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Expert learned that stainless steel parts in a carbon steel world are welded to another metal. Success requires attention, not only to chemistry mixtures (metallurgy) (Ferrite Diagrams), but also to mechanical forces before and during welding, as well as service loads. (Mechanical Engineering Background) Without full attention to all details, this joint is a candidate for later mechanical failure.

Metal from a steel plant must be formed to be useful to customers. For over 30 years, the expert found forming a common complaint issue with customers. "This coil is different than the last, irrespective of specifications and test results." The expert became very knowledgeable in the deep draw and stretching operations common to stainless steel fabrication. Tests are on coil ends. Forming is internal. Solutions were found in either the metal, in forming techniques or combinations.

Inherent ductility is one of the reasons to select metal over other materials. Stainless alloys can mimic other ferrous metals, being austenitic, ferritic, duplex or martensitic. However, Expert learned over 30 years that there are other options available in austenitic and semi-austenitic stainless alloys that can help to improve product yields. Mechanical behavior is also an important part in all the mechanical preparations before welding.

Expert found pipe and tube welding a frequent complaint issue. He has visited many mills. This process, at its heart, is a full-length evaluation of chemistry, dimensions and mechanical properties. Typically, parameters are selected to maximize productivity but unwittingly put demands on the equilibrium of many other factors. The result is that small variations in metal properties, weld conditions or other important physical factors can result in a "bad" weld. Expert has long years of experience finding the reasons for "bad" and the "robust" conditions needed to avoid such welds.

Expert finds that welding is an optimistic business where an operation lasting seconds is expected to produce properties taking significantly greater time and effort everywhere else. Welding is thermally inefficient. Small variations in efficiency produce localized results deemed "failures". But on a root cause basis, these are just the weld properties that result from some different set of welding conditions. Identifying and controlling the factors that allowed this behavior is the essence of finding the root cause for a weld failure. Expert has many years of lab and field experience. Pipe and tube welds are classic examples.

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He has demonstrated that supposed fatigue failures with actual parts were actually the result of severe test conditions not material deficiencies. Experience had suggested that additional un-cracked samples should be examined. These parts actually contained small crack sites.He has worked closely between tube mills back through mill processing to the melt shop to develop solutions to sporadic problems that had inhibited welding speed. Particular attention is due toward slit edge condition and metallurgical cleanliness. Tube mills also have many mechanical and operational requirements.He has found many examples where small amounts of copper surface contamination have caused cracks in stainless steel. He is experienced in finding the sources of the small but lethal copper sources. He has also detected problems that relate back to seemingly trivial failures to pre-clean material.A visit to a supposedly unusual corrosion site was found at its source to be iron contamination presented in an unusual form, not the potentially severe corrosion condition that had been feared.A review of returned stainless steel pump parts found that the problem was not related to heat affected corrosion as seemed plausible but rather related back to lack of good welding controls.