generally TIG, or GMAW) on and off for 5 years and hold an Associates in welding and fabrication. The place where I work for is a fortune 500 company and our particular division averages over $10,000,000 in sales a quarter. Strangely enough there's not a single engineer here with any on the job or formal welding experience, and no one with Welding design experience.
I've been tasked with reviewing all weldment prints, correcting errors, designing a more formal welding procedure(s) and creating a design standards document for the engineers. that's quite a task for an intern! However I have the most practical and formal training of welding and welding design of any of the engineers so I'm the most suited for these tasks. I'll be poking my head in here over the next few weeks (I've already been a long time lurker). As I have questions pop up
The first order at hand is a question I couldn't find a reference to in any of my books. When using an assembly print for a multiple component part. Is there a standard for transmitting the sequence of welds. I understand and know about multiple reference lines, in regards to a signle weld. But say I want to apply "weld flange A, before welding to Frame B" how would I go about that on a print. Secondly how would I specify things like Back welding and tack order, we've been having distortion issues and I think some these will help combat it.
Thanks in advance
When I was doing nuclear reactor work, we specified sequence of welds in the weld procedures. They were workbooks. Follow procedure 1, turn pages, follow procedure 2, ect... I am not aware of a way to do it with weld symbols unless you put a drawing note flag in the tail of the weld symbol.
I have fabrication procedures for some of our more intricate assemblies. I have it referenced in the structural notes or under the bill of material. All welders have a fabrication procedure book and can easily locate the procedure number from the drawings. It's a bit of work but pays off in the long run.
the closest thing we have to a welding procedure is paint pen dots on the welding machines for GMAW wire speed and voltage.
I suppose I'll be making references via tails. Some of the sub assembly weldments will have 3-4 steps in terms of build order but I don't think it's anything complex enough to require a build document. Then again our mild steel skeletal frames have close to no welding symbols or assembly instructions. Only way to figure out how to build one is to ask the welders who've been here a number of years. It's hard to even know what a critical tolerance is and what's just general fab. Our plant definately leans more towards the "Shop knowledge" welding design theory as opposed to code based work.
I will work with our welding foreman when making fab procedures. Some are only one page. If you do a lot of the same type of work these will save the company money. You don't have 10 different welders with there own idea of how to fit and weld something best. Also for training new guys.
"It's hard to even know what a critical tolerance is and what's just general fab. Our plant definately leans more towards the "Shop knowledge" welding design theory as opposed to code based work"
That's scary
On larger assemblies that require a specific welding sequence, we use a "weld map". In the tail of the symbol we just put a number and then that number represents its sequence. We put a note on the print under the BOM that states "number listed in weld symbol tail represents sequence to be welded". This also helps our CWI reports that must be supplied with the assemblies so specific welds can be referenced by number in that report.
thanks for the input. I'll be making short assembly documents for the welders on a few of the more complex assemblies that have welds that need a specific order. I assume this would be a good place to put tack order and backwelding information too.
I actually I just got handed a weldment print about 10 minutes ago that has no welding symbols (ha) and notes from 3 different welders stating that there needs to be a weld order (or it causes problems later on due to interference) and they are asking me how long stitches should be.
I added the symbols easily enough and made a reference of the build order. However I'm staring at the stitch length and I haven't a clue, I'm going to pressure my boss to let me buy the D1.3m code. It would really be nice to have a code to reference so I can have some numbers to put to my welding design.
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