CN113493885A - High-performance hot-work die steel and preparation method thereof - Google Patents
High-performance hot-work die steel and preparation method thereof Download PDFInfo
- Publication number
- CN113493885A CN113493885A CN202010250549.1A CN202010250549A CN113493885A CN 113493885 A CN113493885 A CN 113493885A CN 202010250549 A CN202010250549 A CN 202010250549A CN 113493885 A CN113493885 A CN 113493885A
- Authority
- CN
- China
- Prior art keywords
- treatment
- forging
- die steel
- work die
- hot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/13—Modifying the physical properties of iron or steel by deformation by hot working
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
Abstract
The invention discloses a high-performance hot-work die steel and a preparation method thereof, and the high-performance hot-work die steel comprises 0.9-1.0% of C in percentage by weight; si is 0.7-0.9%; mn is 0.4-0.6%; 7.5 to 8.0 percent of Cr; mo is 2.4-2.7%; v is 0.4-0.6%; ni 0.3-0.4%, B0.0001-0.0003%, and Fe in balance. The hot work die steel prepared by optimizing the components can meet the use requirements of a hot forging die, a die casting die and an extrusion die, and the performance of the hot work die steel can meet the following requirements: the quenching temperature is 1030-.
Description
Technical Field
The invention relates to the field of material component design and preparation, in particular to high-performance hot-work die steel and a preparation method thereof.
Background
The die steel is used for manufacturing dies such as a cold-stamping die, a hot-forging die, a die-casting die and the like, the dies are main processing tools for manufacturing parts in industrial departments such as mechanical manufacturing, radio instruments, motors, electric appliances and the like, the quality of the dies directly influences the quality of a pressure processing process, the precision yield and the production cost of products, and the quality and the service life of the dies generally depend on the aspects of reasonable structural design, processing precision, die materials, heat treatment and the like. According to the service conditions of the die, the die steel can be divided into four categories, including cold-work die steel, hot-work die steel, plastic die steel and plastic die steel. The hot working die is a tool for manufacturing a desired product from a heated metal or a liquid metal, such as a hot forging die, a hot heading die, a hot extrusion die, a die casting die, a high speed forming die, and the like, and the various die steels used are collectively referred to as hot working die steels.
With the rapid development of the automobile industry, the rail transit industry, the aerospace industry, the engineering machinery and other industries in China, the demand of various mechanical equipment forgings is greatly increased, the forgings are machined by adopting forging and pressing machinery, the steel quantity demand of forging and pressing dies is large, and the annual demand of the forging and pressing die steel market in the southwest and the Chongqing areas is about ten thousand tons. Because the temperature difference between the surface and the core of the hot-working die is large under working conditions, the performance requirements on the hot-working die material are high, and the requirements on the hardness, the strength, the toughness, the heat resistance, the wear resistance and the like are required. In particular, the hot work die is repeatedly heated and cooled by water during operation and bears a large impact force, so that the hot work die steel has high requirements such as high strength, high mechanical properties, wear resistance, heat resistance and low die force.
Patent application No.: 201510776761.0, the patent names: a process for preparing 4Cr5MoSiV1 hot-die steel includes adding La and Ce in the condition of controlling oxygen, diffusion homogenizing annealing, three-time upsetting and drawing-out forging, and alternative quick cooling with water and air after forging to obtain 4Cr5MoSiV1 hot-die steel with stable tempering structure whose hardness is up to 45 +/-1 HRC. There is a need to develop a hot-work die steel material having higher hardness, better mechanical properties, high wear resistance, high heat resistance, and low die force.
Disclosure of Invention
The invention aims to provide high-performance hot-work die steel and a preparation method thereof.
According to one aspect of the invention, a high-performance hot-work die steel is provided, which comprises, by weight, 0.9-1.0% of C; si is 0.7-0.9%; mn is 0.4-0.6%; 7.5 to 8.0 percent of Cr; mo is 2.4-2.7%; v is 0.4-0.6%; ni 0.3-0.4%, B0.0001-0.0003%, and Fe in balance.
The composition design reasons of the high-performance hot-work die steel are as follows:
c: carbon is a second only to iron, and directly affects the strength, plasticity, toughness, etc. of steel. The carbon content in the steel determines the matrix hardness of the quenched steel, and in the case of hot work die steel, a part of the carbon in the steel enters the matrix of the steel to cause solid solution strengthening. Another portion of the carbon will combine with the alloying elements to form alloyed carbides. For hot-work die steel, besides a small amount of residual alloy carbide, the alloy carbide also needs to be dispersed and precipitated on a tempered martensite matrix during tempering to generate a secondary hardening phenomenon, and the uniformly distributed residual alloy carbide and tempered martensite structure determine the performance of the hot-work die steel. Along with the increase of the carbon content, the yield point and the tensile strength of the material can be gradually improved, and in order to ensure the comprehensive mechanical property of the hot-work die steel, the content of the added C (carbon) is 0.9-1.0%.
