CN100453681C - High boron wear-resisting casting steel and preparation process thereof - Google Patents

Abstract

The present invention discloses one kind of antiwear high-boron cast steel and its preparation process. The antiwear high-boron cast steel has the chemical components including C 0.10-0.50 wt%, B 0.8-5.0 wt%, Cu 0.3-0.6 wt%, Mn 0.8-2.0 wt%, Cr 1.0-2.5 wt%, Si less than 1.5 wt%, Ti 0.08-0.20 wt%, Ce 0.04-0.12 wt%, Mg 0.02-0.18 wt%, N 0.06-0.18 wt%, S less than 0.05 wt%, P less than 0.05 wt%, and Fe and inevitable impurity for the rest. Its preparation process includes smelting in an electric furnace while adding ferromanganese, frrroboron and Al to deoxidize, composite modification of molten steel, fast cooling, and low temperature tempering to eliminate stress. The present invention has simple production process, low production cost and other advantages.

Description

A kind of high boron wear-resisting casting steel and preparation method thereof

Technical field

The invention belongs to metal wear resistant material and make the field, relate to a kind of cast steel, particularly a kind of high boron wear-resisting casting steel and preparation method thereof.

Background technology

Because the hazardness of engineering goods wear out failure is very big, each industrial sector is all classified its vulnerable part as the emphasis brainstorm subject, and the quality that improves opposing abrasive wear material is to improve the key in vulnerable part life-span.Aspect wear-resistant grinding abrasion material, be extensive use of nickel hard white iron and high-chromium white cast iron both at home and abroad.Chinese invention patent CN1039267 has reported a kind of composition and preparation technology thereof of antiwear high-chromium cast iron, the concrete chemical ingredients (by weight percentage) of this cast iron is 2.9～3.2%C, 0.4～0.8%Si, 0.4～1.0%Mn, 1.2～2.0%Mo, 18.0～20.0%Cr, 4.0～5.0%V, 0.8～1.2%Cu, 0.05～0.5%RE, P＜0.08%, S＜0.05%, all the other are iron.This antiwear high-chromium cast iron is particularly suitable for being produced in the field such as metallurgy, the anti abrasive component that Working environment is very harsh.This cast iron is compared with common high-abrasive material, have wear-resistant, good mechanical property, the thermal treatment process advantage that simply is easy to grasp and cuts down the consumption of energy etc.But contain alloying elements such as more vanadium, molybdenum in this antifriction cast iron, production cost is very high.In addition, the as-cast structure of nickel hard white iron be (Fe, Cr) ₃C+ martensite+austenite, wherein carbide is the cementite that is continuous net-shaped distribution, microhardness is 840～1100Hv, has resistance to abrasion preferably.Because being becoming tight supply day of nickel, price rises steadily, and causes the nickel hard white iron production cost sharply soaring.And the chromium content of high-chromium white cast iron is more, and production cost is higher, and is easy to crack not enough and also usually add alloying elements such as expensive nickel, molybdenum in order to improve hardening capacity when also there is high-temperature heat treatment in high-chromium white cast iron.In recent years, utilize the high rigidity of boride and good thermostability, it with boride the attention that the research of the high-abrasive material of main wear-resisting hard phase is subjected to domestic and international investigation of materials person day by day, it is the hard surfacing electrode of main alloy element that Chinese invention patent CN1086471 has reported with boron, is best suited for to be subjected to the following strong abrasive wear machinery part surface of medium impact to strengthen built-up welding.Adopting core wire is H08 series soft steel, adds heavy dose of norbide and a spot of tungsten, vanadium, niobium, rare earth alloy element in the coating, and its weight coefficient side 50～100% can not eliminate rust during built-up welding, not preheating, and the AC and DC welding machine all can use.The hardness of overlay cladding can reach 65～70HRC, and wear resistance is 17.38 times of quenching 65Mn steel.Be applicable to the built-up welding on The middle pan of scraper conveyor, turbine blade, blast furnace top bell, feed screw blade, drilling rod, brick extruding machine auger, excavator bucket teeth, the coke-oven plant's coke pushing plate.Chinese invention patent CN1277087 has also reported a kind of high-hardness wear-resisting bead welding rod, be exclusively used in the anti abrasive parts of Repair Welding, parts, it is made of core wire and coating layer, the composition and the ratio (by weight percentage) that it is characterized in that the coating layer are as follows: chromium 25～45%, boron powder 10～30%, nickel 0.5～8%, fluorite 10～20%, manganese 0.5～6%, rare earth 5～15%, silicon 0.5～7%, quartz sand 2～8%, molybdenum 0.5～10%, marble 6～15%, vanadium 0.5～8%, rutile 1～10%, titanium dioxide 1～8%, electrode diameter is generally 3.2～5.0mm, and its core wire is the H08A steel core; The built-up welding hardness of welding rod can reach 62～65HRC, has wear resistance preferably.Chinese invention patent CN1065689 has also reported on the surface that contains boride that steel surface adopts boriding process to obtain and has also shown excellent abrasive.But adopt that bead-welding technology obtains contain the boride wearing layer and the body material bonding strength is lower, easily cracked even peel off under the gouging abrasion operating mode, and the boride wearing layer thin thickness that adopts surface boronizing technology to obtain is difficult to resist heavily loaded high stress material abrasion.Therefore, adopt cast moulding method, developing a kind of lath martensite with intensity height, good toughness is matrix, inlays the high boron wear-resisting casting steel of the high rigidity boride of some amount on matrix, to satisfy heavily stressed abrasive wear operating mode, will be extremely important.

