CN103014516B - Borated low-alloy high-speed steel roller and manufacturing method thereof - Google Patents

Abstract

The invention belongs to the technical field of steel rolling, and relates to a roller, in particular to a borated low-alloy high-speed steel roller and a manufacturing method of the borated low-alloy high-speed steel roller. The roller comprises a roller body and a roller core, wherein the roller body comprises the following chemical components by weight percentage: 0.7-0.8% of C, 1.3-2.4% of Cr, 2.50-3.0% of B, 1.0-1.5% of W, 1.0-1.5% of V, less than or equal to 1.0% of Si, less than or equal to 0.4% of Mn, 0.09-0.12% of Ti, 0.16-0.19% of Mg, 0.10-0.12% of RE, less than or equal to 0.03% of P, less than or equal to 0.03% of S, and the balance of Fe and unavoidable trace impurities. The roller core is made of nodular cast iron. The manufacturing method of the roller comprises the steps of smelting, deoxidation and alloying, composite modification of RE-Mg, centrifugal casting and heat treatment, and then a finished product is processed. The roller and the manufacturing method have the major advantages that boride particles are major wear-proof particles; the addition amount of alloying elements is reduced, so that the production cost is lowered; and the roller is high in rigidity, good in wear resistance and thermal fatigue resistance, uniform in material, and high in accident resistance in the later period.

Description

A kind of boracic low-alloy high-speed steel rolls and manufacture method thereof

Technical field

The invention belongs to technical field of steel rolling, relate to a kind of roll, particularly a kind of boracic low-alloy high-speed steel rolls and manufacture method thereof.

Background technology

Roll is the main consumption spare part in Rolling production, and roll quality directly affects the surface quality of stocking, the productivity of milling train operation and stocking production cost; Therefore improve the quality of roll, reduce the alloying constituent of roll, the production cost saving roll always is the focus that manufacturing enterprise pays close attention to.

Conventional hot roll material has high Ni-Cr infinite cold hardness cast iron roll, semisteel roll and high-chromium iron-cast roller, they are widely used because of its excellent use properties, but in high Ni-Cr infinite cold hardness cast iron roll, carbide M3C type is main, and carbide is continuous net-shaped distribution, thus the wearing no resistance of roll, fragility is large; Alloy carbide comparatively small amt in semisteel roll, therefore the hardness of roll is low, easy to wear; Adding in a large number due to chromium element in high-chromium iron-cast roller, make to become with the carbide of the interrupted shape distribution of M7C3 type with the Carbides Transformation of the continuous net-shaped distribution of M3C type, enhance the wear resisting property of roll; But because the content of chromium element is higher, the heat conductivility of roll is poor, in casting and heat treated process, roll is easy to crack, and the scrap rate that roll is produced raises; And in order to improve the hardening capacity of high-chromium iron-cast roller, the nickel element of some amount also to be added, improve the cost that roll manufactures to a certain extent.

Boron a kind ofly significantly can improve the hardening capacity of high-abrasive material and the alloying element of hardenability, and the boron storage of China is very abundant, and cheap, and boron has obtained good application in high-abrasive material field; Chinese invention patent CN1037548 discloses a kind of low-cr, B multi-element alloy anti-wear cast iron, its chemical composition (% by weight) is: C:1.75 ~ 3.0, Cr:1.5 ~ 4.0, B:0.07 ~ 0.4, Mo:0.2 ~ 1.0, Cu:0.8 ~ 1.3, Mn:0.4 ~ 0.8, Si:0.4 ~ 1.2, P≤0.08, S≤0.08, Re:0.01 ~ 0.05, surplus is Fe; Chinese invention patent CN1506487 discloses a kind of complex alloyed cast iron, and its chemical composition (% by weight) is: C:1.5 ~ 3.5, Cr:1.0 ~ 4.0, B:0.1 ~ 0.5, Mo:0.25 ~ 1.0, Cu:0.8 ~ 1.25, Mn:0.4 ~ 0.6, P:0.45 ~ 0.85, surplus is Fe; All show adding of boron, not only reduce the content of the chromium element in cast iron, also make the hardness of antifriction cast iron increase, thus wear resistance improves, its over-all properties is comparatively outstanding.

