The Φ8 mm~12 mm rod coil of 0. 19~0.24C

1.50~1.70Mn steel 20Mn2 was produced by an 80 t DC  UHP EBT are furnace-ladle furnace(LF)- 150 mm×150 mm concasting- high speed rod rolling mill process at Hangzhou  Steel. During LF refining

the soluble aluminium in steel was controlled between 0.020% and 0.025% with feeding Silicon- calcium wire and argon stiring full period

in concasting the long nozzle was adopted and the over heat of liquid steel  was between 25 ℃ and 35 ℃

therefore the cleanliness of steel was higher that the total oxygen content in steel was between  (22~31)×10-⁶  and the inclusion rating was ≤2.0.With controlling beginring rolling temperature between  950  ℃ and  980 ℃

finishing temperature between 820 ℃ and 860 ℃

and after rolling delay cooling process the grain size of steel was  8~10  class

yield  strength  620~650  MPa

tensile  strength  835~875  MPa

elongation  15%～18%  and  hardness(HB)of hot rolled products 175~195 to meet the requirement of standard and service.