Failure modes
Stainless steel problems — and what to write into the order
Search for a supplier and you get a supplier. Search for the defect you are actually fighting — weld decay, pitting, stress-corrosion cracking — and you get an answer. These pages are written for the second kind of search: what the failure is, why it happens, how it is measured, and the sentence to put in your RFQ so it is enforceable afterwards.
Index
The failure modes
Each page carries the same four parts: what it is, why it happens, how it is measured, and what to specify. None of them promise the defect will never occur.
Sensitization & Weld Decay
Why stainless steel corrodes along the weld: carbide precipitation (sensitization), the low-carbon L grades, and how to specify 304L or 316L to avoid it.
2Pitting & Crevice Corrosion
Why stainless steel pits: chlorides breaking the passive film, the PREN number that predicts it, and how to specify 316L or 2205 for chloride service.
3Stress-Corrosion Cracking
Why austenitic stainless cracks under load in chloride service, and why 2205 duplex resists SCC where 304 and 316L fail. Specification guidance.
4Why 304 Stainless Steel Rusts
Why 304 stainless steel rusts: chloride pitting, iron contamination and heat tint. How pickling, passivation and grade choice prevent it.
Why we publish this
Defects are a specification problem before they are a quality problem
Most stainless disputes are not about bad metal. They are about an order that never said what "acceptable" meant. A grade written as "stainless" is not a requirement; "316L to ASTM A240, pickled and passivated after welding" is. A finish written as "mirror" is not a requirement; a measurable Ra value is.
We would rather tell you what to write into the RFQ than argue about it after the container lands. It is also the cheapest quality control either of us will ever pay for.
The second reason is that a supplier who explains a failure mode is easier to evaluate than one who only lists products. If you are comparing us against a mill that has never mentioned PREN or sensitization, that difference is information.