Boron is applied in high-speed steel roll manufacture, boride is utilized to replace the partially carbonized thing in rapid steel can improve the performance of steel, particularly wear resisting property, utilize boride to separate out the stronger feature of Performance Ratio Carbide Precipitation ability simultaneously, the addition of rapid steel interalloy element can be reduced, thus realize low cost, in addition, need the heat treating regime optimizing boracic high-speed steel novel material, thus realize high-performance and the long lifetime of high speed steel roll material, reduce roll consumption, Chinese invention patent CN102409267A discloses a kind of boron-containing high speed steel roller, its chemical composition (% by weight) is: C:0.95 ~ 1.15, Cr:8.5 ~ 9.0, B:0.4 ~ 0.6, Mo:1.0 ~ 1.2, W:0.5 ~ 0.8, V:0.5 ~ 0.8, Al:1.6 ~ 1.8, N:0.18 ~ 0.25, Cu:0.4 ~ 0.6, Si:1.2 ~ 1.4, RE:0.06 ~ 0.10, Mg:0.03 ~ 0.06, Ti:0.04 ~ 0.08, K:0.025 ~ 0.045, Na:0.023 ~ 0.045, Te:0.02 ~ 0.04, Bi:0.02 ~ 0.04, Mn≤0.5, S≤0.025, P≤0.030, surplus is Fe and inevitable impurity, this roll adds due to boron, makes to have the good and feature such as roll neck intensity is high, good toughness of wear resistance, Chinese invention patent CN101805869A discloses a kind of boron-contained high-chromium high-speed steel roller material, and its chemical composition (% by weight) is: C:2.6 ~ 3.0, Cr:24 ~ 28, B:0.5 ~ 0.8, Mo:2.0 ~ 2.8, W:1.0 ~ 1.5, Nb:0.6 ~ 1.0, V:1.0 ~ 1.5, Ni:0.7 ~ 1.2, Si:0.5 ~ 1.0, Mn:0.5 ~ 1.2, Ca:0.008 ~ 0.015, Zn:0.06 ~ 0.08, Ta:0.02 ~ 0.05, RE:0.03 ~ 0.06, K:0.04 ~ 0.10, surplus is Fe and inevitable trace impurity, make the wear resistance of roll be significantly improved due to adding of boron, but, the alloying constituent matching aspect of boron-containing roller of the prior art needs to optimize, main deficiency is that the low boride amount of precipitation that causes of the content of boron is not enough, superfluous expensive alloy element is increased as alloying elements such as tungsten, molybdenum, vanadium, niobium, cobalts for keeping enough boride amount of precipitations, not only increase alloying element consumption and production cost, and, it is large that superfluous alloying element precipitate controls difficulty, cause the wear resistance of roll and later stage to resist the problems such as accident difference, need a kind of new roll material of invention and corresponding heat treating method.

Summary of the invention

The present invention is directed to the major issue that current China metallurgical roller high speed steel material exists, namely expensive alloy element content is high causes cost high and life-span that wear resistance and anti-accident difference etc. cause low critical bottleneck, object is in high-speed steel roll, use cheap boron to replace the alloying elements such as expensive tungsten, molybdenum, vanadium, niobium, cobalt, the obvious reduction of promotion roll cost and increasing substantially of performance, thus save production cost, improve use ability and the security of roll; The reaction of boron and iron can generate the boride of high rigidity, is conducive to the wear resistance improving roll; The boron of suitable surplus adds the hardening capacity and hardenability that can also improve roll, adds form and distribution that the elements such as titanium, yttrium, magnesium effectively can improve boride in addition, improves intensity and the toughness of high-boron low-alloy high-speed steel; The reduction of content of vanadium, then obviously can alleviate the segregation of v element during rotary casting, has good effect for raising and stable roller performance.

The technical scheme realizing the object of the invention is:

The present invention includes the body of roll and roller core two portions composition, its chemical composition of the body of roll (% by weight) is: C:0.7 ~ 0.8, Cr:1.3 ~ 2.4, B:2.50 ~ 3.0, W:1.0 ~ 1.5, V:1.0 ~ 1.5, Si :≤1.0, Mn :≤0.4, Ti:0.09 ~ 0.12, Mg:0.16 ~ 0.19, RE:0.10 ~ 0.12, P :≤0.03, S≤0.03, surplus is Fe and inevitable trace impurity.

