The Study On Domestic Welding Materials Welding Technology For 12Cr2Mo1R Steel

12Cr2Mo1R steel is a typical kind of chromium molybdenum steel,and is widely used in the manufacture of petrochemical equipment like hydrogenation reactor because of its excellent hydrogen resistance,corrosion resistance and high temperature performance.At present,12Cr2Mo1 R steel has been achieved localization in China,but the matching welding material still mainly relies on imports from abroad.To improve the lagging situation of welding material development in our country,Lanzhou Lanshi Co.Ltd.and Harbin Welding Institute cooperate on the research project to achieve domestic manufacture of 12Cr2Mo1 R steel welding material,of which this subject is a sub project.Through the research of this subject,welding and postwelding heat treatment parameters,which is suitable for domestic 12Cr2Mo1 R steel welding material,are obtained and providing the basic data and theoretical basis for the practical application of domestic 12Cr2Mo1 R steel welding material.In this subject,manual electrode arc welding method and R407 C type manual arc welding electrodes developed by Harbin Welding Institute are adopted to weld the 12Cr2Mo1 R steel plate with different electric current parameters,and then operates post-weld heat treatment under different temperature.On the other hand,the automatic submerged arc welding method is adopted to weld 12Cr2Mo1 R steel plate with different electric current parameters by using the H10Cr2 MoG automatic submerged arc welding wire combined with SJ150 flux,which is developed by Harbin Welding Institute,and post heat treatment after welding under different temperature.The chemical composition analysis,scanning electron microscopy,optical microscopy,X ray diffraction analysis are conducted on the test plate,obtained by two welding methods,and the mechanical properties are analyzed through lateral bending test,step cooling test,impact test,microhardness test and endurance test.Through the analysis of tissues and structure,it can be concluded that the weld test plate matching the favorable formation of orthogonal cross joints can meet the technical requirements of the chemical composition of the welded joint.All weld and the parent metal are consisting of a large amount of ferrite and a small amount of carbide;there are no columnar of all welds which is similar to the parent material.The parent material is composed of flaky ferrite and a small amount of granular carbide,while the ferrite in the weld mostly is flake ferrite and a small part is massive ferrite(ferrite is polygonal on 2D section).Furthermore,the size of the flake ferrite in the weld is larger than that of the base metal and the granular carbide is much more than that of the base metal.Pores,cracks and other defects were not found in all joints obtained by adopting suitable process parameters which will lead a good weld.The mechanical properties analysis shows that the bending properties and microhardness of all joints obtained by well formed welding process parameters complies with the relevant technical requirements.The impact toughness of joint achieved by using the manual electrode arc welding method,R407 C type electrode,210 A welding current,690 ? heat treatment temperature after welding is favorable;VTr54+X×?VTr54=-42.5? is in accordance with the technical requirements;endurance test results are qualified.The impact toughness of joint obtained by using the automatic submerged arc welding process,H10Cr2 MoG welding wire with SJ150 solder joints toughness,550 A welding current,690? heat treatment temperature after welding is favorable;VTr54+X×?VTr54=-22 ? is in accordance with the technical requirements;endurance test results are qualified.For 12Cr2Mo1 R steel,using R407 C type manual arc welding electrode developed by Harbin Welding Institute,the welding parameters of the manual electrode arc welding which meets the actual requirements are: 210 A welding current,22~26V welding voltage,150 + 5mm/min welding speed,heat treatment at 690?× 8h after welding.Using the H10Cr2 Mo G automatic submerged arc welding wire developed by Harbin Welding Institute accompanied with flux SJ150,the welding parameters that meet the actual requirements of the manual arc welding process are: 550 A welding current,30~32V welding voltage,welding speed of 350±17mm/min,heat treatment at 690?× 8h after welding.