Si: silicon is added as a reducing agent and a deoxidizing agent in the steelmaking process, the adding amount is 0.15-0.5%, and when the silicon content in the cylinder exceeds 0.5%, the silicon is used as an alloy element in the steel, so that the elastic limit, the yield point and the tensile strength of the cylinder can be obviously improved. The combination of silicon, molybdenum, chromium, etc. has the functions of raising corrosion resistance and resisting oxidation, and can raise the heat resistance of steel. During heat treatment, silicon is soluble in ferrite and austenite, increasing the hardness and strength of the steel. Therefore, the content of Si (silicon) is controlled to be 0.7 to 0.9%.
Mn: manganese is a good deoxidizer and desulfurizer, eliminates the harmful effect of sulfur, can improve the toughness of steel, has higher strength and hardness, improves the quenching property of steel, and improves the hot workability of steel. However, when the manganese content is high, the steel has a relatively remarkable temper brittleness phenomenon, and when the manganese content exceeds 1%, the weldability of the steel is lowered. Therefore, the content of added manganese is 0.4-0.6%.
Cr: chromium is an important alloy element and has favorable effects on the wear resistance, high-temperature strength, hot strength, toughness and hardenability of the hot-work die steel. Chromium increases the hardenability of steel and has a secondary hardening effect, a part of chromium is dissolved in a matrix to play a solid solution strengthening role, and the other part of chromium is combined with carbon to form carbide. Chromium is dissolved in austenite during quenching and heating, and is dissolved in martensite after quenching, so that the tempering softening resistance of the steel can be improved. The content of the added Cr (chromium) is 7.5-8.0%.
Mo: molybdenum can refine the crystal grains of the steel, improve the hardenability and the heat strength of the steel, maintain enough strength and creep resistance at high temperature, improve the mechanical property and prevent brittleness caused by tempering. Special carbide is formed in steel, the secondary hardening capacity and the tempering stability of the steel are improved, molybdenum and carbon are combined, more fine short rod-shaped carbide is separated out during tempering, the tempering stability of the steel is greatly improved, and the content of added Mo (molybdenum) is 2.4-2.7%.
Ni: according to the invention, a certain amount of Ni is added, so that the hot-work die steel has certain hardenability and toughness, and the molybdenum-nickel alloying plays an optimal role, wherein the content of the added Ni (nickel) is 0.3-0.4%.
V: vanadium is an excellent deoxidizer of steel, belongs to a strong carbon compound element, is combined with carbon to form VC carbide, can refine austenite grains, has high red hardness and extremely small thermal wear, improves the strength and toughness of the steel, reduces the overheating sensitivity, increases the tempering stability and the wear resistance, and prolongs the service life. The content of the added V (vanadium) is 0.4-0.6%.
B: boron can improve the compactness and hot rolling performance of steel, improve the strength of the steel and increase the hardenability of the steel. The content of B (boron) is 0.0001-0.0003%.
The invention has the beneficial effects that: the high-performance hot-work die steel is prepared by the contents of elements such as C, Si, Mn, Cr, Mo, V, Ni, B and the like, and the relationship between the contents of the elements and the hardenability and strength of the material is established; the relationship between elements and the toughness of the material is established through the content blending of elements such as C, Cr, Mo and the like; the effect of refining grains is achieved by blending a proper amount of element V. The hot work die steel prepared by optimizing the components can meet the use requirements of a hot forging die, a die casting die and an extrusion die, and the performance of the hot work die steel meets the following requirements: the quenching hardness is 64HRC, the use hardness is 48-62HRC, the impact energy is more than or equal to 450J, and the mechanical property, the impact force, the wear resistance, the heat resistance and the performance of the anti-sticking die force of the existing hot work die steel are greatly improved. The die made of the high-performance hot-working die steel has strong erosion resistance, and can ensure smooth working surface of the die and no abrasion after multiple casting in the using process, thereby prolonging the service life of the die.
In some embodiments, a method of making a high performance hot work die steel comprises the following:
step a, raw material smelting and refining:
smelting and refining the raw materials in sequence to obtain a first forging;
step b, homogenizing:
carrying out pre-deformation treatment and three-stage high-temperature uniform heating treatment on a first forging to obtain a second forging, and carrying out shape-regularizing treatment on the first forging during first firing in the pre-deformation treatment;
step c, ultra-fining treatment:
heating the second forging to a certain temperature, carrying out quick cooling, controlling the cooling speed of the second forging in a temperature range of more than 200 ℃ in the quick cooling process, and discharging the second forging from a furnace and carrying out air cooling to room temperature when the temperature of the second forging is lower than 200 ℃ to obtain a third forging;
step d, forging:
forging the third forging to obtain a fourth forging;
step e, performance heat treatment:
and performing spheroidizing annealing treatment and thermal refining treatment on the fourth forging piece in sequence to obtain the high-performance hot-work die steel. The preparation method of the invention homogenizes the material by high-temperature diffusion, refines the crystal grains by solid phase change in the steel, further optimizes the distribution of precipitated phases by dissolution, nucleation and re-precipitation of the precipitated phases and improves the material performance. By adopting pre-deformation and three-stage high-temperature uniform heating treatment, after the forging is denatured, the number of vacant sites is increased, and the high-temperature treatment can increase the expansion speed of alloy elements and make the components more uniform.
