CN1320148C - High-manganese steel smelting process and high-manganese steel casting - Google Patents

Abstract

The present invention relates to an alloy steel structure, particularly to a smelting process technology of high-manganese steel, and a high-manganese steel casting cast by the technology. The basic element of the high-manganese steel is Fe, the main elements of the high-manganese steel are 10% to 14% of Mn and 1% to 1.4% of C, and ferromanganese, crushed electrode carbon and steel rods are used as raw materials. The present invention is characterized in that the ferromanganese and a crushed electrode are arranged in a furnace once under the protection of covering agents; the steel rods are arranged on the ferromanganese and the crushed electrode and are melted by high power transmission; molten metal is always protected by the covering agents in the whole melting process, and the liquid surface is not allowed to be stirred.

Description

High-manganese steel smelting process and High Manganese Steel Casting

Technical field

The invention relates to a kind of structural alloy steel particularly the melting technology technology of high mangaenese steel and the High Manganese Steel Casting that uses the cast of this technology.

Background technology

High mangaenese steel series austenite wear resisting steel, its matrix have the high-ductility high tenacity that general material is difficult to reach, and High Manganese Steel Casting is through being often used as the impact-resistant component of machine of some wear-resisting anti-damages.To the traditional technology of high mangaenese steel melting, China Machine Press published in " the casting handbook second fascicle cast steel " book in 1997 comparatively detailed description, and its processing requirement adds roasting red ferromanganese and will fully stir molten steel in the clear back of furnace chargeization; In addition published by Kunming University of Science and Technology and climbed the article " high-manganese steel smelting process is to the influence of inclusion " that mechanism company of steel group collaborates in that " new technology novel process " hot-work of 2003 the 3rd phases is technical, this article emphasizes that alloying ferromanganese should add after pre-deoxidation, the fully preheating of alloying ferromanganese, add in batches, will fully stir after every batch of adding.

Traditional technology can meet the demands substantially to the melting and the casting of normal domestic high mangaenese steel, and civilian High Manganese Steel Casting all is to work in coarse environment, as crusher, crawler belt etc., thereby less demanding to the surface and the latent defect of foundry goods.But in the manufacturing of aviation part, use above-mentioned technology just to be difficult to cast out the requirement that to satisfy the relevant structure iron investment casting of China's Aviation Industry technological standard, there are surperficial recessed defective, slag inclusion and seminess mostly when range estimation and fluoroscopy, can not satisfy the aviation part service requirements of high quality requirement.

Analyze the reason that above-mentioned phenomenon occurs, in the melting of high mangaenese steel, free oxygen and manganese in the molten steel, iron and carbon are in conjunction with generating manganese oxide, ferric oxide and carbon monoxide, carbon dioxide, the gas evolution molten steel, ferric oxide is solubilized in the time of 1420 ℃, the Fe element is by C in the molten steel and reduction that Mn replaces, thereby the oxide compound in the molten steel mostly is a manganese oxide, manganese oxide is that a kind of density is big, decomposition temperature height (about 1650 ℃), the oxidation sludge of easy-clear not, traditional technology requires will fully stir molten steel, will inevitably increase the free oxygen in the molten steel, and cause more manganese oxide slag to form.Well-known is that dregginess in the molten steel is the major reason that influences casting quality, reduces as much as possible therefore that the content of manganese oxide slag is the effective way that improves the High Manganese Steel Casting quality in the molten steel.

Summary of the invention

By analysis to traditional technology, improve the quality of High Manganese Steel Casting, emphasis is to control the formation of slag in the stove and how to get rid of slag in the stove in the melting of high mangaenese steel.Purpose of the present invention just provides a kind of high quality High Manganese Steel Casting that utilizes the novel process of induction furnace melting high mangaenese steel and use this processing method to cast.

The fundamental element of high mangaenese steel is Fe; principal element is Mn (10%-14%) and C (1%-1.4%); usually adopt ferromanganese during melting; broken electrode carbon and rod iron are raw material; it is characterized in that under the protection of insulating covering agent; at first with in ferromanganese and the disposable stove of packing into of broken electrode; and then with rod iron place ferromanganese and and broken electrode on; superpower send electrofusion immediately; molten metal is under the protection of insulating covering agent all the time in the whole melting process; do not allow to stir liquid level; treat that the clear back of whole raw materializations changes insulating covering agent, be warming up to 1500 ℃-1680 ℃ rapidly and add a kind of grain-refining agents, stop to heat and leave standstill the cast High Manganese Steel Casting of coming out of the stove after 2-6 minute.

During the high mangaenese steel melting, also a certain proportion of foundry returns can be arranged in the raw material, the adding of foundry returns is to place together on ferromanganese and the broken electrode with rod iron.

Described insulating covering agent is a kind of carbonate material such as MeCO3, metallic element in this salts substances (Me) is stronger than manganese with the avidity of oxygen, require its metal oxide density little simultaneously, the fusing point height, not wandering under the high temperature, just the oxide slag of Xing Chenging easily floats on the alloy liquid level and is eliminated, and the main component of this insulating covering agent can be magnesiumcarbonate or Quilonum Retard.

Described grain-refining agent is a kind of metallic element, its avidity with oxygen is stronger than manganese, the oxide compound of its formation simultaneously is a kind of high-melting-point particulate of densification, crystallization nuclei that can be a large amount of as the high mangaenese steel alloy, the high mangaenese steel crystal grain that prevents the quiescence in high temperature of invar liquid and cause is thick, influences casting quality.

