Study On Continuous Casting Round Billet Solidification And The Quality Of Casting Billet

37Mn5steel is mainly used in the petroleum and chemical industry, whose qualityrequirements are very stringent. Tianjin united special steel company mainly producesthis steel, but which often appears internal crack, center shrinkage, center porosity andshape irregular quality defects. The continuous casting process of secondary coolingwater has important effects on quality of the continuous casting of steel, therefore, it hasgreat significance to study the influence of secondary cooling water and other process onthe billet stress and heat transfer.After making investigation on37Mn5steel problems and low magnification in thelaboratory experiments, it is concluded that: there are four slab quality defects (internalcrack, center shrinkage, center porosity and irregular shaped) exist. The internal defectsare caused by the large zero section water and unreasonable proportion of waterallocation.The methods of secondary cooling boundary processing methods （FCA andMCA） are been compared and their impact on the temperature field. Analysis ofdifferent process parameters such as: crystallizer water, degree of superheat, withdrawalspeed and specific water flow have an effect on the slab surface temperature, the shellthickness and liquid core length. The results showed that: the casting speed greatelyeffects the results. When the casting speed is1.6m/min, and pouring temperature is1526℃, there is temperature decrease and recovery from the mould outlet to the firstperiod. The maximum temperature decrease is91℃and the maximum temperaturerecovery is125℃.The results of thermal mechanical coupling simulation about slab showed that:when the distance from the meniscus is1.01m~2.33m, the slab surface total strainexceeds the critical strain, then the corresponding solidified shell thickness is14mm~25mm. As the radial strain of slab dispaly that total strain is always greater thanthe critical strain from surface into center4mm~6mm, the slab is likely to form cracksunder the skin or in the center.After optimizing of secondary cooling water, the cooling segment water proportionchange into18:28:30:24. The maximum temperature decrease of surface drops from theoriginal91℃to51℃. The maximum recovery drops from125℃to64℃. Optimizedslab surface maximum total strain is0.00721, obviously less than the0.00788which isbefore optimized.Considering the effects of superheat on the surface temperature, the optimizedsecondary cooling water and casting speed are fitted. At last, the reaearch gets thesceondary cooling water meter under different casting speed and superheat.