CN105328168B - Nickel-chrome-molybdenum alloy cast iron composite roll manufacturing process and equipment in a kind of forged steel roll neck - Google Patents

Abstract

The invention discloses nickel-chrome-molybdenum alloy cast iron composite roll Processes and apparatus in a kind of forged steel roll neck, quality of materials percentage：C：3.3~3.8%, Si：0.6~1.2%, Mn：0.4~1.2%, Cr：0.6~1.2%, Mo：0.3~1.0%, Ni：2.0~3.0%, Cu：0.6~1.1%, P：≤ 0.05%, S：≤ 0.O3%, Mg：0.04~0.06%, Ba：1.5~2.5%, Ca：1~2%, RE1.0~2.0%, surplus Fe；It is compound inoculated using rare earth nodularization and Ba, Ca, ferrosilicon, roll mechanical property is improved, roll strength is improved using forged steel roll neck, using sensing heater to integrally heating founding in plug carry out type, Combined water cooling crystallizer is molded, and heater is lifted up forming region directional solidification by lowering or hoisting gear with certain speed, can the compound bed boundary of dynamic control, technique is simple, efficiency high, power consumption is small, and cost is low, composite bed is without component segregation, roll working life length.

Description

Nickel-chrome-molybdenum alloy cast iron composite roll manufacturing process and equipment in a kind of forged steel roll neck

Technical field

The invention belongs to metal-pressed machine technical field, NI-CR-MO alloys are cast in more particularly to a kind of forged steel roll neck Iron composite roll Processes and apparatus, the manufacture of composite roll suitable for Steel-rolling Industry.

Background technology

Roll is described as " mothers of steel ", is metal material is produced plastic deformation in the production of the rolling metals such as steel, aluminium, copper Instrument, be to determine milling train production efficiency and mill bar quality and the important large component of economy, be mill milling can not or Scarce critical piece and most important large consumable part, its consuming cost are about the 5%~15% of Rolling production cost.If The ratio for the factors, then its shared production cost such as the production for considering to bring by roll consumption is shut down, drop is produced and plant maintenance increases Again can be higher.

Milling train is the visual plant in metal-pressed machine production, is the aobvious of one national Iron ＆ Steel Development technical merit of measurement Principal coordinates will.It is the critical component largely consumed in Rolling production and roll is the chief component of milling train, is to determine one The basic guarantee of national rolling technique development level, be a national metal material design, material forming technique, processing and manufacturing and The embodiment directly perceived of the basic industries comprehensive technical levels such as heat treatment.Rolling industry production in, each stocking none be not according to Shaped by the rolling of roll, in other words " no roller is good-for-nothing ", so, the quality of roll and effect are most important.

Roll quality is not only related to Rolling production cost and milling train production operational availability, also largely influences stocking Quality.With the development of steel rolling technology, rolling mill speed and automaticity improve constantly, to the resistance to of roll quality particularly roll Mill property, intensity and toughness etc. propose higher requirement.Roller performance is further improved to adapt to the needs of milling train, realizes steel The energy-saving production of section bar, it is the fresh target that roll development person faces.

China's roll manufacturing industry passes through the development and growth of decades, turns into roll yield big country of the world, roll at present There is very big development in terms of manufacturing technology and material kind.In terms of roll material, from spheroidal graphite cast-iron, alloy infinitely chilled ductile cast iron Acicular constituent spheroidal graphite cast-iron till now, high alloy infinitely chilled ductile cast iron, rich chromium cast iron, hard alloy, semi-high speed steel and High-speed steel etc..It is multiple also to develop into centrifugation from conventional cast single material and press over system casting composite in terms of casting technique Close casting process.Current domestic roll deliverability has reached more than 1,000,000 tons, and design and manufacture ability can reach 120~ 1500000 tons.With China's rolling equipment transformation and constantly introduce advanced milling train from foreign countries, milling train is to automation, continuous Change, heavy-duty direction are developed, and the tissue and performance to roll propose higher requirement.

However, the metallurgical roller rolled steel mean consumption that China voluntarily develops still has larger difference compared with developed countries Away from.Recent statistics from China Steel association, China's steel yield has reached 1,125,570,000 tons within 2014, accounts for global steel production Amount more than 40%, calculated according to the kg/t steel of loss per ton steel roll 1.0~1.2, more than 110~130 ten thousand tons of roll of year consumption, year disappears Consume more than 20,000,000,000 yuan of roll fund.In order to meet being actually needed for Rolling production, China is required for spending a large amount of foreign exchanges every year Import roll, the only high-quality roll of import in 2010 be about more than 3.0 ten thousand ton, and consumption foreign exchange is about more than 200,000,000 dollar.China's roll it is big Amount consumption, causes resource and the huge waste of the energy.In addition, external roll Year's consumption is also above million tons, the market demand Amount is big.No matter so big learies are from the rolling cost of steel rolling mill, or in terms of the energy and resource consumption in China All it is a huge waste, environment and resource is exerted heavy pressures on.Therefore, roll quality is improved, extends roll campaign, no It is only capable of saving a large amount of foreign exchanges, but also substantial amounts of roll material can be saved, develops high-quality long-life roll material and its shaping It technology, can not only meet domestic demand, but also foreign exchange earning can be realized.

To meet requirement of the modern rolling industry to high-performance roll, in recent years, the high property of various new is have developed both at home and abroad Energy roll making technology, wherein the technique developed in terms of casting manufactures combination process mainly has：Centrifugally cast composite roll, Continuously casting (CPC) compound car is shallow, electroslag remelting (ESR) composite roll, combined roll etc..

Centrifugally cast composite roll technique（CF）, it is the method production bimetallic composite roll using centrifugal casting.Mainly It is to produce centrifugal force using rotation, molten metal is poured into the casting mold rotated, using centrifugal force the gold poured into a mould Category liquid gets rid of the outer rim to casting mold from pivot, carries out the solidification ecto-entad order of molten metal, it is tissue to be frozen into outer layer The high abrasion resisting material of densification, the composite roll that internal layer is common material.The flowing of molten metal contribute to the broken of dendritic crystal and Refinement, while the resistance for overcoming intercrystalline " tunnel " carries out feeding, is improved the consistency of casting.In outer sphere molten metal After solidification, casting mold is sling and assembled with bottom and top and rising head sand mold, core and upper lower impressions are filled with gravity-assist pouring, it is real Existing two kinds of materials it is compound.Centrifugal roller casting manufacture composite roll has the advantages of other casting technique does not possess, specifically It is as follows:(1) some parts do not need dead head, effectively improve the service efficiency of molten metal;(2) core need not be used just The casting of annular and empty tubular can be cast out, while the length cast tube different with diameter can also be produced, is had well Production efficiency, production cost be not also high;(3) under the influence of centrifugal force, after molten metal solidification, quality is fine and smooth;(4) with this The skin of the roll of method production has higher wearability, and the toughness material and can of internal layer ensures that roll has higher toughness, With than integral material roll broader practice prospect and higher cost performance.

