We're carbonitriding an 1117 part prior to welding it. We're seeing some occasional porosity issues, and we're wondering if they are related to the nitrogen content of the case hardened area. Is there a "limit" to the nitrogen content that would be considered more weldable than steels that exceed the limit? We use an argon/co2 mix for the shielding gas. Would a mix that includes nitrogen help with the porosity?