The manufacture method of above-mentioned high-boron low-alloy high-speed steel roll, described processing step is:

1) roll alloy material adopts electrosmelting; With the waste material steel scrap of rapid steel, the pig iron, ferrotungsten, the fusing of vanadium iron Hybrid Heating; Ferrochrome is added after molten steel is melting down; Rapid steel waste material, the pig iron are all the raw materials containing C, Si, Mn;

2) after stokehold adjustment C, W, V, Si, Mn composition scope according to the invention, temperature is risen to 1560 ~ 1600 DEG C, add the deoxidation of aluminum-calcium-magnesium-cerium alloy, then add ferrochrome, ferrotianium successively, come out of the stove when molten steel rises to 1630 ~ 1650 DEG C, will 1200 ~ 1300 DEG C be heated to and the ferro-boron particle of the 7 ~ 10mm be crushed to pours ladle with stream simultaneously, carry out degree of depth deoxidation because molten steel have employed aluminum-calcium-magnesium-cerium alloy, the oxidation of the ferro-boron particle added with steel stream is controlled, and realizes high boron; Chromium has small amounts before deoxidation, and the object that second time adds ferrochrome accurately controls content range.

3) adding magnesium-rare earth in advance in ladle bottom, after 200 ~ 230 DEG C dry, with pouring method in bag, compound modification treatment being carried out to molten steel;

4) after molten steel is come out of the stove 4 ~ 6 minutes, carry out Argon purification to ladle, argon blowing time is 4 ~ 8 minutes, and liquid steel temperature reaches 1470 ~ 1490 DEG C and can pour into a mould;

5) method of pouring into a mould adopts centre spinning method to carry out cast roller body; Then spheroidal graphite cast iron cast roller core is used;

6) roll poured into a mould will carry out isothermal annealing process, and annealing heating temperature is 1000 ~ 1040 DEG C, and soaking time is 10 ~ 12 hours, cools to the furnace after below 700 DEG C, and air cooling, to room temperature, carries out roughing;

7) roll after roughing is heated to 900 ~ 950 DEG C, is incubated after 7 ~ 10 hours, comes out of the stove air-cooled 30 ~ 50 minutes, then carries out quench treatment; Quenching adopts atomized water spray cooling roll; Temperature carries out temper lower than 400 DEG C;

8) in roll drawing process, first roll is heated to 560 ~ 580 DEG C, is incubated after 6 ~ 10 hours, is chilled to less than 200 DEG C with stove, air cooling, then tempering twice under same process;

9) roll after temper is good is refined to size and the precision of regulation.

The performance of roll is determined by metallographic structure, and certain tissue depends on chemical composition and thermal treatment process, and chemical composition of the present invention is determined like this:

Carbon: the main carbide forming the high rigidity such as MC, M2C, M6C, M2C3 and high thermal stability with strong carbide of carbon, raising wear resistance and red hardness; Because high-speed steel roll needs enough wear resistancies, therefore the carbide content in roll working lining can not be too low; Carbon can also avoid molten iron to be too oxidized in the process of melting; In high-speed steel roll process of setting, along with the increase of carbon content, liquidus temperature reduces, and fluidity molten steel and castability are improved, and coarse Austenite amount reduces, grain refining, and carbide content increases; But carbon content is too high, although hardness and redhardneas is high, carbide ununiformity increases, and the plasticity of rapid steel and toughness are degenerated, and comprehensive mechanical property is inferior; Carbon content increases simultaneously, and after steel is quenched, retained austenite increases, the corresponding increase of times of tempering, and energy consumption rises; Carbon content is too high, also can cause casting crack, there will be netted M3C type carbide in rapid steel, increases material fragility; Carbon content more than 3.0% after, thermal shock resistance obviously declines; Also can produce carbide segregation simultaneously, reduce the use properties of roll; Consider carbon content control between 0.7% ~ 0.8%.

Chromium: the hardening capacity of high-speed steel roll mainly relies on chromium; First chromium form carbide M3C, M23C6, and these carbide are substantially all dissolved in matrix when Quench heating, adds the stability of matrix, makes high-speed steel roll produce higher hardening capacity; Chromium can also regulate the carbon balance of matrix, can improve anti-oxidant decarburization and resistance to corrosion; But chromium too high levels can form unstable carbide when tempering, reduce stability and red hardness; Chromium also easily produces segregation in centrifugal casting process.

