Cutting welds for inspection purposes question/discussion

[timgramley]

I am looking to start a conversation with folks out there who are cutting and etching their own welds for production certification.

What cutting method are you using?
Vertical Band Saw, Cold saw, portable band saw, chop saw???

Do you have recommendations for equipment that you are using or have used?
How heavy duty? Brands?

We have always been using a vertical band saw to cut our welds and it's done pretty good for low use but our inspection schedule just got bumped up 3 fold. I am looking to upgrade our equipment to a longer lasting and less maintenance model. Also with the increased schedule, the current owner of the band saw we use, Tooling Dept, is really looking to keep their machine from getting torn up or used as much.

Also, how is everyone mitigating the safety of cutting the welds. We've done pretty good so far with some solid safety rules and guidelines, but I fear that the ramped up use will possibly incur an injury or two.

Thanks.

[aevald]

Hello timgramley, I perform WABO testing at our school facility, it is a community college and we handle the state structural certification testing. Mainly all that we do is cutting and bending of test coupons. We do not do any etching for WABO but we do etching as a part of showing students what the process entails as they go through other parts of the program.

We saw our pieces and have a DoAll C916 horizontal bandsaw to handle this. Our particular model is a fixed head unit and has angle cutting provided through adjustable vises. We have a Fischer Industries hydraulic bender to take care of the bend tests. It is able to switch-out the mandrels to provide for a different bend radius if your work requires such a thing. Neither the saw or the bender would fall into the inexpensive category, I believe the saw is probably around $10,000 or so now and the bender could be in the neighborhood of $10,000 or more too. We also use an Ellis Belt Grinder to handle the surface preparation, if you are etching this is good tool to get your surfaces to the proper smoothness level to perform this function. I think the belt grinder is $1,300 or so. I have got a few pictures to show how we utilize the saw for cutting the coupons, hope they make sense. Also, have a couple of photos of the Fischer coupon bender. Best regards, Allan

[aevald]

Here are some more photos of the bend tester. You may notice that I have lined one edge of the two plates, this is the edge that is placed against the fixed vice on the saw and allows for square cuts and parallel cuts as well. For out testing we take 2 coupons from each plate. You may also notice the "VVVVVVV's" these are for identification of the vertical vs. the overhead coupons to allow us to keep track.

[A_DAB_will_do]

Aevald,

I like the gadget for keeping the jaws of the bandsaw vise parallel. Is that something you bought or made in-house?

To the OP, insofar as saws go, I think the only thing to consider is if heating your weld test pieces is an issue. If you need to keep them cool because you're looking at microstructure, then a bandsaw with coolant or an abrasive saw with coolant are mandatory.

If on the other hand, you're etching just to check macroscopic details like penetration, then you can do most anything you want to cross-section the samples. Torches and plasma cutters aren't very gentle tools, so I'd stay away from these in any case. But an abrasive chop saw can be a cheaper alternative. It has the added benefit of doing some "polishing" of the cut surface for you. But they're noisy, dusty, and take some care to operate.

Aevald has a top shelf horizontal bandsaw. For high volume work I'd spend enough to get a saw with some kind of hydraulic or power feed option. Marvel makes some great vertical bandsaws with power feed, but they're expensive. Ellis would be a good choice. Grizzly sells some decent imported saws that are a nice compromise in terms of quality and price.

[aevald]

Hello A DAB will do, actually that piece is made from some re-purposed machine shop items that I threw together to help with keeping the the vise jaws correctly spaced and in good contact with the part being sawed. They do external/internal threading projects across the way from our shop so I hi-graded a couple for this purpose.

You are definitely right about using the friction cut-off saw for cutting parts that he may want to etch, at least that way it won't take too much more effort to get to the correct smoothness to do some etch work. If my memory serves me correctly he may want to search for the thread that CEP had going on etching, I think that I included just a bit there as well. Best regards, Allan

[burns]

At my shop I have a Marvel vertical bandsaw that I use to cut all of my specimens. At school we have a decent horizontal bandsaw and it works ok. While the AWS codebooks allow for plasma cutting of some specimens I don't cut any specimens using anything but the bandsaw. In general I try to stay away from anything that produces lots of heat for cutting specimens including a chop saw. I use a vertical/horizontal 6x48 belt sander to clean up the edges to be etched. If they need a metallographic inspection, D17.1, I will use a laboratory polisher which is a real pain. I don't have to do that very often and 99% of the time the belt sander is great for polishing the surface and the etch is normally very clean. As far as making the testing/sawing go faster, make use of stops and fixtures to speed up the process. Make them idiot proof. Plate tests and fillet tests are fairly easy to cut up but the pipe to plate specimens in the D17.1 can be a little tricky. Also, make sure that you are using the correct blade TPI and proper feeds/speeds.
Mitigating injuries? As far as I am concerned, if I ever thought that ramping up production weld testing would lead to an injury or two I would seriously consider if I am up to the task of doing the work. Cutting up welds in 2015 is not the same type of work as building the Golden Gate bridge in 1930's, injuries are not acceptable when doing such a mundane task. Make sure your work is firmly clamped and let the saw do the work. While people do get injured using bandsaws, I have seen a kid cut through his thumb bone, I would say that the vast majority of them happen because of a total disregard for any basic training and or safety standards. I would also make some sort of plan for cutting up different types of welds. I understand that the first few can be a little tricky, they aren't perfectly square and true, but a little forethought and ingenuity go a long ways.

[Welder Dave]

Just for bend testing purposes, all I've used was a cutting torch and sometimes a straight edge to guide it.