In some embodiments, the refining in step a comprises rare earth treatment after deoxidation and desulfurization treatment, the oxygen content in the raw material after rare earth treatment is less than 12PPm, the proportion of the number of ball-type inclusions in the total amount of the inclusions is more than or equal to 85%, and rare earth with the oxygen content of less than 100PPm is adopted in rare earth treatment.
In some embodiments, the temperature of the three sections in the three-section high-temperature uniform heating treatment in the step b is 1200-1220 ℃, 1220-1240 ℃ and 1250-1300 ℃, respectively, the total heat preservation time is more than or equal to 1h/25mm, and the heat preservation time of each section is the same.
In some embodiments, the second forging piece is rapidly cooled when heated to 1000-1260 ℃ in the step c, and the cooling speed of the second forging piece is more than or equal to 0.7 ℃/S in a temperature range of more than 200 ℃ in the rapid cooling process.
In some embodiments, the spheroidizing annealing treatment in the step e is isothermal spheroidizing annealing treatment, wherein the temperature in the isothermal spheroidizing annealing treatment is kept between AC1 and AC3 for the first time, the keeping time is calculated according to the thickness of 1h/25mm, the furnace is cooled to 800-850 ℃ after the first keeping is finished, the second keeping is carried out, the keeping time is calculated according to the thickness of 1h/25mm, and the furnace is cooled to room temperature after the second keeping is finished.
In some embodiments, the thermal refining in step e includes a quenching process and a double tempering process.
In some embodiments, the quenching treatment is oil quenching, the temperature of the quenching treatment is AC3+ 205-255 ℃, and the heat preservation time of the quenching treatment is calculated according to the thickness of 1h/25 mm.
In some embodiments, the temperature range of the two tempering treatments is 540-610 ℃, the heat preservation time of the two tempering treatments is calculated according to 1h/25mm thickness, and the air cooling is carried out to the room temperature after each tempering in the two tempering treatments.
In some embodiments, the high performance hot work die steel has a quench hardness of 64HRC, a work hardness of 48-62HRC, and a work of impact of 450J or more.
Drawings
FIG. 1 is a structural phase diagram of a high performance hot work die steel at 200-1200 ℃ according to an embodiment of the present invention.
FIG. 2 is a graph showing the hardenability of a high-performance hot-work die steel according to an embodiment of the present invention.
FIG. 3 is a graph showing the high temperature performance of a high performance hot work die steel according to an embodiment of the present invention.
FIG. 4 is a graph showing a transition curve of continuous cooling of a high performance hot work die steel according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples.
Example 1
Referring to fig. 1 to 4, in the embodiment, the high-performance hot-work die steel includes, by weight, 0.9% of C; si is 0.9%; mn is 0.5%; 7.8 percent of Cr; mo is 2.5 percent; v is 0.5%; 0.4% of Ni, 0.0001% of B and the balance of Fe.
In this embodiment, a preparation method of high-performance hot-work die steel includes the following steps:
step a, raw material smelting and refining:
the raw materials of the hot-work die steel in the embodiment are smelted according to the proportion to obtain molten steel, the molten steel is refined, the refining process comprises the steps of carrying out rare earth treatment on the molten steel by using high-purity rare earth with the oxygen content of 99ppm after full deoxidation and desulfurization treatment, the oxygen content of the molten steel after rare earth treatment is 11ppm, the quantity of ball type inclusions accounts for 85% of the total quantity of the inclusions, and the molten steel after rare earth treatment is prepared into a first forging.
Step b, homogenizing:
and carrying out pre-deformation treatment on the first forge piece, namely carrying out shape normalization treatment on the first forge piece during the first firing, and then carrying out three-section type high-temperature component homogenization treatment on the first forge piece to obtain a second forge piece. Wherein the three sections of temperatures are 1200 ℃, 1220 ℃ and 1250 ℃, respectively, the three heating temperatures are gradually increased, the heat preservation time of each section of temperature is the same, and the total heat preservation time is 1h/25 mm. Therefore, the first forging piece can be prevented from overheating and overburning, and alloy elements can be promoted to be rapidly diffused at high temperature, so that the purpose of homogenization is achieved. The holding time in this example is calculated as 1h/25mm thickness, which means: and (4) according to the maximum wall thickness of the forging or hot work die steel, keeping the temperature for 1 hour every 25 mm.
