Study On J4 Stainless Steel Continuous Casting Flux

J4 stainless steel is a Cr-Mn-Ni stainless steel, which is equivalent to the United States series of AISI200 stainless steel, the applications of J4 stainless steel is large widely.At present, the high-temperature thermal properties of J4 stainless steel are lacked.and its lead difficulties in choosing slag and formulating continuous casting technology draft, there is an urgent need for steel based on the thermal properties of high temperature materials, on-site process on the basis of the corresponding flux suitable for research.Southwest Stainless Steel Co Ltd is the Southwest region's largest private steel company. There are depression and cracks with varying degrees of J4 stainless steel slab surface in the continuous casting production process. This paper studies high-temperature of J4 stainless steel mechanical properties, thermal properties, on-site mold the flow characteristics of molten steel, explore in the mold casting solidification and crack sensitivity of the characteristics and the southwest cast stainless steel continuous casting machines and related parameters of the production process conditions, obtain appropriate corresponding flux, through the study of this article:①This paper studies high temperature properties and thermal properties of the J4 stainless steel through use DIL402C use analyzer of thermal expansion, STA449C simultaneous thermal analyzer and Gleeble-1500D thermal simulation testing machine in domestic first systematically, and the scope of expansion coefficient is 23.8915×10-6 ~ 35.1729×10-6 in decreasing process of .Zero strength temperature is 1400℃. Zero plastic temperature is 1350℃. High temperature brittle zone is relatively widely; J4 slab steel high-temperature brittle zone is 1250℃~ melting point , fragile area 650 ~ 950℃, plastic District for the 950 ~ 1250℃, plastic zone cross-section low shrinkage, crack is sensitive. Stainless steel slab J4 poor mechanical properties of high temperature, thermal properties of complex and changeable, and its solidification contraction meniscus region in uneven heat transfer caused by solidification shrinkage Initial Solidification Shell uneven.②The author simulates the on-site mold flow of steel liquid by fluid FLUENT combination of software, analyses the effect on the flow field and temperature field of molten steel in mold of different nozzle parameters and different sections etc. Combined with high-temperature mechanical properties and thermal properties of steel J4, bring forward requirements and limitations of the main performance indicators of the continuous casting mold flux from these two aspects.③Based on performance testing and process analysis of J4 steel, confirming performance of flux, make flux more targeted. Design slag system of CaO-SiO2-Al2O3-Na2O-F--MgO-MnO in the laboratory to study the influence of component on the melting temperature, viscosity and viscous flow activation energy. And ultimately determine the main performance indicators of the steel continuous casting flux suitable for Southwest J4 stainless: R = 1.10, Tm=1140±5℃,η1300℃=0.28±0.04Pa·s, slag consumption is 0.45kg / tsteel.④The field test shows: the slab cracks fall from 2.4 percent to 0.11 percent, the ratio needs to grinding out seriously of the depression deficiencies declines to 12% from 60%, scarring droping from the 2.3% to 0.10%, which basically meet to the requirements of the enterprise and reach a goal to increase the economic efficiency of enterprises substantially.