Welding joint form and weld seam form are two different concepts,and achieving the same quality requirements as double-sided welding for pressure pipeline single-sided welding joints is a comprehensive issue,mainly involving nine factors such as welding method,base material category,welding material,welding position,preheating,back gas inflation protection,heat treatment,electrical characteristics,and technical measures,and also related to welder skills.Skilled welders perform welding according to qualified welding process qualifications,strengthen visual inspection(VT)of welds,especially in the processing of welding joint grooves and VT inspection of weld beads,which are important elements to ensure quality.