Board logo

URGENT - How to find out grade of ali
bi22le - 29/1/15 at 11:48 AM

I have a serious problem at work and need to solve it. Of course LCB is the second place to look (after google!)

We have a supplier that we suspect is changing the grade of out ali. Is there any quick way to test the grading of ali (cast)

I know what makes ali grades different but we have no chemical or spectroscopy test facilities here.

Thoughts?


tegwin - 29/1/15 at 12:04 PM

I'm guessing youd need a chemical composition analysis.... An electron microscope is what youd be wanting.... I have access to a machine but it's pretty busy and wouldn't be cheap...

I would also consider polishing and etching some samples to look at with an optical microscope as it would give an idea of crystal structure. (Hardening etc)


flak monkey - 29/1/15 at 12:06 PM

No way to find out other than have a sample analysed by a metallurgy lab I'm afraid.


liam.mccaffrey - 29/1/15 at 12:20 PM

X-ray diffraction PMI gun will tell you with high probability, metallurgy lab will for certainty its less expensive than you might think too.


loggyboy - 29/1/15 at 12:27 PM

Will ask the wife, she works for a supplier of XRF analysers, they might be able to give you a 'demo'.


britishtrident - 29/1/15 at 12:43 PM

Could it be a heat treatment issue rather than type of alloy issue? Heat treatment makes a big difference to cast alloys.


leon51274 - 29/1/15 at 12:53 PM

Ask for a certificate of conformity and Test certificate, this should give you the chemical composition.


bi22le - 29/1/15 at 01:09 PM

Thanks for all of the info and offers.

We are currently discussing the matters with our supplier (Chinese manufacturer!) and may go down the route of testing depending on the outcome of these matters.

The product is a medical device and requires strict testing. One of the tests has been running for the last 6 days (200000 repetition test) so there are many things we are testing.

I wont keep you posted for obvious reasons but thanks and I will be in touch if needed.


loggyboy - 29/1/15 at 01:15 PM

If you can get a sample to me I could easily get one of the lads at her work to test it.

[Edited on 29-1-15 by loggyboy]


coozer - 29/1/15 at 01:31 PM

Ask the supplier to send a certificate of conformity detailing the grade and chemical content.
Is your company ts or qs9000 approved? If so the request is mandatory...

If not I'm sure a call to your local university will bring up some options.


balidey - 29/1/15 at 02:10 PM

If the parts are from China, requesting a certificate will mean cock all.
We have a similar problem a few weeks ago with steel items that were heat treated.
Toffee had better strength properties, despite what the certificate said otherwise.


SteveWalker - 29/1/15 at 04:17 PM

quote:
Originally posted by bi22le
We are currently discussing the matters with our supplier (Chinese manufacturer!) and may go down the route of testing depending on the outcome of these matters.

The product is a medical device and requires


When the industry I work in has specific material requirements they will not source any materials from China unless each and every piece is individually tested on receipt. China is well known for substituting cheaper grades or just whatever they've got to hand.

[Edited on 29/1/15 by SteveWalker]


bi22le - 30/1/15 at 12:37 PM

I was not going to update this but thought I would becasue its quite funny amusing

Some back ground first.

- We wanted an item made in billet, they gave us 200 items that were cast.
- We tested the cast items and they failed.
- We asked AGAIN for billet samples
- We tested the billet items, they passed
- They send us 200 items that look cast but passed our tests
- I get onto LCB to see if I can test ali type to see if they have just sent through higher grade cast ali.
- We get a response back saying that they decided to sand blast all of their billet parts (never done this before). Why? To get the oils off during machining and prep for powdercoating.

I know they dip these items prior to spraying. I have been to China and watched them do it. NO MENTION OR SIGNS OF SHOT BLASTING WHEN I WAS THERE.

Never get a product made in China if its needs to be decent.

AGHHHHH!