Boron: the amount of containing of boron is very abundant in China, cheap and stable, boron is added in common ferrous materials, by regulating Boron contents and carbon content in alloy, control the percent by volume of boride and the carbon content of matrix, thus make material have excellent wear resistance and obdurability; According to Fe-B binary alloy phase diagram, the maximum solid solution degree of boron in γ phase is 0.02%, makes unnecessary B atom be enriched on crystal boundary, forms hard phase boride; Due to the formation of boride, the relative content of carbon in residue liquid phase is raised, and under room temperature, most of eutectic γ phase in version is α-Fe, and the γ phase do not changed is present in matrix with the form of residual austenite; Carbon-boron compound is net distribution along crystal boundary, and local has suspension and necking; Boron mainly can form Fe2(B, C) boride, its hardness is high, Heat stability is good, and matrix is ferrite, perlite and martensite; Appropriate boron enters hardening capacity and the hardenability that matrix can also improve matrix, is conducive to the prolongation in the work-ing life of roll; But Fe2(B, C) boride is net distribution along crystal boundary, and the fragility of high-speed steel roll can be made to increase, and toughness reduces, therefore Boron contents can not be too high; Consider Boron contents should control between 2.50% ~ 3.0%.

Tungsten: tungsten is the first-selected element promoting rapid steel temper resistance and red hardness; Tungsten mainly forms Fe4W2C and a small amount of W2C; During quenching, a part of Fe4W2C dissolves in matrix, when tempering with W2C form disperse educt, causes secondary hardening, improves hardness and redhardneas; Another part carbide can stop Ovshinsky grain growth, improves wear resistance; Tungsten also has certain oxidation-resistance; If the too high meeting of W content makes to form the frangible M6C type carbide of herring-bone form in roll, reduce its wear resistance; In addition, W elements easily produces segregation, worsens the toughness of roller surface; Consider W content should control between 1.0% ~ 1.5%.

Vanadium: vanadium can form carbide VC; VC disperse educt during tempering, forms secondary hardening; VC hardness is high, and grain fineness number is large, and not easily broken, main balling-up bulk or nearly spherical Dispersed precipitate, on matrix, can improve the impelling strength of material, hardness and wear resistance; Vanadium effectively can also remove the impurity in molten steel; But the too high oxidisability that can increase steel of content of vanadium, and greatly improve the cost of roll material; Consider content of vanadium should control between 1.0% ~ 1.5%.

Silicon: silicon has certain desoxydatoin, but silicone content is too high can form thick M7C3 type carbide and ferrite, reduces toughness and the intensity of tissue, makes roll in use easily occur be full of cracks, produces peeling off of working face time serious; Consider silicone content and should be no more than 1.0%.

Manganese: manganese can reduce martensitic beginning transition temperature, but too high levels that roll can be made to organize is thick, occur hot tearing during casting, in quenching structure, retained austenite increases simultaneously, and the hardenability of roll declines; Consider Fe content and should be no more than 0.4%.

Titanium: titanium and boron easily generate the TiB2 of high strength, in disconnected net distribution, makes roll strength and toughness be greatly improved; High-speed steel roll is after the Metamorphism treatment of titanium elements, and obvious refinement occurs for austenite crystal and eutectic structure, and obvious constriction appears in eutectic carbides; Consider the content of titanium 0.09% ~ 0.12%.

Magnesium: magnesium is strong deoxidation, strong desulfurization element, is also strong constitutional supercooling element simultaneously, adds appropriate magnesium in high-boron low-alloy high-speed steel roll, the suspension and the distribution that are conducive to carbide and boride are isolated, thus improve intensity and the toughness of high-speed steel roll; The content considering magnesium controls 0.16% ~ 0.19%.

Rare earth: comprising the rare earth elements such as yttrium base cerium base can fining austenite grains in high-speed steel roll, rotten inclusion, improve the form of carbide, improve tissue, thus improve its plasticity and toughness, improve the hot workability of thermal fatigue property, thermal shock resistance, quenching crack resistance and high temperature; With do not add rare-earth phase ratio, occur when thermal cycling crackle cycle index improve 42% ~ 160%; But the too high meeting of rare earth makes intensity and toughness reduce; The content considering rare earth controls 0.10% ~ 0.12%.

