Solution Annealing
The problem it solves
When austenitic stainless steel sits in a certain temperature band, chromium carbides precipitate at the grain boundaries and take chromium out of the surrounding metal. Those chromium-depleted boundaries are where corrosion then attacks. Welding puts a band of exactly that temperature through the heat-affected zone, which is why welded stainless so often needs this treatment before it goes into service.
Speed on the way down
Dissolving the precipitates is only half of it. If the part cools slowly through the sensitising range they simply form again and nothing has been achieved. The quench has to be quick, which is what makes section thickness and load arrangement worth discussing before the job is booked rather than after.
What we need from you
The grade matters more here than in almost any other treatment: 304, 316, a duplex, a nickel alloy and a precipitation-hardening grade all want different temperatures and different handling. Send the material specification with the enquiry.
Common questions
Is solution annealing the same as annealing?
No. Ordinary annealing softens carbon and alloy steels by cooling slowly. Solution annealing dissolves precipitates in stainless and superalloys and then quenches fast, and slow cooling would defeat it entirely.
Do welded stainless fabrications need it?
Often, yes. Welding sensitises the heat-affected zone, and where the part will meet a corrosive service environment, solution annealing restores the resistance that welding took away.
Which grades do you handle?
The common austenitic grades and duplex and nickel alloys. Send the specification with the enquiry and we will confirm before booking.