Although the technique has, equipment is simple, and equipment investment is small, and production efficiency is high, and cost is low, suitable for producing it in enormous quantities Feature.But there is following several deficiencies in the technique：

1）When the roll for manufacturing high alloy material, due to often containing the high alloy of big metric density in material, such as Tungsten, molybdenum, vanadium etc., during centrifugal casting, due to the effect of centrifugal force, the high alloy of these density can be segregated in roller surface, make to roll Roller inner alloy constituent content reduces, and makes tissue and composition uneven so as to deteriorate roller surface layer toughness, reduces skin of the roll Wearability, influence the quality of roll.

2）When the fusing point of core material is higher than the fusing point of cladding material, in the inner surface of the cladding material solidified during cast Produce fused layers.Therefore when core material selects cast steel, it is impossible to obtain good compound interface.

3）The composite roll of the forged steel core with high intensity, high tenacity can not be produced.

Continuous cast outer layer forming process (CPC methods), the technique are that the Nippon Steel Corp of Japan grinds with late 1980s Study carefully exploitation to put into production.CPC methods are to integrate material, technique, equipment, the new and high technology automatically controlled^[10], at present in the world Only Nippon Steel and Hitachi, Ltd is used successfully to industrialized production.Its operation principle is to make roller with forged steel, cast steel or waste or old roll Core, last layer silicon systems glass protection film is applied on its surface, prevents roller core surface oxidation.Compound outer sphere molten metal will be needed to pour into To between vertically arranged roller core and water mold, to make the outer layer high-speed steel of casting be fused completely with roller core, using two sets Electromagnetic induction heater carries out concurrent heating and preheating to molten steel and roller core respectively.The outer sphere molten metal of melting is fusing with roller core Order solidification upwards simultaneously, makes the interface of two kinds of materials reach metallurgical binding.It is by stripping equipment, compound good roll is continuous Ground is extracted out from water mold, until composite roll casting complete.In cohesive process, the appearance of roller core surface is micro- molten, makes roller Core and outer layer high speed steel metal realize firm metallurgical binding, improve bond strength.The high-speed steel roller stock of this method production Tissue and grain size are much thinner than centre spinning method, and carbide even dispersion is distributed, and the life-span is than centrifugal casting roll It is high by 30%.

The formation of binder course affects the decrease speed of roll, also just determines the production efficiency of CPC methods.This method has Following features:1. the outer layer material of roll can select a variety of high alloy materials, core material can use obdurability and rigidity high Steel based material, avoid primary carbie segregation and tissue, composition segregation shortcoming that Centrifugal Cast High Speed Steel Roll occurs；② Molten steel solidifies in water cooling knot product device, and cooling velocity is fast, can obtain tiny, fine and close solidified structure, hot-cracking resistance is good, roll Can be good the features such as;3. consecutive solidification from bottom to top, keep away and exerted oneself shrinkage cavity and the generation of the casting flaw such as loose；4. it can both manufacture New roll, also old roll can be carried out to remanufacture reparation.

The shortcomings that CPC is mainly：1. due to using two sets of induction heating systems, equipment is more complicated, and technical difficulty is big；2. by In using stripping mode, production efficiency is relatively low, and the pure brilliant degree of the steel produced is poor；3. need to carry out molten steel in production process Prolonged insulation, power consumption is big, requires high to tundish refractory material, production cost is high；4. factory building and operator are required It is high.Based on above reason, scope very little is promoted the use of at present, and China has not been put to industrialization production so far.

Liquid pouring of electroslag method（ESSLM）, ESSLM is in E.O. bars electric welding research institute invention of the beginning of the nineties in last century 's.Its production technology is put among a copper water mold by compound forging, casting or used waste and old roller Core, then the slag melted in advance is poured into the gap between roller core and crystallizer, it is powered, leads between crystallizer and roller core Cross molten slag and form electrical circuit, caused heat is by the surface melting of roller core in slag, by melted liquid metal with one Fixed technique is poured into the gap between roller core and crystallizer, and liquid metal floats slag, when passing through slag bath by electroslag essence Refining, at the same by roller core cladding get up and the roller core surface preheated with oneself fuse, solidified under the cooling of crystallizer, formed it is compound Layer.In the process, constantly extracted out by stripping device roller core from crystallizer, while constantly pour into liquid metal, until Untill predetermined length.The material for covering layer can be cast iron, high-speed steel and other metals, and made composite roll both may be used To be used as cold roll, hot roll or Continuous Casting Rolls, casting clad can be carried out to waste or old roll again and is remanufactured.But strictly to control The time of melt cinder temperature and roller core in melt cinder, the fusing that core is excessive is prevented, pollute working lining.

ESSLM technologies allow composite diameter from 100 mm to 1800 mm, even more major diameter billet outer surface.Composite bed The mm of thickness 15~20 to 100 mm, even more greatly.The technique is compared with electroslag remelting process, its efficiency high, and poring rate is 200~800 kg/h, power consumption is close to 800 kWh/t steel^[10]。

When the shortcomings that technique is mainly that molten steel injects crystallizer in batches or continuously in recombination process, because poring rate is non- Often slow, molten steel needs to be incubated, and molten steel storage facility is extremely complex and expensive, and the refractory material of holding furnace and steel ladle is by high temperature gold Category liquid washes away for a long time to be caused largely to be lost, and causes nonmetal inclusion to pollute, long under molten metal overheat and high temperature strongly Time, which preserves, can all cause alloying element and deoxidier to aoxidize and accelerate.The energy expenditure of the process is bigger, and is taken out due to using Ingot technique, matching and metal liquid level control technology of the slag temperature with stripping speed are complicated, roller core surface fusion penetration layer control technology difficulty Greatly, low production efficiency.

Although CPC techniques and ESSLM techniques can manufacture the composite bed of big thickness, due to present in technique and equipment Above mentioned problem, it is currently only used for the high-end composite rolls such as high-speed steel of the manufacture less than 10 tons.

Combined roll is that roll is made into several parts, is mechanically combined.Roll internal layer uses tough Property material, outer layer mostly make carbide ring.This roll can save valuable hard alloy, and cost performance is higher.Outer layer Carbide ring can ensure that roll has very high wearability.But due to carbide ring and internal layer roller core be difficult accomplish it is seamless Engagement, can cause roll unbalance stress in the operation of rolling and chipping.

Although having been developed that numerous composite roller manufacturing process both at home and abroad, up to the present, do not have also still The composite roll manufacturing process that one technique is simple, production cost is low, performance is good.Therefore, composite roller system is researched and developed Technique and equipment are made, it is current urgent need solution to carry out low cost, high efficiency, high-performance to various material rolls and large-scale roller to manufacture Problem certainly.It is the new direction of composite roll Manufacturing Technology Development.

