Is Heat Treatment for Metal a Special Process?

[BradM]

The answer is: It depends. Is the heat treatment done solely for hardening the part? Is the hardening of the metal localized to a specific area of the part? Can you effectively measure the hardness of the area without inducing unacceptable denting onto the part?

If you can answer these 3 questions as "yes", then, this is not a process that needs to be validated since you can effectively "inspect" the characteristics at the end of the process, against the requirements.

Hi all! I know I'm late into the discussion. One always hates Old Sayings. But that does not take away from their legitimacy. Saying, it depends.

Whether heat treat is a special process will depend on several factors including the type of material, the ability to run post checks, redundant checks, etc.

If you are solution heat treating aluminum, it's probably too late to find out there was a temperature problem when a part gives way under stress 10,000 feet in the air.

However, (thanks NADCAP) a Chem Mill process was having to do uniformity surveys, which the owners were strongly objecting. They know their process, and they can tell by the condition of the skin when it comes out if there is a hot spot/ cold spot. Now... would uniformity surveys be helpful? Yes. Did it require validation? No. They could justify the acceptance of the product (depth/deviation of etching) from the final product, and did not need the uniformity survey.

You are heat treating to do something to the product/surface. If the acceptable results of that something can be verified through inspection/testing or some other means, that the validation of the process is optional. If it cannot be conclusively tested, then validation is in the forecast.

 

[arin_23]

Already had Enough of heated arguments!!! now it's time for a

Regards

Arin

 

[blue moon]

Is Heat Treatment a Special Process?

Dear Friends

Now in our factory we make heat treatment for metal to raise the rigidity of metal and after finish the heat treatment process we meausre the rigidity " Hardness" of the metal if we didn't reach the desired value we repeat this process again

Is it will be a special process or not ?

where :

clause 7.5.2 at ISO 9001:2008: Validation of processes for production and service provision The organization shall validate any processes for production and service provision where the resulting output cannot be verified by subsequent monitoring or measurement and "But already we have the device to measure the rigidity " Hardness".

, as a consequence, deficiencies become apparent only after the product is in use or the service has been delivered.


please advice

 

[blue moon]

Re: Is Heat Treatment a Special Process?

My Question focus on

1- if we have a device to check the quality and check the characterstics

2- if we can check error in our factory before using by customer or before deliver to customer


at this case the process will not be special process


because the standard say

clause 7.5.2 at ISO 9001:2008: Validation of processes for production and service provision

The organization shall validate any processes for production and service provision where the resulting output cannot be verified by subsequent monitoring or measurement and, as a consequence, deficiencies become apparent only after the product is in use or the service has been delivered.

 

[somashekar]

Re: Is Heat Treatment a Special Process?

My Question focus on

1- if we have a device to check the quality and check the characterstics

2- if we can check error in our factory before using by customer or before deliver to customer


at this case the process will not be special process


because the standard say

clause 7.5.2 at ISO 9001:2008: Validation of processes for production and service provision

The organization shall validate any processes for production and service provision where the resulting output cannot be verified by subsequent monitoring or measurement and, as a consequence, deficiencies become apparent only after the product is in use or the service has been delivered.

I will argue the other way. Just because you have the instrument, are you measuring the hardness of all the parts, at all the surface of the parts ? If you do this process item by item and then test at various places and average it to find the value meeting requirement, I will agree. However I am sure you cannot do this way. You have the measuring ability to assess and fix the heat treatment parameters by several sample results. Heat treatment is a Special process and you have asked this question earlier also if I am correct. Are you still not convinced ?

 

[Umang Vidyarthi]

Re: Is Heat Treatment a Special Process?

Dear Friends

Now in our factory we make heat treatment for metal to raise the rigidity of metal and after finish the heat treatment process we meausre the rigidity " Hardness" of the metal if we didn't reach the desired value we repeat this process again

Is it will be a special process or not ?

where :

clause 7.5.2 at ISO 9001:2008: Validation of processes for production and service provision The organization shall validate any processes for production and service provision where the resulting output cannot be verified by subsequent monitoring or measurement and "But already we have the device to measure the rigidity " Hardness".

, as a consequence, deficiencies become apparent only after the product is in use or the service has been delivered.

please advice

Heat treatment is a special process, since the resulting output can not be verified by subsequent measuring/monitoring.

BTW it is a replica of your post on Is Heat Treatment for Metal a Special Process? which was discussed here in detail. If you need further discussion, it would be better to resume it on the existing thread.

Umang

Nota-bene: oops! Somashekhar beat me on this by two minutes.

 

[blue moon]

Re: Is Heat Treatment a Special Process?

I will argue the other way. Just because you have the instrument, are you measuring the hardness of all the parts, at all the surface of the parts ? If you do this process item by item and then test at various places and average it to find the value meeting requirement, I will agree. However I am sure you cannot do this way. You have the measuring ability to assess and fix the heat treatment parameters by several sample results. Heat treatment is a Special process and you have asked this question earlier also if I am correct. Are you still not convinced ?

Really last time i can't catch points exacatlly so i hope if you help me step by step on this way

i have one question then i will ask general questions

we also deign Molds and Dies and after manfucaturing of it we validate at customer end

then is the process of design of Molds and dies is special process

 

[blue moon]

Re: Is Heat Treatment a Special Process?

Heat treatment is a special process, since the resulting output can not be verified by subsequent measuring/monitoring.

BTW it is a replica of your post on 8 Aug.2009. which was discussed here in detail. If you need further discussion, it would be better to resume it on the existing thread.

Umang

Nota-bene: oops! Somashekhar beat me on this by two minutes.

I am so sorry for this

really i am so sorry

 

[SteelMaiden]

Re: Is Heat Treatment a Special Process?

It's OK, Tech4. We all make mistakes, so don't worry too much about it. The other thread does give a lot of information, as well as examples of heat treating as a special, or a non-special process. Heat treating is not always a special process, we usually think of it as one, but there are some circumstances that do no qualify. Check out the other thread, and also remember that there is a good search function as well as similar threads listed at the bottom of the page.

 

[Phiobi]

Re: Is Heat Treatment a Special Process?

In my experience all aerospace primes call for HT to be used as a special process. This is in both AS9100 and NADCAP terms.