Step c, ultra-fining treatment:
and (3) rapidly cooling the second forging piece when the temperature of the second forging piece is heated to 1000 ℃, wherein the cooling speed of the second forging piece is 0.7 ℃/S in a temperature range of more than 200 ℃ in the rapid cooling process, and when the temperature of the second forging piece is lower than 200 ℃, the second forging piece is taken out of the furnace and cooled to room temperature in an air cooling mode to obtain a third forging piece. In the homogenization treatment, the temperature is higher, the heat preservation time is long, the first forging crystal grains are easily large and irregular, larger internal force is easily caused, and after spheroidizing annealing, spheroidized tissues are uneven and the grain size level is low. The grain can be refined through the ultra-fining treatment, the structure is homogenized, the carbide is prevented from being separated out along the crystal, and a good structure is prepared for the subsequent spheroidizing annealing treatment.
Step d, forging:
forging the third forging to obtain a fourth forging;
step e, performance heat treatment:
isothermal spheroidizing annealing treatment is carried out on the fourth forging, the temperature is kept between AC1 and AC3, AC1 refers to the critical temperature of pearlite transformed into austenite during heat treatment, AC1 is 798.5 ℃ in the embodiment, AC3 refers to the critical temperature of ferrite completely transformed into austenite during heat treatment, and AC3 is 825.4 ℃ in the embodiment. The heat preservation time is calculated according to the thickness of 1h/25mm, then the furnace is cooled to 800 ℃ for continuous heat preservation treatment, the heat preservation time is calculated according to the thickness of 1h/25mm, and then the furnace is cooled to the room temperature. Then quenching and tempering are carried out, the quenching temperature is selected to be AC3+205 ℃, the heat preservation time is calculated according to the thickness of 1h/25mm, and oil quenching is carried out until the temperature is room temperature; and the temperature of the two tempering processes is 540 ℃, the heat preservation time is calculated according to the thickness of 1h/25mm, and the high-performance hot work die steel is obtained after air cooling to the room temperature after each tempering process.
The high-performance hot-work die steel prepared in the embodiment is subjected to performance detection, and the quenching hardness is 64HRC, the working hardness is 48HRC, and the impact energy is 450J.
Example 2
In the embodiment, the high-performance hot-work die steel comprises 1.0% of C in percentage by weight; si is 0.7%; mn is 0.4%; 7.5 percent of Cr; mo is 2.4%; v is 0.4%; 0.3% of Ni, 0.0003% of B and the balance of Fe.
In this embodiment, a preparation method of high-performance hot-work die steel includes the following steps:
step a, raw material smelting and refining:
the raw materials of the hot-work die steel in the embodiment are smelted according to the proportion to prepare molten steel, the molten steel is refined, the refining process comprises the steps of carrying out rare earth treatment on the molten steel by using high-purity rare earth with the oxygen content of 97ppm after deoxidation and desulfurization treatment, the oxygen content in the molten steel after rare earth treatment is 10ppm, and the quantity of ball type inclusions accounts for 87% of the total quantity of the inclusions, and the molten steel after rare earth treatment is prepared into a first forging.
Step b, homogenizing:
and carrying out pre-deformation treatment on the first forge piece, namely carrying out shape normalization treatment on the first forge piece during the first firing, and then carrying out three-section type high-temperature component homogenization treatment on the first forge piece to obtain a second forge piece. Wherein the temperatures of the three sections are 1210 ℃, 1230 ℃ and 1275 ℃, the three heating temperatures are gradually increased, the heat preservation time of each section is the same, and the total heat preservation time is more than 1h/25 mm. The holding time in this example is calculated as 1h/25mm thickness, which means: and (4) according to the maximum wall thickness of the forging or hot work die steel, keeping the temperature for 1 hour every 25 mm.
Step c, ultra-fining treatment:
and (3) rapidly cooling the second forging piece when the temperature of the second forging piece is 1130 ℃ in the rapid cooling process, wherein the cooling speed of the second forging piece is 0.8 ℃/S in a temperature range of more than 200 ℃, and discharging the second forging piece from a furnace when the temperature of the second forging piece is lower than 200 ℃ for air cooling to room temperature to obtain a third forging piece.
Step d, forging:
forging the third forging to obtain a fourth forging;
step e, performance heat treatment:
isothermal spheroidizing annealing treatment is carried out on the fourth forging, the temperature is kept between AC1 and AC3, AC1 refers to the critical temperature of pearlite transformed into austenite during heat treatment, AC1 is 798.5 ℃ in the embodiment, AC3 refers to the critical temperature of ferrite completely transformed into austenite during heat treatment, and AC3 is 825.4 ℃ in the embodiment. The heat preservation time is calculated according to the thickness of 1h/25mm, then the furnace is cooled to 850 ℃ for continuous heat preservation treatment, the heat preservation time is calculated according to the thickness of 1h/25mm, and then the furnace is cooled to the room temperature. Then quenching and tempering are carried out, the quenching temperature is selected to be AC3+230 ℃, the heat preservation time is calculated according to the thickness of 1h/25mm, and oil quenching is carried out until the temperature is room temperature; and the temperature of the two tempering processes is 575 ℃, the heat preservation time is calculated according to the thickness of 1h/25mm, and the high-performance hot work die steel is obtained after air cooling to the room temperature after each tempering process.
