CN111455264A - Vanadium-titanium alloy gray cast iron cylinder sleeve and preparation method thereof - Google Patents

Abstract

The invention provides an alloy gray cast iron cylinder liner, which contains vanadium element and titanium element; the metallographic structure of the alloy gray cast iron cylinder sleeve comprises graphite and a vanadium-titanium phase; the alloy gray cast iron matrix structure comprises pearlite; the amount of pearlite is greater than 98%; the proportion of fine lamellar pearlite in the pearlite is 98% or more. The alloy gray cast iron cylinder sleeve provided by the invention has the advantages that the proportion of fine lamellar pearlite is high, the vanadium-titanium phase structure is uniformly distributed and is large in quantity, the proportion of the pearlite in the matrix structure of the vanadium-titanium alloy gray cast iron cylinder sleeve is large, particularly the proportion of the fine lamellar pearlite can reach 100%, the vanadium-titanium phase structure is more uniformly distributed, is large in quantity and low in impurity content, and the alloy gray cast iron cylinder sleeve has the characteristics of high strength, better wear resistance and the like, meanwhile, the process automation degree is high, the process is compact and more stable, the product quality is stable, the labor cost and the production cost are greatly reduced, and the alloy gray cast iron cylinder sleeve is more suitable.

Description

Vanadium-titanium alloy gray cast iron cylinder sleeve and preparation method thereof

Technical Field

The invention belongs to the technical field of alloy gray cast iron cylinder liner manufacturing, relates to an alloy gray cast iron cylinder liner and a preparation method thereof, and particularly relates to a vanadium-titanium alloy gray cast iron cylinder liner and a preparation method thereof.

Background

The engine of automobile is a heart part of automobile and is composed of two major mechanisms of crank link mechanism and valve actuating mechanism, and five major systems of cooling, lubricating, igniting, fuel supplying and starting system. The working chamber of an automotive engine is called a cylinder, the inner surface of which is cylindrical. The piston reciprocating in the cylinder is hinged to one end of a connecting rod via piston pin, and the other end of the connecting rod is connected to a crankshaft supported by bearings on the cylinder body and capable of rotating in the bearings to constitute a crank-connecting rod mechanism. The engine body is a framework which forms the engine, is a mounting base of each mechanism and each system of the engine, and is internally and externally provided with all main parts and accessories of the engine to bear various loads. Therefore, the body must have sufficient strength and rigidity. The engine body group mainly comprises parts such as an air cylinder body, an air cylinder sleeve, an air cylinder cover, an air cylinder cushion and the like.

The cylinder sleeve is one of key parts of the engine, is a cylindrical part, is arranged in a cylinder body hole of the engine body, and is tightly pressed and fixed by a cylinder cover. The piston reciprocates in its bore and is cooled by cooling water located externally thereof. The cylinder sleeve, the cylinder cover and the piston together form a cylinder working space, and sometimes can bear the side thrust of the piston to form a lead of the reciprocating motion of the piston. In the running process of an engine, the inner surface of the cylinder sleeve is directly acted by high-temperature and high-pressure fuel gas and always generates high-speed sliding friction with a piston ring and a piston skirt. The surface of the steel pipe is contacted with cooling water, and severe thermal stress is generated under a large temperature difference and is corroded by the cooling water. The side thrust of the piston against the cylinder liner not only exacerbates its internal surface friction, but also causes it to bend. The piston also impacts the cylinder liner as the side thrust changes direction. In addition, the device is subjected to large installation pretightening force. At the same time, the gas pressure produces tangential tensile and radial compressive stresses in the cylinder wall, and is greatest at the inner surface, and is a high frequency pulsating stress. In addition, a great thermal stress is generated by a difference in temperature between the inside and outside of the cylinder wall, and generally, a compressive stress is generated in the inner surface at a temperature, and a tensile stress is generated in the cooling surface. However, at extremely high air temperature, the metal near the inner surface is in creep plastic deformation, and after cooling, residual tensile stress is formed on the inner surface, and the low-frequency stress caused by the change along with starting and stopping causes material fatigue.

The cylinder liner has various types, and is divided into common gray cast iron cylinder liners, phosphorus-containing cylinder liners, boron-containing cylinder liners, nodular cast iron cylinder liners and other alloy cylinder liners according to the material, and the cylinder liner has the characteristics of severe working environment, very high explosion pressure bearing, durability, high requirements on the material of a cylinder liner component, enough strength, rigidity and heat resistance, good wear resistance, good lubricating and cooling performance in working and certain oil storage performance. For example, a certain content of copper is added into general gray cast iron to refine pearlite, thereby achieving the purpose of improving the performance; the purpose of improving strength and achieving wear resistance is achieved by adding a trace amount of boron into common gray cast iron to form boron-containing carbide and boron-containing compound, and particularly the vanadium-titanium alloy cylinder sleeve in recent years receives extensive attention in the industry due to good mechanical property. However, the alloy cylinder sleeve still has the problem of low production strength and hardness

Therefore, how to better improve the strength and hardness of the alloy gray cast iron cylinder sleeve and meet the higher requirements of the downstream industry on the material performance of the alloy gray cast iron cylinder sleeve becomes one of the problems to be solved by many research and development enterprises and front-line researchers in the industry.

Disclosure of Invention

In view of this, the technical problem to be solved by the present invention is to provide an alloy gray cast iron cylinder liner and a method for preparing the same, and in particular, to a vanadium-titanium alloy gray cast iron cylinder liner and a method for preparing the same. The vanadium-titanium alloy gray cast iron cylinder sleeve provided by the invention has the characteristics that the fine lamellar pearlite can reach 100%, the vanadium-titanium phase structure is more uniformly distributed, the strength is high, the wear resistance is better, and meanwhile, the preparation process is simple and stable, and the industrial popularization and use are easy.

The invention provides an alloy gray cast iron cylinder sleeve, which contains vanadium element and titanium element;

the metallographic structure of the alloy gray cast iron cylinder sleeve comprises graphite and a vanadium-titanium phase;

the alloy gray cast iron matrix structure comprises pearlite;

the amount of pearlite is greater than 98%;

the proportion of fine lamellar pearlite in the pearlite is 98% or more.

Preferably, the sum of the contents of the vanadium element and the titanium element is 0.3 to 0.45 percent;

the inter-lamellar spacing of the fine lamellar pearlite is not more than 1 mm;

the matrix structure of the alloy gray cast iron cylinder sleeve is a matrix structure of the alloy gray cast iron cylinder sleeve amplified by 500 times;

the graphite comprises uniform type a graphite;

the proportion of the A-type graphite in the total amount of the graphite is more than or equal to 80 percent;

the metallographic structure of the alloy gray cast iron comprises uniform polygonal vanadium-titanium carbonitride;

the number of the polygonal vanadium-titanium carbonitride is more than or equal to 10.

