Arcaloy 312-15 electrodes are used for welding carbon and low alloy steels to themselves, similar steels or stainless steels provided the service temperature does not exceed about 700ºF (370ºC). They can tolerate higher carbon levels in the base metal and higher levels of dilution than other stainless steel electrodes. In many cases, no preheat is necessary provided the carbon level of the steel is less than 0.3%. For higher levels of carbon, a preheat to 300ºF (150ºC) is often sufficient to prevent hydrogen cracking. If these welds were made with a carbon or low alloy steel electrode, higher temperature preheats would be necessary. Arcaloy 312-15 electrodes, especially Arcaloy 312-15, are the electrodes of choice to attempt to weld various grades of free-machining steels that do not contain lead. In the welding of free-machining steels special low stress techniques should be used and even so, success cannot be assured. Care must be taken however when applying these electrodes. Insufficient dilution appropriate to the steel involved, high preheat temperatures and heat input over a period of time or PWHT can embrittle the weld metal that can lead to cracking. In a similar manner, the HAZ of high carbon steels can be free of cracking due to the use of these electrodes but can be hard and brittle with a potential for cracking. The high chromium content gives good oxidation resistance at high temperatures provided an embrittled structure can be tolerated. The high chromium content coupled with the duplex structure gives one of the best compositions for corrosion resistance in pulp digesters and allied equipment. For that reason, 312 filler metals are used for cladding in these applications. The basic coating of Arcaloy 312-15 gives the highest resistance to cracking and excellent vertical welding characteristics. It is therefore the choice for field welding.