Is Heat Treatment for Metal a Special Process?

[Miner]

Re: Is Heat Treatment a Special Process?

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.

I merged these two threads for continuity.

 

[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 ?

many characterstics measured by using sampling plan, where we can't inspect 100% and may be we have a customer compalints regarding this

all of these process could be special process ?

 

[Umang Vidyarthi]

I am so sorry for this

really i am so sorry

Don't have to feel sorry. My purpose of pointing out was that there was a lot of discussion on the parent thread by esteemed covers, who had invested their valuable time, and any duplication of effort is not value added. Besides, many may not see or opine on the second thread. Miner has solved the problem by merging the two threads.

Apparently you are not satisfied by the opinions given thus far. No prob, covers will try to satisfy all your fresh querries.

I merged these two threads for continuity.

Umang

Nota-bene: May we add a poll to this?

 

[Lexylou]

Good Morning.....Speaking of Special Processes, the company that I am working with is a tool shop that sometimes will do some welding in cavity surfaces. Is this considered a Special Process and what will they need to do in order to meet the ISO 9001:2008 requirement?

 

[Big Jim]

Good Morning.....Speaking of Special Processes, the company that I am working with is a tool shop that sometimes will do some welding in cavity surfaces. Is this considered a Special Process and what will they need to do in order to meet the ISO 9001:2008 requirement?

Welding generally is considered a special process.

The premium (but not always cost effective) answer is to certify the welders.

My concept of what you need to prove is that the welds have been properly applied and will hold up to the conditions they will be subject to. You may be able to find a way to accomplish that without full blown certification. It may entail having the welders perform some test welds on material the same as or very similar to what they are doing for production (scrap may be appropriate) and then determine some in-house testing you can do to confirm that the welds have had proper penetration. That could include something like sawing it apart or bending it with a hammer and vice. This should be repeated from time to time to confirm that the skill is still viable. You can determine the interval. It could be monthly or perhaps every six months, depending on how consistent the welders are and how critical the welds are.

If your production managers understand what they need to accomplish, they may be able to come up with a viable test that can fulfill your validation requirements.

Keep in mind that with welding, it is critical that the weld joint is stronger than the parent metal. If pulled apart, the separation needs to come from the parent metal, not the weld joint. The primary skill needed is for the welder to know how to control the molten puddle.

Let us know what you come up with.

 

[w_grunfeld]

Welding is considered a special process and while Jim focused on the welders certification I'd like to point out that there is also the qualification of the process itself. Depending on the type of weldment, there are variables of the process itself that need to be controlled, such as the electrodes, the current, the gas, times, etc. I would say that you need to develop an internal process specification, picking from standards such as the AWS D1.1,the sections that are relevant for your specific application . The level of inspection required may range from visual (to defined criteria) , through die penetrant, to X ray, all depending on the criticality of the application. A weldment for a pressure vessel or airframe structure is obviuosly a lot more stringent than for a household or other non critical application.

 

[6 axis]

I agree heat treatment is a process.I was given a non conformity by external auditors for not maintaining oven temperature logs,now i have improved my process with clear recording of logs and hardness validation.

 

[Lexylou]

6 Axis, the company that I am working with does Heat Treat but on Non-Critical parts. Do you think an auditor will be looking for a log record book for oven temp for that?

 

[Big Jim]

6 Axis, the company that I am working with does Heat Treat but on Non-Critical parts. Do you think an auditor will be looking for a log record book for oven temp for that?

They certainly could be looking for evidence of validation. Process controls such as oven temperatures as well as oven surveys and oven calibrations are certainly possibilities.

How do you validate your heat treating? If you have never considered it, now is the time.

 

[Lexylou]

This company outsources most of their heat treating. When the part returns the toolmaker does a Rockwell inspection to verify the heat treat was done. The only record that is kept of this inspection is the toolmakers initials and date on the shipper that he has accepted it. Most of their customers do not require anything more than that. This shipper is sent to the customer only when they request it.

But this company also does some of their own heat treating on non-critical parts that they basically do the same Rockwell Inspection but once again no records are maintained for this.

Since this is a tool shop that deals more with Special Processes than I do at the sister company I want to make sure that they are meeting the all the requirements and I am pretty sure that they are not.

They do the exact same thing for welding......

Thanks for your help