Preferably, the proportion of fine lamellar pearlite in the pearlite is 100%;

the quantity of the A-type graphite is 100 percent;

the total impurity content of the alloy gray cast iron cylinder sleeve is less than or equal to 0.01 percent;

the air content of the alloy gray cast iron cylinder sleeve is less than or equal to 0.01 percent;

in the gas content, the oxygen content is less than 0.01 percent;

in the gas content, the hydrogen content is less than 0.001%.

Preferably, the composite material comprises the following components in percentage by mass:

the balance being iron.

Preferably, in the alloy gray cast iron, the content of impurity aluminum oxide is less than or equal to 0.01 percent;

in the alloy gray cast iron, the content of impurity calcium oxide is less than 0.005 percent;

the hardness of the alloy gray cast iron is more than or equal to 230 HBW;

the tensile strength of the alloy gray cast iron is more than or equal to 300 Mpa.

The invention also provides a preparation method of the alloy gray cast iron cylinder sleeve, which comprises the following steps:

1) smelting the raw materials in a medium-frequency induction furnace, transferring the raw materials to a heat preservation furnace through a transfer ladle, preserving heat and standing to obtain molten iron discharged from the furnace;

2) and (4) carrying out full-automatic multi-station casting on the discharged molten iron obtained in the step, and then demoulding and forming to obtain the alloy gray cast iron cylinder sleeve.

Preferably, the raw materials comprise, by mass:

the balance being iron.

Preferably, the raw materials comprise iron, scrap steel, a return charge and an alloy material;

the mass ratio of the pig iron to the scrap steel to the foundry returns is (1-4): (4-8): 2;

the alloy material comprises one or more of silicon-manganese alloy, ferrophosphorus alloy, ferrovanadium alloy, ferrotitanium alloy, ferrochrome alloy, ferrosulfur alloy and electrolytic copper;

the smelting temperature of the medium-frequency induction furnace is 1500-1540 ℃;

the smelting time of the medium-frequency induction furnace is 30-60 min.

Preferably, the tapping temperature of the medium-frequency induction furnace after smelting is 1500-1540 ℃;

the temperature of the transfer process of the transfer ladle is 1470-1500 ℃;

the temperature for heat preservation and standing is 1420-1450 ℃;

the heat preservation standing time is 10-30 min;

the full-automatic multi-station casting comprises one or more steps of automatic spraying, automatic baffle plate feeding, automatic casting, automatic water spraying and automatic cylinder discharging;

the full-automatic multi-station casting is accompanied with a downstream inoculation treatment step.

Preferably, the rotation speed of the automatic spraying is 770-830 r/min;

the rotation speed of the automatic casting is 1445-1485 r/min;

the automatic casting time is 4-5 s;

the automatic water-exciting time is 30-85 s;

the inoculant for the downstream inoculation treatment comprises one or more of a silicon-barium inoculant, a silicon-strontium inoculant, a silicon-barium-calcium inoculant, a silicon-iron inoculant and a silicon-strontium-zirconium inoculant;

the addition amount of the inoculant is 0.5-0.7% of the total mass of the molten iron;

the temperature of the automatic cylinder discharging is 650-850 ℃.

The invention provides an alloy gray cast iron cylinder sleeve, which contains vanadium element and titanium element; the metallographic structure of the alloy gray cast iron cylinder sleeve comprises graphite and a vanadium-titanium phase; the alloy gray cast iron matrix structure comprises pearlite; the amount of pearlite is greater than 98%; the proportion of fine lamellar pearlite in the pearlite is 98% or more. Compared with the prior art, the invention aims at the current situation that the performance of the gray cast iron cylinder sleeve needs to be improved in order to meet the higher requirements of mechanical components on material performance in the continuous development of the engine industry, and particularly solves the problem that the strength and hardness of the alloy gray cast iron cylinder sleeve are difficult to meet the requirements of continuous development.

The invention provides an alloy gray cast iron cylinder sleeve which is high in proportion of fine lamellar pearlite and large in quantity of uniformly distributed vanadium-titanium phase structures. The invention aims at the defects that the existing vanadium-titanium cylinder sleeve has different preparation methods although existing for years, mainly adopts cupola smelting or electric furnace smelting, adopts manual casting, and has lower production strength and hardness. The invention combines the processes of electric furnace smelting, holding furnace heat preservation, multi-station automatic casting and the like and corresponding parameters thereof, mutually promotes and advances to obtain the vanadium-titanium alloy gray cast iron cylinder sleeve with a specific tissue structure. The vanadium-titanium alloy gray cast iron cylinder sleeve produced by the invention has a large pearlite proportion in the matrix structure, particularly the proportion of fine lamellar pearlite can reach 100%, and the vanadium-titanium phase structure is more uniformly distributed, more in quantity and low in impurity content, so that the product has the characteristics of high strength, good wear resistance and the like.

Experimental results show that the alloy gray cast iron cylinder sleeve prepared by the invention has the hardness of more than or equal to 240HBW and the tensile strength of more than or equal to 320 Mpa.

Drawings

FIG. 1 is a schematic diagram of a production process of a vanadium-titanium alloy gray cast iron cylinder liner provided by the invention;

FIG. 2 is a schematic view of the work flow of a multi-station casting machine used in the present invention;

fig. 3 is a graphite map (100 times) of the metallographic structure of the vanadium-titanium alloy gray cast iron cylinder liner prepared in example 1 of the present invention;

fig. 4 is a vanadium-titanium phase diagram (500 times) of the metallographic structure of the vanadium-titanium alloy gray cast iron cylinder liner prepared in example 1 of the present invention;

fig. 5 is a metallographic structure matrix diagram (500 times) of the vanadium-titanium alloy gray cast iron cylinder liner prepared in example 1 of the present invention.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

All of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.

The raw material used in the present invention is not particularly limited in purity, and the present invention is preferably industrially pure or may be used in a purity which is conventional in the field of friction materials.

All the raw materials, the marks and the acronyms thereof belong to the conventional marks and acronyms in the field, each mark and acronym is clear and definite in the field of related application, and the raw materials can be purchased from the market or prepared by a conventional method by the technical staff in the field according to the marks, the acronyms and the corresponding application.

In all the processes of the invention, the abbreviations thereof belong to the common abbreviations in the art, each abbreviation is clearly clear in the field of its associated use, and the ordinary process steps thereof can be understood by those skilled in the art from the abbreviations.

The invention provides an alloy gray cast iron cylinder sleeve, which contains vanadium element and titanium element;

the metallographic structure of the alloy gray cast iron cylinder sleeve comprises graphite and a vanadium-titanium phase;

the alloy gray cast iron matrix structure comprises pearlite;

the amount of pearlite is greater than 98%;

the proportion of fine lamellar pearlite in the pearlite is 98% or more.

The definition of the alloy gray cast iron cylinder liner is not particularly limited, and the definition of the alloy gray cast iron cylinder liner known to those skilled in the art can be selected and adjusted by those skilled in the art according to the actual application situation, the product requirement and the quality requirement.

