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Old 02-01-2021, 09:41 PM
Metlmodr Metlmodr is offline
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Join Date: Nov 2009
Location: Adelaide South Australia
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Default welding 430

Weldability

It is difficult to make a sound structural weld in grade 430 by fusion techniques. The limited phase change at higher temperatures gives coarse ferrite grains with grain boundary martensite films in the HAZ. Precipitation of carbides during cooling also leads to sensitisation. Welds are both brittle and have lowered corrosion resistance. Post weld heat treatment is able to achieve tough, corrosion resistant welds, but the cost may outweigh the cost of using an austenitic grade. The grade is not used for structures.
Grade 430 can be joined by spot, seam, and induction welding. Grade 430Ti gives better toughness and corrosion resistance in the welded zone. However, the surface appearance of 430Ti is inferior to 430 due to the presence of particles containing titanium, which intersect the surface.
Grade 309 filler metal is normally used for fusion welding. It is pre-qualified in AS1554.6:1994 for welding grade 430 to itself, carbon steels and most stainless steels except the duplex grades.
Similar curves apply for many different corrosion situations. Grade 430 has slightly lower chromium content than austenitic grade 304, giving inferior corrosion resistance.
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