10-15-2018, 12:50 PM
Stan's concern about strength variations can be at least partly satisfied by doing a hardness test. Hardness and tensile strength of steel are linked.
"Mild" steel only needs a minimum tensile strength. I once saw a set of predictive calculations get invalidated because the vendor used steel that met the minimum strength, but was actually about 50% greater than the nominal strength. We discovered this only by post-mortem trouble shooting. I knew to ask the question because I had seen the problem in copper plates. BTW, a colleague had the insight to ask that earlier question so I learned from him!
The good news is that, by ensuring the test panels are cut from the same plate, comparative tests like the one being done will likely be OK.
If the added security of knowing hardness variations between the plates makes a difference, local machine shops are likely to have testers on site. Testing labs may also be able to do on-site or in-house tests too for a somewhat higher fee. Portable, even pocket-size, testers are available too.
"Mild" steel only needs a minimum tensile strength. I once saw a set of predictive calculations get invalidated because the vendor used steel that met the minimum strength, but was actually about 50% greater than the nominal strength. We discovered this only by post-mortem trouble shooting. I knew to ask the question because I had seen the problem in copper plates. BTW, a colleague had the insight to ask that earlier question so I learned from him!
The good news is that, by ensuring the test panels are cut from the same plate, comparative tests like the one being done will likely be OK.
If the added security of knowing hardness variations between the plates makes a difference, local machine shops are likely to have testers on site. Testing labs may also be able to do on-site or in-house tests too for a somewhat higher fee. Portable, even pocket-size, testers are available too.
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"To those who have fought and almost died for it, freedom has a flavor the protected will never know."
-- Author Unknown
"If at first you do succeed, try not to look astonished!" -- Milton Berle