The definition and the test mode of the metallographic structure and the matrix structure are not particularly limited, and the definition and the test mode of the metallographic structure and the matrix structure of the metal, which are well known to those skilled in the art, can be selected and adjusted by those skilled in the art according to the actual application condition, the product requirement and the quality requirement. The metallographic structure of the present invention is a structure expressed under a microscopic metallographic phase. The matrix structure, i.e. the matrix structure under the microscopic metallographic phase, can be reflected from the microscopic metallographic photograph. Similarly, the specific parameters of the metallographic structure and the matrix structure can also be obtained by measuring and calculating a metallographic photograph.

The alloy gray cast iron cylinder sleeve contains vanadium and titanium. The specific contents of vanadium and titanium in the alloy gray cast iron cylinder liner are not particularly limited in the present invention, and those skilled in the art can select and adjust the contents according to the actual application, product requirements and quality requirements, and the present invention is to better increase the pearlite proportion, especially the fine lamellar pearlite proportion, to increase the uniform distribution and quantity of the vanadium-titanium phase structure, to reduce the impurity content, and to better improve the strength and wear resistance, and the sum of the contents of vanadium and titanium is preferably 0.3% to 0.45%, more preferably 0.32% to 0.43%, more preferably 0.35% to 0.4%, and more preferably 0.37% to 0.38%.

The metallographic structure of the alloy gray cast iron cylinder sleeve comprises graphite and vanadium-titanium phases. The specific type and parameters of the graphite of the alloy gray cast iron cylinder liner are not particularly limited in the present invention, and can be selected and adjusted by those skilled in the art according to the actual application, product requirements and quality requirements, and the present invention is to better increase the pearlite proportion, especially the fine lamellar pearlite proportion, to increase the uniform distribution and quantity of the vanadium-titanium phase structure, to reduce the impurity content, and to better improve the strength and wear resistance, wherein the graphite preferably comprises a type a graphite, and more preferably uniform a type graphite. The proportion of the a-type graphite to the total amount of the graphite is 80% or more, more preferably 85% or more, still more preferably 90% or more, still more preferably 95% or more, and particularly may be 100%.

The invention has no particular limitation on the specific types and parameters of the vanadium-titanium phase of the alloy gray cast iron cylinder sleeve in principle, and can be selected and adjusted by a person skilled in the art according to the actual application condition, the product requirement and the quality requirement. The preferable number of the polygonal vanadium-titanium carbonitride is 10 or more, more preferably 12 or more, and still more preferably 15 or more. In the present invention, the vanadium-titanium phase preferably contains a vanadium-titanium phase such as titanium nitride, titanium carbide, vanadium nitride, and titanium carbonitride.

The matrix structure of the alloy gray cast iron cylinder sleeve comprises pearlite. The specific parameters of the matrix structure of the alloy gray cast iron cylinder liner are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application condition, the product requirement and the quality requirement.

The amount of pearlite is more than 98%, the invention is to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, improve the uniform distribution and amount of vanadium-titanium phase structure, reduce impurity content and better improve the strength and wear resistance, and the amount of pearlite is preferably more than 98.5%, more preferably more than 99%. In the present invention, the proportion of fine lamellar pearlite in pearlite is 98% or more, and in the present invention, it is preferable to increase the pearlite proportion, particularly the proportion of fine lamellar pearlite, to increase the uniform distribution and amount of the vanadium-titanium phase structure, to reduce the impurity content, and to improve the strength and wear resistance, and the proportion of fine lamellar pearlite in pearlite is more preferably 98.5% or more, more preferably 99% or more, more preferably 99.5% or more, and particularly may be 100%.

The specific parameters of the fine lamellar pearlite are not particularly limited in principle, and can be selected and adjusted by those skilled in the art according to the actual application situation, the product requirement and the quality requirement, and the fine lamellar pearlite is preferably increased in the proportion of pearlite, particularly in the proportion of fine lamellar pearlite, in the proportion of vanadium-titanium phase structure, in the uniform distribution and quantity, in the content of impurities, and in the strength and the wear resistance, and is preferably increased in the strength and the wear resistance, and the inter-lamellar spacing of the fine lamellar pearlite is preferably equal to or less than 1mm, more preferably equal to or less than 0.9mm, and more preferably equal to or less than 0.8 mm.

The total impurity content of the alloy gray cast iron cylinder liner is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to practical application conditions, product requirements and quality requirements, and the alloy gray cast iron cylinder liner preferably has the total impurity content of 0.01% or less, more preferably 0.009% or less, and more preferably 0.008% or less, in order to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, to improve the uniform distribution and quantity of vanadium-titanium phase structures, to reduce the impurity content, and to better improve the strength and the wear resistance.

The invention is not particularly limited in principle to the gas content of the alloy gray cast iron cylinder liner, and can be selected and adjusted by a person skilled in the art according to the practical application condition, the product requirement and the quality requirement, and the invention is used for better increasing the pearlite proportion, particularly the fine lamellar pearlite proportion, increasing the uniform distribution and quantity of the vanadium-titanium phase structure, reducing the impurity content and better improving the strength and the wear resistance, and the gas content of the alloy gray cast iron cylinder liner is less than or equal to 0.01 percent, more preferably less than or equal to 0.009 percent, and more preferably less than or equal to 0.008 percent. More specifically, the oxygen content in the gas content is less than 0.01%, more preferably less than 0.008%, and more preferably less than 0.005%. More specifically, the hydrogen content in the gas content is less than 0.001%, more preferably less than 0.0008%, more preferably less than 0.0005%.

The invention is a better complete and refined production process, better improves the pearlite proportion, especially the proportion of fine lamellar pearlite, improves the uniform distribution and quantity of vanadium-titanium phase structures, reduces the impurity content, and better improves the strength and the wear resistance, and the alloy gray cast iron cylinder sleeve preferably comprises the following components in percentage by mass:

the balance being iron.

The content of C is preferably 3.0% to 3.5%, more preferably 3.1% to 3.4%, and still more preferably 3.2% to 3.3%. The content of Si is preferably 2.0% to 2.7%, more preferably 2.1% to 2.6%, more preferably 2.2% to 2.5%, more preferably 2.3% to 2.4%. The content of S is preferably 0.05% to 0.1%, more preferably 0.06% to 0.09%, and still more preferably 0.007% to 0.008%. The content of P is preferably 0.3% to 0.5%, more preferably 0.32% to 0.48%, more preferably 0.35% to 0.45%, more preferably 0.37% to 0.43%, the content of Mn is preferably 0.6% to 1.2%, more preferably 0.7% to 1.1%, more preferably 0.8% to 1.0%, the content of Cr is preferably 0.2% to 0.5%, more preferably 0.25% to 0.48%, more preferably 0.35% to 0.45%. The content of Cu is preferably 0.1% to 0.3%, more preferably 0.12% to 0.28%, and still more preferably 0.15% to 0.25%. The content of V + Ti is preferably 0.3% to 0.45%, more preferably 0.32% to 0.42%, and still more preferably 0.35% to 0.41%.

