CN1754631A

CN1754631A - Manufacturing method for roller-shell smelting and casting for aluminium-casted mill

Info

Publication number: CN1754631A
Application number: CN 200410060543
Authority: CN
Inventors: 宋春雨
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-09-27
Filing date: 2004-09-27
Publication date: 2006-04-05
Anticipated expiration: 2024-09-27
Also published as: CN100364678C

Abstract

This invention relates to one aluminum rolling machine melting and forging process method, which Comprises the following steps: adopting electric arc first melting; fine stove for fine melting; vacuum gas removing; forging electrode crump; electroslag into hollow steel ingot; electroslag annealing; electroslag heating and forging; forge annealing and heat processing to get the invention roller forge part. The invention method controls the harmful metal elements of P,S and non-metal mixture to lengthen the use life with Small forge proportion and fire time within three times and steel ingot usage rate more than 45 percent.

Description

The manufacture method that aluminium casting-rolling mill forges with the smelting and the casting of roller shell

Technical field

The invention belongs to metallurgy and forging technology field, is the manufacture method that a kind of aluminium casting-rolling mill forges with the smelting and the casting of roller shell.

Background technology

Aluminium casting roller shell is the vitals of aluminium strip base casting and rolling machine, also is crucial attrition component, and the casting roller mainly is made up of the roller core and the outer field roller shell at middle part, is evenly equipped with many boshes on the roller core, and liberated heat is taken away in the time of can be with the crystallization of aluminium liquid.The roller shell hot jacket has certain tightening force on roller core, not only salable cooling water makes it that seepage not take place, can also avoid and roller core between slip.In strip casting process, the casting roller need bear multiple combined stress, the bending stress of bearing except roll, distorting stress, the surperficial friction stress, because the special operating conditions of roll own, also to bear the thermal shock power of period effects, and when work the corrosion structure stress that produces because of aluminising of roller shell surface, the circumference tension that hot jacket causes during assembling etc.Under so complicated stress resultant effect, the main cause that causes roller shell to lose efficacy is that heat fatigue is split.Especially roller shell is to work under the operating mode of the periodic hurried variation of temperature, and therefore, the thermal fatigue property of roller case material seems even more important, and the quality of thermal fatigue resistance can directly reflect the roller shell height in service life.In addition, harmful element such as the P in the roller case material, S and molten steel degree of purity also are directly to influence the roller shell principal element in service life.

At present both at home and abroad the manufacture method of roller shell adopts the solid steel ingot of arc melting-vacuum drying oven refining-be cast into usually, and steel ingot carried out jumping-up, perforation, reaming and pulling four road forging process, the forging times of this method needs just can finish with four fire usually, and the steel ingot utilization rate is below 30%; Or adopt the producing tubes by squeezing method to carry out reaming to the steel ingot after the application of vacuum, and this method also needs 4～5 fire just can finish, and the steel ingot utilization rate is about 35%, but to the condition of forging equipment and forge frock and require high.

Summary of the invention

The purpose of this invention is to provide and a kind ofly can prolong aluminium casting roller shell service life, reduce manufacturing cost, improve the manufacture method that the aluminium casting-rolling mill of stock utilization and product quality forges with the smelting and the casting of roller shell.

For realizing that the manufacture method that purpose of the present invention is taked is: in the smelting and the casting of roller case material, in the technical process of forging: the roller case material that requires at different quality at first, can adopt electric arc furnaces just to refine, again by the refining furnace refining, then carrying out vacuum outgas handles, be cast as required electrode base and (or directly be cast as refining furnace refining again after the refining just of electrode base or electric arc furnaces behind the electric arc furnace smelting, be cast as the electrode base then), cast hollow electroslag ingot by electroslag remelting again, after annealing, again electroslag ingot is heated and directly carry out reaming, pulling forging process and heat treatment obtain a kind of roller shell forging thus.

The technological process of making roller case material is: and electric arc furnaces just refines+and the refining furnace refining+vacuum degassing furnace degassing → cast electrode base → electroslag becomes hollow electroslag ingot → electroslag ingot annealing → electroslag ingot heats forged → forging annealing operation, and the concrete processing step of each operation is as follows:

One, the first sweetening process step of electric arc furnaces:

A) in the fusion process of roller case material: institute adds batching crop, low P, the S pig iron and high-quality steel scrap, and joining the C amount is 0.7～0.8%, and P, S are less than 0.040%;

B) the melting stage oxygen blast is fluxed, and be rapidly heated the heat of oxidation, and oxidizing temperature is greater than 1580 ℃, and decarburized amount is greater than 0.30%, and terminal point C is controlled at 0.15～0.25%;

C) reach 1600 ℃ when temperature, P skimmed less than 0.006% o'clock, made reducing slag, adopt the reduction of carbon dust white slag method, insert AI0.5kg/t in advance, composition is adjusted Mo by middle limit in the stove, C, Si, Mn, Cr press lower limit control, the white slag tapping, and tapping temperature is controlled at 1600～1620 ℃.

