CN114672633B - Method for synchronously carrying out rolling annealing and surface hardening in all-austenitic high-manganese steel by utilizing decarburization - Google Patents
Method for synchronously carrying out rolling annealing and surface hardening in all-austenitic high-manganese steel by utilizing decarburization Download PDFInfo
- Publication number
- CN114672633B CN114672633B CN202210308968.5A CN202210308968A CN114672633B CN 114672633 B CN114672633 B CN 114672633B CN 202210308968 A CN202210308968 A CN 202210308968A CN 114672633 B CN114672633 B CN 114672633B
- Authority
- CN
- China
- Prior art keywords
- steel
- manganese steel
- high manganese
- austenitic high
- annealing
- 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.)
- Active
Links
Images
Classifications
-
- 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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/06—Surface hardening
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
-
- 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
- C21D3/00—Diffusion processes for extraction of non-metals; Furnaces therefor
- C21D3/02—Extraction of non-metals
- C21D3/04—Decarburising
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/001—Heat treatment of ferrous alloys containing Ni
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/02—Hardening by precipitation
-
- 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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- 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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
-
- 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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0257—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment with diffusion of elements, e.g. decarburising, nitriding
-
- 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
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
-
- 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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- 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
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
-
- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/004—Dispersions; Precipitations
Abstract
The invention provides a method for synchronously carrying out rolling annealing and surface hardening in full-austenite high-manganese steel by utilizing decarburization, which overcomes the defect of prolonging the production period of steel when the surface hardening treatment is carried out on the steel at present. According to the invention, in the homogenization process, the steel ingot is decarburized, the decarburized layer is introduced on the surface of the steel ingot, different deformation amounts are caused on the surface and the core of the steel material through hot rolling, a structure of fine grains on the surface and coarse grains on the core of the steel material are formed in the recrystallization process, and finally, a large amount of vanadium carbide grains are precipitated on the surface of the steel material through annealing treatment, so that the surface hardness of the all-austenite high-manganese steel is improved.
Description
Technical Field
The invention belongs to the technical field of materials, and particularly relates to a method for synchronously carrying out rolling annealing and surface hardening in fully austenitic high manganese steel by utilizing decarburization.
Background
The austenitic steel has excellent comprehensive properties such as oxidation resistance, corrosion resistance, good low-temperature toughness, biocompatibility and the like, but has low hardness and poor wear resistance. A large number of austenitic stainless steel workpieces are prematurely scrapped due to severe frictional wear. The surface hardening can improve the wear resistance of the parts and prolong the service life of the stainless steel workpiece without influencing the inside of the parts.
At present, nitriding/carburizing treatment, laser surface treatment, surface shot peening treatment, and the like are widely used to improve the surface hardness of steel. For example, chinese patent CN100443597C discloses a laser hardening process for a precipitation hardening stainless steel surface, which utilizes laser to scan and irradiate the stainless steel surface to melt the treated surface, covers the laser action region with low-temperature protective gas to increase the cooling speed, and then performs heat treatment to obtain a hardened layer with a certain thickness and hardness significantly higher than that of the substrate. Chinese patent CN113874538a discloses a method for manufacturing a surface hardened steel part used in the field of aviation, which is to nitride the part in an atmosphere containing ammonia to form a nitride layer with a certain thickness on the surface of the part, thereby obtaining a surface hardened steel material. Chinese patent CN108468014B discloses a treatment method for tool steel surface carburization modification, which is characterized in that the tool steel is buried in a carburizing box by using a special carburizing agent, an atmosphere furnace is heated and then hot-charged with steel, the steel is thoroughly burned and then kept warm, the steel is carburized, and after carburization is finished, the surface hardness is about 15-20% higher than that of the untreated tool steel.
In addition, rolling annealing is an indispensable flow in the production process of steel products, and has important influence on the microstructure and the mechanical property of the steel products. However, the above conventional surface hardening treatment methods are all asynchronous in additional processes to achieve surface hardening before and after rolling annealing, which prolongs the production cycle and cannot form a surface hardening layer synchronously during the rolling annealing.