Sulphur and phosphorus: sulphur and the phosphorus form mainly with lower melting point inclusion in high-speed steel roll is gathered in crystal boundary, in high-temperature heating process, easily occur local melting, reduce intensity and the plasticity of steel, therefore the content of sulphur and phosphorus should be strict controlled in less than 0.03%.

The present invention has following characteristics:

1) the present invention is main alloying element with the boron of cheapness, and not containing alloying elements such as expensive cobalt, nickel, molybdenum, niobiums, the content of Er Qiefan, titanium and tungsten is less, and therefore the production cost of roll of the present invention is lower, can save 20% ~ 30%;

2) to contain hardness high for roll of the present invention, the boride of wear resistance and Heat stability is good, and have higher hardness and good wear resistance, hardness can reach 62 ~ 65GHRC, and the depth of hardening zone of roll is greater than 62mm;

3) carbon content of roll of the present invention is lower, has good thermal fatigue resistance;

4) roll of the present invention adds the deoxidation of aluminum-calcium-magnesium-cerium alloy and microalloying, and adds magnesium-rare earth compound modifier and carry out Metamorphism treatment, and the inclusion therefore in roll is few, the high purity of microstructure, and crystal grain is tiny;

5) roll of the present invention is applied on hot strip rolling mill and merchant bar mill, and steel rolling amount improves more than 4.5 times than high Ni-Cr infinite cold hardness cast iron roll, improve 3 ~ 4 times, and production cost only increases by 20% ~ 25% than bayesian ductile iron roll.

Embodiment

Below in conjunction with embodiment, the invention will be further elaborated; Embodiment only for illustration of the present invention, instead of limits the present invention by any way.

embodiment 1

Adopt the medium-frequency induction furnace melting high-boron low-alloy high-speed steel roll of 500 kilograms, concrete technology step is as follows:

1) roll alloy material adopts electrosmelting; With the waste material steel scrap of rapid steel, the pig iron, ferrotungsten, the fusing of vanadium iron Hybrid Heating; Ferrochrome is added after molten steel is melting down;

2) after stokehold adjustment C, W, V, Si, Mn composition scope according to the invention, temperature is risen to 1520 DEG C, add the deoxidation of aluminum-calcium-magnesium-cerium alloy, then add ferrochrome, ferrotianium, ferromanganese successively, come out of the stove when molten steel rises to 1635 DEG C, will 1230 DEG C be heated to and the ferro-boron particle of the 7 ~ 10mm be crushed to pours ladle with stream simultaneously;

3) adding magnesium-rare earth in ladle bottom in advance and make compound modifier, after 203 DEG C dry, with pouring method in bag, compound modification treatment being carried out to molten steel;

4) after molten steel is come out of the stove 4 minutes, carry out Argon purification to ladle, argon blowing time is 4 minutes, and liquid steel temperature reaches 1474 DEG C and pours into a mould;

5) method of pouring into a mould adopts centre spinning method to carry out cast roller body; Then spheroidal graphite cast iron liquation is used to fill roller core;

6) roll poured into a mould carries out isothermal annealing process, and annealing heating temperature is 1000 DEG C, and soaking time is 10 hours, cools to less than 700 DEG C with the furnace, and air cooling, to room temperature, carries out roughing;

7) roll after roughing is heated to 906 DEG C, is incubated after 7 hours, comes out of the stove air-cooled 34 minutes, then carries out quench treatment; Quenching adopts atomized water spray cooling roll; Temperature carries out temper lower than when 400 DEG C;

8) in roll drawing process, first roll is heated to 562 DEG C, is incubated after 6.5 hours, is chilled to less than 200 DEG C with stove, air cooling, then tempering twice under same process;

9) roll after temper is good is refined to size and the precision of regulation.

The present embodiment roller body chemical composition is in table 1, and body of roll mechanical property is in table 2.