The content of the impurity alumina in the alloy gray cast iron is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application situation, the product requirements and the quality requirements, and the impurity alumina content in the alloy gray cast iron is preferably less than or equal to 0.01%, more preferably less than or equal to 0.009%, and more preferably less than or equal to 0.008%, so that the impurity pearlite proportion is better increased, the vanadium-titanium phase structure is more uniformly distributed and distributed, the impurity content is reduced, and the strength and the wear resistance are better improved.

The content of impurity calcium oxide in the alloy gray cast iron is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application situation, the product requirements and the quality requirements, and the impurity content is preferably less than 0.005%, more preferably less than or equal to 0.004%, and more preferably less than or equal to 0.003% in the alloy gray cast iron, so that the impurity content is better increased, particularly the proportion of fine lamellar pearlite, the uniform distribution and quantity of vanadium-titanium phase structures are increased, the impurity content is reduced, and the strength and the wear resistance are better improved.

The hardness of the alloy gray cast iron cylinder liner is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to practical application, product requirements and quality requirements, and the hardness of the alloy gray cast iron of the invention is preferably equal to or greater than 230HBW, more preferably equal to or greater than 240HBW, and more preferably equal to or greater than 250 HBW.

The tensile strength of the alloy gray cast iron cylinder liner is not particularly limited in the present invention, and those skilled in the art can select and adjust the tensile strength according to the actual application, product requirements and quality requirements, and the tensile strength of the alloy gray cast iron is greater than or equal to 300Mpa, more preferably greater than or equal to 350Mpa, and more preferably greater than or equal to 400 Mpa.

The invention also provides a preparation method of the alloy gray cast iron cylinder sleeve, which comprises the following steps:

1) smelting the raw materials in a medium-frequency induction furnace, transferring the raw materials to a heat preservation furnace through a transfer ladle, preserving heat and standing to obtain molten iron discharged from the furnace;

2) and (4) carrying out full-automatic multi-station casting on the discharged molten iron obtained in the step, and then demoulding and forming to obtain the alloy gray cast iron cylinder sleeve.

The parameters, microstructures and compositions of the alloy gray cast iron cylinder liner in the preparation method, and corresponding optimization principles, and the parameters, microstructures and compositions corresponding to the alloy gray cast iron cylinder liner, and corresponding optimization principles can all correspond, and are not described in detail herein.

The method comprises the steps of firstly smelting raw materials in a medium-frequency induction furnace, transferring the raw materials to a heat preservation furnace through a transfer ladle, preserving heat and standing to obtain molten iron discharged from the furnace.

The specific composition of the raw materials is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application situation, the product requirements and the quality requirements, in order to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, improve the uniform distribution and quantity of vanadium-titanium phase structures, reduce the impurity content and better improve the strength and the wear resistance, the raw materials preferably comprise, in mass percent:

the balance being iron.

The content of C is preferably 3.0% to 3.5%, more preferably 3.1% to 3.4%, and still more preferably 3.2% to 3.3%. The content of Si is preferably 1.8% to 1.9%, more preferably 1.82% to 1.88%, and still more preferably 1.84% to 1.86%. The content of S is preferably 0.05% to 0.1%, more preferably 0.06% to 0.09%, and still more preferably 0.007% to 0.008%. The content of P is preferably 0.3% to 0.5%, more preferably 0.32% to 0.48%, more preferably 0.35% to 0.45%, more preferably 0.37% to 0.43%, the content of Mn is preferably 0.6% to 1.2%, more preferably 0.7% to 1.1%, more preferably 0.8% to 1.0%, the content of Cr is preferably 0.2% to 0.5%, more preferably 0.25% to 0.48%, more preferably 0.35% to 0.45%. The content of Cu is preferably 0.1% to 0.3%, more preferably 0.12% to 0.28%, and still more preferably 0.15% to 0.25%. The content of V + Ti is preferably 0.3% to 0.45%, more preferably 0.32% to 0.42%, and still more preferably 0.35% to 0.41%.

The specific selection and parameters of the raw materials are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application condition, the product requirement and the quality requirement, so that the pearlite proportion, particularly the proportion of the fine lamellar pearlite, can be better increased, the uniform distribution and quantity of the vanadium-titanium phase structure can be improved, the impurity content can be reduced, and the strength and the wear resistance can be better improved. Wherein the alloy material preferably comprises one or more of silicon-manganese alloy, ferrophosphorus alloy, ferrovanadium alloy, ferrotitanium alloy, ferrochrome alloy, ferrosulfur alloy and electrolytic copper, and more preferably comprises a plurality of silicon-manganese alloy, ferrophosphorus alloy, ferrovanadium alloy, ferrotitanium alloy, ferrochrome alloy, ferrosulfur alloy and electrolytic copper. The mass ratio of the pig iron, the scrap steel and the foundry returns is preferably (1-4): (4-8): 2, more preferably (1.5 to 3.5): (4-8): 2, more preferably (2 to 5): (4-8): 2, may be (1-4): (4.5-7.5): 2, may be (1-4): (5-7): 2, may be (1-4): (5.5-6.5): 2.

the smelting temperature of the medium-frequency induction furnace is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application condition, the product requirement and the quality requirement, the smelting temperature of the medium-frequency induction furnace is preferably 1500-1540 ℃, more preferably 1500-1530 ℃, and more preferably 1500-1520 ℃ in order to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, the uniform distribution and quantity of the vanadium-titanium phase structure, reduce the impurity content and better improve the strength and the wear resistance.

The smelting time of the medium-frequency induction furnace is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application condition, the product requirement and the quality requirement, the smelting time of the medium-frequency induction furnace is preferably 30-60 min, more preferably 35-55 min, and more preferably 40-50 min, in order to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, improve the uniform distribution and quantity of vanadium-titanium phase structures, reduce the impurity content, and better improve the strength and the wear resistance.

The tapping temperature of the medium-frequency induction furnace after smelting is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application condition, the product requirement and the quality requirement, the tapping temperature of the medium-frequency induction furnace after smelting is preferably 1500-1540 ℃, more preferably 1510-1530 ℃, and more preferably 1515-1525 ℃ in order to better improve the pearlite proportion, particularly the fine lamellar pearlite proportion, the uniform distribution and the quantity of the vanadium-titanium phase structure, reduce the impurity content and better improve the strength and the wear resistance.

The temperature of the transfer process of the transfer ladle is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application situation, the product requirement and the quality requirement, the temperature of the transfer ladle in the transfer process is preferably 1470-1500 ℃, more preferably 1475-1495 ℃, and more preferably 1480-1490 ℃ in order to better improve the pearlite proportion, particularly the fine flake pearlite proportion, the uniform distribution and quantity of the vanadium-titanium phase structure, reduce the impurity content and better improve the strength and the wear resistance.

The temperature of the heat preservation and standing is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual application conditions, product requirements and quality requirements, the pearlite proportion, particularly the fine lamellar pearlite proportion, the uniform distribution and quantity of vanadium-titanium phase structures, the impurity content and the strength and the wear resistance are better improved, and the temperature of the heat preservation and standing of the tundish is preferably 1420-1450 ℃, more preferably 1425-1445 ℃, and more preferably 1430-1440 ℃.