Therefore, there is a need to find a new method that can improve the surface hardness of steel without affecting the production cycle.
Disclosure of Invention
The invention aims to solve the defect that the production period of steel is prolonged when the surface hardening treatment is carried out on the steel at present, provides a method for synchronously carrying out rolling annealing and surface hardening in the fully-austenitic high manganese steel by utilizing decarburization, and particularly relates to a component design and preparation method of the fully-austenitic high manganese steel with surface hardening.
In order to achieve the purpose, the technical solution provided by the invention is as follows:
a method for improving the surface hardness of full-austenite high-manganese steel is characterized in that:
in the homogenization process, the steel ingot is decarburized, a decarburized layer is introduced on the surface of the steel ingot, different deformation amounts are caused on the surface and the core of the steel material through hot rolling, a structure of fine grains on the surface and coarse grains on the core of the steel material is formed in the recrystallization process, and finally, a large amount of vanadium carbide grains are precipitated on the surface of the steel material through annealing treatment, so that the surface hardness of the all-austenite high-manganese steel is improved.
Meanwhile, the invention also provides a preparation method of the all-austenite high manganese steel, which is characterized by comprising the following steps of:
1) Weighing raw materials according to the component content (the set component of the all-austenite high manganese steel), smelting, and casting into steel ingots;
2) Homogenizing the steel ingot obtained in the step 1) at 1150-1250 ℃ for 22-25h, and carrying out decarburization to form a decarburized layer, wherein the surface of the steel is obviously decarburized.
3) Hot rolling the homogenized steel ingot obtained in the step 2) to a hot rolled plate with the thickness of 20-40mm in multiple passes at 1200-900 ℃ to enable the surface and the center of the steel to deform in different degrees, and then cooling the steel to room temperature by water;
wherein the finishing temperature is more than 700 ℃;
4) Carrying out solution treatment on the hot rolled plate obtained in the step 3) at 1100-1300 ℃ for 20-40min to generate recrystallization; VC possibly formed in the hot rolling process is eliminated, and the heat preservation in a short time ensures that crystal grains are not excessively grown;
5) Annealing at 650-850 deg.C for 3-30min to separate out VC particles on the surface and core of the steel material to realize surface hardening and obtain the fully austenitic high manganese steel.
Further, in the step 1), the raw materials comprise the following components:
c (carbon): 0.05-0.10%, mn (manganese): 25.0-35.0%, ni (nickel): 0.5-2.5%, V (vanadium): 0.2-0.6%, al (aluminum): 0-3%, si (silicon): 0-3%, the balance being Fe and unavoidable impurities; inevitable impurities such as P (phosphorus): less than 0.010 percent; s (sulfur) < 0.010%;
in the element composition, the content of Mn element is regulated and controlled, and the stacking fault energy is 45mJ/m 2 In the above, the deformation mechanism of austenite under the composition is ensured to be dislocation slip; the V element and the C element form VC precipitated phase on the surface of the steel, so that the strength of the surface of the steel is improved.
Further, in the step 1), the raw materials comprise the following components:
c:0.079%, mn:30.24%, ni:1.47%, V:0.39%, P: < 0.005%, S:0.005%, and the balance of Fe and other unavoidable impurities.
Further, in the step 2), the homogenization treatment is carried out at 1200 ℃ for 24h, and the thickness of the decarburized layer is 0.8mm.
Further, in the step 3), the steel is hot rolled at 1200 ℃, and is rolled to 30mm in five passes, wherein the final rolling temperature is about 750 ℃.
Further, in step 4), solution treatment is performed at 1200 ℃ for 30min.
Further, in step 5), annealing treatment is performed at 750 ℃ for 20min.
Further, VC particles which are uniformly distributed and are less than 500nm (the size of a precipitated phase) are precipitated on the surface of the steel after the annealing in the step 5).
The fully austenitic high manganese steel is characterized by being prepared by the method, and the stacking fault energy of the fully austenitic high manganese steel is 45mJ/m 2 In the above, the deformation mechanism is ensured to be dislocation glide; the surface hardness is obviously higher than the core hardness.