Cast iron system roll refers to roll of the phosphorus content 2.50~3.5%, by main material can be divided into plain cast iron roll, Nickel chromium triangle Infinite chilled complex cast iron roll, high Cr complex cast iron roll and the major class of alloy nodular cast iron roll four.Alloy nodular is cast Iron roll has good heat shock resistance and abrasion resistance properties, is widely used and does large-scale blooming mill, shape rolling mill, bar continuous rolling Machine and large-scale seamless-tube rolling mill roller.Main use domestic at present can use centrifugal compound pouring technology to manufacture, by manufacturing process Limitation, core uses spheroidal graphite cast-iron, and due to spheroidal graphite cast-iron low intensity, roll breakage, serious influence easily occur in Rolling production Rolling production and product quality.

Rolling Process Automation, serialization, heavy-duty are the developing direction of modern rolling technique.Due to rolled steel Specific demand, higher requirement is proposed to the size of stocking, surface accuracy, the performance of stocking.In addition, with rolling technique Development, the working environment of roll is also increasingly harsher.Therefore, being equipped with high performance roll for milling train turns into China's roll industry The new problem faced.

The content of the invention

It is an object of the invention to there is the deficiency of technology for oneself, propose that a kind of simple production process, equipment investment are small, raw Produce efficiency high, nickel-chrome-molybdenum alloy cast iron composite roll Processes and apparatus in a kind of forged steel roll neck that cost is low, performance is good, solve from Component segregation easily occurs for heart casting, CPC methods, ESR methods complex manufacturing, the deficiency that power consumption is big, cost is high, efficiency is low, Roll neck is done using forged steel, solves roll breakage problem.

The equipment scheme for solving its technical problem is:The equipment has a planer-type region directional solidification jacking equipment 16, Lifting platform 17 is installed on planer-type region directional solidification jacking equipment 6, being provided with electromagnetic induction above lifting platform 17 adds Hot device 8, lifting screw 15 is rotated by lifting motor 14 or hydraulic test drives lifting platform 17 to be moved down in set speed It is dynamic, the side installation electromagnetic induction electrical power control cabinet 19 of directional solidification jacking equipment 16, electromagnetic induction power supply in planer-type region Two output ends of switch board 19 are connected by water-cooled cable 20 with the both ends of electromagnetic induction heating device 8, are determined in planer-type region There is a base support to the bottom of solidification jacking equipment 16, support plinth 12 is installed on base support 13, in support plinth Water-cooled bottom water tank 11 is installed, the center of bottom water tank 11 is manhole, in being provided with above bottom water tank 11 above 12 The heart is the bottom board 10 of manhole, and Combined water cooling crystallizer 7 is provided with above bottom board 10, is crystallized in water cooling The top of device 7 is provided with insulation ring 6, the center hole that roll plug 5 passes through support plinth 12, bottom water tank 11 and bottom board 12 The center of crystallizer 7 is fixed on, connection has casting runner 3 in the side of bottom board 10, and casting runner 3 is arranged on base support On 13 and sit brick 4 with cast to be connected, cast sits that brick 4 is installed above feed trumpet 2, and casting leakage is provided with the top of feed trumpet Bucket 1, there is pouring ladle 18 above depositing funnel 1.

There are water inlet pipe 23 and outlet pipe 24 respectively in the side of Water-cooled bottom water tank 11；Water mold 7 in crystallizer by justifying The fourplatemold arc water cooling box assembly 7 of equally distributed 2 or 3 integral multiples forms on week, in each arc water cooling box The bottom connection of body component 7 has water inlet pipe 21, and on the top of each arc water cooling box assembly 7, connection has outlet pipe 22, passes through Arc water cooling box assembly 7 is connected into drum-shaped entirety by attachment bolt 9；Insulation ring 6 is resistance to by refractory material or fiber reinforcement Fiery material manufacture；Electromagnetic induction power supply be line-frequency induction power supply, medium frequency induction power supply, high frequency induction power supply, frequency be 500Hz~ 3000Hz。

Solving the process technology scheme that its technical problem uses is:

（1）Mandrel prepares and preheating

It is uniform on its surface after the roll mandrel surface of the required size manufactured is carried out into oil removing, processing of rust removing first Coat one layer of antioxidizing paint, be put into heating furnace after carrying out being preheating to 500 DEG C~700 DEG C, by support plinth, bottom water tank and The center hole of bottom board is fixed on the center of crystallizer, starting region directional solidification lowering or hoisting gear, by electromagnetic induction heating Device drops to the bottom of crystallizer, opens the water inlet pipe and water outlet pipe of water mold and bottom water tank, starts electromagnetic induction heating power supply, leads to The sensing heater crossed outside the water mold carries out surface heating to plug, to be heated to 840 DEG C~1100 DEG C；

（2）Composition design

The mass percent of middle nickel-chrome-molybdenum alloy cast iron composite roller operational layer material composition is：C：3.3~3.8%, Si： 0.6~1.2%, Mn：0.4~1.2%, Cr：0.6~1.2%, Mo：0.3~1.0%, Ni：2.0~3.0%, Cu：0.6~1.1%, P： ≤ 0.05%, S：≤ 0.O3%, Mg：0.04~0.06%, Ba：1.5~2.5%, Ca：1~2%, RE：1.0~2.0%, surplus Fe It is and inevitably micro-；

（3）Molten metal melting

By middle nickel-chrome-molybdenum alloy cast iron roll predetermined material composition weigh base iron, foundry returns, steel scrap, ferro-molybdenum, Ferrochrome, nickel ingot, red copper, melting in intermediate frequency furnace being placed into, it is 1450~1500 DEG C to ensure molten iron temperature in fusion process, and Adjustment each element content is until meet component requirements；

（4）Nodularization and breed, Metamorphism treatment

After ladle is toasted, by the rare earth magnesium nodularizer of preheated required weight and 1/3 need Ba, Ca for adding and Silicon iron inoculator is embedded in the pit in the ladle toasted together, thereon cover 0.5~1% roll iron filings and be compacted, first The molten iron of the qualified composition melted of total amount 2/3 is poured, after spheroidizing reacion terminates, adds remaining 1/3 molten iron, and going out The ferrosilicon grain (75SiFe for breeding in total amount remaining 2/3) of preheating is poured into metal trough with stream, skims plus covers after being sufficiently stirred Agent prepares cast；

（5）Cast

By nodularization, breed, the skin of the roll molten metal that Metamorphism treatment is good is poured into pouring ladle, by the molten metal in pouring ladle The space in crystallizer between plug is poured into by depositing funnel, feed trumpet, casting runner according to predetermined cast program In, in casting process, pouring temperature should be controlled in 1300~1350 DEG C of scopes, and starting cast need to flow greatly, after 40~60s, open Beginning subtracts stream and poured slowly, and whole casting process cannot be greater than 5min, and electromagnetic induction heater does not stop heating, and pouring metal melt finishes Afterwards, sensing heater continues heating 10~50 minutes, poured into a mould molten metal is kept liquid within the regular hour, with Increase the liquid solid time, interface is formed metallurgical binding, starting region directional solidification lowering or hoisting gear is by electromagnetic induction heater with one Fixed speed is lifted up, and gradually disengages the roll shaft composite bed of electromagnetic induction heating successively consecutive solidification from bottom to top, and according to Quality requirement controls the different rates of climb in different regions, forming region directional solidification, insulation is raised to through 5~15 minutes Stop at circle, continue to carry out heating 10~50 minutes to insulation ring, to postpone insulated feeder setting time, rising head is mended Contracting, makes the gas in composite-layer metal liquid and field trash fully float, and eliminates composite-layer metal casting flaw, reaches the scheduled time Stop heating afterwards, continue water flowing and cool down 30 minutes~24 hours, the compound roll shaft cast is taken out out of crystallizer.

