A processing technology for high-toughness and high-wear-resistant steel

Abstract

The present invention relates to the field of metallurgical technology, and specifically to a processing technology for high-toughness and high-wear-resistant steel. A processing technology for high-toughness and high-wear-resistant steel, comprising: smelting treatment, composite inoculant preparation, wire feeding inoculation treatment, casting and heat treatment. By using and adding composite silicon carbide powder in the composite inoculant, it is convenient to utilize the size effect of nano silicon carbide, so that nano silicon carbide can diffuse rapidly in molten steel and quickly disperse in the molten steel, which is beneficial to refine the grain size and increase the strength and plasticity of the steel. Moreover, after the molten steel is cast, the surface of the casting is quickly cooled by spraying water, which can accelerate the solidification of the molten steel and refine the internal structure of the steel. Then, after isothermal quenching heat treatment and tempering heat treatment at the corresponding temperature, a complex phase structure of martensite, bainite and residual austenite can be obtained, which effectively improves the toughness and wear resistance of the steel.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and more particularly to a processing technology for high-toughness and high-wear-resistant steel. Background Art

[0002] High-strength alloy steel, also known as high-strength steel, is a type of steel characterized by high tensile strength, high yield strength and good fatigue resistance. This material has very excellent physical and chemical properties, can cope with harsh working conditions such as heavy load, high speed, high temperature, etc., and has strong wear resistance and corrosion resistance, and can withstand long-term repeated use. It is widely used in automotive, aviation, marine and other fields.

[0003] Among them, martensitic high-strength steel is a stainless steel with excellent mechanical properties. Because it is very suitable for applications with high tensile strength and toughness, it is also widely used in the actual production process of pick bodies. However, martensitic high-strength steel itself has internal stress, is prone to deformation and cracking, and has unstable properties. When used under actual working conditions, its mechanical properties are manifested as insufficient plasticity and toughness, and low delayed fracture resistance, which leads to poor overall toughness and wear resistance of the steel.

[0004] Therefore, developing high-strength alloy steel with high hardness and high toughness and further improving the toughness and wear resistance of high-strength alloy steel are of great significance to improving the overall performance. Summary of the invention

[0005] In view of this, and in view of the deficiencies in the prior art, the present invention provides a processing technology for high-toughness and high-wear-resistant steel for improving the toughness and wear resistance of high-strength alloy steel.

[0006] A high-toughness and high-wear-resistant steel, characterized in that its chemical composition (weight %) includes:

[0007] C: 0.2-0.4%, Si: 1.5-1.8%, Mn: 1.3-1.5%, Cr: 0.6-0.8%, Ni: 0.3-0.5%, Mo: 0.3-0.4%, composite inoculant 0.4-1.5%, and the balance of Fe and inevitable impurity elements, wherein the composite inoculant includes: Al-10%Cr alloy, ferroniobium, boron carbide, 10μm silicon carbide and 50nm silicon carbide;

[0008] A processing technology for high-toughness and high-wear-resistant steel, comprising:

[0009] S1: smelting treatment,

[0010] According to the chemical composition of the steel, respectively calculate and weigh scrap steel, ferrosilicon, ferromanganese, ferrochrome, nickel plate, and ferromolybdenum, melt the scrap steel first, add nickel plate and ferromolybdenum to continue smelting after the scrap steel begins to melt, add ferrosilicon, ferrochrome and ferromanganese to refine after all the added metals are melted, obtain molten steel, and pour the molten steel into a molten steel treatment bag;

[0011] S2: Preparation of composite inoculant,

[0012] Al-10%Cr alloy, ferroniobium and boron carbide are mixed and smelted to react to form a master alloy, silicon carbide with an average particle size of 10 μm and silicon carbide with a particle size of 50 nm are mixed by magnetic stirring to obtain composite silicon carbide powder, the composite silicon carbide powder is added to the master alloy for mixing, the master alloy and the composite silicon carbide powder are mixed to prepare a composite inoculant, and the composite inoculant is added to a wire feeder;

[0013] S3: feeding wire inoculation treatment,

[0014] The molten steel treatment ladle is transferred to the wire feeding treatment place, and the composite inoculant in the wire feeding machine is sent into the molten steel in the molten steel treatment ladle. After the composite inoculant is completely sprayed into the molten steel, the wire feeding inoculation treatment is completed;

[0015] S4: Casting and heat treatment,

[0016] The molten steel after wire feeding inoculation treatment is poured into the mold on the casting machine. After all the molten steel enters the mold, water is sprayed on the outer surface of the mold to cool it down. After the casting solidifies and cools for a period of time, the casting is taken out of the mold, sanded and polished, and the casting is heated at 950-980℃, cooled, heated and kept at 300-340℃, and quenched. Then, the casting is subjected to secondary tempering treatment to complete the heat treatment operation and obtain steel.

