Where the
world gathers for metal finishing
Q&As since 1989




-----

Are hardened steel test panels available?

Hi, I am chief of a surface treatment dept. in an aerospace company. For our periodic testing for chromium and sulphamate nickel, we have to use hardened test panels for hardness, adhesion and porosity testing, since the parts we plate are also hardened (to about 58 HRC) Does anyone have an idea where I can get such test panels? Required material is AISI 4130 or alike. I can only find suppliers of non-hardened material. To make it even more complex, according some specifications, hot rolled steel test panels are required for representing forged parts.

I hope you guys can help me out, because google isn't of much use to me.

Thanks in advance!

John Van Sornsen
head of dept. - Toulouse, France
November 1, 2010

---

Go for non hardened steel sheet ,cut to shape and heat treatment at around 450 to 650 °C ,and you can get your req. hardness. Good luck

Khair Shishani
aircraft maintenance - Al Ain, UAE
November 8, 2010

---

Dear Mr Shishani,

Thank you for your reply. If there isn't a company which sells them, my only option left would be having the panels hardened. I'd rather just buy them somewhere, so I don't have to worry about certification. I have very little heat treatment knowledge.

Another question on my mind regards bend adhesion testing with hardened material. I wonder whether a bend test over a mandrel or till rupture will work out. I expect hardened material to "snap" when bended and pieces of the panel flying around like shrapnel. Anyone experience with that?

Looking forward to your reply.

John

John van Sornsen
- Toulouse, France
November 8, 2010

---

The furnace section of your company can surely harden and "draw" test panels for you. After that, it would require sanding the surface and doing a simple Rockwell C hardness test to assure that it is in the right range.
Next, you are not talking about super hard and the mandrel is of reasonably generous diameter. Catastrophic failure of a test panel is not likely. Work behind a Plexiglas shield if you have serious safety concerns.

James Watts
- Navarre, Florida
November 9, 2010

---

Dear Mr. John,
Why not try almen strips which are used for shotpeening, I believe they have hardness around 50 Rc ,and it is easy to get them.Good luck

Khair Shishani
aircraft maintenance - Al Ain, UAE
November 11, 2010

---

I am not real sure any Nadcap Auditor would ever require hardened samples except definitely for Hydrogen embrittlement testing.

Heat treating involves Quenching, and without fixtures your sheet metal test coupons will become potato chips.

The Almen Test strips work pretty well for DOD-std-16232 [ed. note: replaced by MIL-DTL-16232 [from DLA] ] Manganese Phosphate 1.5 hour salt spray because the surface is much less work hardened on the 45 to 50 HRC surface than on the 95 HRB surface.

Russell Beard
- Harrison Township, Michigan, USA
February 27, 2012