Research On Welding Process Of Pressure Vessel Head

There are many technical problems such as welding,thermoforming,heat treatment in pressure vessel head manufacturing,which influences the manufacturing quality directly.13 MnNiMoR steel plate as the raw material,experimental studies were deeply conducted to the welding process of the head.Firstly,the weldability of 13 MnNiMoR steel plate was analyzed,determined the welding parameters and welding materials.Secondly,the heat treatment experiments had been done in different positive fire outlet cooling modes and tempering heat preservation time.Finally,the influence of different process parameters on the mechanical properties of 13 MnNiMoR seams was analyzed,obtained the best process parameters and solutions.The results showed that:(1)With H10Mn2 NiMoA welding material,the tensile strength of its molten metal is higher than that of H09 MnNiMoG welding material,and side bending performance also meets the requirements.However,its impact toughness is very poor.Therefore,the welding performance of H09 MnNiMoG welding material is better.(2)Through calculation,the deformation rate of 13 MnNiMoR head when pressing is more than 5%.According to the standard,it is necessary to conduct the recovery performance heat treatment after the hot pressing for the head.Thermoforming temperature is 950 ~ 980 ?,and the temperature of final pressure is not less than 850 ?.(3)The best heat treatment process as follows: the normalizing temperature is 920 ?,and the holding time is 150 min with the water-cooling method,and the tempering temperature is 650 ?,and the holding time is 270 min ~ 325 min.The mechanical properties of the deposited metal is better under water cooling than natural cooling after normalizing.But the temperature of water-cooling is not very important.That is to say,both the middle or the room temperature can be discharged after the normalizing.The tempering heat preservation time is between 270 min and 325 min,while the tensile strength and impact toughness of the deposited metal greatly decreased beyond this time.The experiment results are very helpful to the improvement of 13 MnNiMoR head production technology in the future and have been well received in actual production.At the same time,it will also provide references for other technology research and development.