[0017] Furthermore, step S1 smelting treatment specifically includes the following steps:

[0018] S1.1: According to the chemical composition of steel, calculate and weigh the scrap steel, ferrosilicon, ferromanganese, ferrochrome, nickel plate and ferromolybdenum respectively;

[0019] S1.2: Add the scrap steel into the crucible of the vacuum smelting furnace, preheat the crucible to 500-600°C, and evacuate to below 150Pa, fill the furnace with argon gas to keep the furnace in a state of slight negative pressure, the slight negative pressure range is -10--5Pa, melt the scrap steel at a melting rate of 3-5kg / min, and add nickel plate and ferromolybdenum to continue smelting after the scrap steel starts to melt;

[0020] S1.3: When all the metals added in the furnace are melted, ferrosilicon, ferrochrome and ferromanganese are added, and the temperature in the crucible is raised to 1500-1650°C for refining for 20-40 minutes to obtain molten steel;

[0021] S1.4: The molten steel is heated to 1680-1700°C and then taken out of the furnace into a molten steel treatment bag. After the molten steel is taken out of the furnace, a molten steel heat preservation agent is covered on the liquid surface of the molten steel.

[0022] Furthermore, step S2 of preparing the composite inoculant specifically comprises the following steps:

[0023] S2.1: Using a vacuum arc furnace, Al-10%Cr alloy, ferroniobium and boron carbide are melted in a weight ratio of 20:(1-3) to react and form a master alloy;

[0024] S2.2: Silicon carbide with an average particle size of 10 μm and silicon carbide with a particle size of 50 nm are mixed by magnetic stirring to obtain composite silicon carbide powder;

[0025] S2.3: adding the composite silicon carbide powder to the master alloy for mixing, wherein the weight ratio of the master alloy to the composite silicon carbide powder is 10:(1-3), and after mixing evenly, a composite inoculant is prepared;

[0026] S2.4: Add the composite inoculant into the wire feeder.

[0027] Further, step S3, the feeding wire inoculation process, specifically comprises the following steps:

[0028] S3.1: Transfer the molten steel treatment ladle to the feeding line treatment area;

[0029] S3.2: Under the condition of 1550-1600℃, the composite inoculant in the wire feeder is fed into the molten steel in the molten steel treatment ladle, and the composite inoculant is fed to the position 20-50mm from the bottom of the molten steel treatment ladle. The wire feeding speed is 12-15m / min, and the wire diameter is 9-12mm.

[0030] S3.3: After all the composite inoculant is sprayed into the molten steel, it is allowed to stand until the temperature of the molten steel drops to 1450-1500°C, completing the wire feeding inoculation process.

[0031] Furthermore, step S4 casting and heat treatment specifically includes the following steps:

[0032] S4.1: pouring the molten steel after the wire feeding inoculation treatment into the mold on the casting machine;

[0033] S4.2: After all the molten steel has entered the mold, immediately spray water on the outer surface of the mold to cool it for 60 to 80 seconds to accelerate the solidification of the molten steel and refine the internal structure of the steel;

[0034] S4.3: When the casting surface temperature is 280-300℃ after solidification and cooling, the casting is taken out from the mold, and after sand removal and grinding, the casting is placed in a high-temperature resistance furnace and heated to 950-980℃ at a heating rate of 12-15℃ / min and kept at this temperature for 2-3h to transform the steel structure into austenite.

[0035] S4.4: When the furnace temperature drops to 240-260°C, reheat to 300-340°C and keep warm for 40-50 minutes. Then, quickly put the casting into water preheated to 110-120°C for quenching. The cooling rate is 8-12°C / min and the heating rate is 12-15°C / min.

