The production process of Ф5.5~15mm wire rod of stainless steel 0Cr13C is 60t medium frequency induction fumace-90t AOD-LF-180mmx180mm billet casting-continuous rolling. The surface “exposed crystal” defect of wire rod of steel 0Cr13C (/%: 0.021C

0.32Si

0.35Mn

0.030P

0.004S

12.10Cr) is analyzed by optical and scanning electron microscope to get the defects take its source at mixed crystal due to (a) large overheating extent of casting liquid and small secondary cooling water rate led to larger dendritic inter-planar spacing of ferrite in casting billet and (b) higher temperature in heating furnace led to abnormal growth of ferrite grains in steel. With the process measures including decreasing overheating extent of liquid in tundish to 30℃ from 50℃

decreasing casting speed of billet to 1.0m/min from original 1.2m/min

improving electromagnetic stirring to 280A-6Hz from original 150A-3Hz

increasing secondary water cooling rate to 0.33L/kg from 0.19L/kg and reducing casting billet heating temperature to 1020℃ from original 1080~1130℃，the surface “exposed crystal” defects of wire rod are avoided.