Summary of the invention

The object of the invention provides a kind of high boron wear-resisting casting steel and preparation method thereof, adds more boron in plain carbon stool, makes its boride that forms more high rigidity, improves the cast steel wear resistance.Because the solid solubility of boron in α-Fe and γ-Fe is extremely low, in order to improve the hardening capacity of steel, has also added an amount of copper and manganese.In order to improve the anti-temper resistance of high-boron cast steel, also add an amount of chromium.In addition,, improve the intensity and the toughness of high-boron cast steel, also add elements such as a spot of cerium, magnesium, titanium, nitrogen for form and the distribution that improves boride.High boron wear-resisting casting steel of the present invention can be used general smelting equipment melting molten steel, and fluidity molten steel is good, and Tc is low, adopts the conventional cast method easily to be shaped.In conjunction with adopting the normal quenching treatment process, can obtain intensity and the good high boron wear-resisting casting steel of hardness height, toughness and wear resistance.

Purpose of the present invention can be achieved by following technical measures:

A kind of high boron wear-resisting casting steel is characterized in that the chemical ingredients and the weight percent thereof of this high boron wear-resisting casting steel of making is: C:0.10%～0.50%; B:0.8%～5.0%; Cu:0.3%～0.6%; Mn:0.8%～2.0%; Cr:1.0%～2.5%; Si＜1.5%; Ti:0.08%～0.20%; Ce:0.04%～0.12%; Mg:0.02%～0.18%; N:0.06%～0.18%; S＜0.05%; P＜0.05%; Surplus is Fe and inevitable trace impurity.

Electrosmelting is adopted in the preparation of above-mentioned high boron wear-resisting casting steel, and its manufacturing technology steps is:

1. with ordinary scrap steel, the pig iron, ferrochrome, the fusing of copper coin Hybrid Heating, the molten clear back of molten steel adds ferromanganese and ferro-boron;

2. the stokehold is adjusted to branch and temperature is risen to 1580～1650 ℃ after qualified, adds the aluminium deoxidation that accounts for molten steel weight 0.10%～0.35%, then comes out of the stove;

3. ferrotianium, cerium base magnesium-rare earth and nitrogenous substances are crushed to the fritter of granularity less than 15mm, after oven dry below 250 ℃, place the casting ladle bottom, with the method that pours in the bag molten steel is carried out composite inoculating and handle;

4. be shaped 1420～1480 ℃ of pouring molten steel temperature with the conventional cast method;

5. foundry goods adopts modes such as water-cooled or oil cooling to cool off fast after 900～1050 ℃ of high temperature austeniteizations, subsequently after 150～300 ℃ of insulations the cold or air cooling of stove to room temperature.

The technique effect that the present invention brings has the following aspects:

1. produce high boron wear-resisting casting steel with the present invention, sufficient raw does not contain valuable alloying element, low production cost, and technology is easy.

2. produce high boron wear-resisting casting steel with the present invention, contain the high rigidity eutectic boride more than 5% in the metallographic structure, matrix is the good tiny lath martensite of obdurability, and high-boron cast steel of the present invention is the hardness height not only, and intensity and good toughness.

3. produce high boron wear-resisting casting steel with the present invention, handle by adopting cerium, titanium and nitrogen to carry out composite inoculating, it organizes obvious refinement, and obdurability increases substantially.After magnesium was handled, The amount of inclusions reduced, and form and also further improvement of distribution, and the performance of high boron wear-resisting casting steel is further improved.