[0036] S4.5: After quenching, the furnace is cooled to a temperature of 120-150°C, and then the casting is placed in a high-temperature resistance furnace, the temperature is raised to 550-560°C, and kept at this temperature for 2-3 hours. The furnace is then cooled to a temperature of 80-100°C, and then the temperature is raised to 530-540°C, and kept at this temperature for 2-3 hours. The cooling rate is 5-10°C / min, and the heating rate is 8-12°C / min. The casting is taken out of the furnace and air-cooled to room temperature to complete the secondary tempering and obtain the steel.

[0037] Furthermore, the Al-10%Cr alloy is an aluminum-chromium alloy in which the chromium content accounts for 10%.

[0038] Furthermore, the molten steel insulation agent used in step S1.4 contains silicate, aluminum oxide and magnesium oxide.

[0039] Furthermore, in step S2.2, the weight ratio of 10 μm silicon carbide to 50 nm silicon carbide in the composite silicon carbide powder is 10:(2-5).

[0040] Furthermore, in step S3.2, the weight ratio of the amount of composite inoculant used for wire feeding to the molten steel is (1-3):200.

[0041] The present invention has the following advantages:

[0042] 1. In the process of preparing the composite inoculant, the present invention prepares and adds the composite silicon carbide powder, so that a large number of nano silicon carbide particles are attached to the surface of the micron silicon carbide particles, the agglomeration and floating of the nano silicon carbide particles are reduced, and the nano silicon carbide acts in a concentrated manner in a small area. When the composite inoculant is used to inoculate the molten steel, the size effect of the nano silicon carbide is utilized to make the nano silicon carbide diffuse rapidly in the molten steel and quickly dispersed in the molten steel, so as to ensure that the cores of the effective heterogeneous nucleation in the molten steel can exist in large quantities and dispersedly, which is beneficial to refine the grain size, increase the strength and plasticity of the steel, and thus improve the toughness of the steel. In addition, the addition of the composite silicon carbide powder can increase the wear-resistant hard phase of the steel component and improve the wear resistance of the steel.

[0043] 2. In the present invention, during the inoculation treatment, the composite inoculant is continuously and evenly inserted into the appropriate position at the bottom of the molten steel treatment ladle that isolates the air and effectively flows at a certain speed and length by using an automatic feeding line, which is conducive to stable and controlled inoculation treatment at a suitable molten steel temperature and high pressure, improves the absorption rate and reaction stability of the composite inoculant, and further improves the processing effect and wear resistance and high toughness of the steel.

[0044] 3. In the present invention, after the molten steel is cast, the outer surface of the casting mold is quickly cooled by spraying water, so that the solidification of the molten steel can be accelerated and the internal structure of the steel can be refined. After isothermal quenching heat treatment and tempering heat treatment at corresponding temperatures, the steel structure can be completely transformed into austenite, so that the structure after phase transformation has high strength and fine grains, and then most of the austenite in the steel structure is divided to form lower bainite, and the untransformed austenite is transformed into lath martensite or forms retained austenite, so as to obtain a complex phase structure of martensite, bainite and retained austenite, and effectively improve the plasticity, toughness and wear resistance of the steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a structural schematic diagram of the processing technology of high-toughness and high-wear-resistant steel used in an embodiment of the present invention.

[0046] Figure 2 It is a table diagram of the steel mechanical property testing of the embodiments and comparative examples of the present invention.

[0047] Figure 3 The table is a diagram showing the wear resistance of steel materials according to the embodiments and comparative examples of the present invention. DETAILED DESCRIPTION

[0048] In order to enable persons skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0049] Embodiment 1: A processing technology of high toughness and high wear-resistant steel, such as Figure 1 As shown, the specific steps include:

[0050] S1: smelting treatment,

[0051] S1.1: According to the chemical composition of steel, calculate and weigh the scrap steel, ferrosilicon, ferromanganese, ferrochrome, nickel plate and ferromolybdenum respectively;

[0052] S1.2: Add the scrap steel into the crucible of the vacuum smelting furnace, preheat the crucible to 600°C, and evacuate it to below 150Pa, fill the furnace with argon gas to keep the furnace at a slightly negative pressure of -5Pa, melt the scrap steel at a melting rate of 5kg / min, and add nickel plate and ferromolybdenum to continue smelting after the scrap steel begins to melt;

