Changchun welder training school. In Changchun, adults who want to learn electric welding can go to Changchun welder training school, which specializes in teaching electric welding. Changchun, formerly known as Xi Du and Chachong, is a prefecture-level city, provincial capital, sub-provincial city, I-type city and the core city of Harbin-Changzhou urban agglomeration under the jurisdiction of Jilin Province.