Investigation On The Effects Of Annealling Process On Magnetic And Mechanical Property Of Elctromagnetic Pure Iron DT4E

Control Rod Drive Mechanism(CRDM)is a power equipment used in the power plant.It is a marching type lifting equipment used for control the reactivity of the reactor through lifting,inserting or keeping at a certain place.It is a key equipment for controlling the reaction rate or emergency stop of the reactors,so it will directly affect the safety of the reactors.The magnetic yoke is the key part in the control rod position component.Safe and steady running of the whole equipment will directly depend on the magnetic and mechanical property of the parts.This is the first time for DT4E to be used as magnetic yoke material,and the present annealing process is hardly meet the technical requirements of the parts.This paper studied the magnetic property and mechanical property of the material DT4E through annealing heat treatment,chemical analysis,tension test,hardness test,quantitative grain size test,metallographic test and test to get the best annealing process so that the magnetic property and mechanical property of CRDM magnetic yoke can be obtained.It was concluded through test that under the same annealing temperature,the magnetic strength will increase while the coercivity will decrease with the annealing time increase;With the same annealing time,the magnetic strength will increase while the coercivity will decrease with the holding temperature increase under 900?;the magnetic strength will decrease and then increase while the coercivity will increase and then decrease with the annealing temperature increase between 900? and 1000?.With the annealing temperature,the tensile strength and hardness will decrease with the annealing time increase;When the annealing temperature is under 900?,the tensile strength and hardness will increase and then decrease with the holding temperature increase between 900? to 1000?,With the same annealing time,the elongation will increase with the annealing temperature increase.With the same annealing time,the elongation will increase with the annealing temperature increase.Through lots of tests and data analysis,the economic elements are considered after the magnetic and mechanical requirements met,the annealing process was improved,the suggested annealing temperature is 850?,and annealing time is 240-300min.