[0053] S1.3: When all the metals added in the furnace are melted, ferrosilicon, ferrochrome and ferromanganese are added, and the temperature in the crucible is raised to 1650°C for refining for 40 minutes to obtain molten steel;

[0054] S1.4: The molten steel is heated to 1700°C and then discharged into a molten steel treatment ladle. After the molten steel is discharged, a molten steel heat preservation agent is applied to the surface of the molten steel;

[0055] S2: Preparation of composite inoculant,

[0056] S2.1: using a vacuum arc furnace to melt Al-10%Cr alloy, ferroniobium and boron carbide in a weight ratio of 20:3 to react and form a master alloy;

[0057] S2.2: Silicon carbide with an average particle size of 10 μm and silicon carbide with a particle size of 50 nm are mixed by magnetic stirring at a weight ratio of 10:5 to obtain composite silicon carbide powder;

[0058] S2.3: adding the composite silicon carbide powder to the master alloy for mixing, wherein the weight ratio of the master alloy to the composite silicon carbide powder is 10:3, and after mixing evenly, a composite inoculant is prepared;

[0059] S2.4: Add the composite inoculant into the wire feeder;

[0060] S3: feeding wire inoculation treatment,

[0061] S3.1: Transfer the molten steel treatment ladle to the feeding line treatment area;

[0062] S3.2: Under the condition of 1700℃, the composite inoculant in the wire feeder is fed into the molten steel in the molten steel treatment ladle. The wire diameter of the composite inoculant is 12mm. The composite inoculant is fed to the position 50mm from the bottom of the molten steel treatment ladle. The weight ratio of the composite inoculant feeding amount to the molten steel is 3:200, and the wire feeding speed is 15m / min.

[0063] S3.3: After all the composite inoculant is sprayed into the molten steel, the steel is allowed to stand until the temperature of the molten steel drops to 1500°C, completing the wire feeding inoculation process;

[0064] S4: Casting and heat treatment,

[0065] S4.1: pouring the molten steel after the wire feeding inoculation treatment into the mold on the casting machine;

[0066] S4.2: After all the molten steel has entered the mold, immediately spray water on the outer surface of the mold to cool it for 80 seconds to accelerate the solidification of the molten steel and refine the internal structure of the steel;

[0067] S4.3: When the casting is solidified and cooled to a surface temperature of 300°C, the casting is taken out of the mold, and after sand removal and polishing, the casting is placed in a high-temperature resistance furnace and heated to 980°C at a heating rate of 15°C / min for 3 hours to transform the steel structure into austenite;

[0068] S4.4: When the furnace temperature drops to 260°C, reheat to 340°C and keep warm for 50 minutes. Then, quickly put the casting into water preheated to 120°C for quenching. The cooling rate is 12°C / min and the heating rate is 15°C / min.

[0069] S4.5: After quenching, the furnace is cooled to 150°C, and then the casting is placed in a high-temperature resistance furnace. The temperature is raised to 560°C and kept at this temperature for 2 hours. The furnace is then cooled to 100°C, and then the temperature is raised to 540°C and kept at this temperature for 2 hours. The cooling rate is 10°C / min and the heating rate is 12°C / min. The casting is taken out of the furnace and air-cooled to room temperature to complete the secondary tempering and obtain the steel.

[0070] Embodiment 2: A processing technology of high toughness and high wear-resistant steel, such as Figure 1 As shown, the specific steps include:

[0071] S1: smelting treatment,

[0072] S1.1: According to the chemical composition of steel, calculate and weigh the scrap steel, ferrosilicon, ferromanganese, ferrochrome, nickel plate and ferromolybdenum respectively;

[0073] S1.2: Add the scrap steel into the crucible of the vacuum smelting furnace, preheat the crucible to 500°C, and evacuate it to below 150Pa. Fill the furnace with argon gas to keep the furnace at a slightly negative pressure of -10Pa. Melt the scrap steel at a melting rate of 3kg / min. After the scrap steel begins to melt, add nickel plate and ferromolybdenum to continue smelting.