The principle of the invention is as follows:
the invention firstly introduces a decarburized layer with a certain thickness by heating the steel at a high temperature in a furnace and directly contacting the steel with air. In the present invention, for convenience of reference, the decarburized region is referred to as the steel surface, and the regions in the thickness direction except the decarburized layer are referred to as the steel core. Subsequently, since C element can pin dislocation and improve work hardening ability, different amounts of deformation are caused on the surface and the core of the steel by hot rolling using the difference in work hardening ability between the surface and the core of the steel introduced by decarburization. And finally, utilizing different driving forces of recrystallization of the surface and the core of the steel with different deformation quantities to form a structure of fine crystals on the surface of the steel and coarse crystals on the core of the steel in the recrystallization process, and when the steel is further annealed, the grains on the surface of the steel are fine, the volume fraction of the grain boundary is higher, and a large amount of Vanadium Carbide (VC) is induced to be separated out. Through the steps, the purpose of synchronously realizing the surface hardening of the all-austenite high manganese steel in the rolling and annealing process is achieved.
The invention has the advantages that:
1. the high manganese steel has low component cost and simple preparation method and process, effectively utilizes the phenomenon of decarburization of the steel during high-temperature heating in a furnace, and successfully uses the phenomenon which is generally considered as unfavorable phenomenon for inducing surface hardening. Generally, when steel is heated at a high temperature in a furnace, carbon in the surface layer and an oxidizing gas (e.g., O) in the furnace gas 2 、CO 2 、H 2 O, etc.) and some reducing gases (e.g., H) 2 ) Chemical reaction occurs to cause a decrease in the carbon content of the surface layer, which is called decarburization. The decarburization defects are formed when the decarburization remains on the part. Decarburization reduces the hardness and wear resistance of the steel, and the wear rate of the steel without decarburization is more than twice that of the case of the decarburized steel. After the steel is decarburized, the mechanical properties of the part may not meet the standard requirements, and the part or the material may be scrapped. Therefore, in the production of steel products, it is attempted to avoid the occurrence of decarburization. The invention utilizes the conventional decarburization phenomenon which avoids the trouble, has extremely important significance, and simultaneously achieves the purpose of synchronously realizing surface hardening in the rolling and annealing process on the premise of not carrying out additional asynchronous treatment, thereby saving time cost and economic cost.
2. The fully-austenitic high manganese steel obtained by the method is strengthened by VC precipitation, a large number of VC particles are precipitated on the surface of the steel, the surface hardness is improved, and the annealing time can be adjusted according to the surface hardness requirement to obtain the steel with different surface hardness.
Drawings
FIG. 1 is a graph showing the hardness distribution of the high manganese steel at different depths from the surface after annealing in example 1 of the present invention;
FIG. 2 is a microstructure diagram of a high manganese steel in example 1 of the present invention at different process stages, wherein (a) the surface in a hot rolled state, (b) the core in a hot rolled state, (c) the surface at which solution treatment is finished, (d) the core at which solution treatment is finished, (e) the surface at which annealing treatment is finished, (f) the core at which annealing treatment is finished;
FIG. 3 is a scanning chart of a surface precipitated phase spectrum point after annealing of the medium-high manganese steel in the embodiment 1 of the invention;
FIG. 4 shows hardness distributions of the high manganese steel at different depths from the surface after annealing treatment in example 2 of the present invention;
FIG. 5 is the hardness distribution of the high manganese steel in example 3 of the present invention at different depths from the surface in the annealing treatment;
Detailed Description
The invention is described in further detail below with reference to the following figures and specific examples:
example 1
The fully austenitic high manganese steel of the embodiment comprises the following components in percentage by mass: c:0.079%; mn:30.24 percent; v:0.39 percent; ni:1.47%; p: less than 0.005 percent; s:0.005 percent; the balance being Fe and unavoidable impurities.
