CN114540712A - Non-coating enhanced high-temperature oxidation resistant hot stamping forming steel added with Ce element - Google Patents
Non-coating enhanced high-temperature oxidation resistant hot stamping forming steel added with Ce element Download PDFInfo
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Abstract
The invention provides a Ce element-added uncoated enhanced high-temperature oxidation resistant hot stamping forming steel, which comprises the following alloy components in percentage by mass: c: 0.2-0.4%, Si: 1.3-2.0%, Mn: 1.0-1.8%, Al: less than or equal to 0.05 percent, Cr: 0.15-1.5%, Ti: 0.01-0.15%, B: 0.0008-0.004%, Ce: 0.0002-0.01%, S: less than or equal to 0.01 percent, P: less than or equal to 0.01 percent, and the balance of Fe and inevitable impurities. The invention can inhibit the formation of loose oxide skin of hot stamping formed steel at high temperature, prevent the damage of a die and the generation of flaw on the surface of a product, reduce and avoid the level that the adhesive force of a paint film directly coated in a shot blasting procedure is equal to that of the existing coating product and the uncoated product after shot blasting, reduce the procedures, reduce the production cost, improve the dimensional precision, obviously enhance the toughness on the premise of ensuring the strength, and meet the requirements of high-temperature oxidation resistance and mechanical property of the hot stamping formed steel.
Description
Technical Field
The invention is applied to the technical field of steel materials, and particularly relates to a Ce element-added uncoated enhanced high-temperature oxidation resistant hot stamping forming steel.
Background
The use of the ultra-high strength steel is an important way for realizing the lightweight of the automobile, is one of the steel with the maximum strength for the structural application of the automobile body, has the tensile strength of 1500MPa, is directly processed and formed by adopting a hot stamping mode, is mainly applied to the production of high-strength and difficult-to-form parts of the automobile, and can avoid the defects of difficult forming, large resilience, poor size and shape stability of parts and the like in cold forming. However, with the improvement of strength performance, the formability of the super-strong steel plate is remarkably reduced, and iron and alloy elements on the surface of the steel react with oxygen in an air medium, carbon dioxide, moisture in the air and the like to form an oxidation film during heating, namely, an oxidation phenomenon. The oxide film formed on the surface of the steel plate is easy to fall off in the forming process, abrasive wear is formed between the die and the steel plate, the precision and the attractiveness of the steel plate are influenced, the surface of the die is damaged, the service life of the die is shortened, the steel plate body is induced to crack in the film cracking process to form a crack source, and the steel plate has potential quality hazards. Meanwhile, the loose iron oxide scale on the surface is not beneficial to subsequent painting treatment, and shot blasting equipment is also needed to eliminate the iron oxide scale on the surface, so that the shot blasting can cause surface deformation of parts, and the production cost is further increased.
In order to solve the problem of high-temperature oxidation resistance of formed steel, two main solutions exist at present: firstly, adopting a plating technology and secondly adopting a non-plating technology. As for the coating technology, the coating technology can prevent surface oxidation and decarburization in the forming process and improve the corrosion resistance after painting, but also increases the production procedures and improves the production cost. For the non-coating technology, the high-temperature oxidation resistance of hot stamping forming steel is improved mainly by designing and regulating alloy elements and component proportions, but the technology is few in research at present, the commercial application degree is inferior to that of the coating technology, and the non-coating technology mainly conducts researches on a forming method, strength, oxidation degree and the like at present, but does not conduct researches on steel plate adhesion. China CN109972061A discloses an anti-oxidation ultrahigh-strength steel plate for hot stamping forming and a low-temperature hot forming process, the patent technology increases the content of Mn to 6-8% by adding elements C and Mn in an austenite region, further remarkably reduces the austenitizing heating temperature, thereby reducing the high-temperature oxidation degree of the steel plate, simultaneously determines the appropriate addition amount of Cr, Si and Al alloy elements by accurate calculation and reference tests, greatly improves the high-temperature anti-oxidation performance of the steel plate while reducing the austenitizing temperature, and finally obtains the thermal shock forming steel plate with the yield strength not lower than 1400MPa, the tensile strength not lower than 1700MPa and the elongation greater than 10%. However, Mn is an easily-oxidized element, a large amount of Mn obviously reduces the oxidation resistance of steel, and the oxidation weight gain of the steel plate is less than 0.5g/m2The thickness of the oxide layer is less than or equal to 8 μm, and is unfavorable for the performances of welding adhesion and the like. Patent CN111926248A discloses a Ce alloy-added hot stamping forming steel and a hot stamping forming process, which promote the rapid formation of a Si-rich oxide layer by adding Ce (0.03-0.08%) element, thereby realizing the improvement of the surface oxide layer structure, strictly controlling the thickness of the oxide layer, and obtaining a thinner oxide layer. The Ce element content of the patent technology is too high, so that a water gap of a crystallizer is easily blocked, continuous casting of steel cannot be realized, the processability is reduced, and the production cost is increased.
