| Oil casing steel as a supporting oil well structure material,once the sleeve during use due to the endoplasmic reason fracture,will have a greater economic losses,steel pipe plant in the process need to conduct a comprehensive inspection of the pipe.The results of analysis of quality problems,the interior of a steel material is often found because larger particles caused by inclusions,so the steel mills use bagasse wash process in the steel production process,the top slag modifier,select the appropriate refining slag Department of deep desulfurization,calcium treatment technology to remove inclusions in steel.This paper analyzes the technology analyzes the Baosteel Group Bayi Iron&Steel Co.,Ltd.?hereinafter referred to as eight steel?120 tons of converter steel production of J55 oil casing in the existing problems,and proposed solutions to those problems.In this paper,the historical performance data through the production control process capability analysis,field residue samples taken and steel samples,measured the oxygen content of the molten steel and tracking production methods,the use of metallurgical analysis equipment analysis of the chemical composition of steel samples,inclusions and total oxygen content Diagnostic Analysis of the problems found.Combined with existing resources,research eight J55 steel grade oil casing steel production process improvement direction,focusing on the composition of the end of the converter control,refining slag system,steel[S]content,[Ca]/[Al]ratio,refining the initial stop temperature control technology starting,suggest improvements,the site of the effective implementation of the measures,the following conclusions:?1?refinery slag CaO:48%?50%,SiO2:5%-8%,Al2O3:26%?30%,CaO/Al2O3 ratio decreased to 1.7 to 1.9,basicity 5?8,desulfurization and inclusion removal effect is obvious,reducing the amount of fluorite;?2?a certain amount of synthetic slag should be used in refining furnace,reducing the use of high-melting active lime to speed up the process of refining slag and slag formation speed;?3?the quantity of the slag involved must be effectively controlled,and the effect of ladle slag modifier should be promoted,so that to ensure plenty time for refining furnace to remove inclusions;?4?by reducing the argon stirring intensity during tapping process,temperature loss was well controlled.5 pit furnace steel production ladle of molten steel temperatures are not less than 1550 ?,and the time for temperature rising in LF refining furnace was shortened;?5?TO content in the molten steel before refining was controlled below 40 × 10-6,TO content in end of refining is reduced to less than 30 × 10-6,with?8-14?× 10-6 of TO content decreased.in addition,TO content in tundish was controlled below 26 × 10-6,with?5?10?× 10-6 decreased compared to that of without process optimization ppm,and the TO content in final material was within 20 × 10-6.?6?class B inclusions in final material was less than 1.5 level,the sum of the inclusions was less than 2.5 level. |
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