The preparation of the case-hardened all-austenitic high manganese steel in the example was carried out specifically according to the following steps:
1) Taking and mixing the element components according to the proportion, and smelting in a 50kg vacuum induction furnace to obtain a square ingot;
2) After the ingot is subjected to heat preservation at 1200 ℃ for 24 hours, the surface of the steel product is contacted with the air in the furnace at high temperature, decarburization occurs in the heat preservation process, and the thickness of the decarburized layer is measured to be 0.8mm;
3) Hot rolling at 1200 ℃, rolling to 30mm in five passes, wherein the final rolling temperature is about 750 ℃, and cooling to room temperature after rolling;
4) Carrying out solution treatment on the hot rolled plate at 1200 ℃ for 30min to eliminate VC formed in the hot rolling process and simultaneously carrying out recrystallization;
5) And (3) annealing at 750 ℃ for 20min, so that VC particles are precipitated on the surface and the core of the steel in different degrees, and surface hardening is realized.
FIG. 1 shows the hardness distribution at different distances from the surface after annealing at 750 ℃ for 20min, the surface hardness of the hot rolled steel is obviously higher than the core hardness, the hardness reaches 255HV at a position 0.5mm away from the surface, and the hardness is only 137HV at a position 3.5mm away from the surface. Therefore, the embodiment achieves the purpose of synchronously realizing the surface hardening in the rolling annealing process.
FIG. 2 shows the microstructure of 30Mn steel at different stages. After hot rolling treatment, the surface structure of the steel retains rolling characteristics, grains are severely elongated along the rolling direction, grain boundaries are difficult to identify, the elongation degree of the grains at the center of the steel is obviously lower, and the grain boundaries are clear and visible. After the solution treatment, the steel surface and the core both have obvious recovery and recrystallization, the grains with serious deformation completely disappear, fine equiaxed crystals of about 35um are formed on the steel surface, and coarse equiaxed crystals of about 155um are formed in the core. After annealing at 750 ℃ for 20min, a large number of precipitated particles appeared on the surface, while only a small amount of precipitated particles appeared in the core.
As shown in fig. 3, four points were selected for the energy spectrum point scan, where there were distinct precipitated particles at points 1 and 2, and no distinct precipitated particles at points 3 and 4. The atomic percent of the element V at the point 1 was 10.01%, the atomic percent of the element V at the point 2 was 7.28%, the atomic percent of the element V at the point 3 was 1.16%, and the atomic percent of the element V at the point 4 was 0.92%, so the element contents of the elements V at the points 1 and 2 were significantly higher than those at the points 3 and 4. As can be seen, the concentration of V element is obvious at the position of the precipitated phase particles.
As shown in table 1, the C element content was measured by carbon sulfur analysis, and the V and Ni element contents were measured by EPMA (electron probe microanalyzer). After hot rolling treatment, the C element content (0.0336 wt.%) on the surface of the steel is much lower than the nominal C element content (0.079 wt.%) in the sample, while the C element content (0.0795%) in the core of the steel is approximately equal to the nominal content. After the solution treatment, the content of element C on the steel surface was further reduced to 0.0228wt.%, and the content of element C in the core sample was almost unchanged. After annealing treatment, the content of C element on the surface and the core of the steel is not changed greatly, the content of V element on the surface is as high as 1.132wt.%, which is 2.83 times of the nominal composition, while the content of V element in the core sample is approximately equal to the nominal composition, and Ni element is almost kept unchanged at each stage. Therefore, after the hot rolling treatment, the steel surface has undergone a significant decarburization behavior, and after the annealing, the V element is enriched on the surface, which is considered to be caused by the precipitation of VC particles.
TABLE 1 Mass percent of C, V, ni at different stages in inventive example 1
Example 2
The all-austenitic high manganese steel comprises the following components in percentage by mass: c:0.079%; mn:30.24 percent; v:0.39 percent; ni:1.47%; p: less than 0.005 percent; s:0.005 percent; the balance being Fe and unavoidable impurities.