[0074] S1.3: When all the metals added in the furnace are melted, add ferrosilicon, ferrochrome and ferromanganese, raise the temperature in the crucible to 1500℃ for refining, and refine for 30 minutes to obtain molten steel;

[0075] S1.4: The molten steel is heated to 1680°C and then discharged into a molten steel treatment bag. After the molten steel is discharged, a molten steel heat preservation agent is applied to the surface of the molten steel;

[0076] S2: Preparation of composite inoculant,

[0077] S2.1: using a vacuum arc furnace to melt Al-10%Cr alloy, ferroniobium and boron carbide in a weight ratio of 20:3 to react and form a master alloy;

[0078] S2.2: Silicon carbide with an average particle size of 10 μm and silicon carbide with a particle size of 50 nm are mixed by magnetic stirring at a weight ratio of 10:5 to obtain composite silicon carbide powder;

[0079] S2.3: adding the composite silicon carbide powder to the master alloy for mixing, wherein the weight ratio of the master alloy to the composite silicon carbide powder is 10:3, and after mixing evenly, a composite inoculant is prepared;

[0080] S2.4: Add the composite inoculant into the wire feeder;

[0081] S3: feeding wire inoculation treatment,

[0082] S3.1: Transfer the molten steel treatment ladle to the feeding line treatment area;

[0083] S3.2: Under the condition of 1680℃, the composite inoculant in the wire feeder is fed into the molten steel in the molten steel treatment ladle. The wire diameter of the composite inoculant is 9mm. The composite inoculant is fed to the position 30mm from the bottom of the molten steel treatment ladle. The weight ratio of the composite inoculant feeding amount to the molten steel is 3:200, and the wire feeding speed is 12m / min.

[0084] S3.3: After all the composite inoculant is sprayed into the molten steel, the steel is allowed to stand until the temperature of the molten steel drops to 1450°C, completing the wire feeding inoculation process;

[0085] S4: Casting and heat treatment,

[0086] S4.1: pouring the molten steel after the wire feeding inoculation treatment into the mold on the casting machine;

[0087] S4.2: After all the molten steel has entered the mold, immediately spray water on the outer surface of the mold to cool it for 60 seconds to accelerate the solidification of the molten steel and refine the internal structure of the steel;

[0088] S4.3: When the casting surface temperature is 280℃ after solidification and cooling, the casting is taken out from the mold, and after sand removal and grinding, the casting is placed in a high-temperature resistance furnace and heated to 950℃ at a heating rate of 12℃ / min and kept at this temperature for 2h, so that the steel structure is completely transformed into austenite;

[0089] S4.4: When the furnace temperature drops to 240°C, reheat to 300°C and keep warm for 40 minutes. Then, quickly put the casting into water preheated to 110°C for quenching. The cooling rate is 8°C / min and the heating rate is 12°C / min.

[0090] S4.5: After quenching, the furnace is cooled to 120°C, and then the casting is placed in a high-temperature resistance furnace, the temperature is raised to 550°C, and kept at this temperature for 3 hours. The furnace is then cooled to 80°C, and then the temperature is raised to 530°C, and kept at this temperature for 3 hours. The cooling rate is 5°C / min, and the heating rate is 8°C / min. The casting is taken out of the furnace and air-cooled to room temperature to complete the secondary tempering and obtain the steel.

[0091] Embodiment 3: A processing technology of high toughness and high wear-resistant steel, such as Figure 1 As shown, the specific steps include:

[0092] S1: smelting treatment,

[0093] S1.1: According to the chemical composition of steel, calculate and weigh the scrap steel, ferrosilicon, ferromanganese, ferrochrome, nickel plate and ferromolybdenum respectively;

[0094] S1.2: Add the scrap steel into the crucible of the vacuum smelting furnace, preheat the crucible to 600°C, and evacuate it to below 150Pa, fill the furnace with argon gas to keep the furnace at a slightly negative pressure of -5Pa, melt the scrap steel at a melting rate of 5kg / min, and add nickel plate and ferromolybdenum to continue smelting after the scrap steel begins to melt;

[0095] S1.3: When all the metals added in the furnace are melted, ferrosilicon, ferrochrome and ferromanganese are added, and the temperature in the crucible is raised to 1650°C for refining for 40 minutes to obtain molten steel;

[0096] S1.4: The molten steel is heated to 1700°C and then discharged into a molten steel treatment ladle. After the molten steel is discharged, a molten steel heat preservation agent is applied to the surface of the molten steel;

[0097] S2: Preparation of composite inoculant,

[0098] S2.1: using a vacuum arc furnace to melt Al-10%Cr alloy, ferroniobium and boron carbide in a weight ratio of 20:1 to react and form a master alloy;

