Objective To measure the microstructure of laser- welded cast pure titanium by different gap distance. Methods Forty specimens were sectioned and welded at four gap（s 0.00 mm, 0.25 mm, 0.50 mm and 1.00 mm）. Took microhardness test and metallographic examination of welded zone surface. Results There were no difference in microhardness value and metallographic observation between welded specimens. The width of heat - effected zone was different. The smaller grains and needle- like αmartensitic structure were found in the heat- affected zone. Conclusion The effects of the joint gap were not significant.