Described roll mandrel material is forging or cast low alloy steel, medium carbon steel or spheroidal graphite cast-iron.

Described 75SiFe innoculant adding quantities are 0.2~0.4%.

Described fourplatemold can both have been realized by adding or reducing various sizes of arc water cooling box assembly The adjustment of fourplatemold inner diameter size within the specific limits, meet the manufacture of different different-diameter size composite rolls, So as to reduce mould expense.

The composition of the mandrel surface antioxidizing paint is Na2B407, Si02, Na20, K20, A1203, CaO therein one Kind or Multiple components composition.

Beneficial effect

The roll that the methods of the inventive method and centre spinning, CPC methods, ESLLM methods produces is very different, and it is led Wanting feature is:

1st, composite roll is manufactured using the invented technology, because special casting method makes the metal of melting coagulate from bottom to top Gu being advantageous to the feeding of liquid metals, the defects of centre spinning is also easy to produce microstructure segregation, manufactured composite roll are overcome Material does not have gravity segregation, and crystalline structure is excellent, even tissue, and the tiny consistency of crystal grain is high.The choosing of plug and composite material Select that scope is wide, forging or the rod cast thereby material and not of varying strength requirement can be freely selected according to different requirements With the composite material of performance, skin of the roll can use high alloy material, make it have good red hardness and high-temperature wearable Property.

2nd, roll mandrel is directly preheated in crystallizer before cast using electromagnetic induction heater, it is right after cast Roll mandrel and the molten metal poured into a mould are incubated, and reduce the temperature difference between roller core and outer sphere molten metal, are advantageous to double Metal material it is good compound, there is good mechanical performance.On the other hand in order to reduce casting flaw, metallic composite is allowed Realize to lower and upper consecutive solidification, the flowing of molten metal automatically from top to bottom, be advantageous to molten metal feeding from top to bottom, so as to contract The short length in feeding area, reduce casting flaw, form the fine and close composite roll without shrinkage cavity；Continue in casting process to multiple Condensation material carries out electromagnetic induction heating, can reduce the oxidation for by the preheating temperature of composite, reducing composite, Ke Yizeng The liquid feeding solid time, promote the diffusion of two phase material more abundant, while function composite by electromagnetic stirring can be utilized, increase liquid metals pair By washing away for mandrel material surface, promote the matter and energy exchange between two phase material, make compound bed boundary easily controllable, from And greatly improve the bond strength at interface, it is possible to achieve good metallurgical bonding interface, product quality are easily controllable.

3rd, the present invention is using water mold substitution sand mold and metal mold shaping, in roll forming process, due to roll Outer sphere molten metal is the cooled and solidified in water mold, and cooling velocity is high, and nucleation ability is strong, can obtain tiny solidifying of crystal grain Gu tissue, dense structure degree is high, and hardness is uniform, and mechanical property is good, improves the obdurability and thermal fatigue resistance of roll, have compared with The properties possessed needed for high wearability and cold-resistant, thermal fatigue and modern roll working layer, and with excellent Machinability, casting and forging can be achieved, the service life of roll is improved, so as to meet modern rolling steel industry to high-performance The requirement of roll.Sand mold and metal mold shaping are substituted using water mold, the technique recovery rate of casting is high, liquid metals consumption Reduce, 15~30% are saved than sand casting；Rate of metal is high.Product size precision, surface light Zhi Dugao, machinery add remaining At least, while cast(ing) surface is without viscosity sand layer.And quality and dimensionally stable.Meanwhile reduced by very little allowance, it is corresponding to improve Rate of metal, has saved material.

4th, the present invention is cast using water mold, can be completely without molding sand, so reducing the work of molding sand processing Sequence.Casting can be poured into a mould again after going out type simultaneously, thus be easy to do mechanization and automated production, and production efficiency is high.

5th, due to being molded using water mold, the mold use life-span is up to thousands of times or even tens of thousands of times, great section Modeling Material has been saved, has reduced die cost, due to without sand molding, when having saved a large amount of molding sand and moulder, improving Efficiency.Substantial amounts of manufacturing expense has been saved, has reduced manufacturing cost, has reduced the waste of resource and the energy and the dirt of environment Dye.

6th, it is domestic at present usually using centrifugal compound technique manufacture roll, this roll exist during long-term use with Lower deficiency：1. hardness drop is big, roll use for the first time and the last time of centrifugal process manufacture use, and material structure changes Greatly, hardness wearability declines very fast, and rolling tonnage can decline 50-70 tons；2. thermal fatigue resistance is poor, roll long-term work exists Under the condition of high temperature, low thermal fatigue resistance causes roll in use for some time, and it is existing to be also easy to produce crackle and top layer chip off-falling etc. As having a strong impact on rolled piece quality；3. the toughness for centrifuging bainite roll is low, fragility is big, roll breakage phenomenon happens occasionally.The present invention adopts Composite roll is manufactured with imbedding process, in casting process, although mandrel has carried out the preheating of certain temperature, but relative to being poured For the high temperature fluent metal of note, mandrel material acts on equivalent to chill in casting process, cold inside roll so as to improve But effect, increase roll cast when inside cooling velocity, improve and enhance roll dense internal organization, make interface by Fused layers, diffusion layer and Quench solidification layer composition, reduce the hardness drop of composite material radial direction, and whole composite material is hard It is minimum to spend drop, further increases compound roll shaft performance, manufactured composite roll is repaiied every time in whole service life It is small that service life after multiple reduces amplitude.Meanwhile the present invention is molded using water mold, composite-layer metal liquid is by crystallizer Quick cooling, change composite bed crystalline structure, improve composite material performance, answered through what the technique was manufactured/remanufactured Close roll and the life-span is intended for single use more than the new roll more than 20~30% of material used in original.Comprehensive life improves more than 50%.

