Complex technology for finishing of metal in an intermediate ladle of a continuous casting machine

The technology ensures high quality ingots according to nonmetal impurities and gases and includes the following:

  • technology for microalloying of metal in a ladle;
  • estimation of hydrodynamics of metal flows in an intermediate ladle;
  • estimation and optimization of arrangement of partitions and blowoff tuyeres (if needed);
  • estimation of argon consumption;
  • estimation of temperature-velocity conditions of casting.

Individual and complex approach ensures maximum efficiency of slag work and possibility to process the whole volume of metal directly before crystallization.

The technology introduction implies manufacture and shipment of all of the necessary associated equipment, guidance on utilizing raw products and materials, development and delivery of technological documentation, determination and inclusion of all of the quantitative and qualitative indicators in a Contract.

 

Given technology results in:

  • increasing the extent of steel desulphuration which ensures obtaining of mass content of sulphur at the rate of not more than 0,010% in finished metal;

  • globularization of sulfide impurities in the mentioned steel by their conversion to hardly deformable during rolling sulfides and oxysulfides of calcium, which causes increase of plasticity and impact strength of finished products;
  • transformation of solid impurities of alumina into liquid (in the presence of the temperature of casting) calcium aluminates, that come to the surface and assimilate with clinker easily, eliminating by this a possibility of overgrowing of openings of casting cups with accumulation of solid impurities of alumina;
  • pollution of metal by impurities not larger than 10 micrometers diminishes by the factor of 2,5-3,5;
  • improvement of mechanical attributes and characteristics of steel: relative stretching increases by the factor of 1,5-2,2; impact strength increases 15-20% in the presence of negative temperatures;
  • rejection of rolled metal according to defects, which are revealed by ultrasonic control, reduces by ?30-40%.

 

 

Advantages of given technology:

  • low capital costs;
  • short period of the technology introduction – around 6-8 months;
  • no need for constructional change of the main equipment;
  • no need to stop production;
  • reduction of prime cost of high-quality steel grades with low content of hydrogen, nitrogen, non-metal impurities (high-quality piped steel grades, deep-drawing steels and others) due to partial or complete rejection of steel vacuumization, due to technological deoxidizing techniques, which enable to increase coefficients of assimilation of expensive materials and energy resources;
  • stabilization of seriality duу to maximal elimination of overgrowing of immersion cups and dosing cups with nonmetal impurities;
  • guarantee of low sulphur content (less than 0,010%) in finished metal;
  • broadening the assortment of manufactures products.

Given practical results show that:

Introduced technology enables to manufacture assorted products on continuous casting machines, the mentioned products greatly surpass the branch standard (OST) requirements according to macrostructure.

Comparison of macrostructure defects for carbonaceous steels

Macrostructure in points

Branch standard (OST) requirements 14-21

Average value of obtained results

Central porosity

≤3

0,7

Axial chemical heterogeneity

≤3

1,2

Liq. Stripes and cracks

≤2

0,7

Border point impurity

≤2

0,7


Comparison of macrostructure defects for alloyed steels

Macrostructure in points

Branch standard (OST) requirements 14-21

Average value of obtained results

Central porosity

≤2

0,2

Axial chemical heterogeneity

≤2

0,85

Liq. Stripes and cracks

≤1

0,66

Border point impurity

≤1

0,625

Introduced technology enables to obtain assorted products after rolling, the mentioned products surpass the API standard requirements according to nonmetal impurities.

Steelmaking

 
English (United Kingdom)Русский (Russian Federation)