Is Heat Treatment for Metal a Special Process?

[Randy]

Hey Sidney.don't hit people with "out of the box", that'll really mess 'em up

I kinda like "professionals" existing in their own induced state of Tunopia...it leavse more room for me to move around

 

[w_grunfeld]

With all due respect, this is not thinking out of the box, this is bending backwards to prove a personal opinion. Everything in your example are just opinions. May I ask how exactly you determine the required hardness "based on your experience"? How many rails have you designed and installed and monitored for years to arrive at the required hardness?
"I use a simple MAPP (methacetylene propadine) gas torch to harden the metal."
Well this is the exact opposite of professional metal hardening by heat treatment.
For your info the process is done in a furnace with controlled temperaure for a defined number of hours that is dependent on the steelyou start with and the hrdness you want to achieve (this is based on engineering tables , not on anyone's OPINION
With a hand burner the chances of getting the same hardness at 10 points along the rail is same as winning the lottery. And if I may ask , what do you do if you get 10 different hardness values ?.....
You give an example of a process that you perform as a non-process and then go on and state it doesn't need validation. I agree that the way you carry out the process it cannot be validated because a priori each rail hardened this way will have different values...

 

[AndyN]

So, Sidney, how do you feel about the stress risers you introduced by hitting the part with an indentor? I fully agree with Mr. Grunfeld and his analysis of your post. And please, don't ever suggest that we have a hard time thinking out of the box.......simply because someone takes a contrary position to your own.....

 

[Sidney Vianna]

For your info the process is done in a furnace with controlled temperaure for a defined number of hours that is dependent on the steelyou start with and the hrdness you want to achieve (this is based on engineering tables , not on anyone's OPINION

Someone should tell the master sword-smiths making samurai swords for centuries that they need enclosed furnaces with calibrated thermocouples and the profile checked every 3 months or so and engineering tables to achieve the end result. And, golly, they better have records of those validation steps.

I've exhausted my argumentation. I think it is very useful that readers know very clearly where some of the covers (and possibly their employers) stand on this issue.

 

[bobdoering]

Someone should tell the master sword-smiths making samurai swords for centuries that they need enclosed furnaces with calibrated thermocouples and the profile checked every 3 months or so and engineering tables to achieve the end result. And, golly, they better have records of those validation steps.

If we are going there, how about Henry Ford's SPC charts and MSA's?

 

[AndyN]

Someone should tell the master sword-smiths making samurai swords for centuries that they need enclosed furnaces with calibrated thermocouples and the profile checked every 3 months or so and engineering tables to achieve the end result. And, golly, they better have records of those validation steps.

I've exhausted my argumentation. I think it is very useful that readers know very clearly where some of the covers (and possibly their employers) stand on this issue.

The simple fact is that in modern manufacturing volumes, we don't have the luxury of waiting for 20 - 30 years before those chaps learned their trades..... I find it almost ridiculous that you'd compare an artisan's skills to production technology. The 'special process' requirements are there because we no longer have artisans.....

Oh, and in case any Covers need to know - like most of us and our employees we usually post in our personal - not professional - capacity just as you do Sidney!

 

[Sidney Vianna]

The simple fact is that in modern manufacturing volumes, we don't have the luxury of waiting for 20 - 30 years before those chaps learned their trades..... I find it almost ridiculous that you'd compare an artisan's skills to production technology. The 'special process' requirements are there because we no longer have artisans.....

The example I offered for my sliding gate project is an industrial application, albeit low volume. Since you agree with Mr. Grunfeld, you also agree that my example does not constitute a heat treating process, just because it is not done in enclosed, profile verified furnaces.

You keep limiting the discussion to modern manufacturing volume and the like. I don't. ISO 9001 was developed in a open, generic manner by design, so it would accommodate the specifics of the business at hand. There are many unconventional business that use ISO 9001 as a model for their quality management system. While in the majority of cases, heat treatment processes need to be validated, that does not apply in 100% of the cases. That is why the standard leaves it open; that is why we have to determine what are the requirements associated with the product and the process, before we assess if the process needs to be validated or not.

When it comes to ISO 9001 implementation, one size does not fit all.

I think it is extremelly important for us to remember that if I unecessarily impose a process validation requirement onto an organization, I am adding costs to their operation. We should not forget the financial implications of mandating steps which might not be required, nor value-adding, in terms of improving product performance or reliability.

 

[markwebertampa]

the National Aerospace and Defense Contractors Accreditation Program (NADCAP) is an accreditation organization specializing in Special Processes; they definitely define heat treating as one of these. Just Google "NADCAP" if you want more info. They have a glossary of terms that you may fine helpful.

As mentioned by other folks posting here, it depends on how you are using the process, I suppose, but really it is not that hard to validate this process through work instructions, specifications (both of which you can obtain externally from various sources, including oven and hardness testing equipment manufacturers) and qualification of your operators.

The point I am trying to make is it is easier to validate this process than get in a discussion with your auditor on why you didn't. It is my experience that Heat Treating is assumed to be a Special Process by auditors, so just go ahead and validate it.

 

[Sidney Vianna]

the National Aerospace and Defense Contractors Accreditation Program (NADCAP) is an accreditation organization specializing in Special Processes; they definitely define heat treating as one of these. Just Google "NADCAP" if you want more info. They have a glossary of terms that you may fine helpful.

Yes, I am very familiar with NADCAP and it's implications to aerospace & defense organizations as you can tell by this post. But not every organization out there is in the aerospace, automotive, nuclear, etc. supply chains. There are organizations that have an unsophisticated, non-critical product lines that still have to demonstrate compliance with ISO 9001.

The point I am trying to make is it is easier to validate this process than get in a discussion with your auditor on why you didn't. It is my experience that Heat Treating is assumed to be a Special Process by auditors, so just go ahead and validate it.

As someone who works for a certification body, I offer you a different opinion. Because true process validation will add cost to your organization. Accepting unjustified expectations by a third-party auditor is a sure fire way to end up with a dysfunctional quality system. Imagine, for example, if you have a curing process that requires the part to be in the oven at 250 degrees +/- 10, for 45 minutes. You tell the auditor that you use a log to record when the parts went in the oven and the wall clock tells you the elapsed time. If the auditor tells you that you have to calibrate the wall clock, would you accept it?

 

[markwebertampa]

I didn't mean to imply that NADCAP was appropriate for the man who made the original post-just that their website was a good resource.

...still contend that the assumption is HT is a special process by most auditors and customers for that matter. It may be easier to go ahead and validate it as mentioned in my earlier post (work instructions, specifications, personnel qualification).

I am in 100% agreement with you that if a requirement is not applicable and complying will be expensive and non-value added then you should not do it. Exception of course is if it is a customer requirement. I saw a post here the other day which was very astute: "sometimes the only ROI (return on investment) is keeping the customer satisfied"