The preparation of the case-hardened fully austenitic high manganese steel in the example was carried out in the following steps:
1) Taking and mixing the element components according to the proportion, and smelting in a 50kg vacuum induction furnace to obtain a square ingot;
2) After the ingot is subjected to heat preservation at 1200 ℃ for 24 hours, the surface of the steel product is contacted with the air in the furnace at high temperature, decarburization occurs in the heat preservation process, and the thickness of the decarburized layer is measured to be 0.8mm;
3) Hot rolling at 1200 ℃, rolling to 25mm in five passes, wherein the final rolling temperature is about 800 ℃, and cooling to room temperature after rolling;
4) Carrying out solution treatment on the hot rolled plate at 1200 ℃ for 20min, eliminating VC formed in the hot rolling process, and simultaneously carrying out recrystallization;
5) Annealing at 750 deg.C for 3min to separate out VC particles on the surface and core of steel material to realize surface hardening.
FIG. 4 shows the hardness distribution at different distances from the surface after annealing treatment, and the surface hardness of the hot rolled steel is significantly higher than the core hardness. Therefore, the embodiment achieves the purpose of synchronously realizing the surface hardening in the rolling annealing process. However, the surface hardening degree was relatively lower than that of example 1, which shows that the strengthening phase VC particles were less precipitated and the surface hardness was less improved in a shorter annealing time. Therefore, the annealing time can be adjusted according to the surface hardness requirement.
Example 3
The fully austenitic high manganese steel of the embodiment comprises the following components in percentage by mass: c:0.09%; mn:30.16 percent; v:0.37 percent; al:2.92 percent; si:2.77 percent; ni:1.42 percent; p: less than 0.005 percent; s:0.0031%; the balance of Fe and inevitable impurities.
The preparation of the case-hardened fully austenitic high manganese steel in the example was carried out in the following steps:
1) Taking and mixing the element components according to the proportion, and smelting in a 50kg vacuum induction furnace to obtain a square ingot;
2) After the cast ingot is subjected to heat preservation at 1200 ℃ for 22h, the surface of the steel product is contacted with the air in the furnace at high temperature, decarburization occurs in the heat preservation process, and the thickness of the decarburized layer is measured to be 0.6mm;
3) Hot rolling at 1200 ℃, rolling to 35mm in five passes, wherein the final rolling temperature is about 750 ℃, and cooling to room temperature after rolling;
4) Carrying out solution treatment on the hot rolled plate at 1150 ℃ for 30min to eliminate VC formed in the hot rolling process and simultaneously carrying out recrystallization;
5) And (3) annealing at 750 ℃ for 30min, so that VC particles are precipitated on the surface and the core of the steel in different degrees, and surface hardening is realized.
FIG. 5 shows the hardness distribution at different distances from the surface after annealing treatment, and the surface hardness of the hot rolled steel is significantly higher than the core hardness. Therefore, the embodiment achieves the purpose of synchronously realizing surface hardening in the rolling annealing process.
In addition, the research team of the application also carries out the same test on the all-austenitic high manganese steel with other components except the embodiment within the range of the process parameters, and the result shows that the surface hardness of the all-austenitic high manganese steel can be changed by introducing the phenomenon of decarburization and adjusting the annealing time, so that the purpose of synchronously realizing the surface hardening in the rolling and annealing process is realized.
While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications or substitutions can be easily made by those skilled in the art within the technical scope of the present disclosure.
Claims (10)
1. A method for improving the surface hardness of full-austenite high-manganese steel is characterized by comprising the following steps:
in the homogenization process, the steel ingot is decarburized, a decarburized layer is introduced on the surface of the steel ingot, different deformation amounts are caused on the surface and the core of the steel material through hot rolling, a structure of fine grains on the surface and coarse grains on the core of the steel material is formed in the recrystallization process, and finally, a large amount of vanadium carbide grains are precipitated on the surface of the steel material through annealing treatment, so that the surface hardness of the all-austenite high-manganese steel is improved.