4. high boron wear-resisting casting steel of the present invention, after heat treatment, homogeneous microstructure, mechanical property is improved, and its hardness is greater than 60HRC, and impelling strength is greater than 150kJ/m ², bending strength is greater than 1200MPa, and the wear resistance under the gouging abrasion operating mode obviously is better than nickel hard white iron and high-chromium white cast iron.

Embodiment

The embodiment that provides below in conjunction with the contriver describes in further detail the present invention.

According to technical scheme of the present invention, the chemical ingredients of this high boron wear-resisting casting steel that makes and weight percent thereof are: C:0.10%～0.50%; B:0.8%～5.0%; Cu:0.3%～0.6%; Mn:0.8%～2.0%; Cr:1.0%～2.5%; Si＜1.5%; Ti:0.08%～0.20%; Ce:0.04%～0.12%; Mg:0.02%～0.18%; N:0.06%～0.18%; S＜0.05%; P＜0.05%; Surplus is Fe and inevitable trace impurity.

The performance of alloy material is by the metallographic structure decision, and alloy organizing depends on chemical ingredients and thermal treatment process, and chemical ingredients of the present invention is to determine like this:

Carbon: carbon is the principal element in the wearable cast steel, it mainly acts on is to improve hardenability and hardening capacity, and carbon content is low excessively, will occur the pearlitic structure that hardness is low, wear no resistance in the quenching structure, even ferritic structure appears, be unfavorable for improving the high-boron cast steel wear resistance.When carbon content is too high, a large amount of brittle high carbon martensites can appear in the quenching structure, reduced the intensity and the toughness of high-boron cast steel, cause easily peeling off in the high-boron cast steel use even rupturing, take all factors into consideration, carbon content is controlled at 0.10%～0.50%.

Boron: boron is the main alloy element in the high-boron cast steel, mainly is in order to obtain the boride of high rigidity, and part of boron is dissolved in matrix, helps improving the hardening capacity and the hardenability of high-boron cast steel.The boron add-on is very few, and boride quantity is few, and the cast steel wear resistance is low, and the boron add-on is too much, and boride quantity is too many, and the intensity of cast steel and toughness are reduced significantly, takes all factors into consideration, and boron content is controlled at 0.8%～5.0%.

Copper: copper is non-carbide and boride forming element, mainly is dissolved in matrix, can obviously improve matrix hardening capacity, and the copper that is dissolved in the matrix improves the corrosion proof effect of high-boron cast steel in addition.The copper add-on is very few, not obvious to the hardening capacity effect that improves high-boron cast steel, add-on is too much, part copper also can be separated out at grain boundary precipitate, inoperative to the hardening capacity of improving high-boron cast steel, the copper that precipitation is separated out reduces the wear resistance of high-boron cast steel on the contrary because its hardness is too low, take all factors into consideration, copper content is controlled at 0.3%～0.6%.

Manganese: manganese is the element that enlarges the γ phase region, manganese enters the boride except part in high-boron cast steel, mainly be dissolved in matrix, obviously improve high-boron cast steel hardening capacity, when add-on was too much, retained austenite obviously increased in the quenching structure, reduced the high-boron cast steel wear resistance on the contrary, take all factors into consideration, manganese content is controlled at 0.8%～2.0%.

Chromium: chromium part in high-boron cast steel enters boride, improve the stability of boride, part enters matrix, improves the hardening capacity and the temper resistance of high-boron cast steel, the chromium add-on very little, effect to high-boron cast steel is not obvious, and add-on is too much, chromium carbide can occur containing, matrix carbon content is reduced, reduced the hardening capacity and the hardenability of matrix, taken all factors into consideration, chromium content has been controlled at 1.0%～2.5%.

Silicon: silicon is non-carbide and boride forming element, mainly dissolves in matrix in high-boron cast steel, has the matrix effect of reinforcement and matrix is become fragile, and therefore should reduce the silicone content in the high-boron cast steel as far as possible, and its content is controlled at below 1.5%.

