"Marc Heusser" d wrote in
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In article ,
wrote:

Are the sub-contractors qualified to an approved quality assurance
standard?
Do they have an approved inspection and test plan? Who does the quality
control during fabrication?
What method is used to inspect the welding and the purchased steel? It
is
not uncommon to see burned through welds and treated steel that exceeds
hardness specifications (Rockwell or Vickers scale)

Same questions for inhouse production.

Modern quality assurance does rely on producing quality, not testing it
in afterwards.

As you have stated Quality Assurance is intented for Manuals to follow.
Quality Control is the physical control of a product as the inspection and
test plan. Quality control of welding is something else. Surface cracks
are detected by using liquide penetrant or magnaflux. To measure the depth
of a crack or burned trought you need a destructive test.
X rays will not tell you exactly the magnetute of the welding defect. At
the end of the day no Quality Assurance and Control can replace the skill
and craftsmanship of the workers not mention a sound design, specifications
and selection of material.

Anyway - just my thoughts (I have managed precision heavy machinery
fabrication and know have seen different setups - heavy QC and still
difficulties, qualified people with good results but less QC).
Some of the best products we had built were by subcontractors knowing
their business very well.
In doubt I favour welders who are used to producing high quality work,
wherever they are. And make sure they are well paid and proud of their
work.

Marc

PS: Testing of the anchors for mechanical stability can be done, but it
requires quite an effort (both machinery and money).

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