The heat preservation and standing time of the tundish is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual application conditions, product requirements and quality requirements, the heat preservation and standing time of the tundish is preferably 10-30 min, more preferably 18-27 min, more preferably 15-25 min, and more preferably 18-23 min, in order to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, improve the uniform distribution and quantity of vanadium-titanium phase structures, reduce the impurity content, and better improve the strength and the wear resistance.

According to the invention, the discharged molten iron obtained in the above steps is subjected to full-automatic multi-station casting, and then is subjected to demoulding and forming, so that the alloy gray cast iron cylinder sleeve is obtained.

The fully automatic multi-station casting step is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual application conditions, product requirements and quality requirements, the fully automatic multi-station casting method is used for better improving the pearlite proportion, particularly the proportion of fine lamellar pearlite, uniformly distributing and quantity of vanadium-titanium phase structures, reducing impurity content and better improving strength and wear resistance, and preferably comprises one or more steps of automatic spraying, automatic baffle-up, automatic casting, automatic water spraying and automatic cylinder discharging, and more preferably comprises the steps of automatic spraying, automatic baffle-up, automatic casting, automatic water spraying and automatic cylinder discharging.

The invention has no special limitation on the parameters of the automatic spraying in principle, and a person skilled in the art can select and adjust the parameters according to the actual application condition, the product requirement and the quality requirement, in order to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, improve the uniform distribution and quantity of vanadium-titanium phase structures, reduce the impurity content and better improve the strength and the wear resistance, the rotating speed of the automatic spraying is preferably 770-830 r/min, more preferably 780-820 r/min, and more preferably 790-810 r/min.

The invention has no special limitation on the parameters of the automatic casting in principle, and a person skilled in the art can select and adjust the parameters according to the actual application condition, the product requirement and the quality requirement, and the invention aims to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, the uniform distribution and quantity of vanadium-titanium phase structures, reduce the impurity content and better improve the strength and the wear resistance, wherein the rotation speed of the automatic casting is preferably 1445-1485 r/min, more preferably 1450-1480 r/min, and more preferably 1455-1470 r/min. The rotation speed of the automatic casting is preferably 1445-1485 r/min, more preferably 1450-1480 r/min, more preferably 1455-1470 r/min, the time of the automatic casting is preferably 4-5 s, more preferably 4.2-4.8 s, and more preferably 4.4-4.6 s.

The time for automatically watering is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application situation, the product requirements and the quality requirements, the time for automatically watering is preferably 30-85 s, more preferably 40-75 s, and more preferably 50-65 s, in order to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, improve the uniform distribution and quantity of vanadium-titanium phase structures, reduce the impurity content, and better improve the strength and the wear resistance.

The method is a complete and refined integral process, the pearlite proportion, particularly the proportion of fine lamellar pearlite, is better improved, the uniform distribution and quantity of vanadium-titanium phase structures are improved, the impurity content is reduced, the strength and the wear resistance are better improved, and the full-automatic multi-station casting is preferably accompanied with a downstream inoculation treatment step.

The inoculant for the forward stream inoculation is not particularly limited in principle, can be selected and adjusted by a person skilled in the art according to actual application conditions, product requirements and quality requirements, and preferably comprises one or more of a silicon-barium inoculant, a silicon-strontium inoculant, a silicon-barium-calcium inoculant, a silicon-iron inoculant and a silicon-strontium-zirconium inoculant, and more preferably comprises the silicon-barium inoculant, the silicon-strontium inoculant, the silicon-barium-calcium inoculant, the silicon-iron inoculant or the silicon-strontium-zirconium inoculant.

The addition amount of the inoculant is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to the actual application situation, the product requirement and the quality requirement, in order to better improve the pearlite proportion, particularly the fine lamellar pearlite proportion, improve the uniform distribution and quantity of the vanadium-titanium phase structure, reduce the impurity content and better improve the strength and the wear resistance, the addition amount of the inoculant is preferably 0.5-0.7% of the total mass of the molten iron, more preferably 0.52-0.68% of the total mass of the molten iron, and more preferably 0.55-0.65% of the total mass of the molten iron.

In principle, the temperature of the automatic cylinder discharging is not particularly limited, and a person skilled in the art can select and adjust the temperature according to actual application conditions, product requirements and quality requirements, the temperature of the automatic cylinder discharging is preferably 650-850 ℃, more preferably 670-830 ℃, and more preferably 690-810 ℃, in order to better improve the pearlite proportion, particularly the proportion of fine lamellar pearlite, improve the uniform distribution and quantity of vanadium-titanium phase structures, reduce the impurity content and better improve the strength and the wear resistance.

The invention is a complete and refined integral process, better improves the pearlite proportion, especially the proportion of fine lamellar pearlite, improves the uniform distribution and quantity of vanadium-titanium phase structures, reduces the impurity content, and better improves the strength and the wear resistance, and the preparation method of the alloy gray cast iron cylinder sleeve can specifically comprise the following steps:

① molten iron smelting, namely using pig iron, scrap steel and foundry returns, wherein the proportion of the pig iron, the scrap steel and the foundry returns can be controlled according to the cost, for example, the ratio is controlled to be 1.5:6.5:2, smelting is carried out in an electric furnace, alloys (ferroalloys such as silicomanganese, ferrophosphorus, ferrovanadium, ferrotitanium, ferrochromium, ferrosulfur and the like, electrolytic copper and the like) are added after all the materials are dissolved, the temperature is continuously increased to 1500-1540 ℃, a furnace cover is covered, standing and heat preservation is carried out for 10-20 min, and micro-seasonings are carried out, so that the component control is shown in table 1, and table 1 is the proportion range of the raw materials for preparing the alloy gray cast.

TABLE 1

②, slagging off the smelted molten iron to ensure that the molten iron has no inclusion such as iron slag, transferring the molten iron into a holding furnace by a transfer ladle, wherein the tapping temperature is ensured to be 1500-1540 ℃, the temperature of the molten iron entering the holding furnace is controlled to be 1470-1500 ℃, the temperature of the holding furnace is controlled to be 1420-1450 ℃, and the holding time is controlled to be 10-30 min.

③ casting, namely automatically casting molten iron from a heat preservation furnace, controlling the casting temperature to 1420-1450 ℃, using a silicon-barium inoculant, controlling the amount of the inoculant to be within 0.5-0.7%, automatically feeding the inoculant by an automatic feeding system, controlling the casting time to 4-5 s, using a full-automatic multi-station casting machine (the number of stations is not less than 9) to produce, wherein the multi-station casting machine comprises the steps of automatic spraying, upper baffle plate, casting, water exciting, automatic cylinder discharging and the like, the spraying rotating speed is 800r/min, the rotating speed of the casting machine is 1465r/min, the water exciting time is controlled to 30-85 s, the cylinder discharging temperature is controlled to 650-850 ℃, and the final cylinder sleeve component is shown in table 2, and the table 2 is the proportion range of the alloy gray cast iron cylinder sleeve product prepared by the invention.

