Manufacturing Method of Special Welding Broom Casts with Excellent Internal Quality

摘要

PURPOSE: A method for manufacturing bloom for use to specific welding wire such as CO2 welding, MIG welding, and MAG welding is provided to restrain the growth of inner-structural pores and crack through proper controlling of continuous-casting conditions of bloom. CONSTITUTION: In a manufacturing method of the bloom comprising the process of (i) receiving a molten steel for welding rod containing C 0.026-0.074wt.%, Si 0.7-0.9wt.%, Mn 1.4-1.6wt.%, P 0.020wt.% or less, S 0.020wt.% or less, Ti 1.6-2.1wt.%, Ni 0.007wt.% or less, a balance of Fe, and other inevitable impurities in a tundish ladle and (ii) carrying out cooling/reduction operation of cast strip after injecting received molten steel in a continuous casting mold, the present method is characterized in that the overheating degree of tundish is controlled in the temperature range of 20 to 25deg.C and the amount of spraying water in the second cooling of strip is controlled within the range of 0.16 to 0.18L/Kg. Further, the reduction depth of the strip is controlled within 2-2.5mm while the overall continuous casting is carried out within the continuous-casting rate of 0.65 to 0.75m/min.