Cerium: add micro-cerium mischmetal element in the ferrous materials, help improving the as cast condition crystal structure, crystal grain thinning, purification crystal boundary, the harmful toughness that is mingled with, improves cast steel of removal.Cerium is a surface active element, can on the eutectic boride, select absorption, during eutectic solidification, it mainly is gathered on the direction of eutectic boride preferred growth, stop atoms such as Fe, B, Cr in the molten steel normally to be grown in the crystal of eutectic boride, thereby reduced the leading speed of growth of eutectic boride, forced that the eutectic boride diminishes, rust in this direction.In addition, eutectic austenite will stretch in the cold phase region grows, and the boride on this direction of growth is formed surround shell, also limits and reduced the speed of growth of eutectic boride on this direction, and this just further impels, and the eutectic boride diminishes, rust.Cerium increases the effect of austenite forming core in addition, impels austenite structure tightr, tiny and even, because eutectic boride and austenitic refinement, the intensity and the toughness of high-boron cast steel significantly improve.But excessive cerium impels that inclusion increases in the cast steel, reduces the intensity and the toughness of high-boron cast steel on the contrary, therefore cerium content is controlled at 0.04%～0.12%.

Nitrogen and titanium: the main purpose that adds nitrogen and titanium in the high-boron cast steel is to utilize nitrogen and titanium to have the ability of stronger formation high-melting-point TiN, and TiN is 3.9% with γ mismatch mutually.According to Turnbull and Vonnegut (Turnbull D and Vonnegut B.Nucleation Catalysis.Industrial and Engineering Chemistry.1952,44 (6): 1292～1298.) the mismatch theory of Ti Chuing, in alloy graining process, when the two-phase mismatch less than 12%, dystectic compound is on good terms as non-spontaneous core, promotes forming core, make the as-cast structure refinement, and mismatch is more little, and effect is obvious more.Titanium nitride and high temperature γ lattice have very low mismatch, have very high fusing point again simultaneously, so intensive promotion forming core, can become crystallization nuclei, make the as cast condition grain refining, improve the obdurability of high-boron cast steel.Nitrogen and titanium add-on are very few, and the TiN particle of formation is very few, and not obvious to the improvement of high-boron cast steel structure refinement, add-on is too much, and the TiN particle too much and is easily assembled and grown up, and is unfavorable for refinement high-boron cast steel tissue, improves its mechanical property.Take all factors into consideration, titanium content is controlled at 0.08%～0.20%, nitrogen content is controlled at 0.06%～0.18%.

Magnesium: magnesium and sulphur, oxygen have great avidity, and violent metallurgical reaction can take place, and remove sulphur and oxygen in the cast steel, reduce oxide compound and sulfide inclusion in the cast steel.During solidification of molten steel, at first form MgO, it can be used as MgS, MnS and other core that is mingled with after coagulation.Because MgO disperses in molten steel especially, so magnesium can change type, quantity, size, form and the distribution of inclusion in the cast steel.An amount of magnesium can make in the cast steel inclusion become tiny, disperse.Life size is big, the Al of band corner angle ₂O ₃Be mingled with by size MgO little, spherical in shape and the duplex impurity that contains MgO and replace; Life size is big, the MnS of strip is mingled with by little, the subglobose MgO of size, contains the MgO duplex impurity and the MgS.MgO duplex impurity replaces, thereby has improved inclusion and form and the ability of expanding with matrix opposing crackle, has improved the toughness of cast steel.Magnesium add-on deficiency can not make cast steel that sufficient deoxidation, desulphurization reaction take place, and be unfavorable for the removal of inclusion.Add-on too much not only causes the waste of magnesium, and owing to reaction is too violent, MgO, the MgS etc. that float to the molten steel surface on making is mingled be involved in again in the molten steel, and the high-boron cast steel performance is produced adverse influence.Therefore Mg content is controlled at 0.02%～0.18%.

Inevitably trace impurity is to bring in the raw material, and p and s is wherein arranged, and all is harmful elements, and intensity, toughness and wear resistance in order to guarantee high-boron cast steel are controlled at sulphur content below 0.05%, and phosphorus content is controlled at below 0.05%.

High boron wear-resisting casting steel of the present invention can adopt common electrosmelting, and raw material is selected ordinary scrap steel, the pig iron, ferrochrome, copper coin, ferromanganese, ferro-boron, ferrotianium, cerium base magnesium-rare earth and nitrogenous substances for use.In the molten steel fusion process, earlier with steel scrap, the pig iron, ferrochrome, the fusing of copper coin Hybrid Heating, the molten clear back of molten steel adds ferromanganese and ferro-boron.Temperature is risen to 1580～1650 ℃ when the stokehold is adjusted to branch after qualified, add the aluminium deoxidation that accounts for molten steel weight 0.10%～0.35%, then come out of the stove.In advance ferrotianium, cerium base magnesium-rare earth and nitrogenous substances are crushed to the fritter of granularity less than 15mm, and after oven dry below 250 ℃, place the casting ladle bottom, with the method that pours in the bag molten steel is carried out composite inoculating and handle.

