Development Of Saw Consumables For 2.25Cr1Mo Steel And Study On Microstructure And Mechanical Properties Of Deposited Metal

Hot wall hydrogenation reactor is the key equipment of modern oil refining and coal liquefaction projects,it runs in high temperature,high pressure and hydrogen for long term operation.After years of development,it has become increasingly mature for our country manufacturing technology of hot wall hydrogenation.The main material including 2.25Cr1 Mo steel plates and forgings has achieved nationalization,while its key matching welding consumables mainly depended on imported product.The mechanical property of homemade 2.25Cr1 Mo steel welding consumables was unsteady especially for big impact toughness fluctuation at low temperature and heavy temper brittleness inclination,which made it hardly meet the requirements of domestic hot wall hydrogenation manufacturing.In this thesis,the matching welding consumables for 2.25Cr1 Mo steel were developed and mechanical property and microstructure of all welded metal have been systematically studied.Results have shown that the all-weld metal has relatively high purity,low diffusible hydrogen content,desired matched relationship between strength and toughness and low temper brittleness susceptibility.The effect of heat input on the microstructure and mechanical property of allweld metal was investigated.Results has shown that the heat input increased,the strength reduced,while the toughness firstly rose and fallen.The welding process window range was between 20 k J/cm~28.29 k J/cm.The effect of PWHT on the microstructure and mechanical property of all-weld metal was investigated.Results has shown that temper parameter P increased,the strength of all-weld metal fell sharply,while the toughness firstly rose and fallen.When P was approximately 20.62,the toughness was best.The desirable P range was between 19.26~20.71.The developed welding consumables for 2.25Cr1 Mo steel “H10Cr2Mo LSJ150L”,its comprehensive property of was almost at the same level with the same type imported products “US-521S/PF-200”,and it has been applied in many key projects and remarkable social and economic benefit has been achieved.