Lincolnweld 309/309L description:
Top Features
Designed for joining stainless steel to mild or low alloy steel
Designed to be used primarily with basic fluxes that recover nearly all of the wire chromium in the deposit
Provides good resistance to hot cracking

Typical Applications
For joining carbon or mild alloy steel to austenitic stainless steels
Can also be used on "18-8" steels, since it overmatches the corrosion resistance, if the weldment will not be exposed to temperatures of 538°C to 927°C (1000°F to 1700°F)
ASTM A240 Type 309S