CN101289723B

CN101289723B - Novel composite modifier for austenitic manganese steel

Info

Publication number: CN101289723B
Application number: CN2007101007826A
Authority: CN
Inventors: 张国庆; 王仲珏; 章成希; 杨洁; 何义成
Original assignee: TONGLING DAMING FORGING CAST CO Ltd
Current assignee: TONGLING DAMING FORGING CAST CO Ltd
Priority date: 2007-04-19
Filing date: 2007-04-19
Publication date: 2010-12-08
Anticipated expiration: 2027-04-19
Also published as: CN101289723A

Abstract

The invention discloses a novel composite modifier for austenitic manganese steel, comprising rare earth alloy, ferrotitanium, calcium silicon and aluminum, wherein the dosage of the Re-containing rare earth alloy accounts for 0.20-0.25 percent of the weight of molten steel; the dosage of the ferrotitanium accounts for 0.02-0.03 percent of the weight of the molten steel; the dosage of the calciumsilicon accounts for 0.20-0.25 percent of the weight of the molten steel; and the dosage of the aluminum accounts for 0.15-0.20 percent of the weight of the molten steel. Treatment inside a furnace is carried out in the alloying adjustment stage for the composition of the molten steel after ferromanganese is added for the fine adjustment of the manganese content of the molten steel; one third of the rare earth alloy is added to a molten pool, and the aluminum is added before the tapping of the molten steel. Treatment outside the furnace is to add the calcium silicon, two thirds of the rare earth alloy and the ferrotitanium to a steel ladle. The adoption of the Re-Ca-Ti-Al multi-element composite modifier prolongs the effective time of the modification process of the molten steel and guarantees good modification effect.

Description

A kind of compound modifier that is used for manganese steel difficult to understand

Technical field

The present invention relates to a kind of compound modifier that is used for manganese steel difficult to understand.

Background technology

Tradition manganese steel difficult to understand is that the production technique of Austenitic Manganese Steel (Medium Manganese Steel, high mangaenese steel, ultra-high manganese steel) mainly contains two classes: a class is to carry out melting according to traditional melting technology after the basal component of manganese steel difficult to understand is determined, usually do not implement rotten processing, inoculation owing to carry out melting by traditional melting technology, be net distribution with the carbide in the manganese steel as-cast structure difficult to understand of this explained hereafter along crystal boundary, this carbide network is flourishing when carbon content is higher, the net sheet is thicker, causes the fragility of material very big.Secondly the nonmetal inclusion in the molten steel also easily is net distribution usually, these characteristics not only cause the fragility of material under the as cast condition, in process of setting and production process, cause the fracture of foundry goods easily, and in the tough treating processes of water subsequently, often require under higher austenitizing temperature and long soaking time, just can finish the fusion of carbide, reach the purpose that obtains single austenite structure.Because austenitizing temperature increases with soaking time elongated, make crystal grain thick, and the fusion in the position of original distribution of carbides owing to carbide has stayed micro-flaw, and these all are unfavorable for improving the toughness of material, and these all make material cause the inefficacy of part in-service easily easily.

China begins to adopt simple rare earth ferrosilicon to the manganese steel difficult to understand processing of going bad in the later stage seventies, form, the size of rotten back carbide have all taken place to change comparatively significantly, but comparatively inhomogeneous from the distribution of carbide matrix, the form that it is mainly reflected in the skewness even carbide of carbide in matrix is bigger in each local deviation with size; The form of non-metallic inclusion and size have also taken place comparatively significantly to change, but similar with the variation of carbide, its distribution and also be uneven at regional area.

In the last few years, along with the development of national mining metallurgical engineering, the high mangaenese steel spare yearly consumptions such as jaw, ball grinding machine lining board, pulverizer hammer that are used for the cone crusher of the jaw crusher of ore corase grind and fine grinding had reached 1,000,000 tons.This impels people to begin more to pay attention to carrying out useful exploration on the new process of production of high-quality manganese steel difficult to understand, has obtained bigger progress on the material modification to traditional high mangaenese steel, makes manganese steel tissue difficult to understand and performance obtain bigger improving.People notice that more and more the interactively of this variation and composite inoculating is bigger.Chinese patent CN1219103C discloses a kind of manganese steel manufacture method, carrying out composite inoculating with rare earth alloy and vanadium iron when tapping handles, can improve the toughness of manganese steel, its defective is: before rare earth goes bad molten steel is not carried out more efficiently deoxidation and make rare earth metamorphism instability; Though rare earth alloy and vanadium iron have comparatively significantly effect to modification effect owing to do not take in the stove and the outer stage treatment of stove lacks control to the austenitic form of first phase separation; Vanadium iron in recent years the ton valency up to making the cost increase rate bigger more than 150,000 yuan.

Summary of the invention

The purpose of this invention is to provide a kind of compound modifier that is used for manganese steel difficult to understand, in stove, outside the stove, carry out " two step method " and handle and press the order of the living nuclear energy size design stage treatment of the heterogeneous forming core of modified alloy, to strengthen rotten treatment effect, improve and improve the uniform distribution of carbide and nonmetal inclusion.