TABLE 2

④ casting machine adopts metal type wet paint centrifugal casting conventional process to produce cylinder sleeve casting (for example, conventional horizontal centrifugal casting machine can be adopted, the mold adopts metal type mold, and the mold cavity is sprayed with conventional wet paint to produce).

⑤ the blank cylinder liner was extracted for hardness, tensile strength and metallographic examination.

Referring to fig. 1, fig. 1 is a schematic diagram of a production process flow of a vanadium-titanium alloy gray cast iron cylinder liner provided by the invention.

Referring to fig. 2, fig. 2 is a schematic view of the working process of the multi-station casting machine adopted by the invention.

The invention provides a vanadium-titanium alloy gray cast iron cylinder sleeve and a preparation method thereof, and particularly relates to a method for smelting materials by adopting a high-frequency electric furnace, then carrying out heat preservation and purification treatment by using a heat preservation furnace, and carrying out casting by using an automatic multi-station casting machine. In the preparation process, the molten iron can be purified in the heat-preserving furnace, so that the molten iron is purer, the performance of the product obtained by casting is better, the strength is higher, and the vanadium-titanium phase distribution is more uniform; and meanwhile, the automatic multifunctional casting machines such as the 9-station casting machine and the 11-station casting machine are used, so that automation and intellectualization of casting are realized, the direction of future industrial development is met, the labor cost is reduced, and the alloy gray cast iron cylinder sleeve with high proportion of fine lamellar pearlite and uniform and large quantity of vanadium-titanium phase structures is obtained.

The invention combines the processes of electric furnace smelting, holding furnace heat preservation, multi-station automatic casting and the like and corresponding parameters thereof, mutually promotes and advances to obtain the vanadium-titanium alloy gray cast iron cylinder sleeve with a specific tissue structure. The vanadium-titanium alloy gray cast iron cylinder sleeve produced by the invention has a large pearlite proportion in a matrix structure, particularly the proportion of fine lamellar pearlite can reach 100%, the vanadium-titanium phase structure is more uniformly distributed, the quantity is large, the impurity content is low, so that the product has the characteristics of high strength, good wear resistance and the like, meanwhile, the preparation process is simple, the process instability factors caused by human factors are reduced, and the stability of the product quality is ensured, and the process is more stable due to the use of a heat preservation furnace and a multi-station automatic casting machine, so that the product quality is more ensured, particularly, the condition of popularizing industry 4.0 in China is met, the automation degree is improved, the number of personnel is reduced, the popularization value is better and stable, and the method is more suitable for industrial popularization and use.

Experimental results show that the alloy gray cast iron cylinder sleeve prepared by the invention has the hardness of more than or equal to 240HBW and the tensile strength of more than or equal to 320 Mpa.

To further illustrate the present invention, an alloy gray cast iron cylinder liner and a method for manufacturing the same according to the present invention will be described in detail with reference to the following examples, but it should be understood that the embodiments are carried out on the premise of the technical solution of the present invention, and the detailed embodiments and the specific operation procedures are given only for further illustrating the features and advantages of the present invention, not for limiting the claims of the present invention, and the scope of protection of the present invention is not limited to the following examples.

Example 1

The preparation method of the vanadium-titanium sleeve comprises the following steps:

smelting molten iron: pig iron, scrap steel and foundry returns, wherein the ratio of the pig iron to the scrap steel to the foundry returns is 1.5:6.5:2, the pig iron, the scrap steel and the foundry returns are smelted in an electric furnace, alloys (ferroalloys such as silicon-manganese alloy, ferrophosphorus, ferrovanadium, ferrotitanium, ferrochrome, ferrosulfur and the like, electrolytic copper and the like) are added after all the materials are dissolved, the temperature is continuously increased to 1508 ℃ until the materials are completely dissolved, a furnace cover is covered, the mixture is kept stand for 18min, and micro-seasonings are carried out, so that the component control is shown in Table 3.

TABLE 3

Order of item	C	S	Si	P	Mn	Cr	Cu	V+Ti
									Require that	3.22	0.065	1.82	0.38	1.05	0.35	0.15	0.32

And carrying out slagging-off treatment on the smelted molten iron to ensure that the molten iron does not contain impurities such as iron slag and the like, transferring the molten iron into a heat preservation furnace by using a transfer ladle, wherein the tapping temperature is 1508 ℃, the temperature of the molten iron entering the heat preservation furnace is 1482 ℃, the temperature of the heat preservation furnace is 1438 ℃, and the heat preservation time is controlled to be 20 min.

Casting: the molten iron is automatically poured out of the heat preservation furnace, the pouring temperature is 1435 ℃, a silicon-barium inoculant is used, the amount of the inoculant is controlled to be 0.6%, the inoculant is automatically fed by an automatic feeding system, and the pouring time is controlled to be 4 s. And (3) producing by using a full-automatic multi-station casting machine (the number of stations is not less than 9). The multi-station casting machine comprises the steps of automatic spraying, baffle plate feeding, casting, water spraying, automatic cylinder discharging and the like. The spraying speed is 800r/min, the casting machine speed is 1465r/min, the water spraying time is controlled at 50s, and the cylinder discharging temperature is controlled at 690 ℃. Cylinder liner final composition is seen in table 4.

TABLE 4

Order of item	C	S	Si	P	Mn	Cr	Cu	V+Ti
									Require that	3.18	0.065	2.23	0.38	1.05	0.35	0.15	0.32

The casting machine adopts metal type wet paint to centrifugally cast the cylinder sleeve casting by a conventional process (for example, a conventional horizontal centrifugal casting machine can be adopted, the mold adopts a metal type mold, and the inner cavity of the mold is sprayed with conventional wet paint for production). After the casting is demoulded, the casting is naturally cooled to room temperature and then is put into a casting frame.

And extracting the blank cylinder sleeve to check the hardness, the tensile strength and the metallographic phase.

The vanadium titanium alloy gray cast iron cylinder liner prepared in example 1 of the present invention was characterized.

Referring to fig. 3, fig. 3 is a graphite map (100 times) of the metallographic structure of the vanadium-titanium alloy gray cast iron cylinder liner prepared in example 1 of the present invention;

referring to fig. 4, fig. 4 is a vanadium-titanium phase diagram (500 times) of the metallographic structure of the vanadium-titanium alloy gray cast iron cylinder liner prepared in example 1 of the present invention;

referring to fig. 5, fig. 5 is a metallographic structure matrix diagram (500 times) of a vanadium-titanium alloy gray cast iron cylinder liner prepared in example 1 of the present invention.

As is clear from fig. 3 to 5, the metallographic structure is mainly a type a, the content of a type graphite is 100%, the number of vanadium-titanium phases is nearly 23, and the matrix is fine lamellar pearlite. The amount of fine lamellar pearlite was 99%.

The performance test of the vanadium-titanium alloy gray cast iron cylinder liner prepared in the embodiment 1 of the invention shows that the tensile strength of the produced cylinder liner is 343Mpa, and the hardness is 250 HBW.