The high-performance hot-work die steel prepared in the embodiment is subjected to performance detection by referring to GB/T229-1994 metal Charpy notched impact test method and GB/T230-1991 metal Rockwell hardness test method to obtain the high-performance hot-work die steel with the quenching hardness of 64HRC, the working hardness of 62HRC and the impact energy of more than 450J. When the high-performance hot-work die steel of this embodiment is subjected to an impact power test, the maximum impact energy 450J is used for the test, and the test result shows that the high-performance hot-work die steel of this embodiment is not broken, which indicates that the high-performance hot-work die steel of this embodiment can also withstand an impact energy test greater than 450J, but the test apparatus cannot provide an impact energy greater than 450J, so that the test apparatus is limited, and a higher impact energy test cannot be performed. Therefore, the impact energy of the high-performance hot-work die steel prepared by the embodiment is more than 450J.
Example 3
In the embodiment, the high-performance hot-work die steel comprises, by weight, 0.95% of C; si is 0.8%; mn is 0.6%; 8.0 percent of Cr; mo is 2.7%; v is 0.6%; 0.35% of Ni, 0.002% of B and the balance of Fe.
In this embodiment, a preparation method of high-performance hot-work die steel includes the following steps:
step a, raw material smelting and refining:
the raw materials of the hot-work die steel in the embodiment are smelted according to the proportion to prepare molten steel, the molten steel is refined, the refining process comprises the steps of carrying out rare earth treatment on the molten steel by using high-purity rare earth with the oxygen content of 95ppm after deoxidation and desulfurization treatment, the oxygen content in the molten steel after rare earth treatment is 10ppm, and the quantity of ball type inclusions accounts for 90% of the total quantity of the inclusions, and the molten steel after rare earth treatment is prepared into a first forging.
Step b, homogenizing:
and carrying out pre-deformation treatment on the first forge piece, namely carrying out shape normalization treatment on the first forge piece during the first firing, and then carrying out three-section type high-temperature component homogenization treatment on the first forge piece to obtain a second forge piece. Wherein the temperatures of the three sections are 1220 ℃, 1240 ℃ and 1300 ℃, respectively, the three heating temperatures are gradually increased, the heat preservation time of each section is the same, and the total heat preservation time is 1h/25mm thick. The holding time in this example is calculated as 1h/25mm thickness, which means: and (4) according to the maximum wall thickness of the forging or hot work die steel, keeping the temperature for 1 hour every 25 mm.
Step c, ultra-fining treatment:
and (3) rapidly cooling the second forging piece when the temperature of the second forging piece is heated to 1260 ℃, wherein in the rapid cooling process, the cooling speed of the second forging piece is 0.9 ℃/S in a temperature range of more than 200 ℃, and when the temperature of the second forging piece is lower than 200 ℃, the second forging piece is taken out of the furnace and cooled to room temperature in an air cooling mode to obtain a third forging piece.
Step d, forging:
forging the third forging to obtain a fourth forging;
step e, performance heat treatment:
isothermal spheroidizing annealing treatment is carried out on the fourth forging, the temperature is kept between AC1 and AC3, AC1 refers to the critical temperature of pearlite transformed into austenite during heat treatment, AC1 is 798.5 ℃ in the embodiment, AC3 refers to the critical temperature of ferrite completely transformed into austenite during heat treatment, and AC3 is 825.4 ℃ in the embodiment. The heat preservation time is calculated according to the thickness of 1h/25mm, then the furnace is cooled to 850 ℃ for continuous heat preservation treatment, the heat preservation time is calculated according to the thickness of 1h/25mm, and then the furnace is cooled to the room temperature. Then quenching and tempering are carried out, the quenching temperature is selected to be AC3+255 ℃, the heat preservation time is calculated according to the thickness of 1h/25mm, and oil quenching is carried out until the temperature reaches the room temperature; the temperature of the two tempering processes is 610 ℃, the heat preservation time is calculated according to the thickness of 1h/25mm, and the high-performance hot work die steel is obtained after air cooling to the room temperature after each tempering process.
