Elevated Tensile Round Robin

[sarahtaylor6]

Hello

I am trying to work out what would be the best material for doing a round robin test on a elevated tensile between 350-500 degrees C. I have never done a round robin before has anyone got any advice on how i would do this?

 

[metengr]

sarahtaylor6;
Are you going to use the "round robin test" to qualify a particular test lab for elevated temperature tensile testing or to qualify specific material for elevated temperature use in service?

Normally, for qualification of a mechanical test laboratory you can audit them and review their procedures and accreditation.

 

[sarahtaylor6]

What i am trying to do is a round robin test on elevated tensile testing on a particular metal (not got a clue what metal to use between 350-450 degrees C) in order that i can say that one particular machine is comparable to other machines that are doing the testing.

 

[EdStainless]

There are rules for setting these up. The number of samples, test points, labs and such all factor in. I believe that there is an ASTM spec that covers the rules, since they require it for all new test method specs. Check Vol. 3.01, the test set up may be in an appendix to one of the test specs.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[TVP]

Sarah,

Start by reviewing ASTM E 8 or E 8M (standard for tensile testing). You will see that there are a number of other ASTM standards related to force verification of testing machines (ASTM E 4), verification of extensometers (ASTM E 83), and for conducting an interlaboratory study (ASTM E 691). You can obtain these standards directly from ASTM (

http://www.astm.org)

or from a licensed vendor such as IHS (

http://www.ihs.com).

With regards to the appropriate material, why don't you pick the one grade that is generating the requirement for elevated temperature testing at 350-500 C? I presume that you have some internal request or customer demand for verifying mechanical properties of a part within this temperature range?

 

[JamesCKelly]

One material that might suit for testing anywhere from room temperature through 500C would be a variety of 304 stainless (there are several varieties within the "304" designation). 304 is not subject to phase changes at 500C, and it is the most readily available of the stainless grades.

If you will cut specimens from plate, then 304L would be appropriate.

Bar has a slightly different chemistry to maximize machinability. I believe just plain 304 would suit.

You might want to avoid 303 bar, the high sulfur free machining grade, to have slightly more uniform properties.

Whatever metal you pick, if your aim is to check uniformity of testing machines you must have uniform metal. The properties of a given alloy vary from heat lot to heat lot, from bar to plate, and from one producer to another. For that matter, they vary from one plate to another even if it is the same heat lot (identical chemistry). Rolled Alloys is one distributor that can get you metal all from one individual plate, if you wish.

Get yourself a large quantity of your chosen metal from one mill source, certified to be all the same heat lot. Usually one of the metal distributors can help.

If you machine specimens out of plate, be aware that the properties in the mill rolling direction ("with the grain") may be slightly different than transverse to the rolling direction ("across the grain")

If you have further questions, I'll be glad to address them. I log on maybe once a week or so.

 

[consultmet]

Sarataylor6:
Sorry this maybe a little late. As a member of ASTM E 21, we participated in a round robin test program on elevated tensile testing a few years back. Check with ASTM headquarters request RR-E28-1015. I still have a few specimens left, standard high temp. Specimen, shoulders and 0.250 diameter.I believe it was 304.