# Ideas for Re-Using Plate & Sheet Coupons



## erikmannie (Mar 29, 2022)

I use a lot of pipe welding coupons + rectangular (or square) coupons, almost all of which are carbon steel.

I already have it figured out how to re-use pipe & tubing welding coupons. After welding up the joint, I just chuck it up in the lathe, maybe cut out the HAZ, & make a fresh new pipe or tubing welding coupon.

With plate & sheet, I don’t have any good ideas. Looking at plate, I suppose one would maybe cut out the HAZ, & make a new (grooved) coupon (I do this on a milling machine). The trouble with this idea is that I don’t have a bandsaw or a cold saw, so I would be using a cutoff wheel (on an angle grinder) or an O/A cutting torch. I don’t mind having my coupons contaminated with HAZ or filler material; I cannot afford every coupon to be new material.

With sheet, I think that I would be time and money ahead to just buy new sheet coupons every time. For sheet, I like between .090” and 3/16”, & I pay the LSS to shear them because I don’t have a press brake.

I like 3” X 3” for sheet coupons. There are ways to get your money’s worth out of a bunch of squares: I start with a T-joint. Then I do another T-joint. Flip one T-joint upside down, & there is a lap joint. Do this twice, & you have a butt (or edge or corner) joint to join those together, & so on & so forth. I sure would like to know how I could do something constructive with this at the end other than scrap it. Maybe practice torch cutting & salvage a few good bits?

My main reason for making this post is to see if anybody had any ideas on how I could re-use plate coupons. The plate would probably be 1” thick & be a 6” X 6” square. This is *very* expensive material. I sure would like to buy only 1 or 2 plates, & then use them many, many times.

With my present financial situation combined with the high price of steel, I am not cutting out the HAZ.


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## erikmannie (Mar 29, 2022)

Here is what I would like to use, but I want to make them myself:

plate coupon:









						1" (6" Width) Carbon Steel Plate Coupon Set
					

steel plate, plate coupon, welder coupons, weld test coupons, test plates, backing strip, welder test materials, mill certification, ASME



					wttiweldtestcoupons.com
				




backing strip:









						1/4" Carbon Steel Backing Strip
					

steel plate, steel backing strap, plate coupon, welder coupons, weld test coupons, test plates, backing strip, welder test materials, mill certification



					wttiweldtestcoupons.com


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## erikmannie (Mar 29, 2022)

Here is a drawing of the HAZ:


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## erikmannie (Mar 29, 2022)

In the drawing above, you can imagine milling down the weld bead, cutting the square perpendicular to the old weld joint, & then machining the 2 pieces to get another coupon.


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## erikmannie (Mar 29, 2022)

I have heard that people grind off the backing strips (or “straps”). This guy uses an O/A gouging tip:






I would use a milling machine (I am not bend testing). I plan to re-use the coupon again & again.


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## benmychree (Mar 29, 2022)

How are you testing?  When I was an apprentice, I worked on quite a lot of test coupons for welder tests: bends, reduced section tensile tests and charpy impact tests, which were for the large diameter submerged arc welds on line pipe up to 48" diameter with 1" wall thickness.


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## Aaron_W (Mar 29, 2022)

Get a bandsaw at least a portaband, you will marvel at how you got along without one all this time. My band saws get more work than any other tools in my shop because they get used on pretty much every project.

A 4x6 horizontal is not that big and will quickly pay for itself just helping you reuse that 1" plate, although you may find 5x5 coupons will be easier, 6" will tax the little saw. You could also just by 5" bar stock in varying thicknesses and cut to length. You end up paying a lot to have them cut your stock down. Locally I think it is $4 a cut so the cutting feels can quickly equal the cost of the material. 
To reuse just cut between the welds and reweld until there is no open steel left.

As far as other uses... weight? I can't think of much else that a mass of weld beads would be good for. Maybe use a fly cutter to flatten it all down and start over?


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## erikmannie (Mar 30, 2022)

benmychree said:


> How are you testing?  When I was an apprentice, I worked on quite a lot of test coupons for welder tests: bends, reduced section tensile tests and charpy impact tests, which were for the large diameter submerged arc welds on line pipe up to 48" diameter with 1" wall thickness.


The only testing that I do is visual inspection. When I machine it down, I can see if there are any missed spots.


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## erikmannie (Mar 30, 2022)

Aaron_W said:


> Get a bandsaw at least a portaband, you will marvel at how you got along without one all this time. My band saws get more work than any other tools in my shop because they get used on pretty much every project.
> 
> A 4x6 horizontal is not that big and will quickly pay for itself just helping you reuse that 1" plate, although you may find 5x5 coupons will be easier, 6" will tax the little saw. You could also just by 5" bar stock in varying thicknesses and cut to length. You end up paying a lot to have them cut your stock down. Locally I think it is $4 a cut so the cutting feels can quickly equal the cost of the material.
> To reuse just cut between the welds and reweld until there is no open steel left.
> ...


I definitely need a bandsaw. My local steel yard charges $10/cut.

I cannot afford new steel every time. Like I said, I am not even cutting out the HAZ; as a result, a lot of my welding practice is on welding filler material.

I use an end mill to flatten down the weld bead.


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## Illinoyance (Mar 30, 2022)

On 1" coupons I started using a shaper to remove the backing.  Later I used a mill.  I used a 4x6 saw to cut out the side bend coupons.
I do not see any way to reclaim coupons where bend tests are required.


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## erikmannie (Mar 31, 2022)

In the case of re-using welding coupons many, many times (and not removing the HAZ and/or weld bead), I wonder how much of a difference there is between (1) welding a mixture of fresh base metal, old filler material and HAZ, & (2) welding a fresh coupon.

If somebody can’t (or won’t) spring for fresh material for every coupon, I have to believe that there is still a great deal of (welding practice) value in practicing on re-used material.

In the case of carbon steel, I know that the tensile strength of most filler materials is higher than that of the base material.

Also, there are many additives in filler materials that help the weld bead to wet in, behave nicely, etc. As you know, there is a whole industry behind this.

Practice welding on heterogeneous material, & you probably don’t know where the base material ends, & the HAZ or old weld beads begin, cannot possibly be any kind of advantage (other than the economic advantage, of course!).


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## stupoty (Mar 31, 2022)

erikmannie said:


> I definitely need a bandsaw. My local steel yard charges $10/cut.
> 
> I cannot afford new steel every time. Like I said, I am not even cutting out the HAZ; as a result, a lot of my welding practice is on welding filler material.
> 
> I use an end mill to flatten down the weld bead.



10 dorra ? I take a hacksaw and they only charge £0.50 where I go 

Stu


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