The high-boron cast steel liquation has good flowability and cast form performance, can adopt methods such as ordinary sand casting, lost foam casting, dewax precision casting, permanent mold casting and resin sand casting to be shaped.1420～1480 ℃ of pouring molten steel temperature.Foundry goods is difficult for scab, and the dead head cleaning is convenient.

As cast condition high-boron cast steel matrix is made up of martensite, austenite, perlite and ferrite, and homogeneity of structure is poor, and mechanical property is low, wear resistance is also poor, need heat-treat, mainly be in order to obtain the martensitic stucture that homogeneous microstructure distributes, to improve the wear resistance of high-boron cast steel.High-boron cast steel is after 900～1050 ℃ of high temperature austeniteizations, adopt modes such as water-cooled or oil cooling to cool off fast, can obtain the complex tissue that lath martensite adds boride, subsequently after 150～300 ℃ of insulations the cold or air cooling of stove to room temperature, reach the purpose of eliminating quenching stress, obtained intensity and the good high-boron cast steel of hardness height, toughness and wear resistance.

Below be the embodiment that the contriver provides, need to prove that following examples only are used to illustrate the present invention, the invention is not restricted to these embodiment.

Embodiment 1:

1. with the Hybrid Heating fusing in 500 kilograms of medium-frequency induction furnaces of ordinary scrap steel, the pig iron, ferrochrome and copper coin, the molten clear back of molten steel adds ferromanganese and ferro-boron;

2. the stokehold is adjusted to branch and temperature is risen to 1630 ℃ after qualified, adds the aluminium deoxidation that accounts for molten steel weight 0.23%, then comes out of the stove;

3. ferrotianium, cerium base magnesium-rare earth and nitrogenous substances are crushed to the fritter of granularity less than 15mm, after 245 ℃ of oven dry, place the casting ladle bottom, with the method that pours in the bag molten steel is carried out composite inoculating and handle;

4. foundry goods is shaped with unselected clay sand mold casting, 1450 ℃ of pouring molten steel temperature;

5. foundry goods adopts the oil cooling mode to cool off fast after 1020 ℃ of high temperature austeniteizations, subsequently 260 ℃ the insulation 4 hours after stove be chilled to room temperature.

The chemical ingredients of high-boron cast steel sees Table 1.On foundry goods, cut the sample testing hardness of φ 15mm * 20mm, cut 10mm * 10mm * 55mm non-notch sample, test impelling strength, cut φ 30mm * 340mm sample, the test bending strength, hardness is got 7 mean value, and impelling strength and bending strength are got the mean value of 3 samples, and the mechanical property of high-boron cast steel sees Table 2.

The chemical ingredients of table 1 high-boron cast steel (weight %)

Element	C	B	Cu	Mn	Cr	Si	Ti	Ce	Mg	N	S	P	Fe
														Composition	0.44	4.37	0.44	1.18	1.25	0.87	0.16	0.06	0.05	0.14	0.031	0.040	Surplus

The mechanical property of table 2 high-boron cast steel

Hardness (HRC)	Impelling strength (kJ/m 2)	Bending strength (MPa)
			62.7	169	1273

Embodiment 2:

1. with the Hybrid Heating fusing in 1500 kilograms of medium-frequency induction furnaces of ordinary scrap steel, the pig iron, ferrochrome, copper coin, the molten clear back of molten steel adds ferromanganese and ferro-boron;

2. the stokehold is adjusted to branch and temperature is risen to 1595 ℃ after qualified, adds the aluminium deoxidation that accounts for molten steel weight 0.14%, then comes out of the stove;

3. ferrotianium, cerium base magnesium-rare earth and nitrogenous substances are crushed to the fritter of granularity less than 15mm, after 230 ℃ of oven dry, place the casting ladle bottom, with the method that pours in the bag molten steel is carried out composite inoculating and handle;

4. foundry goods is shaped with ordinary resin sand mold casting, 1428 ℃ of pouring molten steel temperature;

5. foundry goods adopts water-cooling pattern to cool off fast after 915 ℃ of high temperature austeniteizations, subsequently 180 ℃ the insulation 6 hours after air cooling to room temperature.

The chemical ingredients of high-boron cast steel sees Table 3.On foundry goods, cut the sample testing hardness of φ 15mm * 20mm, cut 10mm * 10mm * 55mm non-notch sample, test impelling strength, cut φ 30mm * 340mm sample, the test bending strength, hardness is got 7 mean value, and impelling strength and bending strength are got the mean value of 3 samples, and the mechanical property of high-boron cast steel sees Table 4.