Example 2

The preparation method of the vanadium-titanium sleeve comprises the following steps:

smelting molten iron: pig iron, scrap steel and foundry returns are used, the proportion of the pig iron, the scrap steel and the foundry returns can be controlled according to the cost, for example, the ratio is controlled to be 2.5:5.5:2, the pig iron, the scrap steel and the foundry returns are smelted in an electric furnace, alloys (ferroalloys such as silicon-manganese alloy, ferrophosphorus, ferrovanadium, ferrotitanium, ferrochromium, ferrosulfur and the like, electrolytic copper and the like) are added after all the materials are dissolved, the temperature is continuously raised to 1532 ℃, a furnace cover is covered, the temperature is kept for 21min, and micro-seasonings are carried out, wherein the components are.

TABLE 5

Order of item	C	S	Si	P	Mn	Cr	Cu	V+Ti
									Require that	3.34	0.084	1.88	0.41	0.72	0.35	0.17	0.36

And carrying out slagging-off treatment on the smelted molten iron to ensure that the molten iron does not contain impurities such as iron slag and the like, transferring the molten iron into a heat preservation furnace by using a transfer ladle, wherein the tapping temperature is 1531 ℃, the temperature of the molten iron entering the heat preservation furnace is 1495 ℃, the temperature of the heat preservation furnace is 1442 ℃, and the heat preservation time is controlled to be 23 min.

Casting: and automatically pouring the molten iron from the heat preservation furnace, wherein the pouring temperature is 1436 ℃, a silicon-strontium inoculant is used, the amount of the inoculant is 0.65%, the inoculant is automatically added by an automatic feeding system, and the pouring time is controlled to be 5 s. And (3) producing by using a full-automatic multi-station casting machine. The multi-station casting machine comprises the steps of automatic spraying, baffle plate feeding, casting, water spraying, automatic cylinder discharging and the like. The spraying speed is 800r/min, the casting machine speed is 1465r/min, the water spraying time is controlled at 48s, and the cylinder discharging temperature is controlled at 720 ℃. Cylinder liner final composition is seen in table 6.

TABLE 6

Order of item	C	S	Si	P	Mn	Cr	Cu	V+Ti
									Require that	3.32	0.084	2.35	0.41	0.72	0.35	0.17	0.36

The casting machine adopts metal type wet paint to centrifugally cast the cylinder sleeve casting by a conventional process (for example, a conventional horizontal centrifugal casting machine can be adopted, the mold adopts a metal type mold, and the inner cavity of the mold is sprayed with conventional wet paint for production). After the casting is demoulded, the casting is naturally cooled to room temperature and then is put into a casting frame.

And extracting the blank cylinder sleeve to check the hardness, the tensile strength and the metallographic phase.

The result shows that the metallographic structure graphite mainly contains A type, the content of the A type graphite is 95%, the matrix structure is pearlite, the content is more than 98%, and the number of vanadium-titanium phases is 25.

The performance test of the vanadium-titanium alloy gray cast iron cylinder liner prepared in the embodiment 2 of the invention shows that the tensile strength of the produced cylinder liner is 333Mpa, and the hardness is 255 HBW.

Example 3

The preparation method of the vanadium-titanium sleeve comprises the following steps:

smelting molten iron: pig iron, scrap steel and foundry returns are used, the proportion of the pig iron, the scrap steel and the foundry returns can be controlled according to the cost, for example, the ratio is controlled to be 3:5:2, the pig iron, the scrap steel and the foundry returns are smelted in an electric furnace, alloys (ferroalloys such as silicon-manganese alloy, ferrophosphorus, ferrovanadium, ferrotitanium, ferrochrome, ferrosulfur and the like, electrolytic copper and the like) are added after all the materials are dissolved, the temperature is continuously increased to 1515 ℃, a furnace cover is covered, the mixture is kept still for 20min, and micro-flavoring is carried out according to the detection result, wherein.

TABLE 7

Order of item	C	S	Si	P	Mn	Cr	Cu	V+Ti
									Require that	3.41	0.062	1.83	0.36	0.95	0.42	0.24	0.42

And carrying out slagging-off treatment on the smelted molten iron to ensure that the molten iron does not contain impurities such as iron slag and the like, transferring the molten iron into a holding furnace by using a transfer ladle, wherein the tapping temperature is 1515 ℃, the temperature of the molten iron entering the holding furnace is 1482 ℃, the temperature of the holding furnace is 1438 ℃, and the holding time is controlled to be 26 min.

Casting: and automatically pouring the molten iron from the heat preservation furnace, wherein the pouring temperature is 1436 ℃, a silicon-barium inoculant is used, the amount of the inoculant is 0.68%, the inoculant is automatically added by an automatic feeding system, and the pouring time is controlled to be 5 s. And (3) producing by using a full-automatic multi-station casting machine. The multi-station casting machine comprises the steps of automatic spraying, baffle plate feeding, casting, water spraying, automatic cylinder discharging and the like. The spraying speed is 800r/min, the casting machine speed is 1465r/min, the water spraying time is controlled at 70s, and the cylinder discharging temperature is controlled at 780 ℃. Cylinder liner final composition is seen in table 8.

TABLE 8

Order of item	C	S	Si	P	Mn	Cr	Cu	V+Ti
									Require that	3.39	0.062	2.51	0.36	0.95	0.42	0.24	0.42

The casting machine adopts metal type wet paint to centrifugally cast the cylinder sleeve casting by a conventional process (for example, a conventional horizontal centrifugal casting machine can be adopted, the mold adopts a metal type mold, and the inner cavity of the mold is sprayed with conventional wet paint for production). After the casting is demoulded, the casting is naturally cooled to room temperature and then is put into a casting frame.

And extracting the blank cylinder sleeve to check the hardness, the tensile strength and the metallographic phase.

The result shows that the metallographic structure graphite mainly contains A type, the content of the A type graphite is 100 percent, the matrix structure is pearlite, the content is more than 99 percent, and the number of vanadium-titanium phases is 26.

The performance test of the vanadium-titanium alloy gray cast iron cylinder liner prepared in the embodiment 3 of the invention shows that the tensile strength of the produced cylinder liner is 345Mpa, and the hardness is 258 HBW.

Example 4

The preparation method of the vanadium-titanium sleeve comprises the following steps:

smelting molten iron: pig iron, scrap steel and foundry returns are used, the proportion of the pig iron, the scrap steel and the foundry returns can be controlled according to the cost, for example, the ratio is controlled to be 3.5:4.5:2, the pig iron, the scrap steel and the foundry returns are smelted in an electric furnace, alloys (ferroalloys such as silicon-manganese alloy, ferrophosphorus, ferrovanadium, ferrotitanium, ferrochromium, ferrosulfur and the like, electrolytic copper and the like) are added after all the materials are dissolved, the temperature is continuously increased to 1535 ℃, a furnace cover is covered, the temperature is kept for 20min, and micro-flavoring is carried out according to the detection result, wherein the.

