Inspection of austenitic stainless steel 1
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Inspection of austenitic stainless steel 1: Why is it necessary to measure ferrite? Acceptance criteria? What kind of measuring equipment should be used? What is the quality of domestic equipment, and what are its prices?
Under normal circumstances, in the welding of austenitic stainless steels, it is desirable to have about 5% ferrite in the weld, as this can effectively prevent the occurrence of welding hot cracks. If it is necessary to measure the ferrite content in austenitic stainless steel, it is for the purpose of considering corrosion resistance – that is, the issue of embrittlement caused by the precipitation of σ-phase. A lower ferrite content is preferable; a portable ferrite meter can be used, or samples can be taken for metallographic analysis. As for the standards regarding ferrite content, I have not come across them; generally, they are implemented in accordance with the contract or technical agreement
Ferrite meters generally cost a few thousand yuan
GB-T 1954-2008 Method for determining the ferrite content in welds of chromium-nickel austenitic stainless steels ISO 8249
According to the caster, there is also some ferrite in cast stainless steel CF8