Study on Double-sided & Double-layered 3-wire Automatic SAW Process for 09MnNiDR Cryogenic Steel Pipe

Elaborated in the article are the main aspects about manufacturing of the 09MnNiDR cryogenic steel pipe, including welding material, welding method, follow-up heat treatment, determination of inspection/testing processes, and the trail production activities, etc.It is regarded that quality of the said low temperature steel pipe depends on such elements as welding material, welding energy, adoption of CHW-S13 weld wire and CHF105DR weld agent, and observation of the principle of taking heat input control as the priority.As a result, the pipe weld seam possesses stable anti-low temperature impact property.Owing to the double-sided and multi-wire SAW process as performed on the JCOE operation line, multi-pass welding of the pipe is realized, and accordingly, grains of the metal are refined, and acicular ferrite structure is developed.Moreover, properties of the weld joint will be improved by means of the follow-up heat treatment of off-furnace air cooling under the conditions as 590~620℃ holding temperature, 60 minutes holding time, and 300℃ furnace outlet temperature.