[0099] S2.2: Silicon carbide with an average particle size of 10 μm and silicon carbide with a particle size of 50 nm are mixed by magnetic stirring at a weight ratio of 10:2 to obtain composite silicon carbide powder;

[0100] S2.3: adding the composite silicon carbide powder to the master alloy for mixing, wherein the weight ratio of the master alloy to the composite silicon carbide powder is 10:3, and after mixing evenly, a composite inoculant is prepared;

[0101] S2.4: Add the composite inoculant into the wire feeder;

[0102] S3: feeding wire inoculation treatment,

[0103] S3.1: Transfer the molten steel treatment ladle to the feeding line treatment area;

[0104] S3.2: Under the condition of 1700℃, the composite inoculant in the wire feeder is fed into the molten steel in the molten steel treatment ladle. The wire diameter of the composite inoculant is 12mm. The composite inoculant is fed to the position 50mm from the bottom of the molten steel treatment ladle. The weight ratio of the composite inoculant feeding amount to the molten steel is 1:200, and the wire feeding speed is 15m / min.

[0105] S3.3: After all the composite inoculant is sprayed into the molten steel, the steel is allowed to stand until the temperature of the molten steel drops to 1500°C, completing the wire feeding inoculation process;

[0106] S4: Casting and heat treatment,

[0107] S4.1: pouring the molten steel after the wire feeding inoculation treatment into the mold on the casting machine;

[0108] S4.2: After all the molten steel has entered the mold, immediately spray water on the outer surface of the mold to cool it for 80 seconds to accelerate the solidification of the molten steel and refine the internal structure of the steel;

[0109] S4.3: When the casting is solidified and cooled to a surface temperature of 300°C, the casting is taken out of the mold, and after sand removal and polishing, the casting is placed in a high-temperature resistance furnace and heated to 980°C at a heating rate of 15°C / min for 3 hours to transform the steel structure into austenite;

[0110] S4.4: When the furnace temperature drops to 260°C, reheat to 340°C and keep warm for 50 minutes. Then, quickly put the casting into water preheated to 120°C for quenching. The cooling rate is 12°C / min and the heating rate is 15°C / min.

[0111] S4.5: After quenching, the furnace is cooled to 150°C, and then the casting is placed in a high-temperature resistance furnace. The temperature is raised to 560°C and kept at this temperature for 2 hours. The furnace is then cooled to 100°C, and then the temperature is raised to 540°C and kept at this temperature for 2 hours. The cooling rate is 10°C / min and the heating rate is 12°C / min. The casting is taken out of the furnace and air-cooled to room temperature to complete the secondary tempering and obtain the steel.

[0112] Comparative Example 1: Compared with Example 1, the difference of Comparative Example 1 is that the preparation and addition operations of the composite silicon carbide powder in step S2 are removed, and the other steps remain unchanged, and the steel is processed and prepared, which is recorded as Comparative Example 1.

[0113] Comparative Example 2: Compared with Example 1, the difference of Comparative Example 2 is that step S2.4 and step S3 are removed, and the composite inoculant is added to the molten steel by the ordinary flushing method, that is, in the process of flushing the molten steel into the molten steel treatment ladle, the composite inoculant is flushed in with the flow, and the other steps remain unchanged, and the steel is processed and prepared, which is recorded as Comparative Example 2.

[0114] Comparative Example 3: Compared with Example 1, the difference of Comparative Example 3 is that step S4.5 is removed, and the other steps remain unchanged, and the steel is processed and prepared, which is recorded as Comparative Example 3.

[0115] The steel materials processed in Examples 1-3 and Comparative Examples 1-3 were tested for yield strength, tensile strength, elongation after fracture and hardness according to GB / T24186-2009 standard. Figure 2 It can be seen that the performance parameters of yield strength, tensile strength, elongation after fracture and hardness of the steel prepared in Examples 1-3 are better than those of the steel prepared in Comparative Examples 1-3. It is shown that the preparation and addition of composite silicon carbide powder can improve the plasticity and toughness of steel, and compared with the traditional punching method, the automatic wire feeding method can insert the composite inoculant wire into the bottom of the molten steel treatment bag, which can stably and controllably perform the inoculation treatment operation, further assisting in improving the plasticity and toughness of the steel. In addition, after the quenching of the casting, the secondary tempering operation can also assist in improving the toughness of the steel.