The high-performance hot-work die steel prepared in the embodiment is subjected to performance detection by referring to GB/T229-1994 metal Charpy notched impact test method and GB/T230-1991 metal Rockwell hardness test method to obtain the high-performance hot-work die steel with the quenching hardness of 64HRC, the working hardness of 58HRC and the impact energy of more than 450J. When the high-performance hot-work die steel of this embodiment is subjected to an impact power test, the maximum impact energy 450J is used for the test, and the test result shows that the high-performance hot-work die steel of this embodiment is not broken, which indicates that the high-performance hot-work die steel of this embodiment can also withstand an impact energy test greater than 450J, but the test apparatus cannot provide an impact energy greater than 450J, so that the test apparatus is limited, and a higher impact energy test cannot be performed. Therefore, the impact energy of the high-performance hot-work die steel prepared by the embodiment is more than 450J.
Example 4
The high-performance hot-work die steel prepared in example 2 of the present invention was used as a test material in this example, and the hot-work die steel model 8418 supplied by the company victory, sweden was used as a control material, the component ratios of the two were compared, and the quenching temperature, the quenching hardness, the service hardness, and the impact energy of the test material and the control material in this example were measured with reference to GB/T230-1991 "metal rockwell hardness test method" and GB/T229-1994 "metal charpy notched impact test method", to obtain tables 1 and 2 below:
TABLE 1 ingredient distribution ratio table
According to the table, the proportion of the high-performance hot-work die steel in the embodiment is different from that of the reference product, wherein the content difference of elements C, Si, Cr, V, Ni and B is large, the content of C in the reference product is 0.35%, while the content of C in the detected product is 1.0% and is higher than 186.7% of that of the reference product; the Si content in the reference substance is 0.2 percent, while the Si content in the detection substance is 0.7 percent and is higher than the reference substance by 250 percent; the Cr content in the control article is 5.0 percent, the Cr content in the detection article is 7.5 percent, and the Cr content in the detection article is 50 percent higher than that in the control article; the V content in the control was 0.6%. The content of V in the detected product is 0.4 percent and is lower than that of the reference product by 33.33 percent; the photograph did not contain Ni and B, but the Ni content in the test article was 0.3%, and the B content was 0.0003%.
The high-performance hot-work die steel is prepared by the contents of elements such as C, Si, Mn, Cr, Mo, V, Ni, B and the like, and the relationship between the contents of the elements and the hardenability and strength of the material is established; the relationship between elements and the toughness of the material is established through the content blending of elements such as C, Cr, Mo and the like; the effect of refining crystal grains is achieved by blending a proper amount of element V, and the mechanical property, impact force, wear resistance, heat resistance and erosion resistance of the hot work die steel are greatly improved by the elements and the proportion.
TABLE 2 comparison of Properties
In the embodiment, the quenching hardness of the detection product is 64HRC, and compared with a reference product, the quenching hardness of the detection product exceeds 18.52 percent of that of the reference product; the use hardness of the detection product is 62HRC, and compared with a reference product, the use hardness of the detection product exceeds 19.23-40.90% of that of the reference product; the impact energy of the detection product is more than 450J, and compared with the reference product, the impact energy of the detection product exceeds that of the reference product. The high-performance hot-work die steel has greatly improved mechanical performance and impact force compared with other existing hot-work die steels, and has excellent wear resistance, heat resistance and anti-die sticking performance.
In conclusion, the invention homogenizes the material by high-temperature diffusion, refines the crystal grains by solid phase change in the steel, further optimizes the distribution of precipitated phases by dissolution, nucleation and re-precipitation of the precipitated phases, improves the material performance, increases the number of vacant sites after the forging is deformed by adopting a pre-deformation and three-stage high-temperature uniform heating process, and can increase the diffusion speed of alloy elements by high-temperature treatment so as to make the components more uniform.
The high-performance hot-working die steel prepared by the invention has stable performance after high-temperature diffusion homogenization treatment and modulation treatment, can meet the use requirements of hot-forging dies, die-casting dies, extrusion dies and the like, and has the following performance: the quenching hardness is 64HRC, the service hardness is 48-62HRC, and the impact energy is more than or equal to 450J. The preparation method of the high-performance hot-work die steel can be widely applied to the preparation of the hot-work die steel. The die made of the high-performance hot-working die steel has higher erosion resistance and can prolong the service life of the die.
The above description is only for the embodiments of the present invention, and it is obvious to those skilled in the art that various changes and modifications can be made without departing from the inventive concept of the present invention, and these changes and modifications are all within the scope of the present invention.
Claims (10)
1. The high-performance hot-work die steel is characterized by comprising 0.9-1.0% of C in percentage by weight; si is 0.7-0.9%; mn is 0.4-0.6%; 7.5 to 8.0 percent of Cr; mo is 2.4-2.7%; v is 0.4-0.6%; ni 0.3-0.4%, B0.0001-0.0003%, and Fe in balance.