2. The preparation method of the all-austenitic high manganese steel is characterized by comprising the following steps of:
1) Weighing raw materials according to the component content, smelting, and casting into steel ingots;
2) Homogenizing the steel ingot obtained in the step 1) at 1150-1250 ℃ for 22-25h, and decarbonizing to form a decarburized layer;
3) Hot rolling the homogenized steel ingot obtained in the step 2) to a hot rolled plate with the thickness of 20-40mm in multiple passes at 1200-900 ℃ to enable the surface and the center of the steel to deform in different degrees, and then cooling the steel to room temperature by water;
wherein the finishing temperature is more than 700 ℃;
4) Carrying out solution treatment on the hot rolled plate obtained in the step 3) at 1100-1300 ℃ for 20-40min to generate recrystallization;
5) Annealing at 650-850 deg.C for 3-30min to separate out VC particles on the surface and core of the steel material to realize surface hardening and obtain the fully austenitic high manganese steel.
3. The method of producing a fully austenitic high manganese steel according to claim 2, characterized in that:
in the step 1), the raw materials comprise the following components in percentage by weight:
c:0.05-0.10%, mn:25.0-35.0%, ni:0.5-2.5%, V:0.2-0.6%, al:0-3%, si:0-3%, and the balance of Fe and inevitable impurities.
4. The method of producing a fully austenitic high manganese steel according to claim 3, characterized in that:
in the step 1), the raw materials comprise the following components in percentage by weight:
c:0.079%, mn:30.24%, ni:1.47%, V:0.39%, P: < 0.005%, S:0.005%, and the balance of Fe and inevitable impurities.
5. The method of producing a fully austenitic high manganese steel according to claim 4, characterized in that:
in the step 2), homogenization treatment is carried out for 24 hours at 1200 ℃, and the thickness of the decarburized layer is 0.8mm.
6. The method of producing a fully austenitic high manganese steel according to claim 5, characterized in that:
in the step 3), hot rolling is carried out at 1200 ℃, five-pass rolling is carried out until the thickness is 30mm, and the final rolling temperature is about 750 ℃.
7. The method of producing a fully austenitic high manganese steel according to claim 6, characterized in that:
in step 4), solution treatment is carried out for 30min at 1200 ℃.
8. The method of producing a fully austenitic high manganese steel according to claim 7, characterized in that:
in step 5), annealing treatment is carried out at 750 ℃ for 20min.
9. The method for producing a fully austenitic high manganese steel according to claim 7, characterized in that:
and 5) precipitating uniformly distributed VC particles smaller than 500nm on the surface of the annealed steel.
10. An all-austenitic high manganese steel, characterized in that it is produced by a method according to any of claims 2-9, and has a stacking fault energy of 45mJ/m 2 In the above, it is ensured that the deformation mechanism is dislocation slip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210308968.5A CN114672633B (en) | 2022-03-27 | 2022-03-27 | Method for synchronously carrying out rolling annealing and surface hardening in all-austenitic high-manganese steel by utilizing decarburization |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210308968.5A CN114672633B (en) | 2022-03-27 | 2022-03-27 | Method for synchronously carrying out rolling annealing and surface hardening in all-austenitic high-manganese steel by utilizing decarburization |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114672633A CN114672633A (en) | 2022-06-28 |
| CN114672633B true CN114672633B (en) | 2022-11-18 |
Family
ID=82076391
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210308968.5A Active CN114672633B (en) | 2022-03-27 | 2022-03-27 | Method for synchronously carrying out rolling annealing and surface hardening in all-austenitic high-manganese steel by utilizing decarburization |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114672633B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021161679A1 (en) * | 2020-02-13 | 2021-08-19 | Ｊｆｅスチール株式会社 | High-strength steel sheet and method for producing same |
| CN113430461A (en) * | 2021-06-24 | 2021-09-24 | 马鞍山钢铁股份有限公司 | Nb and V microalloyed gear steel and preparation method, heat treatment method, carburization method and carburized gear steel thereof |