Therefore, the high-temperature oxidation resistance, the paint film adhesion, the toughness and other properties in the prior art are difficult to realize simultaneously, and in order to solve the problems, the invention researches on the basis of the prior art, enhances the high-temperature oxidation resistance and the toughness of hot stamping formed steel, and can ensure that the paint film adhesion is qualified without directly coating by shot blasting after hot forming.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides the uncoated reinforced high-temperature oxidation resistant hot stamping forming steel added with the Ce element, which is researched for solving the problems that the steel in the prior art is difficult to simultaneously solve the problems of high-temperature oxidation resistance, high paint film adhesive force, high toughness and the like, can realize direct coating without shot blasting after hot stamping forming, reduces the production cost and meets the requirements of high-end markets.
The technical problem to be solved by the invention is realized by adopting the following technical scheme:
the technical scheme adopted by the invention is as follows: the uncoated enhanced high-temperature oxidation resistant hot-press forming steel added with the Ce element is characterized by comprising the following alloy components in percentage by mass: c: 0.2-0.4%, Si: 1.3-2.0%, Mn: 1.0-1.8%, Al: less than or equal to 0.05 percent, Cr: 0.15-1.5%, Ti: 0.01-0.15%, B: 0.0008-0.004%, Ce: 0.0002-0.01%, S: less than or equal to 0.01 percent, P: less than or equal to 0.01 percent, and the balance of Fe and inevitable impurities.
Further, the hot stamping steel contains 0.2-0.4% of C. C is an effective element for improving hardenability and enhancing steel strength, forms a martensite structure when the mold is cooled, and 0.2% or more of C must be added to obtain a desired strength; in addition, if the C content exceeds 0.4%, the strength after cooling of the die becomes too high and exceeds the target range, and the properties such as ductility, toughness, weldability, delayed fracture (hydrogen embrittlement) and the like are lowered.
Further, the hot stamping steel contains 1.3-2.0% of Si. Si affects scale generation and adhesion thereof, and is an important element of the present invention. During heating, a layer of secondary oxide scale is formed on the surface of Si, so that the oxidation inhibition effect is realized, and the generation amount of loose oxide scale at high temperature is obviously reduced; too high Si content decreases the toughness of the weld heat affected zone and deteriorates the weldability thereof, and Si increases the decarburization sensitivity of the steel sheet surface to thereby decrease the overall strength of the hot-formed part.
Further, the hot stamping steel contains 1.0-1.8% of Mn. Mn is an effective element for improving hardenability and enhancing steel strength, and in order to obtain a desired strength value at the time of mold cooling, Mn must be controlled to 1.0% or more. However, if the amount exceeds 1.8%, segregation becomes remarkable, and the uniformity of the material after hot rolling and cooling of the mold is lowered. Preferably, the content of Mn is 1.2-1.5%, and better hardenability and steel strength are obtained.