2. The method for preparing the high-performance hot-work die steel according to claim 1, characterized by comprising the following steps:
step a, raw material smelting and refining:
smelting and refining the raw materials in sequence to obtain a first forging;
step b, homogenizing:
carrying out pre-deformation treatment and three-stage high-temperature uniform heating treatment on the first forging to obtain a second forging, wherein in the pre-deformation treatment, the first forging is subjected to shape-regularizing treatment at the first firing time;
step c, ultra-fining treatment:
heating the second forge piece to a certain temperature, carrying out quick cooling, controlling the cooling speed of the second forge piece in a temperature range of more than 200 ℃ in the quick cooling process, and discharging the second forge piece from a furnace and carrying out air cooling to room temperature when the temperature of the second forge piece is lower than 200 ℃ to obtain a third forge piece;
step d, forging:
forging the third forging to obtain a fourth forging;
step e, performance heat treatment:
and performing spheroidizing annealing treatment and thermal refining treatment on the fourth forging piece in sequence to obtain the high-performance hot-work die steel.
3. The method for preparing the high-performance hot-work die steel according to claim 2, wherein the refining in the step a comprises rare earth treatment after deoxidation and desulfurization treatment, the oxygen content in the raw material after the rare earth treatment is less than 12ppm, the proportion of the number of the ball-type inclusions in the total amount of the inclusions is more than or equal to 85%, and the rare earth treatment adopts rare earth with the oxygen content of less than 100 ppm.
4. The method for preparing high-performance hot-work die steel according to claim 2, wherein the temperature of the three sections in the three-section high-temperature uniform heating treatment in the step b is 1200-1220 ℃, 1220-1240 ℃ and 1250-1300 ℃, respectively, the total heat preservation time is more than or equal to 1h/25mm, and the heat preservation time of each section is the same.
5. The preparation method of the high-performance hot-work die steel as claimed in claim 2, wherein the second forging in the step c is subjected to rapid cooling when heated to 1000-1260 ℃, and in the rapid cooling process, the cooling speed of the second forging is more than or equal to 0.7 ℃/S in a temperature range of more than 200 ℃.
6. The method for preparing the high-performance hot-work die steel according to claim 2, wherein the spheroidizing annealing treatment in the step e is isothermal spheroidizing annealing treatment, the temperature in the isothermal spheroidizing annealing treatment is kept for the first time and is between AC1 and AC3, the keeping time is calculated according to the thickness of 1h/25mm, the furnace cooling is carried out to 800-850 ℃ after the first keeping is finished, the second keeping is carried out, the keeping time is calculated according to the thickness of 1h/25mm, and the furnace cooling is carried out to the room temperature after the second keeping is finished.
7. The method for preparing a high performance hot work die steel according to claim 2, wherein the quenching and tempering treatment in the step e comprises a quenching treatment and a twice tempering treatment.
8. The preparation method of the high-performance hot-work die steel as claimed in claim 7, wherein the quenching treatment is oil quenching, the temperature of the quenching treatment is AC3+ 205-255 ℃, and the heat preservation time of the quenching treatment is calculated according to 1h/25mm thickness.
9. The method for preparing high-performance hot-work die steel according to claim 2, wherein the temperature range of the two tempering treatments is 540-610 ℃, the heat preservation time of the two tempering treatments is calculated according to 1h/25mm thickness, and the air cooling is carried out to the room temperature after each tempering treatment in the two tempering treatments.
10. The high-performance hot-work die steel as claimed in any one of claims 1 to 9, wherein the high-performance hot-work die steel has a quenching hardness of 64HRC, a working hardness of 48-62HRC, and an impact energy of 450J or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010250549.1A CN113493885A (en) | 2020-04-01 | 2020-04-01 | High-performance hot-work die steel and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010250549.1A CN113493885A (en) | 2020-04-01 | 2020-04-01 | High-performance hot-work die steel and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113493885A true CN113493885A (en) | 2021-10-12 |
Family
ID=77993978
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010250549.1A Pending CN113493885A (en) | 2020-04-01 | 2020-04-01 | High-performance hot-work die steel and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113493885A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115505838A (en) * | 2021-06-23 | 2022-12-23 | 宝武特种冶金有限公司 | High-strength-toughness low-alloy die steel and preparation method thereof |
