The invention relates to a preparation method of a
niobium rod with uniformly crushed
crystal grains, which comprises the following steps: firstly,
casting an
alloy raw material to obtain a cast
ingot, and preheating the cast
ingot to obtain a first blank; then the first blank is subjected to multiple times of axial
forging and first heat treatment, and a second blank is obtained; then carrying out surface treatment on the second blank to remove defects on the surface of the second blank, and carrying out
radial forging on the second blank to obtain a third blank; then, the third blank is subjected to oxidation treatment so that an oxidation film can be generated on the surface of the third blank to protect the third blank, hole pattern rolling is conducted on the third blank with the oxidation film generated multiple times, and a first bar is obtained; secondly, the first bar is subjected to rotary
swaging and
polishing, and a second bar is obtained; and finally, the second bar is subjected to second heat treatment, and a finished bar is obtained. Through multiple times of axial
forging, radial rotary
forging and groove rolling rotary forging, the obtained finished bar is uniform and fine in
grain structure, the grain size GS is 7-9 grade, the elongation is larger than or equal to 40%, and the
hardness (HV / 2.9 N) is smaller than or equal to 60.