Two, refining furnace refinery practice step:

A) to the logical argon gas of the ladle before tapping, the ladle after the tapping goes to that refining furnace heats, intensification, Argon, sampling, composition complete analysis, add slag charge, deoxidation;

B) trimming is carried out in the constituent analysis after the feedback, C, Si, Mn are adjusted at the upper limit in the specification, Cr, Mo, V are controlled at middle limit, and slag system is controlled at low basicity (about 2.5) scope, and heating-up temperature is to enter the vacuum drying oven processing that outgases about 1650 ℃.

Three, VD vacuum processing technique step:

A) molten steel through the refining of LF stove is further carried out vacuum outgas and handle, when the molten steel composition of refining in the LF stove is suitable, temperature is carried out vacuum outgas and is handled during greater than 1650 ℃, and 15 minutes following retention times of condition of high vacuum degree;

B) abolish and disregard scaling loss after the vacuum and add Ti0.05%, insert AI1kg/t eventually, about 1570 ℃ of the temperature of stealthily substituting directly are cast as the cast electrode base that electroslag furnace uses after the calmness.

Four, casting electroslag cast electrode base

According to the weight of different roller shell forging and the size of crystallizer for electroslag furnace, directly be cast as the circular electrode base by the method for teeming, the tapering of electrode base is 3～15 °, and excision rising head end has the slag part.

Five, electroslag remelting becomes hollow electroslag ingot processing step:

A) electroslag remelting cleaning molten steel utilizes the slag thermal resistance to melt in reflow process and carries out wash heat when being the molten drop shape, improves the clarity of molten steel;

B) electroslag remelting is cast hollow electroslag ingot;

C) the electroslag ingot stress relief annealing is handled; Annealing temperature is about 780 ℃; (different materials is carried out different temperature);

D) electroslag ingot heating; Heating-up temperature is about 1100 ℃.

Six, the Forging Technology step of hollow electroslag ingot:

A) when forging, directly carry out reaming, pulling operation, forge the roller shell forging that becomes to need;

B) roller shell forging annealing in process: 870 ± 20 ℃ of normalizings, 650 ± 20 ℃ are expanded hydrogen annealing.

According to the manufacture method of above-mentioned aluminium casting-rolling mill with the smelting and the casting forging of roller shell, its beneficial effect is: by vacuum refining and electric slag refusion and smelting, element such as the most harmful P, S and the nonmetal foreign material content that adds can be controlled effectively (P, S can reach below 0.01%), and prolonged the service life of roller shell.Directly obtain hollow electroslag ingot simultaneously behind the electroslag remelting, the institutional framework of hollow electroslag ingot is fine and close, forging by reaming, pulling operation improves, can satisfy the instructions for use of roller shell spare, and forging ratio is little, the forging crack tendency is low, forging times can drop in 3 fire, the utilization rate of electroslag ingot can reach more than 45%, improves lumber recovery, saves great amount of cost.Thereby reach the purpose that the roller shell manufacturing cost reduces significantly, product quality is very good.

The specific embodiment

The manufacture method that aluminium casting-rolling mill of the present invention forges with the smelting and the casting of roller shell, adopted cast electrode base, the heavy stove of electroslag to cast hollow electroslag ingot, hollow electroslag ingot is after annealing, directly heating is used for reaming and pulling operation, reduce the thick and punching operation of pier in forging, and improve stock utilization and product quality.

In the present invention, the smelting of roller sleeve steel and casting Forging Technology flow process are as follows:

Electric arc furnaces just refines+and the refining furnace refining+vacuum degassing furnace degassing → cast electrode base → electroslag becomes hollow electroslag ingot → electroslag ingot annealing → electroslag ingot heats forged → forging annealing in process.

Be embodiment now, further specify the technical process of each operation with middle carbon Cr-Mo-V roller shell steel:

Electric arc furnace smelting: in order to improve the metallurgical quality of this steel grade, require electric furnace under the working of a furnace is in shape, could smelt this steel,, require batching to form by crop, low P, the S pig iron and high-quality steel scrap in order to reduce harmful element in the steel.Join C amount 0.7～0.8%, P, S are less than 0.040%, the melting stage oxygen blast is fluxed, heat up the heat of oxidation as early as possible, require oxidizing temperature greater than 1580 degree, decarburized amount is greater than 0.30%, and terminal point C is controlled at 0.15～0.25% and carries out the field trash work of degassing, when 1600 ℃ of temperature, P can skim less than 0.006%, make reducing slag after skimming as early as possible,, adopt the reduction of carbon dust white slag method so that reach and keep good reducing condition, the pre-interior composition of AI0.5kg/t stove of inserting is adjusted Mo by middle limit, C, Si, Mn, Cr press lower limit control, white slag tapping, 1600～1620 ℃ of tapping temperatures.

