Weld Inspection of Assemblies - Agricultural spreaders manufacturer

[Karen]

We manufacture agricultural spreaders for lime and fertilizers. Parts are fabricated (sheet metal) and welded according to customer specifications. We currently do not have any criteria for Weld Inspection. Our lead people bring an experience level to know when a weld is "good" but we want to document some criteria to incorporate into Measurement and Monitoring of Product. We would hope to satisfy the requirement with visual inspection. This is what we have so far.

* No Weld Cracks
* No Cold Lap
* No Undercuts
* No Overlap
* Proper Fusion/Penetration
* Adequate Fillet Size
* Alignment of Parts (per drawing spec)
* Even/Clean Weld

Do we need to be more specific? Do we need to define to some sort of standard regarding fusion and fillet size? We don't need rocket science, but want to be measureable.

Thanks As Usual!

 

[Tom Goetzinger]

Welding is normally defined as a "special process", in that it is only through destructive testing that the quality (strength) of the weld can be determined. For that reason,I would caution use regarding inspection criteria, unless it is the cosmetic aspects that you are concerned with.
I would suggest relying on the skill of your operators as opposed to inspection. We covered special processes in our procedures, indicating that those functions could only be performed by certified operators or operators in-training. Those in-training work under the direction of those certified and are allowed to perform those type of operations at which they have become proficient.

 

[Randy]

I believe there are some ANSI specs governing welding. Also check some professional organizations for accepted criteria.

I used to inspect aircraft welding and you're right farm equipment is not rocket science.

 

[KWZPENG]

You might want to use ANSI/AWS D9.1-90 Standard Sheet Metal Welding Code as a guideline. It includes:
-General Provisions for Arc Welding
-Arc Welding Procedure Qualification
-Qualification of Arc Welders and Arc
Welding Operators
-Arc Welding Workmanship
-Inspection of Arc Welding Work

 

[David Mullins]

When you go to ANSI's site and enter welding, 50 something documents appear. These include:

SS-EN 729-4
Quality requirements for welding - Fusion welding of metallic materials - Part 4: Elementary quality materials $ 28
SS-EN 729-3
Quality requirements for welding - Fusion welding of metallic materials - Part 3: Standard quality requirements $ 40
SS-EN 729-2
Quality requirements for welding - Fusion welding of metallic materials - Part 2: Comprehensive quality requirements $ 40
SS-EN 729-1
Quality requirements for welding - Fusion welding of metallic materials - Part 1: Guidelines for selection and use

Good hunting.

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[gmac]

Without getting too deep into the welding/materials side of things, you could look at having one of your personnel qualified as a visual inspector, as long as your customer isn't expecting non destructive examination at a higher qualification level i.e. magnetic particle or radiography visual inspection to a recognised standard should suffice.

 

[Jase Eyre]

In a recent post on Welding Inspection, Tom Goetzinger replied with the following:

Originally posted by Tom Goetzinger:
Welding is normally defined as a "special process", in that it is only through destructive testing that the quality (strength) of the weld can be determined. For that reason,I would caution use regarding inspection criteria, unless it is the cosmetic aspects that you are concerned with.
I would suggest relying on the skill of your operators as opposed to inspection. We covered special processes in our procedures, indicating that those functions could only be performed by certified operators or operators in-training. Those in-training work under the direction of those certified and are allowed to perform those type of operations at which they have become proficient.

My question is this: Is there such a thing as a "Special Process" in the 2000 revision, or is this a term devised by an individual company? I can find no reference to this concept in the Standard.

In my industry (building design), the outcome of the design process likewise cannot be tested through traditional 'inspection' regimes (short of trying to knock down new buildings), but must rely on the skill of the designers. What implications does this have for compliance? How can we prove we've followed the relevant building standards short of documenting everything with checklists? Or can we rely on the fact that our designers are highly qualified, highly competant professionals?

...Or am I just confusing the issues (probable, given the day I'm having!)?

In fact, I think I'll go and have a lie down...

 

[Tom Goetzinger]

Jase,
This is something our registrar asked us to address. He referenced it to 4.9.g. My impression was that the term "special processes" was quite commonly used to refer to processes which cannot be validated except by destructive testing, but maybe that is a United States thing. You are right that specific term are is not specifically used in the standard.

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Tom Goetzinger

 

[Marc]

For a little more info on special processes see:
http://Elsmar.com/ubb/Forum2/HTML/000019.html

 

[Alan Cotterell]

The normal practice in Australia, for assuring the quality of a weld is to have a 'weld procedure'. Once this has been established test plates are welded and a 'macro' and a 'tensile' test is performed on pieces cut fron the plates. The plates must be of the same material to be used on the job.
A caution - in the early 1960's Melbourne's King Street Bridge cracked and serious damage resulted. The failure was due to heat treated plate (quench and tempered)being used with no change to the weld procedure - low hydrogen electrodes should have been used with pre and post heating.
I believe an engineer committed suicide over this accident, as the production people refused to listen to his advice prior to the incident.
The visual inspection you quoted in the original message will not assure that MIG (metal inert gas) welds are sound. MIG welds are notorious for looking good and having 'lack of fusion'.
Australian Standard 1445.1 is I believe, the standard which relates to welding for structural purposes in Australia. Try www.standards.com.au if you wish to find it. However I am sure the US has good standards in this area.