Excessive interpass temperatures can negatively influence corrosion resistance of austenitic stainless through carbide and intermetallic phase formation. The exact effect will vary through the various stainless steel families. Martensitic stainless steels can be somewhat crack prone if welded without preheat and interpass controls. The higher the carbon, the greater the chance of cracking. Also, the HAZ can be hardened excessively causing other issues.
Dekdee, I had similar thoughts, but also attributed the questions to the number of companies that throw a warm body in to the mix and expect them to control a welding (or other) program without prior experience. It's a sign of the times and there are a lot of "flat earthers" out there who underestimate the importance of good welding and welding programs, you know the ones, managers who just want it done. I've been there more than once over the years and have had to learn with limited knowledge and no help in sight. For SSKlara, there are training courses and reference books available which will help you with many of these questions. There are also online free resources at Miller, Lincoln and ESAB which may prove very useful. If you've been thrown to the wolves, ask questions but also do as much research on your own as you can. Knowing what reference has the answer is as important sometimes as knowing the answer right off the top of your head.
After reading all of ssklara's previous questions, I concur with an earlier reader on a previous thread: This poster does not (yet!) at the present time have the knowledge and skill set to safely and correctly design, review, approve, write, or authorize any weld in any metal under any circumstances.
The OP MUST first obtain the basic training skillset before continuing. And an open on-line forum crossing international borders is NOT the place to get that initial skillset.
Many of this links posted here may not work.
However if google with your querry(if you're specific, then get better results), you'll come up with tons of references.
The basic reason of controlling interpass temperature:-
-austenitic stainless steels-- avoid or control sensitization (i.e preferential seggregation of Cr-Carbide, which causes a loss of corrosion resistance).Also excessively high IPT could coarsen grainsize and deteriorate impact propertises.
-for ferritic stainless steels predominantly for improving the impact strength
-for martensitic stainless steels- to get the maximum amount of martensite.Higher IPT would causse slower cooling thus hindering "formation of martensite in this alloy.
By and large there're tons of texts avaliable, and give a try.