Further, the hot stamping steel contains 0.15-1.5% of Cr. Cr is an important element affecting the scale generation and adhesion thereof, and is an important element in the present invention. During heating, Cr can form a layer of secondary oxide scale on the surface, so that the oxidation is inhibited, the generation amount of loose oxide scale at high temperature is obviously reduced, and the hardenability is also obviously improved. Too high a Cr content affects the weldability of the hot formed parts and increases the alloy cost.
Further, the hot stamping steel contains 0.01-0.15% of Ti. Ti is a nitride-forming element, and B preferentially forms a nitride, thereby preventing the generation of BN and ensuring the solid solution strengthening of B. In order to obtain these effects, the content must be controlled to 0.01% or more. However, if the content exceeds 0.15%, the hot rolling load becomes large, so that hot rolling becomes very difficult, the hardenability is lowered, and the toughness of the hot-formed part is further lowered. Preferably, the content of Ti is 0.01-0.05%.
Further, the hot stamping steel contains 0.0008 to 0.004% of B. B is an effective element for improving hardenability and also can improve toughness under the premise of containing a small amount of B. In order to obtain these effects, the B content must be controlled to 0.0008% or more. However, if B exceeds 0.004%, the hot rolling load increases significantly, and martensite and bainite are produced after hot rolling, resulting in breakage of the steel sheet.
Further, the hot stamping steel contains 0.0002 to 0.01% of Ce. Ce affects scale generation and adhesion thereof, and is one of important elements of the present invention. Ce inhibits the production of scale and improves the adhesion of scale, and the content thereof must be 0.0002% or more. If the content exceeds 0.01%, the above effects are saturated, and the desired results cannot be obtained, and the workability is lowered and the production cost is increased.
Further, Al is not included in the raw materials of the hot-stamping steel, and Al in the alloy components of the hot-stamping steel is a deoxidizer introduced in the preparation process.
Furthermore, the hot stamping forming steel also comprises Nb and/or V and/or W and/or Ni which are less than or equal to 1.0 percent. Nb, V, W, Ni, and Mo are effective elements for strengthening steel and improving hardenability, and can be optionally added.
Furthermore, the hot stamping forming steel also comprises Mo which is less than or equal to 1.0 percent.
Further, after the hot stamping forming steel is heated at 930 ℃ for 5min and is rapidly quenched under pressure, the yield strength is more than or equal to 1000MPa, the tensile strength is more than or equal to 1450MPa, the total elongation is more than or equal to 7.0%, and the product of strength and elongation is more than or equal to 12.0 Gpa.
Furthermore, the thickness of the hot stamping steel oxide layer is less than or equal to 6.0 μm.
Further, the preparation process of the hot stamping forming steel comprises the working procedures of steel making, continuous casting, hot rolling, pickling, cold rolling and annealing.
Further, the hot stamping forming process comprises: heating the steel plate for hot stamping forming to 880-950 ℃, and preserving heat for 3-10 min to completely austenitize the steel plate; after the steel plate is completely austenitized, the steel plate is sent into a die with a cooling system inside for stamping and forming; and maintaining the pressure, rapidly cooling and quenching, controlling the cooling speed to be 15-200 ℃/s, converting austenite into martensite, and directly coating to obtain the hot-formed steel plate.
In summary, compared with the prior art, the invention has the following beneficial effects:
1. in the present invention, by adding Ce, on the one hand, oxide is formed on the surface of the steel sheet as Cr2O3、SiO2On the other hand, the atomic radius of Ce is larger, and the Ce penetrates into the steel plate to expand the lattice of the steel plate, so that short circuit is increasedThe density of the diffusion channels promotes the formation of a scale of the hot formed steel. Meanwhile, Ce inhibits the diffusion of the cation crystal lattice vacancy and relieves the transverse growth of the oxide skin, so that the stress and the deformation of the oxide skin are reduced, the surface of the oxide skin is flat and straight without wrinkling, the oxidation resistance of the oxide skin is improved, and the thickness of the high-temperature oxide skin of the hot forming steel can be reduced.