To achieve these goals, the present invention has adopted following technical scheme: a kind of compound modifier that is used for manganese steel difficult to understand, it is characterized in that described compound modifier comprises rare earth ferrosilicon alloy, ferrotianium, silicocalcium and aluminium, consumption is respectively the rare earth ferrosilicon alloy that contains Re and account for molten steel weight 0.20%～0.25%, ferrotianium that titanium accounts for molten steel weight 0.02%～0.03%, account for the silicocalcium of molten steel weight 0.20%～0.25% and account for the aluminium of molten steel weight 0.15%～0.20%; Described compound modifier divides in the stove and outer two steps of stove add: handling in the stove is to add in the alloying stage of adjusting the molten steel composition, joining day is after adding ferromanganese is finely tuned the manganese content of molten steel, the rare earth ferrosilicon alloy of adding 1/3 in the molten bath adds aluminium before the tapping;

Stove is outer handle be in ladle, add silicocalcium, 2/3 rare earth ferrosilicon alloy and ferrotianium.

Adopt the Re-Ca-Ti-Al compound modifier that molten steel is implemented the classification composite inoculating, this comprises two contents: 1, " two step method " handled.That is, with rare earth alterative respectively in the stove, stove handles outward, like this can refinement primary crystal austenite, also can control the tissue crystals of solidification of molten steel process.2, alterant is pressed the size that component element heterogeneous forming core in molten steel is given birth to nuclear energy, dissolved in molten steel respectively, thereby not only desulfurization, deoxidation effectively, degassing purifies molten steel, and significantly strengthened anti-" decline " ability of rotten tissue.The technological effect that adopts the classification composite inoculating to handle is mainly reflected in:

1, improved the form and the size of carbide in the as-cast structure, the crystal boundary that has reduced carbide distributes, and has increased the intracrystalline distribution, and has reduced the quantity of carbide;

2, changed the form of carbide, made carbide be tending towards block or a shape;

3, obviously reduced the quantity of nonmetal inclusion, and made nonmetal inclusion be a shape distribution;

4, adopt the classification composite inoculating to handle, adopt above-mentioned compound modifier to carry out the classification Combined Processing, because the obvious change of carbide and non-metallic inclusion, the toughness of as-cast structure is increased, and the soaking time of austenitizing is subsequently shortened, the austenitizing holding temperature obtains certain reduction, so not only help preventing the alligatoring of austenite crystal, and obviously weakened obviously because the possibility that the micro-flaw that carbide causes exists makes manganese steel tissue difficult to understand obtain higher toughness;

5, because going bad, compoundization of classification that carry out melting later stage and stokehold make rotten being evenly distributed that is organized on the austenitic matrix.

The invention has the advantages that: adopt Re-Ca-Ti-Al multielement compound modifier to carry out going bad molten steel; What multielement was rotten is a little because alterant element has different separately physical propertys and chemical property, therefore in the process that molten steel goes bad and in the process of setting that in casting mold, carries out of molten steel along with variation of temperature, these complex elements will carry out going bad to molten steel successively in order, thereby prolonged the working lipe of metamorphic process, and the modification effect of each element can be accomplished a kind of clear mutually effect of benefiting.On the other hand alterant is realized " two-step approach " stage treatment in stove, outside the stove, can energy-conservation refinement primary crystal austenite, also can control the tissue crystals of solidification of molten steel process.

Embodiment

Smelting target basal component (%) sees the following form:

Used compound modifier comprises rare earth ferrosilicon alloy, ferrotianium, silicocalcium and aluminium, and consumption is respectively the rare earth ferrosilicon alloy that contains Re and account for molten steel weight 0.20%～0.25%, ferrotianium that titanium accounts for molten steel weight 0.02%～0.03%, account for the silicocalcium of molten steel weight 0.20%～0.25% and account for the aluminium of molten steel weight 0.15%～0.20%.

With the intermediate frequency furnace is example, desired raw material is added melting in the stove, after treating in the molten bath to add ferromanganese and carrying out pre-deoxidation with silico-calcium, add in the following order in the alloying stage: ferromanganese (nitrogenize ferromanganese) → rare earth ferrosilicon alloy, wherein, rare earth ferrosilicon alloy adopts 1# Baotou rare earth ferro-silicon, and add-on is 1/3 of a total amount; Add the aluminium final deoxygenation before the tapping, 1500 ℃～1550 ℃ of tapping temperatures.

Pour silicocalcium with stream during tapping; 1# Baotou rare earth ferro-silicon, the ferrotianium of residue 2/3 are positioned in the bag, treat that molten steel pours processing.1420 ℃～1470 ℃ of teeming temperatures.Molten steel required watered in 5～7 minutes.

The result of use of compound modifier sees the following form:

Can find out from last table: mechanical property still is that wear resisting property all is significantly improved after rotten, Medium Manganese Steel is particularly remarkable, its reason be the Medium Manganese Steel workpiece under working condition except that producing the second phase particle pinning high density dislocation, the strain-induced martensite of certain volume percentage ratio has also appearred having.

Claims

1. compound modifier that is used for manganese steel difficult to understand, it is characterized in that described compound modifier comprises rare earth ferrosilicon alloy, ferrotianium, silicocalcium and aluminium, consumption is respectively the rare earth ferrosilicon alloy that contains Re and account for molten steel weight 0.20%～0.25%, ferrotianium that titanium accounts for molten steel weight 0.02%～0.03%, account for the silicocalcium of molten steel weight 0.20%～0.25% and account for the aluminium of molten steel weight 0.15%～0.20%; Described compound modifier divides in the stove and outer two steps of stove add: handling in the stove is to add in the alloying stage of adjusting the molten steel composition, joining day is after adding ferromanganese is finely tuned the manganese content of molten steel, the rare earth ferrosilicon alloy of adding 1/3 in the molten bath adds aluminium before the tapping;

Stove is outer to be handled is to add silicocalcium, 2/3 rare earth ferrosilicon alloy and ferrotianium in ladle.