Table 1 roller body chemical composition (massfraction, %)

Element	C	Cr	B	W	V	Si	Mn	Ti
									Composition	0.69	1.32	2.53	1.12	1.20	0.54	0.22	0.08
Element	Mg	RE	P	S	Fe
									Composition	0.16	0.10	0.032	0.027	Surplus

Table 2 roller body mechanical property

Hardness/HRC	Impelling strength/(J/cm2)	Tensile strength/MPa	Depth of hardening zone/mm
				63.2	13.6	988.4	79.7

embodiment 2

Adopt the medium-frequency induction furnace melting high-boron low-alloy high-speed steel roll of 1000 kilograms, concrete technology step is as follows:

1) roll alloy material adopts electrosmelting; With the waste material steel scrap of rapid steel, the pig iron, ferrotungsten, the fusing of vanadium iron Hybrid Heating; Ferrochrome is added after molten steel is melting down;

2) after stokehold adjustment C, W, V, Si, Mn composition scope according to the invention, temperature is risen to 1564 DEG C, add the deoxidation of aluminum-calcium-magnesium-cerium alloy, then add ferrochrome, ferrotianium, ferromanganese successively, come out of the stove when molten steel rises to 1644 DEG C, will 1278 DEG C be heated to and the ferro-boron particle of the 7 ~ 10mm be crushed to pours ladle with stream simultaneously;

3) adding magnesium-rare earth in ladle bottom in advance and make compound modifier, after 220 DEG C dry, with pouring method in bag, compound modification treatment being carried out to molten steel;

4) after molten steel is come out of the stove 6 minutes, carry out Argon purification to ladle, argon blowing time is 6 minutes, and liquid steel temperature reaches 1482 DEG C and pours into a mould;

5) method of pouring into a mould adopts centre spinning method to carry out cast roller body; Then spheroidal graphite cast iron liquation is used to fill roller core;

6) roll poured into a mould carries out isothermal annealing process, and annealing heating temperature is 1023 DEG C, and soaking time is 11 hours, cools to less than 700 DEG C with the furnace, and air cooling, to room temperature, carries out roughing;

7) roll after roughing is heated to 925 DEG C, is incubated after 8.5 hours, comes out of the stove air-cooled 45 minutes, then carries out quench treatment; Quenching adopts atomized water spray cooling roll; Temperature carries out temper lower than when 400 DEG C;

8) in roll drawing process, first roll is heated to 575 DEG C, is incubated after 8 hours, is chilled to less than 200 DEG C with stove, air cooling, then tempering twice under same process;

9) roll after temper is good is refined to size and the precision of regulation.

The present embodiment roller body chemical composition is in table 3, and body of roll mechanical property is in table 4.

Table 3 roller body chemical composition (massfraction, %)

Element	C	Cr	B	W	V	Si	Mn	Ti
									Composition	0.74	2.24	2.71	1.38	1.42	0.62	0.35	0.12
Element	Mg	RE	P	S	Fe
									Composition	0.19	0.12	0.023	0.034	Surplus

Table 4 roller body mechanical property

Hardness/HRC	Impelling strength/(J/cm2)	Tensile strength/MPa	Depth of hardening zone/mm
				64.1	13.3	1004.8	82.4

embodiment 3

Adopt the medium-frequency induction furnace melting high-boron low-alloy high-speed steel roll of 1000 kilograms, concrete technology step is as follows:

1) roll alloy material adopts electrosmelting; With the waste material steel scrap of rapid steel, the pig iron, ferrotungsten, the fusing of vanadium iron Hybrid Heating; Ferrochrome is added after molten steel is melting down;

2) stokehold adjusting component qualified after temperature is risen to 1604 DEG C, add the deoxidation of aluminum-calcium-magnesium-cerium alloy, then add ferrochrome, ferrotianium, ferromanganese successively, come out of the stove when molten steel rises to 1656 DEG C, will 1300 DEG C be heated to and the ferro-boron particle of the 7 ~ 10mm be crushed to pours ladle with stream simultaneously;

3) adding the compound modifier containing the trace element such as rare earth, magnesium alloy in ladle bottom in advance, after 230 DEG C dry, with pouring method in bag, compound modification treatment being carried out to molten steel;

4) after molten steel is come out of the stove 6 minutes, carry out Argon purification to ladle, argon blowing time is 8 minutes, and liquid steel temperature reaches 1488 DEG C and pours into a mould;

5) method of pouring into a mould adopts centre spinning method to carry out cast roller body; Then spheroidal graphite cast iron liquation is used to fill roller core;