7th, using the technique and device fabrication composite roll, because using integrally being preheated in type, Quick pouring is molded, region Directional solidification controls crystalline structure, and it is big, right using stripping technique productions low production efficiency, power consumption to solve CPC methods, ESLLM methods Factory building and operator require high；CPC methods use two sets of induction heating systems, equipment compared with it is complicated, technical difficulty is big, the pure crystalline substance of steel Degree is poor；Matching and metal liquid level control technology of the ESLLM method slag temperature with stripping speed are complicated, roller core surface fusion penetration layer control technology The drawbacks such as difficulty is big, have the production efficiency higher than centrifuging process, and overcome present in Centrifugal compound foundry process into The drawbacks of dividing segregation and can not manufacturing forged steel roll neck roll, controllable process parameters are few, and simple production process is easily operated, production effect Rate is high, and power consumption is small, production cost lower than electroslag remelting process 1/2, lower than submerged arc bead welding method 2/3, and equipment is simply invested small, is adapted to Batch production.It can not be limited by equipment and technique, realization manufactures large-sized multilayer laminar joint product with mini-plant Or Gradient Composite Layer product, it is applied widely.

8th, using rare earth silicon and magnesium nodulizer and Ba, Ca, ferrosilicon composite inoculant, nodularization and pregnant effect are enhanced, is improved Graphite form, improve the strength of materials and toughness.By being matched to the reasonably optimizing of alloying element, using rotten inoculation, make Carbide morphology is significantly improved in roll, above-mentioned resultant effect, is improved the bending strength of roll, impact toughness, is scratched Degree, the contraction percentage of area, elongation after fracture and yield strength, cast condition ductile iron tensile strength >=500Mpa, toughness ak >= 9J/cm2, and solve the problems, such as the peeling of precision rolling working roll body of roll hole slot endosexine, and improve the amount of rolling of milling train.

9th, roll plug is done using low-alloy steel, medium carbon steel forged steel or cast steel, improves roller neck intensity, Rolling production When core there is no the danger of roll breakage, improve security, fundamentally solve roll breakage accident, improve production efficiency, meet Requirement of the modern steel industry to high intensity roller core composite roll.It can be used for large-scale top load and HI high impact load roll, As Wide and Thick Slab Heat Working Rolls, high roll-force when wide and heavy plate mill rolls and the big requirement of impact load are met, is carried significantly High working roll service life.

Brief description of the drawings

Fig. 1 is present device installation diagram, wherein 1 is depositing funnel, 2 be feed trumpet, and 3 be a cast runner, and 4 sit for cast Brick, 5 be roll plug, and 6 be insulation ring, and 7 be fourplatemold, and 8 be electromagnetic induction heater, and 9 be attachment bolt, and 10 be to pour Bottom plate is noted, 11 be bottom water tank, and 12 be support plinth, and 13 be base support, and 14 be lifting motor, and 15 be lifting screw, and 16 be dragon Gate-type region directional solidification jacking equipment, 17 be lifting platform, and 18 be pouring ladle, and 19 electromagnetic induction electrical power control cabinets, 20 be water cooling Cable, 23 be bottom tank inlet pipe, and 24 be bottom radiator drain.

Fig. 2 is fourplatemold structure chart of the present invention, wherein 7 be fourplatemold.

Fig. 3 is fourplatemold arc water cooling casing modular construction top view of the present invention, wherein 21 be that combined type crystallizes Device water inlet pipe, 22 be fourplatemold outlet pipe, and 7 be crystallizer arc water cooling box assembly.

Fig. 4 is cisten mechanism figure in bottom of the present invention, wherein 11 be bottom water tank.

Fig. 5 is cisten mechanism top view in bottom of the present invention, wherein 11 be bottom water tank, 23 be bottom tank inlet pipe, and 24 be bottom water Case outlet pipe.

Fig. 6 repairs roller structure figure for the present invention, wherein 25 be roll working lining, 26 be roll mandrel.

Embodiment

With reference to accompanying drawing, it is as follows to provide embodiments of the invention:

Embodiment 1:In Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, the equipment has a planer-type region directional solidification lifting Equipment 16, lifting platform 17 is installed on planer-type region directional solidification jacking equipment 6, electricity is installed above lifting platform 17 Magnetic induction heaters 8, lifting screw 15 is rotated by lifting motor 14 or hydraulic test drives lifting platform 17 with set speed Degree moves up and down, the side installation electromagnetic induction electrical power control cabinet 19 of directional solidification jacking equipment 16, electromagnetism in planer-type region Two output ends of induction power supply switch board 19 are connected by water-cooled cable 20 with the both ends of electromagnetic induction heating device 8, at gantry There is a base support bottom of formula region directional solidification jacking equipment 16, support plinth 12 is provided with base support 13, Water-cooled bottom water tank 11 is installed, the center of bottom water tank 11 is manhole, above bottom water tank 11 above support plinth 12 The bottom board 10 that center is manhole is installed, Combined water cooling crystallizer 7 is installed above bottom board 10, The top of water mold 7 is provided with insulation ring 6, and roll plug 5 passes through support plinth 12, bottom water tank 11 and bottom board 12 Center hole is fixed on the center of crystallizer 7, and in the side of bottom board 10, connection has casting runner 3, and casting runner 3 is arranged on On base support 13 and sit brick 4 with cast to be connected, cast sits that brick 4 is installed above feed trumpet 2, installs at the top of feed trumpet There is sprue cup 1, there is pouring ladle 18 above depositing funnel 1.

There are water inlet pipe 23 and outlet pipe 24 respectively in the side of Water-cooled bottom water tank 11；Water mold 7 in crystallizer by justifying Equally distributed 2 fourplatemolds arc water cooling box assembly 7 forms on week, in each arc water cooling box assembly 7 Bottom connection has water inlet pipe 21, and on the top of each arc water cooling box assembly 7, connection has outlet pipe 22, passes through attachment bolt 9 Arc water cooling box assembly 7 is connected into drum-shaped entirety；Insulation ring 6 is by refractory material or fiber reinforcement refractory material system Make；Electromagnetic induction power supply is line-frequency induction power supply, medium frequency induction power supply, high frequency induction power supply, frequency 1000Hz.