TABLE 9

Order of item	C	S	Si	P	Mn	Cr	Cu	V+Ti
									Require that	3.32	0.081	1.85	0.40	0.68	0.28	0.28	0.33

And carrying out slagging-off treatment on the smelted molten iron to ensure that the molten iron does not contain impurities such as iron slag and the like, transferring the molten iron into a heat preservation furnace by using a transfer ladle, wherein the tapping temperature is 1535 ℃, the temperature of the molten iron entering the heat preservation furnace is 1491 ℃, the temperature of the heat preservation furnace is 1445 ℃, and the heat preservation time is controlled to be 18 min.

Casting: the molten iron is automatically poured out of the heat preservation furnace, the pouring temperature is 1443 ℃, a silicon-barium inoculant is used, the amount of the inoculant is 0.55 percent, the inoculant is automatically added by an automatic feeding system, and the pouring time is controlled to be 5 s. And (3) producing by using a full-automatic multi-station casting machine. The multi-station casting machine comprises the steps of automatic spraying, baffle plate feeding, casting, water spraying, automatic cylinder discharging and the like. The spraying speed is 800r/min, the casting machine speed is 1465r/min, the water spraying time is controlled at 45s, and the cylinder discharging temperature is controlled at 738 ℃. Cylinder liner final composition is seen in table 10.

Watch 10

Order of item	C	S	Si	P	Mn	Cr	Cu	V+Ti
									Require that	3.30	0.081	2.28	0.40	0.68	0.28	0.28	0.33

The casting machine adopts metal type wet paint to centrifugally cast the cylinder sleeve casting by a conventional process (for example, a conventional horizontal centrifugal casting machine can be adopted, the mold adopts a metal type mold, and the inner cavity of the mold is sprayed with conventional wet paint for production). After the casting is demoulded, the casting is naturally cooled to room temperature and then is put into a casting frame.

And extracting the blank cylinder sleeve to check the hardness, the tensile strength and the metallographic phase.

The result shows that the metallographic structure graphite mainly contains A type, the content of the A type graphite is 90 percent, the matrix structure is pearlite, and the content of the pearlite is more than 98 percent. The number of vanadium-titanium phases is 23.

The performance test of the vanadium-titanium alloy gray cast iron cylinder liner prepared in the embodiment 4 of the invention shows that the tensile strength of the produced cylinder liner is 322Mpa, and the hardness is 248 HBW.

The vanadium-titanium alloy gray cast iron cylinder sleeve and the preparation method thereof provided by the invention are described above. Having described in detail, the principles and embodiments of the present invention have been described herein using specific examples, which are intended to facilitate an understanding of the principles of the invention and their core concepts, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims (10)

1. The alloy gray cast iron cylinder liner is characterized by comprising vanadium elements and titanium elements;

the metallographic structure of the alloy gray cast iron cylinder sleeve comprises graphite and a vanadium-titanium phase;

the alloy gray cast iron matrix structure comprises pearlite;

the amount of pearlite is greater than 98%;

the proportion of fine lamellar pearlite in the pearlite is 98% or more.

2. The alloy gray cast iron cylinder liner according to claim 1, characterized in that the sum of the contents of vanadium and titanium elements is between 0.3% and 0.45%;

the inter-lamellar spacing of the fine lamellar pearlite is not more than 1 mm;

the matrix structure of the alloy gray cast iron cylinder sleeve is a matrix structure of the alloy gray cast iron cylinder sleeve amplified by 500 times;

the graphite comprises uniform type a graphite;

the proportion of the A-type graphite in the total amount of the graphite is more than or equal to 80 percent;

the metallographic structure of the alloy gray cast iron comprises uniform polygonal vanadium-titanium carbonitride;

the number of the polygonal vanadium-titanium carbonitride is more than or equal to 10.

3. The alloy gray cast iron cylinder liner according to claim 2, characterized in that the proportion of fine lamellar pearlite in the pearlite is 100%;

the quantity of the A-type graphite is 100 percent;

the total impurity content of the alloy gray cast iron cylinder sleeve is less than or equal to 0.01 percent;

the air content of the alloy gray cast iron cylinder sleeve is less than or equal to 0.01 percent;

in the gas content, the oxygen content is less than 0.01 percent;

in the gas content, the hydrogen content is less than 0.001%.

4. The alloy gray cast iron cylinder liner according to claim 1, characterized by comprising, in mass percent:

the balance being iron.

5. The alloy gray cast iron cylinder liner according to claim 4, characterized in that, in the alloy gray cast iron, the impurity alumina content is less than or equal to 0.01%;

in the alloy gray cast iron, the content of impurity calcium oxide is less than 0.005 percent;

the hardness of the alloy gray cast iron is more than or equal to 230 HBW;

the tensile strength of the alloy gray cast iron is more than or equal to 300 Mpa.

6. The preparation method of the alloy gray cast iron cylinder sleeve is characterized by comprising the following steps of:

1) smelting the raw materials in a medium-frequency induction furnace, transferring the raw materials to a heat preservation furnace through a transfer ladle, preserving heat and standing to obtain molten iron discharged from the furnace;

2) and (4) carrying out full-automatic multi-station casting on the discharged molten iron obtained in the step, and then demoulding and forming to obtain the alloy gray cast iron cylinder sleeve.

7. The preparation method according to claim 6, wherein the raw materials comprise, by mass:

the balance being iron.

8. The production method according to claim 6, wherein the raw materials include iron, scrap and alloy;

the mass ratio of the pig iron to the scrap steel to the foundry returns is (1-4): (4-8): 2;

the alloy material comprises one or more of silicon-manganese alloy, ferrophosphorus alloy, ferrovanadium alloy, ferrotitanium alloy, ferrochrome alloy, ferrosulfur alloy and electrolytic copper;

the smelting temperature of the medium-frequency induction furnace is 1500-1540 ℃;

the smelting time of the medium-frequency induction furnace is 30-60 min.

9. The preparation method of claim 6, wherein the tapping temperature of the medium frequency induction furnace after smelting is 1500-1540 ℃;

the temperature of the transfer process of the transfer ladle is 1470-1500 ℃;

the temperature for heat preservation and standing is 1420-1450 ℃;

the heat preservation standing time is 10-30 min;

the full-automatic multi-station casting comprises one or more steps of automatic spraying, automatic baffle plate feeding, automatic casting, automatic water spraying and automatic cylinder discharging;

the full-automatic multi-station casting is accompanied with a downstream inoculation treatment step.

10. The preparation method according to claim 9, wherein the rotation speed of the automatic spraying is 770 to 830 r/min;

the rotation speed of the automatic casting is 1445-1485 r/min;

the automatic casting time is 4-5 s;

the automatic water-exciting time is 30-85 s;

the inoculant for the downstream inoculation treatment comprises one or more of a silicon-barium inoculant, a silicon-strontium inoculant, a silicon-barium-calcium inoculant, a silicon-iron inoculant and a silicon-strontium-zirconium inoculant;

the addition amount of the inoculant is 0.5-0.7% of the total mass of the molten iron;

the temperature of the automatic cylinder discharging is 650-850 ℃.

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