309LMo

Typically utilized for buffer layers and overlays on C-Mn, mild steel, or low alloy steels, and for joining 316L clad plates. Subsequent layers are added with an appropriate filler to align with the cladding, such as 316L or 318. Additionally, it functions as a buffer layer before engaging in hardsurfacing with chromium carbide types. Its ability to tolerate dilution is harnessed when joining stainless types 410, 304L, 321, and 316L to mild and low alloy steels, including stiffeners, brackets, and other attachments. Service temperatures exceeding 300°C are generally avoided. For some applications, a more economical alternative like 309L or 307 may be suitable. The high level of alloying and ferrite content allows dilution from a wide range of alloyed and hardenable steels, ensuring crack-free welds. Preheat and interpass temperatures are influenced by the base material hardenability, with no preheat typically required for mild steels, and it can extend up to 250°C for hardenable steels.

23%Cr-13%Ni-2.5%Mo (309Mo) austenitic stainless steel.

Austenite with ferrite normally in the range 10-30FN.

Mainly used under high dilution conditions, particularly dissimilar welds between stainless and CMn steels. There are no comparable base materials.