Roll manufacture uses following processing step：

（1）Mandrel prepares and preheating

It is uniform on its surface after the roll mandrel surface of the required size manufactured is carried out into oil removing, processing of rust removing first One layer of antioxidizing paint is coated, is put into heating furnace after carrying out being preheating to 500 DEG C, passes through support plinth, bottom water tank and cast bottom The center hole of plate is fixed on the center of crystallizer, starting region directional solidification lowering or hoisting gear, electromagnetic induction heater is declined To the bottom of crystallizer, the water inlet pipe and water outlet pipe of water mold and bottom water tank is opened, starts electromagnetic induction heating power supply, passes through installation Sensing heater outside water mold carries out surface heating to plug, to be heated to 840 DEG C；

（2）Composition design

The mass percent of middle nickel-chrome-molybdenum alloy cast iron composite roller operational layer material composition is：C：3.5%, Si：0.8%, Mn：0.6%, Cr：0.7%, Mo：0.5%, Ni：2.0%, Cu：0.6%, P：≤ 0.05%, S：≤ 0.O3%, Mg：0.04%, Ba： 1.7%, Ca：1.2%, RE：1.5%, surplus is Fe and inevitable trace element；

（3）Molten metal melting

Base iron, foundry returns, steel scrap, ferrochrome are weighed by middle nickel-chrome-molybdenum alloy cast iron composite roll predetermined material composition to close Gold, ferro-molybdenum, nickel ingot, red copper, melting in intermediate frequency furnace is placed into, it is 1480 DEG C to ensure molten iron temperature in fusion process, and is adjusted Whole each element content is until meet component requirements；

（4）Nodularization and breed, Metamorphism treatment

After ladle is toasted, by the rare earth magnesium nodularizer of preheated required weight and 1/3 need Ba, Ca for adding and Silicon iron inoculator and Nb, Ti, V alloy alterant are embedded in the pit in the ladle toasted together, thereon mulching straw ash And be compacted, the molten iron of the qualified composition melted of total amount 2/3 is first poured, after spheroidizing reacion terminates, adds remaining 1/3 iron Water, and the ferrosilicon grain (75SiFe for breeding in total amount remaining 2/3) of preheating is poured into iron notch with stream, taken off after being sufficiently stirred Slag plus coverture prepare cast；

（5）Cast

By nodularization, breed, the skin of the roll molten metal that Metamorphism treatment is good is poured into pouring ladle, by the molten metal in pouring ladle The space in crystallizer between plug is poured into by depositing funnel, feed trumpet, casting runner according to predetermined cast program In, in casting process, pouring temperature should be controlled in 1300~1320 DEG C of scopes, and starting cast need to flow greatly, after 40s, start to subtract Stream pours slowly, and whole casting process cannot be greater than 5min, and electromagnetic induction heater does not stop heating, after pouring metal melt, sense Answer heater to continue heating 17 minutes, poured into a mould molten metal is kept liquid within the regular hour, consolidated with increasing liquid Time, interface is set to form metallurgical binding, starting region directional solidification lowering or hoisting gear is by electromagnetic induction heater with certain speed It is lifted up, gradually disengages the roll shaft composite bed of electromagnetic induction heating successively consecutive solidification from bottom to top, and according to quality requirement The different rates of climb is controlled in different regions, forming region directional solidification, was raised at insulation ring and stops through 8 minutes, after It is continuous that heating 20 minutes is carried out to insulation ring, to postpone insulated feeder setting time, feeding is carried out to rising head, makes composite-layer metal liquid In gas and field trash fully float, eliminate composite-layer metal casting flaw, reach and stop heating after the scheduled time, continue to lead to Water cooling 14 hours, the compound roll shaft cast is taken out out of crystallizer.

Described roll mandrel material is forging low-alloy steel.

Described 75SiFe innoculant adding quantities are 0.2%.

The composition of the mandrel surface antioxidizing paint is Na2B407, Si02, Na20, K20, A1203, CaO therein one Kind or Multiple components composition.

Embodiment 2：In Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, the equipment has a planer-type region directional solidification lifting Equipment 16, lifting platform 17 is installed on planer-type region directional solidification jacking equipment 6, electricity is installed above lifting platform 17 Magnetic induction heaters 8, lifting screw 15 is rotated by lifting motor 14 or hydraulic test drives lifting platform 17 with set speed Degree moves up and down, the side installation electromagnetic induction electrical power control cabinet 19 of directional solidification jacking equipment 16, electromagnetism in planer-type region Two output ends of induction power supply switch board 19 are connected by water-cooled cable 20 with the both ends of electromagnetic induction heating device 8, at gantry There is a base support bottom of formula region directional solidification jacking equipment 16, support plinth 12 is provided with base support 13, Water-cooled bottom water tank 11 is installed, the center of bottom water tank 11 is manhole, above bottom water tank 11 above support plinth 12 The bottom board 10 that center is manhole is installed, Combined water cooling crystallizer 7 is installed above bottom board 10, The top of water mold 7 is provided with insulation ring 6, and roll shaft plug 5 passes through support plinth 12, bottom water tank 11 and bottom board 12 Center hole is fixed on the center of crystallizer 7, and in the side of bottom board 10, connection has casting runner 3, and casting runner 3 is arranged on On base support 13 and sit brick 4 with cast to be connected, cast sits that brick 4 is installed above feed trumpet 2, installs at the top of feed trumpet There is sprue cup 1, there is pouring ladle 18 above depositing funnel 1.

There are water inlet pipe 23 and outlet pipe 24 respectively in the side of Water-cooled bottom water tank 11；Water mold 7 in crystallizer by justifying Equally distributed 3 fourplatemolds arc water cooling box assembly 7 forms on week, in each arc water cooling box assembly 7 Bottom connection has water inlet pipe 21, and on the top of each arc water cooling box assembly 7, connection has outlet pipe 22, passes through attachment bolt 9 Arc water cooling box assembly 7 is connected into drum-shaped entirety；Insulation ring 6 is by refractory material or fiber reinforcement refractory material system Make；Electromagnetic induction power supply is line-frequency induction power supply, medium frequency induction power supply, high frequency induction power supply, frequency 500Hz.

Roll manufacture uses following processing step：

（1）Mandrel prepares and preheating

It is uniform on its surface after the roll mandrel surface of the required size manufactured is carried out into oil removing, processing of rust removing first One layer of antioxidizing paint is coated, is put into heating furnace after carrying out being preheating to 600 DEG C, passes through support plinth, bottom water tank and cast bottom The center hole of plate is fixed on the center of crystallizer, starting region directional solidification lowering or hoisting gear, electromagnetic induction heater is declined To the bottom of crystallizer, the water inlet pipe and water outlet pipe of water mold and bottom water tank is opened, starts electromagnetic induction heating power supply, passes through installation Sensing heater outside water mold carries out surface heating to plug, to be heated to 900 DEG C；

（2）Composition design

The mass percent of middle nickel-chrome-molybdenum alloy cast iron composite roller operational layer material composition is：C：3.7%, Si：0.9%, Mn：0.9%, Cr：0.9%, Mo：0.7%, Ni：2.5%, Cu：0.8%, P：≤ 0.05%, S：≤ 0.O3%, Mg：0.05%, Ba： 2.0%, Ca：1.7%, RE：1.8%, surplus is Fe and inevitable trace element；

（3）Molten metal melting

Base iron, foundry returns, steel scrap, ferrochrome are weighed by middle nickel-chrome-molybdenum alloy cast iron composite roll predetermined material composition to close Gold, ferro-molybdenum, nickel ingot, red copper, melting in intermediate frequency furnace is placed into, it is 1500 DEG C to ensure molten iron temperature in fusion process, and is adjusted Whole each element content is until meet component requirements；

