Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
  • C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires

Definitions

• the invention relates to an agent for treating molten metal in the form of a metal-coated filled wire.
• One goal of metallurgical processes is to set the analysis and temperature of the molten metal in the ladle homogeneously.
• the convective currents in the pan due to density differences are too slow and in practice have to be accelerated by introducing inert purge gases.
• Improved mixing is often carried out by blowing argon or nitrogen through porous soil stones or through lances.
• Pig iron desulphurization not only ensures the pneumatic transport of the fine-grained solids, but also the homogeneous distribution of the additives in the melt.
• DE 41 03 197 A1 describes a process for the rapid cooling of a metallurgical melt with a wire suitable for this purpose, which consists of a metal shell, for example of low-carbon Steel sheet, and a filling consists of granules, described, in which the melt, wire shell and wire filling consist of essentially the same material.
• the introduction of this wire onto the pan base causes the granulate particles to be released rapidly in the lower melting range; however, due to the small particle size of 0.2 to 0.5 mm, the granules melt quickly, limiting the main cooling effect to the bottom of the pan.
• the cooled melt components are only distributed more or less homogeneously with the normal bath movement.
• the distribution of the components of the wire filling in the melt depends exclusively on the thermal bath movement or the vapor pressure of the wire fillers. Since substances with little or no vapor pressure are introduced into the melt with the cored wire injection, there is no additional, distributing gas development in the absence of porous gas purging stones, which is disadvantageous for a number of practical applications.
• DE 22 52 796 describes the use of polyethylene as a solid, ethene-releasing component of a multi-component desulfurization agent for pig iron and Ferro-alloy melts are known which are introduced into the molten bath with the aid of the aforementioned lance method by means of a carrier gas stream.
• the main task of polyethylene in this case is to create reducing conditions in the molten iron.
• the invention has for its object to provide a means of the type mentioned with a wire filling, the special admixtures at the application temperatures release gas and thus force turbulence in the metal bath, which leads to a homogenization of the melt, without the composition of the melt negative influence.
• a wire fill which contains a gas-releasing compound based on an organic polymer in amounts of 0.2 to 20 g per meter of filler wire.
• the agent according to the invention preferably contains polyethylene, polypropylene and / or polystyrene as organic polymers.
• the organic polymer is preferably in granular form.
• the grain size is 0.1 to 10 mm, particularly preferably ⁇ 2.0 mm, enclosed by the cored wire sheath.
• the wire casing consists of a metallic jacket made of steel or iron.
• the wire filling preferably also contains irreplaceable inorganic substances which are introduced as oxides of alkaline earth metals and / or aluminum, oxides and / and nitrides of silicon or as metals or metal oxides of the VIII group of the periodic table of the elements.
• Particularly preferred additives are quick lime, magnesium oxides and lime aluminates.
• a preferred embodiment of the invention Means is a cored wire for iron and steel melts from an iron sheath, which encloses a filling of 0.1 to 10 wt .-% polyethylene and 90 to 99.9 wt .-% filler, such as iron powder.
• the use of one of the aforementioned organic polymers according to the invention provides the necessary gas quantities even when amounts of only 1 to 2% by weight are added to the wire filler.
• a larger or smaller addition of polymers in the cored wire depends on the geometry of the existing pans or the type of use of the cored wire.
• the amounts of carbon and hydrogen introduced by the thermal decomposition of the organic polymers are not critical in the form according to the invention, since the metal melt analysis is not adversely affected by them.
• the released gas quantities increase the turbulence flow of the molten metal and influence the bath movement favorably. Primary or secondary reactions with the other filler additives can be excluded.
• the agent according to the invention is primarily used for homogenizing, refining and briefly cooling molten metals. Iron and steel melts come into question as metal melts.
• the agent according to the invention is also suitable for alloying metal melts by introducing microalloying elements such as titanium, molybdenum, boron and others.
• microalloying elements such as titanium, molybdenum, boron and others.
• these elements or these elements are also provided in the wire filling, releasing compounds under the melting conditions.
• the flux cored wire according to the invention generally has a diameter of approximately 5 to 16 mm, preferably 9 to 13 mm.
• the wall thickness is between 0.1 and 0.8 mm, preferably 0.4 to 0.6 mm.
• the core diameter is accordingly 4.8 to 15.8 mm, preferably 8.2 to 11.8 mm.
• the cored wire can be produced by known methods, e.g. in DE-41 03 197, column 3, lines 49-58 and 64-68, and Figures 2 and 3 are described.
• the use can consist, for example, of simply stirring; by introducing the agent according to the invention in wire form, the batches in question are protected from qualitative devaluation.
• PE polyethylene
• a cored wire with a filling mixture of calcium aluminate refining slag and 3% PE is injected into a melt of high-carbon tool steel in a pan. Strong turbulence evenly distributes the slag particles in the melt in the lower pan area. As a result, the rising liquid particles wash out the finest suspended non-metallic inclusions (aluminum oxide) that collect in the slag.
• the degree of purity can be reproducibly improved from the initial value Ko 60 to Ko ⁇ 10 according to the steel-iron test sheet.
• the agent according to the invention is introduced into a molten steel in the form of iron cored wire with PE addition.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Treatment Of Steel In Its Molten State (AREA)
• Compositions Of Macromolecular Compounds (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6471765

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (13)

Citations (6)

Family Cites Families (6)

• 1992
  • 1992-10-30 DE DE4236727A patent/DE4236727C2/de not_active Expired - Lifetime
• 1993
  • 1993-10-28 US US08/144,683 patent/US5376160A/en not_active Expired - Lifetime
  • 1993-10-29 EP EP93117603A patent/EP0600236A1/fr not_active Withdrawn
  • 1993-10-29 JP JP5271731A patent/JP2956022B2/ja not_active Expired - Fee Related
  • 1993-10-29 KR KR1019930022697A patent/KR940008780A/ko not_active Application Discontinuation

Patent Citations (6)

Also Published As

Similar Documents

Legal Events