The test of welding on the 0.5 mm thick maraging steel plate has been done by electron-beem elliptic scanning at various rates. It has been found that the undercut which formed by electron-beem scanning at constant rate is modified, when the scanning frequency equals to 100 Hz, the solidification structure of weld metal is completely changed from coarse columnar into fine equiaxed, and the strength of weld metal increases and the distributions of Mo, Ti in weld metal reach the same level as that of base metal. The relationships among the scanning frequency, the solidification structure of weld metal, the distributions of Mo, Ti in weld metal and the properties of welded joint are discussed. It is pointed out that there exists a linear relation between the refinement coefficient and the tension strength of welded joint, i.e. σ_(UST) = σ_(NS) + (18-23)η. The results of this work show that there is possibility of cancelling the post-weld heat treatment procedure.
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