High-manganese steel smelting process of the present invention; in molten clear process; raw material during 100 ℃-200 ℃ of initial stages of heating up in the stove is that solid is difficult for oxidation basically; and the free oxygen in the raw material at first reduces with the evaporation of damp atmosphere; further rising along with furnace temperature; the alloying ferromanganese and the carbon that are positioned at furnace bottom progressively melt; because molten steel is under the protection of insulating covering agent all the time in fusion process; forbid stirring the destruction liquid level; farthest reduced airborne oxygen and contacted, made that the generation of manganese oxide slag eases down to minimum in the molten steel with molten steel.

So traditional technology only will fully stir molten steel, be because ferromanganese adds in molten steel fusing back, the density of molten steel is little more a lot of than ferromanganese, ferromanganese sinks naturally, and the specific heat capacity of manganese (481.48J/Kg. ℃) may cause the segregation of alloy and manganese metal to freeze greater than specific heat capacity (460.55J/Kg. ℃) burn-off rate of iron slowly, for avoiding segregation and freezing, traditional technology is taked the ferromanganese preheating is burnt in the molten steel red and adding fusing in batches, simultaneously molten steel is fully stirred, make airborne oxygen enter molten steel in a large number and combine the formation manganese oxide slag with manganese metal, finally influence the quality of High Manganese Steel Casting.

High mangaenese steel melting method of the present invention, though ferromanganese time of melting in stove is longer, ferromanganese is under strict and the oxygen isolation, so ferromanganese lacks than existing technology scaling loss on the contrary, the manganese oxide slag of formation is also less; Simultaneously because the ferromanganese that is positioned at furnace bottom and carbon dioxide process carbon electrode at first melted by heat become liquid, position rod iron thereon melts gradually and slips into furnace bottom, and the ferromanganese liquation is pressed to top, is tending towards uniform state, has avoided the even fusion that realizes between each alloying element by stirring.7 stoves have been refined in our congruent melting in the practice, the underproof phenomenon of alloy composition never occurs, a large amount of burning phenomenon of manganese also do not occur.The High Manganese Steel Casting that uses this melting method cast is after Overheating Treatment, the smooth surface of foundry goods, its microstructure is the austenite of homogeneous, unnecessary carbide is dissolved in the austenite fully, its maximum diameter of the slag inclusion of fluoroscopic examination cast(ing) surface and pore is less than 3 millimeters, the quantity of slag inclusion and pore is no more than 3 on 25 square centimeters surface, the distance between the pore is greater than 15 millimeters.

Compared with prior art, invented technology has reduced the formation of manganese oxide slag to greatest extent, has improved the quality of High Manganese Steel Casting greatly, has satisfied the requirement of the relevant structure iron investment casting of China's Aviation Industry technological standard (HB5001-92).

Specific embodiment

Use medium-frequency induction furnace melting high mangaenese steel alloy, main raw material has: carbon steel GB699, specification φ 80mm * 250mm; Ferromanganese GB3795 FeMn84C0.4, lumpiness≤5 * 10 * 30; Fine aluminium GB1196; What insulating covering agent was selected for use is deslagging agent, and main component is a magnesiumcarbonate.

During shove charge; furnace bottom one deck insulating covering agent of packing into; to calculate required ferromanganese (containing scaling loss) and calculate in the form adding stove of required carbon (containing scaling loss) with broken electrode; on ferromanganese and carbon dioxide process carbon electrode, sprinkle one deck insulating covering agent again; then carbon steel rod iron and the vertical jam-packed of foundry returns are inserted on ferromanganese and the broken electrode; superpower send electrofusion immediately; molten metal is under the insulating covering agent protection all the time in the whole melting process; do not allow to destroy easily liquid level; after treating that wholeization of raw material clearly in the stove; the insulating covering agent of metal bath surface is pulled down; simultaneously changing new insulating covering agent rapidly covers; in stove, add the metallic aluminium that accounts for molten metal weight 0.03%～0.08% when furnace temperature is risen to 1600 ℃, have a power failure and leave standstill the cast of coming out of the stove after 4 minutes.

If molten steel injects casting ladle earlier, then in casting ladle, put into 0.01% fine aluminium in advance.The purpose of putting into fine aluminium is to prevent that molten steel from bringing the reaction of airborne oxygen and manganese in ladle-to-ladle process and generating manganese oxide slag.

The High Manganese Steel Casting that uses above-mentioned melting method cast is after Overheating Treatment, the smooth surface of foundry goods, its microstructure is the austenite of homogeneous, unnecessary carbide is dissolved in the austenite fully, and the fluoroscopic examination cast(ing) surface meets the requirement of the relevant structure iron investment casting of China's Aviation Industry technological standard (HB5001-92).

Claims (2)

1; the high mangaenese steel alloy smelting process; main raw material has ferromanganese; carbon; rod iron and insulating covering agent; utilize the induction furnace melting; it is characterized in that under the protection of insulating covering agent; at first with in ferromanganese and the disposable stove of packing into of broken electrode; and then rod iron placed on ferromanganese and the broken electrode; superpower send electrofusion immediately; molten metal is under the protection of insulating covering agent all the time in the whole melting process; do not allow to stir liquid level; treat that the clear back of whole raw materializations changes insulating covering agent, be warming up to 1500 ℃-1680 ℃ rapidly and add a kind of grain-refining agents, stop to heat and leave standstill the cast High Manganese Steel Casting of coming out of the stove after 2-6 minute.

2, the described melting high mangaenese steel of claim 1 alloy technology, the main component that it is characterized in that described insulating covering agent is a carbonate, the metallic element of this salt is stronger than manganese with the avidity of oxygen.