Study On Microstructure And Property Of Deposited Metal Prepared By Electrode CHR132 And CHR172

In this paper, overlaying process is conducted by shielded metal arc welding process on the 45 steel substrate using electrode CHR132 and CHR172. The analyses on microstructure and micro-hardness of deposited metal are made, which includes following two main parts.The first part is that the analyses on microstructure and microhardness of deposited metal are conducted under the condition of varying welding parameters. The experimental results show that (1) the effect of the alloying elements on the microstructure and the microhardness of deposited metal is significant. (2) The action of the first deposited metal layer diluted by substrate metal is largest, but the action of the second deposited metal layer diluted by substrate metal is smaller, and the effect of the third deposited metal layer diluted by substrate metal is smallest, the property of electrode deposited metal is almost equal to that of electrode metal. (3) If two deposited metal layers are put, and when the average welding speed and arc voltage are constant, with the increase of the welding current, then welding heat input is gradually increased, and the microhardness of CHR132 and CHR172 deposited metal is gradually decreased.The second part is that the analyses on microstructure and microhardness of deposited metal are carried out after the postweld heat treatment is performed using following heat treatment parameters: 400℃×2h, 550℃×2h and 700℃×2h.The experimental results show that (1) compared with as-welded deposited metal, the microstructure of heat treated deposited metal is obviously different. (2) When two deposited metal layers are put, the microhardness of CHR132 and CHR172 deposited metal is gradually decreased with the temperature increase. (3) When three deposited metal layers are put, the highest hardness value is got applying 550℃×2h heat treatment process, next hardness value is obtained for 400℃×2h heat treatment, and the minimum hardness value is got for 700℃×2h heat treatment. However, the hardness values of as-welded deposited metal are higher than that of the heat treated deposited metal.