| 摘要 |
PURPOSE: A method is provided to produce a non-heat treating type slurry steel pipe in which Brinell hardness of products is guaranteed to 180 or more, hardness difference between upper and lower surfaces of the steel pipe is less, and hardness uniformity of the steel pipe is good. CONSTITUTION: The method for manufacturing a non-heat treating type slurry steel pipe for hardness guarantee comprises the processes of hot finish rolling a hot rolled coil comprising 0.1 to 0.6 wt.% of C, 0.1 to 0.4 wt.% of Si, 1.0 to 2.0 wt.% of Mn, 0.02 wt.% or less of P, 0.005 wt.% or less of S and maximum 0.05 wt.% of Al in the temperature range of 810 to 850 deg.C; and manufacturing the steel pipe by injecting the coiled coil into the pipe making process after coiling the hot finish rolled coil in the temperature range of 540 to 620 deg.C, wherein the slurry steel pipe is manufactured by water cooling the hot rolled steel sheet in the hot finish rolling temperature range of 690 to 730 deg.C after rolling a hot rolled steel sheet comprising 0.1 to 0.6 wt.% of C, 0.1 to 0.4 wt.% of Si, 1.0 to 2.0 wt.% of Mn, 0.02 wt.% or less of P, 0.005 wt.% or less of S, maximum 0.05 wt.% of Al, 0.02 to 0.6 wt.% of Nb, 0.04 to 0.08 wt.% of V, and 0.01 to 0.04 wt.% of Ti, and then making the steel pipe in the temperature range of 400 to 480 deg.C using the water cooled steel sheet.
|