2. Ce and oxides of Si and Cr are formed at an oxide skin-matrix interface, Ce blocks a short-circuit channel for outward diffusion of cations in the oxide skin, so that oxygen ions are diffused inwards along the crystal boundary of the oxide skin and enter the matrix along the crystal boundary or in the crystal to form a pinning effect, the actual contact area of the oxide layer and matrix metal is increased, the adhesion force of the oxide skin and the matrix is increased, and the anti-stripping performance of an oxide film is improved. Meanwhile, the Ce oxide is used as a vacancy trap, so that a vacancy source for generating a cavity on an oxide skin/matrix interface is basically cut off, the adhesion of the oxide skin is fundamentally improved, the adhesive force is improved, and direct coating after hot forming can be realized.
3. According to the invention, the Ce element is added, so that the prior austenite and martensite lath bundles are effectively refined, and the strength and toughness of the steel plate can be improved.
4. Aiming at the problems that in the prior art, when Cr and Al exist simultaneously, although the anti-oxidation effect of the material is good, the adhesion force of the material is poor, and in order to simultaneously keep the characteristics of good anti-oxidation performance, high toughness, high adhesion force and the like, Al element is not added in the invention, and only trace Al element introduced in the preparation process is utilized to improve the toughness of the material, so that the toughness performance similar to that of the prior art is obtained; the addition of Cr element can improve the oxide layer structure of the material, thereby controlling the thickness of the oxide layer, and the obtained material has the adhesion force reaching 0 grade and good adhesion effect. The addition of Cr improves the corrosion resistance and high-temperature oxidation resistance of the steel, and direct lacing of the steel sheet is not required to be performed with shot blasting after forming, so that the production cost is reduced, the production profit margin is high, and the steel sheet is suitable for industrial application.
Drawings
FIG. 1 is a surface oxide layer thickness and pinning structure topography of example 1 and comparative example 2 in a non-coating enhanced high temperature oxidation resistant hot stamping steel added with Ce element of the present invention (a is a surface oxide layer topography and thickness of comparative example 2, b is a surface oxide layer topography and thickness of example 1).
FIG. 2 is a graph showing adhesion detection in a non-coated enhanced high temperature oxidation resistant hot stamping steel to which Ce element is added (a is the adhesion detection graph of comparative example 2, and b is the adhesion detection graph of example 1).
Detailed Description
The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
In one embodiment, there is provided a Ce-added uncoated enhanced high temperature oxidation resistant hot press-formed steel comprising, in mass percent, the following alloy components: c: 0.2-0.4%, Si: 1.3-2.0%, Mn: 1.0-1.8%, Al: less than or equal to 0.05 percent, Cr: 0.15-1.5%, Ti: 0.01-0.15%, B: 0.0008-0.004%, Ce: 0.0002-0.01%, S: less than or equal to 0.01 percent, P: less than or equal to 0.01 percent, and the balance of Fe and inevitable impurities.
In a specific embodiment, the uncoated enhanced high temperature oxidation resistant hot stamping forming steel added with the Ce element comprises the following alloy components in percentage by mass: c: 0.2-0.4%, Si: 1.3-2.0%, Mn: 1.0-1.8%, Al: less than or equal to 0.05 percent, Cr: 0.15-1.5%, Ti: 0.01-0.15%, B: 0.0008-0.004%, Ce: 0.0002-0.01%, S: less than or equal to 0.01 percent, P: less than or equal to 0.01 percent, Nb: less than or equal to 1.0 percent, and the balance of Fe and inevitable impurities.
