MMA electrode – rutile aluminosilicate flux on high purity 304L core wire giving very low typical carbon level. ‘Low hydrogen’manufacturing technology ensures high resistance to weld metal porosity. ‘Supermet Technology’ gives acid rutile operability combined with controlled silicon content for maximum cracking/corrosion resistance. Designed for ease of use, exceptional weld bead appearance and high weld metal integrity, primarily in the down hand and HV positions; smaller sizes offer all-positional operability. Recovery is about 115% with respect to core wire, 65% with respect to whole electrode.
There are 3 main areas of application: Buffer layers and clad steels: Overlays on CMn, mild steel or low alloy steels and for joining 304L/321 clad plate. Subsequent layers are deposited with an electrode chosen to match the cladding, eg 308L, 347. Dissimilar joints: Tolerance to dilution is exploited in joining stainless types 410, 304L, 321 and 316L to mild and low alloy steels such as stiffeners, brackets and other attachments. Service temperatures above 400°C are normally avoided. It is also used for welding 12%Cr ‘utility ferritics’ such as Cromweld 3CR12, to itself and other steels. Similar metal joints: Wrought and cast steels of 23Cr-12Ni type (eg ASTM 309 and CH8, BS 309S24 and 309C30) can be welded if the service requirement is corrosion resistance below 400°C. However, for high temperature structural service, weld metal with controlled higher carbon and lower ferrite should be used (Thermet 309CF).
AWS A5.4: E309L-17
BS EN 1600: E 23 12 LR 32
BS 2926: 23.12.L.A.R
DIN 8556: E 23 12 LR 23