[0116] According to the national standard GB / T12444-2006, the friction and wear performance of the steels processed by Examples 1-3 and Comparative Examples 1-3 was tested using an M-2000 abrasive wear testing machine. The load was 200N, the test time was 2h, the speed was 200rad / min, the weight of the steel before and after wear was weighed and recorded, and the wear rate was calculated.

[0117] The wear rate calculation formula is: Wear rate (%) =

[0118] Among them, M0 and M1 are the weights of the steel before and after wear, respectively.

[0119] like Figure 3 It can be seen that after the wear performance test, the wear rates of the steels prepared in Examples 1-3 are all lower than those of the steels prepared in Comparative Examples 1-3, and the steel prepared in Example 1 has the best wear resistance. It is shown that the preparation and addition of composite silicon carbide powder can increase the wear-resistant hard phase of the steel component and improve the wear resistance of the steel. Compared with the traditional punching method, the automatic wire feeding method can be used to insert the composite inoculant wire into the bottom of the molten steel treatment bag, which can stably and controllably perform the inoculation treatment operation. In addition to assisting in improving the plasticity and toughness of the steel, it can also simultaneously improve the wear resistance. In addition, after the quenching of the casting, the secondary tempering operation can also assist in improving the wear resistance of the steel.

[0120] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all such improvements and changes should fall within the scope of protection of the appended claims of the present invention. Parts not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A processing technology for high-toughness and high-wear-resistant steel, characterized in that: The chemical composition of steel (weight %) includes: C: 0.2-0.4%, Si: 1.5-1.8%, Mn: 1.3-1.5%, Cr: 0.6-0.8%, Ni: 0.3-0.5%, Mo: 0.3-0.4%, composite inoculant 0.4-1.5%, and the balance of Fe and unavoidable impurity elements, wherein the composite inoculant includes: Al-10% Cr alloy, ferroniobium, boron carbide, 10μm silicon carbide and 50nm silicon carbide; The specific steps include: S1: smelting treatment, According to the chemical composition of the steel, respectively calculate and weigh scrap steel, ferrosilicon, ferromanganese, ferrochrome, nickel plate, and ferromolybdenum, melt the scrap steel first, add nickel plate and ferromolybdenum to continue smelting after the scrap steel begins to melt, add ferrosilicon, ferrochrome and ferromanganese to refine after all the added metals are melted, obtain molten steel, and pour the molten steel into a molten steel treatment bag; S2: Preparation of composite inoculant, Al-10% Cr alloy, ferroniobium and boron carbide are mixed and smelted to react to form a master alloy, silicon carbide with an average particle size of 10 μm and silicon carbide with a particle size of 50 nm are mixed by magnetic stirring to obtain composite silicon carbide powder, the composite silicon carbide powder is added to the master alloy for mixing, the master alloy and the composite silicon carbide powder are mixed to prepare a composite inoculant, and the composite inoculant is added to a wire feeder; S3: feeding wire inoculation treatment, The molten steel treatment ladle is transferred to the wire feeding treatment place, and the composite inoculant in the wire feeding machine is sent into the molten steel in the molten steel treatment ladle. After the composite inoculant is completely sprayed into the molten steel, the wire feeding inoculation treatment is completed; S4: Casting and heat treatment, The molten steel after the wire feeding inoculation treatment is poured into the casting mold on the casting machine. After the molten steel is completely in the casting mold, water is sprayed on the outer surface of the casting mold to cool it down immediately. After the casting solidifies and cools for a period of time, the casting is taken out of the casting mold, and after sand cleaning and grinding, the casting is heated at 950-980°C, cooled, heated at 300-340°C and quenched, and then the casting is subjected to secondary tempering treatment to complete the heat treatment operation to obtain steel; Step S1: smelting treatment, specifically comprising the following steps: S1.1: According to the chemical composition of steel, calculate and weigh the scrap steel, ferrosilicon, ferromanganese, ferrochrome, nickel plate and ferromolybdenum respectively; S1.2: Add the scrap steel into the crucible of the vacuum smelting furnace, preheat the crucible to 500-600°C, and evacuate to below 150Pa, fill the furnace with argon gas