| CN113462985A (en) * | 2021-07-16 | 2021-10-01 | 鞍钢股份有限公司 | Low-cost high-surface-hardness tool steel with excellent annealing-free bending performance |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018220430A1 (en) * | 2017-06-02 | 2018-12-06 | Arcelormittal | Steel sheet for manufacturing press hardened parts, press hardened part having a combination of high strength and crash ductility, and manufacturing methods thereof |
-
2022
- 2022-03-27 CN CN202210308968.5A patent/CN114672633B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021161679A1 (en) * | 2020-02-13 | 2021-08-19 | Ｊｆｅスチール株式会社 | High-strength steel sheet and method for producing same |
| CN113430461A (en) * | 2021-06-24 | 2021-09-24 | 马鞍山钢铁股份有限公司 | Nb and V microalloyed gear steel and preparation method, heat treatment method, carburization method and carburized gear steel thereof |
| CN113462985A (en) * | 2021-07-16 | 2021-10-01 | 鞍钢股份有限公司 | Low-cost high-surface-hardness tool steel with excellent annealing-free bending performance |
Non-Patent Citations (2)
| Title |
|---|
| 加热工艺对重轨钢奥氏体晶粒尺寸与脱碳层深度的影响;张旭峰等;《轧钢》;20130815(第04期);全文 * |
| 脱碳层对GCr15轴承钢带状组织的影响;赵永桥等;《上海金属》;20170731(第04期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114672633A (en) | 2022-06-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112831723B (en) | High-temperature carburization resistant gear steel with large crystal grains and control method | |
| CN108517461B (en) | High-performance martensitic stainless steel flange and manufacturing method thereof | |
| US4464207A (en) | Dispersion strengthened ferritic stainless steel | |
| CN111549287B (en) | Medium carbon steel and production process thereof | |
| CN113430405B (en) | High-strength and high-toughness face-centered cubic high-entropy alloy and preparation method thereof | |
| CN109371332A (en) | A kind of 16MnCrS5 pinion steel and its production method | |
| CN113774281A (en) | 2000 MPa-grade high-ductility high-corrosion-resistance maraging stainless steel and preparation method thereof | |
| CN114717488A (en) | 1800MPa grade high-ductility high-corrosion-resistance maraging stainless steel and preparation method thereof | |
| EP3561104B1 (en) | Grain-oriented electrical steel sheet and manufacturing method therefor | |
| CN113322415A (en) | Martensitic stainless steel for aviation bearing and preparation method thereof | |
| CN101824582B (en) | Oriented electrical steel plate band adopting multivariate inhibiting agent and production method thereof | |
| CN114672633B (en) | Method for synchronously carrying out rolling annealing and surface hardening in all-austenitic high-manganese steel by utilizing decarburization | |
| CN109694983A (en) | A kind of high mirror surface corrosion-resistant plastic mould steel and its manufacturing method | |
| CN114622145B (en) | Cobalt-free maraging steel with dual-phase structure and preparation method thereof | |
| CN115404390A (en) | Rare earth microalloyed high-temperature carburized bearing steel and preparation method thereof | |
| CN116103472A (en) | Heat treatment process for improving low-temperature toughness of low-carbon high-strength martensitic stainless steel | |
| CN115449692A (en) | High-damping high-entropy steel plate with TWIP effect and preparation method thereof | |
| JPH0280512A (en) | Heat-treatment of highly alloyed chromium steel | |
| CN113774288A (en) | Ultra-high-strength high-performance medium plate maraging stainless steel and preparation method thereof | |
| CN113774291A (en) | Ultra-low carbon high-performance maraging stainless steel and preparation method thereof | |
| JPH0559527A (en) | Production of steel excellent in wear resistance and rolling fatigue characteristic | |
| CN117107143B (en) | Boron-containing surface modified layer steel and preparation method thereof | |
| CN108220801A (en) | A kind of Austenitic stainless steel pipe and its preparation process | |
| CN116287965A (en) | V-Ti-N microalloyed high-strength steel and P-Q & P process thereof | |
| JPS6148761B2 (en) |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20230703 Address after: 215126 Unit A, Plant 8, Modern Industrial Park, No. 333, Xingpu Road, Suzhou Industrial Park, Suzhou Pilot Free Trade Zone (Jiangsu), Jiangsu Province Patentee after: Suzhou JunJing Metal Technology Co.,Ltd. Address before: 710072 No. 127 Youyi West Road, Shaanxi, Xi'an Patentee before: Northwestern Polytechnical University |
|
| TR01 | Transfer of patent right |