The purity of nitrogen used in селективная пайка волной typically needs to be above 99.99%. This high level of purity is necessary to effectively reduce the oxygen content, thereby minimizing the oxidation of molten metal and ensuring soldering quality.
However, the specific requirements for nitrogen purity may vary depending on factors such as the materials being soldered and environmental conditions. Therefore, it is recommended to refer to relevant soldering specifications or consult with professionals to determine the nitrogen purity suitable for your specific needs.