to keep the furnace in a state of slight negative pressure, the slight negative pressure range is -10--5Pa, melt the scrap steel at a melting rate of 3-5kg / min, and add nickel plate and ferromolybdenum to continue smelting after the scrap steel starts to melt; S1.3: When all the metals added in the furnace are melted, ferrosilicon, ferrochrome and ferromanganese are added, and the temperature in the crucible is raised to 1500-1650°C for refining for 20-40 minutes to obtain molten steel; S1.4: The molten steel is heated to 1680-1700°C and then discharged into a molten steel treatment bag. After the molten steel is discharged, a molten steel heat preservation agent is applied to the surface of the molten steel; Step S2: preparing the composite inoculant, specifically comprising the following steps: S2.1: using a vacuum arc furnace to melt Al-10% Cr alloy, ferroniobium and boron carbide in a weight ratio of 20:(1-3) to react and form a master alloy; S2.2: Silicon carbide with an average particle size of 10 μm and silicon carbide with a particle size of 50 nm are mixed by magnetic stirring to obtain composite silicon carbide powder; S2.3: adding composite silicon carbide powder to the master alloy and mixing them, wherein the weight ratio of the master alloy to the composite silicon carbide powder is 10:(1-3), and after mixing evenly, a composite inoculant is prepared; S2.4: Add the composite inoculant into the wire feeder; Step S3: feeding wire inoculation treatment, specifically comprising the following steps: S3.1: Transfer the molten steel treatment ladle to the line feeding treatment area; S3.2: Under the condition of 1550-1600℃, the composite inoculant in the wire feeder is fed into the molten steel in the molten steel treatment ladle, and the composite inoculant is fed to the position 20-50mm from the bottom of the molten steel treatment ladle. The wire feeding speed is 12-15m / min, and the wire diameter is 9-12mm. S3.3: After all the composite inoculant is sprayed into the molten steel, the steel is allowed to stand until the temperature of the molten steel drops to 1450-1500°C, completing the wire feeding inoculation process; Step S4 casting and heat treatment specifically includes the following steps: S4.1: pouring the molten steel after wire feeding inoculation treatment into the mold on the casting machine; S4.2: After all the molten steel has entered the mold, immediately spray water on the outer surface of the mold to cool it for 60 to 80 seconds to accelerate the solidification of the molten steel and refine the internal structure of the steel; S4.3: When the casting surface temperature is 280-300℃ after solidification and cooling, the casting is taken out from the mold, and after sand removal and grinding, the casting is placed in a high-temperature resistance furnace and heated to 950-980℃ at a heating rate of 12-15℃ / min and kept at this temperature for 2-3h to transform the steel structure into austenite. S4.4: When the furnace temperature drops to 240-260°C, reheat to 300-340°C and keep warm for 40-50 minutes. Then, quickly put the casting into water preheated to 110-120°C for quenching. The cooling rate is 8-12°C / min and the heating rate is 12-15°C / min. S4.5: After quenching, the furnace is cooled to a temperature of 120-150°C, and then the casting is placed in a high-temperature resistance furnace, the temperature is raised to 550-560°C, and kept at this temperature for 2-3 hours. The furnace is then cooled to a temperature of 80-100°C, and then the temperature is raised to 530-540°C, and kept at this temperature for 2-3 hours. The cooling rate is 5-10°C / min, and the heating rate is 8-12°C / min. The casting is taken out of the furnace and air-cooled to room temperature to complete the secondary tempering and obtain the steel.

2. A processing technology for high-toughness and high-wear-resistant steel according to claim 1, characterized in that: Al-10%Cr alloy is an aluminum-chromium alloy with a chromium content of 10%.

3. A processing technology for high-toughness and high-wear-resistant steel according to claim 2, characterized in that: The molten steel insulation agent used in step S1.4 contains silicate, aluminum oxide and magnesium oxide.

4. A processing technology for high-toughness and high-wear-resistant steel according to claim 3, characterized in that: Step S2.2: The weight ratio of 10 μm silicon carbide to 50 nm silicon carbide in the composite silicon carbide powder is 10:(2-5).

5. The processing technology of high-toughness and high-wear-resistant steel according to claim 4 is characterized in that: In step S3.2, the weight ratio of the amount of composite inoculant used for wire feeding to the molten steel is (1-3):200.

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