The refining furnace refining:

Before the electric furnace steel tapping, ladle connects tunger tube and logical argon gas, when electric furnace has gone out steel, ladle is transferred to refining furnace carry out heat temperature raising, and continuation Argon, the composition complete analysis is carried out in sampling simultaneously, adds slag charge after the intensification and carries out deoxidation, carries out trimming after the constituent analysis feedback, C, Si, Mn are adjusted at the upper limit in the specification, Cr, Mo, V are controlled at middle limit, and slag system is controlled at low basicity scope, the processing that outgases of about 1650 ℃ vacuum drying ovens of being allowed for access of heating-up temperature.Because ladle bottom Argon, produce a large amount of bubbles power that produces that constantly floats and stirred molten steel by throwing the gas brick, so not only make the chemical composition and the temperature of molten steel even, simultaneously because the existence of Argon Bubble constantly makes gas in the steel be penetrated in the bubble is pulled away, take in the slag but also adsorb a large amount of foreign material that add, great effect has been played in this purification to molten steel.Argon pressure should determine according to top of the slag boiling situation, the purpose of making low basicity slag is in order to increase FeO activity, quicken the form of deoxidation and control field trash, while slag system good fluidity, the field trash that so more helps in the molten steel is adsorbed to the top of the slag in Argon and tapping process, improve the clarity of molten steel.

VD application of vacuum: in order to guarantee the metallurgical quality of steel grade, molten steel through the refining of LF stove is further carried out vacuum outgas to be handled, when the molten steel composition of refining in the LF stove suitable, temperature is during greater than 1650 ℃, can enter the vacuum station and carry out the vacuum outgas processing, for guaranteeing degassing quality, require 15 minutes following retention times of condition of high vacuum degree.Because molten steel is under the state of negative pressure, the solubility of gas in molten steel and in the slag reduces, being penetrated into the gas that floats in the Argon Bubble reaches capacity in slag behind the state, can be taken away by negative pressure, reached the effect of degassing, the field trash of Argon Bubble absorption is simultaneously also continued to take in the slag, has further purified molten steel.For molten steel fully being outgased and helping obtaining fine-grained steel, disregard scaling loss behind the broken sky and add Ti0.05%, insert AI1kg/t eventually, directly pour into the electrode base that electroslag remelting is used after about 1570 ℃ calmness of the temperature of stealthily substituting.

Electroslag remelting becomes hollow electroslag ingot:

Electroslag remelting further is purified molten steel, and crystalline structure is fine and close more, and helps improving the composition segregation.Because metal electrode utilizes the slag thermal resistance to melt in reflow process and is the molten drop shape and carries out wash heat; the clarity of molten steel is further improved; because molten steel has the protection of slag liquid all the time in process of setting; not only prevent the molten steel secondary oxidation; surface of steel ingot is smooth simultaneously; there are not rimhole, the crackle of electric furnace steel ingot, defective such as scab, fully guaranteed hollow electroslag ingot inherence and surface quality.

The forging of hollow electroslag ingot: because hollow electroslag ingot has obtained inside and outside fine and close institutional framework, when forging, only need pass through reaming,, the pulling operation, can obtain the needed face shaping of roller shell, jumping-up and punching two procedures have been saved, and the required tendency that has ftractureed when showing tremendous enthusiasm time less (generally in 3 fire) have reduced forging that adds of forging ratio little (generally below 2.5) has reduced the consumption of the energy, has reduced cost.

Roller shell forging annealing: through normalizing+expansions hydrogen annealing, can crystal grain thinning, adjust tissue, remove the hydrogen content in the steel, reduce the hydrogen embrittlement phenomenon, for necessary tissue preparation is done in the roller shell heat treatment at rear portion.

Claims

1, the manufacture method that a kind of aluminium casting-rolling mill forges with the smelting and the casting of roller shell, in the technical process that the smelting and the casting of roller case material are forged, adopt electric arc furnaces just to refine, again by the refining furnace refining, then carrying out vacuum outgas handles, be cast as required electrode base and (or directly be cast as refining furnace refining again after the refining just of electrode base or electric arc furnaces behind the electric arc furnace smelting, be cast as the electrode base then), it is characterized in that: with fluid origin electrode base, electroslag remelting is cast hollow electroslag ingot, and electroslag ingot is carried out stress relief annealing handle, to the electroslag ingot heating, in forging, directly carry out reaming then again, the pulling operation is forged the roller shell forging that becomes to need.