The following three aspects are discussed:the metallurgical behavior of hydrogen during welding;the oxygen content and the modes of oxide inclusions in weld metal; and the basicity calculation of welding slag.The met...The following three aspects are discussed:the metallurgical behavior of hydrogen during welding;the oxygen content and the modes of oxide inclusions in weld metal; and the basicity calculation of welding slag.The metallurgical behaviors of hydrogen during welding are determined according to the results of measuring the hydrogen contents in welding fume, slag and the weld metal with E4303(ilmenite type) and E5015 (low hydrogen type) electrodes respectively.It is verified that hydrogen exists mostly in welding fume in the form of moisture and that secondly in welding slag.The mechanism of dehydrogenation in MMA welding process is proposed and relevant calculation and experiments have been conducted to verify the course. The total amount of oxygen in weld metal is mainly determined by the amount of oxygen which can be dissociated from various oxides in the molten slag and can be predicted through calculation.The modes of oxide inclusions in weld metal are determined by the structures of the slag.A formula for basicity calculation is proposed which is based on the free energy of the reaction between oxides and the free energy of forming oxide compound. And the basicity of CaF2 is also specified.展开更多
文摘The following three aspects are discussed:the metallurgical behavior of hydrogen during welding;the oxygen content and the modes of oxide inclusions in weld metal; and the basicity calculation of welding slag.The metallurgical behaviors of hydrogen during welding are determined according to the results of measuring the hydrogen contents in welding fume, slag and the weld metal with E4303(ilmenite type) and E5015 (low hydrogen type) electrodes respectively.It is verified that hydrogen exists mostly in welding fume in the form of moisture and that secondly in welding slag.The mechanism of dehydrogenation in MMA welding process is proposed and relevant calculation and experiments have been conducted to verify the course. The total amount of oxygen in weld metal is mainly determined by the amount of oxygen which can be dissociated from various oxides in the molten slag and can be predicted through calculation.The modes of oxide inclusions in weld metal are determined by the structures of the slag.A formula for basicity calculation is proposed which is based on the free energy of the reaction between oxides and the free energy of forming oxide compound. And the basicity of CaF2 is also specified.