（4）Nodularization and breed, Metamorphism treatment

After ladle is toasted, by the rare earth magnesium nodularizer of preheated required weight and 1/3 need Ba, Ca for adding and Silicon iron inoculator and Nb, Ti, V alloy alterant are embedded in the pit in the ladle toasted together, thereon mulching straw ash And be compacted, the molten iron of the qualified composition melted of total amount 2/3 is first poured, after spheroidizing reacion terminates, adds remaining 1/3 iron Water, and the ferrosilicon grain (75SiFe for breeding in total amount remaining 2/3) of preheating is poured into iron notch with stream, taken off after being sufficiently stirred Slag plus coverture prepare cast；

（5）Cast

By nodularization, breed, the skin of the roll molten metal that Metamorphism treatment is good is poured into pouring ladle, by the molten metal in pouring ladle The space in crystallizer between plug is poured into by depositing funnel, feed trumpet, casting runner according to predetermined cast program In, in casting process, pouring temperature should be controlled in 1310~1330 DEG C of scopes, and starting cast need to flow greatly, after 45s, start to subtract Stream pours slowly, and whole casting process cannot be greater than 5min, and electromagnetic induction heater does not stop heating, after pouring metal melt, sense Answer heater to continue heating 19 minutes, poured into a mould molten metal is kept liquid within the regular hour, consolidated with increasing liquid Time, interface is set to form metallurgical binding, starting region directional solidification lowering or hoisting gear is by electromagnetic induction heater with certain speed It is lifted up, gradually disengages the roll shaft composite bed of electromagnetic induction heating successively consecutive solidification from bottom to top, and according to quality requirement The different rates of climb is controlled in different regions, forming region directional solidification, was raised at insulation ring and stops through 7 minutes, after It is continuous that heating 25 minutes is carried out to insulation ring, to postpone insulated feeder setting time, feeding is carried out to rising head, makes composite-layer metal liquid In gas and field trash fully float, eliminate composite-layer metal casting flaw, reach and stop heating after the scheduled time, continue to lead to Water cooling 18 hours, the compound roll shaft cast is taken out out of crystallizer.

Described roll mandrel material is forging or cast low alloy steel, medium carbon steel or spheroidal graphite cast-iron.

Described 75SiFe innoculant adding quantities are 0.3%.

The composition of the mandrel surface antioxidizing paint is Na2B407, Si02, Na20, K20, A1203, CaO therein one Kind or Multiple components composition.

Embodiment 3：In Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, the equipment has a planer-type region directional solidification jacking equipment 16, lifting platform 17 is installed on planer-type region directional solidification jacking equipment 6, electromagnetism sense is installed above lifting platform 17 Heater 8 is answered, lifting screw 15 is rotated by lifting motor 14 or hydraulic test drives lifting platform 17 with set speed Lower movement, the side installation electromagnetic induction electrical power control cabinet 19 of directional solidification jacking equipment 16, electromagnetic induction in planer-type region Two output ends of electrical power control cabinet 19 are connected by water-cooled cable 20 with the both ends of electromagnetic induction heating device 8, in planer-type area There is a base support bottom of domain directional solidification jacking equipment 16, support plinth 12 is provided with base support 13, is supporting Water-cooled bottom water tank 11 is installed, the center of bottom water tank 11 is manhole, is installed above bottom water tank 11 above base 12 The bottom board 10 for having center to be manhole, is provided with Combined water cooling crystallizer 7, in water cooling above bottom board 10 The top of crystallizer 7 is provided with insulation ring 6, the center that roll shaft plug 5 passes through support plinth 12, bottom water tank 11 and bottom board 12 Circular hole is fixed on the center of crystallizer 7, and in the side of bottom board 10, connection has casting runner 3, and casting runner 3 is arranged on base On support 13 and sit brick 4 with cast to be connected, cast sits that brick 4 is installed above feed trumpet 2, is provided with and pours at the top of feed trumpet Funnel 1 is cast, there is pouring ladle 18 above depositing funnel 1.

There are water inlet pipe 23 and outlet pipe 24 respectively in the side of Water-cooled bottom water tank 11；Water mold 7 in crystallizer by justifying Equally distributed 6 fourplatemolds arc water cooling box assembly 7 forms on week, in each arc water cooling box assembly 7 Bottom connection has water inlet pipe 21, and on the top of each arc water cooling box assembly 7, connection has outlet pipe 22, passes through attachment bolt 9 Arc water cooling box assembly 7 is connected into drum-shaped entirety；Insulation ring 6 is by refractory material or fiber reinforcement refractory material system Make；Electromagnetic induction power supply is line-frequency induction power supply, medium frequency induction power supply, high frequency induction power supply, frequency 2000Hz.

Roll manufacture uses following processing step：

（1）Mandrel prepares and preheating

It is uniform on its surface after the roll mandrel surface of the required size manufactured is carried out into oil removing, processing of rust removing first One layer of antioxidizing paint is coated, is put into heating furnace after carrying out being preheating to 650 DEG C, passes through support plinth, bottom water tank and cast bottom The center hole of plate is fixed on the center of crystallizer, starting region directional solidification lowering or hoisting gear, electromagnetic induction heater is declined To the bottom of crystallizer, the water inlet pipe and water outlet pipe of water mold and bottom water tank is opened, starts electromagnetic induction heating power supply, passes through installation Sensing heater outside water mold carries out surface heating to plug, to be heated to 880 DEG C；

（2）Composition design

The mass percent of middle nickel-chrome-molybdenum alloy cast iron composite roller operational layer material composition is：C：3.8%, Si：1.1%, Mn：1.1%, Cr：1.0%, Mo：1.0%, Ni：3.0%, Cu：0.7%, P：≤ 0.05%, S：≤ 0.O3%, Mg：0.06%, Nb： 0.2%, Ti：0.25%, V：0.5%, Ba：2.5%, Ca：2%, RE：2.0%, surplus is Fe and inevitable trace element；

（3）Molten metal melting

Base iron, foundry returns, steel scrap, molybdenum-iron are weighed by middle nickel-chrome-molybdenum alloy cast iron composite roll predetermined material composition to close Gold, ferrochrome, nickel ingot, red copper, melting in intermediate frequency furnace is placed into, it is 1480 DEG C to ensure molten iron temperature in fusion process, and is adjusted Whole each element content is until meet component requirements；

（4）Nodularization and breed, Metamorphism treatment

After ladle is toasted, by the rare earth magnesium nodularizer of preheated required weight and 1/3 need Ba, Ca for adding and Silicon iron inoculator and Nb, Ti, V alloy alterant are embedded in the pit in the ladle toasted together, thereon mulching straw ash And be compacted, the molten iron of the qualified composition melted of total amount 2/3 is first poured, after spheroidizing reacion terminates, adds remaining 1/3 iron Water, and the ferrosilicon grain (75SiFe for breeding in total amount remaining 2/3) of preheating is poured into iron notch with stream, taken off after being sufficiently stirred Slag plus coverture prepare cast；