6) roll poured into a mould carries out isothermal annealing process, and annealing heating temperature is 1045 DEG C, and soaking time is 11 hours, cools to less than 700 DEG C with the furnace, and air cooling, to room temperature, carries out roughing;

7) roll after roughing is heated to 946 DEG C, is incubated after 10 hours, comes out of the stove air-cooled 48 minutes, then carries out quench treatment; Quenching adopts atomized water spray cooling roll; Temperature carries out temper lower than when 400 DEG C;

8) in roll drawing process, first roll is heated to 582 DEG C, is incubated after 10 hours, is chilled to less than 200 DEG C with stove, air cooling, then tempering twice under same process;

9) roll after temper is good is refined to size and the precision of regulation.

The present embodiment roller body chemical composition is in table 5, and body of roll mechanical property is in table 6.

Table 5 roller body chemical composition (massfraction, %)

Element	C	Cr	B	W	V	Si	Mn	Ti
									Composition	0.82	2.38	2.98	1.47	1.51	0.63	0.37	0.12
Element	Mg	RE	P	S	Fe
									Composition	0.19	0.12	0.028	0.027	Surplus

Table 6 roller body mechanical property

Hardness/HRC	Impelling strength/(J/cm2)	Tensile strength/MPa	Depth of hardening zone/mm
				63.6	13.1	1012.5	81.6

Claims (2)

1. a boracic low-alloy high-speed steel rolls, is made up of the body of roll and roller core two portions, and roller core is Nodular cast iron material, it is characterized in that: its chemical composition of the body of roll calculates according to weight percentage and is: C:0.7 ~ 0.8, Cr:1.3 ~ 2.4, B:2.50 ~ 3.0, W:1.0 ~ 1.5, V:1.0 ~ 1.5, Si :≤1.0, Mn :≤0.4, Ti:0.09 ~ 0.12, Mg:0.16 ~ 0.19, RE:0.10 ~ 0.12, P :≤0.03, S≤0.03, surplus is Fe and inevitable trace impurity.

2. the manufacture method of a kind of boracic low-alloy high-speed steel rolls as claimed in claim 1, is characterized in that comprising the steps:

1) roll alloy material adopts electrosmelting; With the waste material steel scrap of rapid steel, the pig iron, ferrotungsten, the fusing of vanadium iron Hybrid Heating; Ferrochrome is added after molten steel is melting down;

2) after stokehold adjustment C, W, V, Si, Mn composition meets scope, temperature is risen to 1560 ~ 1600 DEG C, add the deoxidation of aluminum-calcium-magnesium-cerium alloy, then add ferrochrome, ferrotianium successively, come out of the stove when molten steel rises to 1630 ~ 1650 DEG C, will 1200 ~ 1300 DEG C be heated to and the ferro-boron particle being crushed to 7 ~ 10mm pours ladle with stream simultaneously;

3) adding magnesium-rare earth in advance in ladle bottom, after 200 ~ 230 DEG C dry, with pouring method in bag, compound modification treatment being carried out to molten steel;

4) after molten steel is come out of the stove 4 ~ 6 minutes, carry out Argon purification to ladle, argon blowing time is 4 ~ 8 minutes, and liquid steel temperature reaches 1470 ~ 1490 DEG C and can pour into a mould;

5) method of pouring into a mould adopts centre spinning method to carry out cast roller body; Then spheroidal graphite cast iron cast roller core is used;

6) roll poured into a mould will carry out isothermal annealing process, and annealing heating temperature is 1000 ~ 1040 DEG C, and soaking time is 10 ~ 12 hours, cools to the furnace after below 700 DEG C, and air cooling, to room temperature, carries out roughing;

7) roll after roughing is heated to 900 ~ 950 DEG C, is incubated after 7 ~ 10 hours, comes out of the stove air-cooled 30 ~ 50 minutes, then carries out quench treatment; Quenching adopts atomized water spray cooling roll; Temperature carries out temper lower than 400 DEG C;

8) in roll drawing process, first roll is heated to 560 ~ 580 DEG C, is incubated after 6 ~ 10 hours, is chilled to less than 200 DEG C with stove, air cooling, then tempering twice under same process;

9) roll after temper is good is refined to size and the precision of regulation.