Research On Behavior Of Non-metallic Inclusions Of Casting Slab In Process Of Convertor Bearing Steel

Bearings steel have not only high strength and good toughness, but also haveresistances to fatigue and corrosion. At the same time, the weld ability and mach inabilityperformance of the steel must not be worsened by the improvement of the mechanical. Theamounts, dimensions and distributions of nonmetallic inclusions have great impact onbearings steel.By way of tracer addition,system sampling,synthetic analysis, study on theamounts,dimensions and distributions of nonmetallic inclusions during the productionprocess and conditions of BOF—LF—VD—CC bearing steel at the BOF steel makingworkshop of SISCO, it is found that : (1) The total oxygen conteut of slab is 9.3×10^-6with the number of the micro inclusions 2.72/mm²,the conclusion volume 0.31percentum and the macro inclusions 1.5mg /10kg,it is high level in cleanliness. (2)Microscopic oxide inclusions in the steel appear to be global silicate inclusions and singlecalcium inclusions after LF furnace,therefore they become the main inclusions in thesteel of slab. (3) It is demonstrated by analyzing the tracer that the micro inclusions in slabmainly come from the the turdish cover material, secondly mold flux and molten steelcontainer cinders. (4) It is demonstrated by analyzing the tracer that the macro inclusionsin slab mainly come from the mold flux, secondly the turdish cover material and moltensteel container cinders. (5) Unsteady casting plays an important role in the cleanliness ofthe steel. How to improve the cleanliness of steel during unsteady state casting plays acrucial part in the whole quality of bearing steel.By way of mathematics model systemic research the flow actions of steel liquid theblowing AR and in LF,which we can find out the best blowing Ar position and fittingamount of blowing Ar. Through these measures,which can improve the frame of moltensteel container and optimize the flowing state of steel liquid,so we can produce perfecttemperature and ingredient steel liquid for CC process.We put forward lots of rationalization suggestions for reducing the inclusions throughresearching the inclusions distribution rules,causing of formation and influencing factorsin slab by way of analysing the smelt techniques,homologize cinders and casting slab. Atthe same time, these measures will provide a good condititos for reducing the amount ofinclusions.