（5）Cast

By nodularization, breed, the skin of the roll molten metal that Metamorphism treatment is good is poured into pouring ladle, by the molten metal in pouring ladle The space in crystallizer between plug is poured into by depositing funnel, feed trumpet, casting runner according to predetermined cast program In, in casting process, pouring temperature should be controlled in 1320~1350 DEG C of scopes, and starting cast need to flow greatly, after 50s, start to subtract Stream pours slowly, and whole casting process cannot be greater than 5min, and electromagnetic induction heater does not stop heating, after pouring metal melt, sense Answer heater to continue heating 20 minutes, poured into a mould molten metal is kept liquid within the regular hour, consolidated with increasing liquid Time, interface is set to form metallurgical binding, starting region directional solidification lowering or hoisting gear is by electromagnetic induction heater with certain speed It is lifted up, gradually disengages the roll shaft composite bed of electromagnetic induction heating successively consecutive solidification from bottom to top, and according to quality requirement The different rates of climb is controlled in different regions, forming region directional solidification, was raised at insulation ring and stops through 5 minutes, after It is continuous that heating 25 minutes is carried out to insulation ring, to postpone insulated feeder setting time, feeding is carried out to rising head, makes composite-layer metal liquid In gas and field trash fully float, eliminate composite-layer metal casting flaw, reach and stop heating after the scheduled time, continue to lead to Water cooling 18 hours, the compound roll shaft cast is taken out out of crystallizer.

Described roll mandrel material is forging or cast low alloy steel, medium carbon steel or spheroidal graphite cast-iron.

Described 75SiFe innoculant adding quantities are 0.4%.

The composition of the mandrel surface antioxidizing paint is Na2B407, Si02, Na20, K20, A1203, CaO therein one Kind or Multiple components composition.

General principle, principal character and the advantages of the present invention of the present invention has been shown and described above.The technology of the industry For personnel it should be appreciated that the present invention is not limited by step embodiment, that described in step embodiment and specification is the present invention Principle, without departing from the spirit and scope of the present invention, design of the invention can by other various forms implement transport With also having various changes and modifications, these changes and improvements equally all fall within the protetion scope of the claimed invention.The present invention Claimed scope is by appended claims and its equivalent thereof.

Claims (2)

1. A kind of 1. nickel-chrome-molybdenum alloy cast iron composite roll technique in forged steel roll neck, it is characterised in that：Roll manufacture uses following work Skill step：

   （1）Mandrel prepares and preheating

   After the roll mandrel surface of the required size manufactured is carried out into oil removing, processing of rust removing first, uniformly coated on its surface One layer of antioxidizing paint, it is put into heating furnace after carrying out being preheating to 500 DEG C~700 DEG C, passes through support plinth, bottom water tank and cast The center hole of bottom plate is fixed on the center of crystallizer, starting region directional solidification lowering or hoisting gear, by under electromagnetic induction heater The bottom of crystallizer is dropped to, opens the water inlet pipe and water outlet pipe of water mold and bottom water tank, starts electromagnetic induction heating power supply, passes through peace Sensing heater outside water mold carries out surface heating to plug, to be heated to 840 DEG C~1100 DEG C；

   （2）Composition design

   The mass percent of middle nickel-chrome-molybdenum alloy cast iron composite roller operational layer material composition is：C：3.3~3.8%, Si：0.6~ 1.2%, Mn：0.4~1.2%, Cr：0.6~1.2%, Mo：0.3~1.0%, Ni：2.0~3.0%, Cu：0.6~1.1%, P：≤ 0.05%, S：≤ 0.03 %, Mg：0.04~0.06%, Ba：1.5~2.5%, Ca：1~2%, RE：1.0~2.0%, surplus Fe It is and inevitably micro-；

   （3）Molten metal melting

   Base iron, foundry returns, steel scrap, ferro-molybdenum, ferrochrome are weighed by middle nickel-chrome-molybdenum alloy cast iron roll predetermined material composition Alloy, nickel ingot, red copper, melting in intermediate frequency furnace is placed into, it is 1450~1500 DEG C to ensure molten iron temperature in fusion process, and is adjusted Each element content is until meet component requirements；

   （4）Nodularization and inoculation

   After ladle is toasted, Ba, Ca and ferrosilicon that the rare earth magnesium nodularizer of preheated required weight and 1/3 are needed to add Inovulant is embedded in the pit in the ladle toasted together, covers the roll iron of roll percentage by weight 0.5~1% thereon Consider to be worth doing and be compacted, first pour the molten iron of the qualified composition melted of total amount 2/3, after spheroidizing reacion terminates, add remaining 1/3 Molten iron, and the silicon iron inoculator of preheating is poured into iron notch with stream, that is, breed in total amount remaining 2/3 Ba, Ca and ferrosilicon Inovulant, skims after being sufficiently stirred plus coverture prepares cast；

   （5）Cast

   By nodularization, breed, the roll working lining molten metal that Metamorphism treatment is good is poured into pouring ladle, the molten metal in pouring ladle is pressed Poured into according to predetermined cast program by depositing funnel, feed trumpet, casting runner in the space in crystallizer between plug, In casting process, pouring temperature should be controlled in 1300~1350 DEG C of scopes, and starting cast need to flow greatly, after 40~60s, start to subtract Stream pours slowly, and whole casting process cannot be greater than 5min, and electromagnetic induction heater does not stop heating, after pouring metal melt, sense Answer heater to continue heating 10~50 minutes, poured into a mould molten metal is kept liquid within the regular hour, with increase The liquid solid time, interface is set to form metallurgical binding, starting region directional solidification lowering or hoisting gear is by electromagnetic induction heater with certain Speed is lifted up, and gradually disengages the roll shaft composite bed of electromagnetic induction heating successively consecutive solidification from bottom to top, and according to quality It is required that controlling the different rates of climb in different regions, forming region directional solidification, it was raised to through 5~15 minutes at insulation ring Stop, continuing to carry out heating 10~50 minutes to insulation ring, to postpone insulated feeder setting time, feeding is carried out to rising head, made Gas and field trash in composite-layer metal liquid fully float, and eliminate composite-layer metal casting flaw, stop after reaching the scheduled time Only heat, continue water flowing and cool down 30 minutes~24 hours, the compound roll shaft cast is taken out out of crystallizer；

   Described roll mandrel material is forging or cast low alloy steel, medium carbon steel or spheroidal graphite cast-iron；

   Described silicon iron inoculator addition is roll percentage by weight 0.2~0.4%.
2. 2. nickel-chrome-molybdenum alloy cast iron composite roll technique in forged steel roll neck according to claim 1, it is characterized in that：The plug The composition of surface anti-oxidation coating is Na₂B₄O₇, SiO₂, Na₂O, K₂O, A1₂O₃, CaO one or more composition compositions therein.