| CN117660734A (en) * | 2024-01-31 | 2024-03-08 | 成都先进金属材料产业技术研究院股份有限公司 | Cold work die steel surface strengthening treatment method and cold work die steel |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1122742A1 (en) * | 1983-09-19 | 1984-11-07 | Предприятие П/Я Р-6762 | Tool steel |
| CN1295625A (en) * | 1998-03-27 | 2001-05-16 | 尤迪霍尔姆工具公司 | Cold work steel |
| CN104630637A (en) * | 2015-01-30 | 2015-05-20 | 宝钢轧辊科技有限责任公司 | Low-alloy high-speed steel cold rolling working roll and manufacturing method thereof |
| CN105525078A (en) * | 2015-11-15 | 2016-04-27 | 内蒙古北方重工业集团有限公司 | Preparation method for improving performance of 4Cr5MoSiV1 hot work die steel |
| JP2016156081A (en) * | 2015-02-26 | 2016-09-01 | 大同特殊鋼株式会社 | Alloy tool steel |
| CN109055671A (en) * | 2018-09-28 | 2018-12-21 | 柳州科沃塑业有限公司 | A kind of mould steel and its manufacturing method |
| CN110699597A (en) * | 2018-07-10 | 2020-01-17 | 中国科学院金属研究所 | Hot work die steel and preparation method thereof |
-
2020
- 2020-04-01 CN CN202010250549.1A patent/CN113493885A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1122742A1 (en) * | 1983-09-19 | 1984-11-07 | Предприятие П/Я Р-6762 | Tool steel |
| CN1295625A (en) * | 1998-03-27 | 2001-05-16 | 尤迪霍尔姆工具公司 | Cold work steel |
| CN104630637A (en) * | 2015-01-30 | 2015-05-20 | 宝钢轧辊科技有限责任公司 | Low-alloy high-speed steel cold rolling working roll and manufacturing method thereof |
| JP2016156081A (en) * | 2015-02-26 | 2016-09-01 | 大同特殊鋼株式会社 | Alloy tool steel |
| CN105525078A (en) * | 2015-11-15 | 2016-04-27 | 内蒙古北方重工业集团有限公司 | Preparation method for improving performance of 4Cr5MoSiV1 hot work die steel |
| CN110699597A (en) * | 2018-07-10 | 2020-01-17 | 中国科学院金属研究所 | Hot work die steel and preparation method thereof |
| CN109055671A (en) * | 2018-09-28 | 2018-12-21 | 柳州科沃塑业有限公司 | A kind of mould steel and its manufacturing method |
Non-Patent Citations (2)
| Title |
|---|
| ADAM GRAJCAR、MATEUSZ MORAWIEC等: "Austenite Decomposition and Precipitation Behavior of Plastically Deformed Low-Si Microalloyed Steel", 《METALS》 * |
| 张洪奎等: "浅析我国模具钢的发展空间", 《热处理》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115505838A (en) * | 2021-06-23 | 2022-12-23 | 宝武特种冶金有限公司 | High-strength-toughness low-alloy die steel and preparation method thereof |
| CN117660734A (en) * | 2024-01-31 | 2024-03-08 | 成都先进金属材料产业技术研究院股份有限公司 | Cold work die steel surface strengthening treatment method and cold work die steel |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101481780B (en) | Easy-to-weld superfine austenite crystal steel with superhigh intensity and high tenacity and manufacturing method thereof | |
| US11466334B2 (en) | Nitrogen-containing microalloyed spring steel and preparation method thereof | |
| CN108220815B (en) | Hot work die steel with high heat resistance and high impact toughness for hot forging and preparation method thereof | |
| CN111424219B (en) | Method for manufacturing gear shaft steel capable of being directly subjected to cold forging | |
| CN101440456B (en) | Hot die steel with excellent heat resistance and high toughness | |
| CN102691005B (en) | Low alloy die steel | |
| CN109735777B (en) | Anti-oxidation hot-work die steel and preparation method thereof | |
| CN104313462A (en) | High wear-resistant hot-stamping die steel and manufacturing method thereof | |
| CN111500928B (en) | Low-temperature high-toughness high-temperature high-strength and high-hardenability hot die steel and preparation technology thereof | |
| CN104561802A (en) | High-hardness high-toughness cold work die steel as well as preparation method thereof | |
| CN103911556A (en) | Hot work die steel material and preparation method thereof | |
| CN104313483A (en) | High-carbon cold-rolled automobile diaphragm spring steel and production method thereof | |
| EP4310216A1 (en) | Steel for high-temperature carburized gear shaft and manufacturing method for steel | |
| CN112430771B (en) | Cold-rolled steel plate for precision stamping high-speed cutting chain saw blade and manufacturing method thereof | |
| CN104313472A (en) | High-carbon hot-rolled automobile diaphragm spring steel and production method thereof | |
| CN113493885A (en) | High-performance hot-work die steel and preparation method thereof | |
| CN109536844B (en) | High-temperature-resistant die steel and preparation method thereof | |
| CN109695001A (en) | A kind of novel rare-earth hot die steel and preparation method thereof | |
| CN114134397B (en) | Steel suitable for cold extrusion of ball screw and production method thereof | |
| CN109694983B (en) | High-mirror-surface corrosion-resistant plastic die steel and manufacturing method thereof | |
| CN106544583A (en) | A kind of super abrasive H13 mould steel | |
| CN106319375A (en) | Punching alloy structural steel cold-rolled plate and preparation method thereof | |
| CN102181787B (en) | Refractory corrosion-resisting steel as well as preparation and heat treatment method thereof | |
| CN114196875A (en) | Stainless steel for valve plate and heat treatment method thereof | |
| CN107217211A (en) | A kind of flange disk-like accessory and its manufacture method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20211012 |
|
| RJ01 | Rejection of invention patent application after publication |