The chemical ingredients of table 3 high-boron cast steel (weight %)

Element	C	B	Cu	Mn	Cr	Si	Ti	Ce	Mg	N	S	P	Fe
														Composition	0.14	1.87	0.57	1.73	2.05	1.26	0.11	0.08	0.13	0.10	0.027	0.038	Surplus

The mechanical property of table 4 high-boron cast steel

Hardness (HRC)	Impelling strength (kJ/m 2)	Bending strength (MPa)
			60.3	192	1316

Make spare parts easy to wear such as grinder hammerhead, ball mills and ball grinding machine lining board with the high boron wear-resisting casting steel of the foregoing description preparation and carried out the installation use, the use result is as follows: the high boron wear-resisting casting steel abrading-ball uses on cement ball mill, ton cement ball consumption is 23 grams, the high boron wear-resisting casting steel abrading-ball uses on the ball body of powder of iron ore grinding machine, and ton breeze ball consumption is 874 grams.The high boron wear-resisting casting steel liner plate is used to grind coal dust in power plant, and the abrasion loss of average every month is 0.72mm.When the high boron wear-resisting casting steel tup was used for broken rhombspar, the tup unit consumption only was 4.7 gram/tons.

High boron wear-resisting casting steel of the present invention compared with prior art has following advantage:

High boron wear-resisting casting steel intensity of the present invention is high, good toughness, and high abrasion resistance does not rupture in the use procedure, and security is good. High boron wear-resisting casting steel of the present invention uses at hammer mill, its anti-wear performance obviously is better than potassium steel and steel alloy tup, suitable with the high-chromium white cast iron tup with nickel hard white iron, but overcome the deficiency that nickel hard white iron and high-chromium white cast iron easily peel off and rupture. High boron wear-resisting casting steel of the present invention uses at ball grinding machine lining board, its anti-wear performance obviously is better than potassium steel and steel alloy liner plate, suitable with nickel hard white iron and Cr White Cast Iron Liner Plate, and overcome the deficiency that nickel hard white iron and high-chromium white cast iron easily peel off and rupture. High boron wear-resisting casting steel of the present invention uses in ball mills, and its anti-wear performance obviously is better than wrought alloy steel abrading-ball, and is suitable with nickel hard white iron and Grinding Ball for High-Chromium White Cast Iron, and has overcome nickel hard white iron and the breakable deficiency of high-chromium white cast iron. High boron wear-resisting casting steel production technology of the present invention is simple, need not add the precious alloy element, and production cost is low. Use high boron wear-resisting casting steel of the present invention can significantly improve equipment operation rate, reduce broken, mill spare parts cost, alleviate labor strength, have good economic and social benefit.

Claims (2)

1. high boron wear-resisting casting steel is characterized in that the chemical ingredients and the weight percent thereof of this high boron wear-resisting casting steel of making is: C:0.10%～0.50%; B:4.37%～5.0%; Cu:0.3%～0.6%; Mn:0.8%～2.0%; Cr:1.0%～2.5%; Si＜1.5%; Ti:0.08%～0.20%; Ce:0.04%～0.12%; Mg:0.02%～0.18%; N:0.06%～0.18%; S＜0.05%; P＜0.05%; Surplus is Fe and inevitable trace impurity.

2, the preparation method of the described high boron wear-resisting casting steel of claim 1 adopts electrosmelting, it is characterized in that its processing step is:

1. with ordinary scrap steel, the pig iron, ferrochrome, the fusing of copper coin Hybrid Heating, the molten clear back of molten steel adds ferromanganese and ferro-boron;

2. the stokehold is adjusted to branch and temperature is risen to 1580 ℃～1650 ℃ after qualified, adds the aluminium deoxidation that accounts for molten steel weight 0.10%～0.35%, then comes out of the stove;

3. ferrotianium, cerium base magnesium-rare earth and nitrogenous substances are crushed to the fritter of granularity less than 15mm, after oven dry below 250 ℃, place the casting ladle bottom, with the method that pours in the bag molten steel is carried out composite inoculating and handle;

4. foundry goods is shaped with the conventional cast method, 1420 ℃～1480 ℃ of pouring molten steel temperature;

5. foundry goods adopts water-cooled or oil cooling mode to cool off fast after 900 ℃～1050 ℃ high temperature austeniteizations, subsequently after 150 ℃～300 ℃ insulations the cold or air cooling of stove to room temperature.