Abstract: Designed are the geometric dimension s and the chemical composition,and the manufacturing process flow of the small-sized GCr15 bearing-purposed steel tube.And accordingly small batch trial production is conducted.Based on the relevant analysis it is regarded that it is possible to produce the said small-sized bearing-purposed tube with the mandrel mill hot-rolling process;and that the major problem as identified through the the said hot-rolling production is the inner fold defect which,via the judgment is very possibly due to the factors,including the flaws as staying with the CC billet like central porosity or crack,etc.,improper the heating scheme of the circular heating furnace,and the improper process parameters as designed for the piercing mill.According to these three influencing factors,a in-deep study is made,resulting in the solution of the above mentioned inner fold defect problem.