In a specific embodiment, the uncoated enhanced high temperature oxidation resistant hot stamping forming steel added with the Ce element comprises the following alloy components in percentage by mass: c: 0.2-0.4%, Si: 1.3-2.0%, Mn: 1.0-1.8%, Al: less than or equal to 0.05 percent, Cr: 0.15-1.5%, Ti: 0.01-0.05%, B: 0.0008-0.004%, Y: 0.0002-0.001%, S: less than or equal to 0.01 percent, P: less than or equal to 0.01 percent, less than or equal to 1.0 percent of V, less than or equal to 1.0 percent of Ni, and the balance of Fe and inevitable impurities.
In a specific embodiment, the uncoated enhanced high temperature oxidation resistant hot stamping forming steel added with the Ce element comprises the following alloy components in percentage by mass: c: 0.2-0.4%, Si: 1.3-2.0%, Mn: 1.2-1.5%, Al: less than or equal to 0.05 percent, Cr: 0.15-1.5%, Ti: 0.01-0.05%, B: 0.0008-0.004%, Ce: 0.0002-0.01%, S: less than or equal to 0.01 percent, P: less than or equal to 0.01 percent, less than or equal to 1.0 percent of V, less than or equal to 1.0 percent of W, and the balance of Fe and inevitable impurities.
In one embodiment, the raw material of the hot press formed steel does not include Al, and the Al in the alloy composition of the hot press formed steel is a deoxidizer introduced during the manufacturing process. Aiming at the influence of simultaneous addition of Cr and Al on the performances such as adhesive force and the like in the prior art, no Al element is added into the raw materials, the amount of Al impurities introduced in the preparation process is controlled, and a small amount of Al improves the toughness and the adhesion of the material, so that the material simultaneously obtains the characteristics such as better oxidation resistance, high toughness, high adhesive force and the like, and too high Al element can coarsen nonmetallic inclusions to reduce the yield strength and influence the adhesive force of a steel plate.
The hot stamping process of the hot stamping steel comprises the working procedures of steel making, continuous casting, hot rolling, pickling, cold rolling and annealing.
The hot stamping forming process comprises the following steps: heating the steel plate for hot stamping forming to 880-950 ℃, and preserving heat for 3-10 min to completely austenitize the steel plate; after the steel plate is completely austenitized, the steel plate is sent into a die with a cooling system inside for stamping and forming; and (3) maintaining the pressure, rapidly cooling and quenching, controlling the cooling speed at 15-30 ℃/s, converting austenite into martensite, directly coating without shot blasting, and finally obtaining the hot-formed part. The method specifically comprises the following steps: smelting and casting by adopting a 50kg vacuum induction furnace, controlling the content of impurity elements as much as possible in the smelting process, then heating the steel ingot to 1200 ℃, preserving heat for 2 hours, and carrying out homogenization treatment, wherein the initial forging temperature is 1150 ℃, and the final forging temperature is 850 ℃; forging the cast ingot into a long billet after multiple times of forging, and then carrying out heat preservation for 1 hour at 1200 ℃ for homogenization treatment. Hot rolling for several times to obtain hot rolled plate, and removing the hot rolled plate by acid washingAnd (3) rolling the surface oxide skin on a cold rolling mill for multiple times until the thickness of the cold-rolled plate is 1.0-1.5 mm. Annealing at 780-820 deg.C with N2-H2And (4) atmosphere protection, which ensures the homogenization annealing of the matrix and eliminates the banded structure.
In order to better practice the invention, Table 1 shows the alloy compositions of some examples of the hot press formed steel of the invention and the alloy compositions of comparative examples (S content. ltoreq.0.01%, P. ltoreq.0.01% in each of the examples and comparative examples of the invention).
TABLE 1 chemical composition tables of examples and comparative examples (% by mass)
| Sample (I) | C | Si | Mn | Al | Cr | Ti | B | Ce | Ni | Nb | V | W |
| Example 1 | 0.24 | 1.8 | 1.32 | 0.031 | 0.6 | 0.031 | 0.0021 | 0.003 | - | + | - | - |
| Example 2 | 0.20 | 1.5 | 1.5 | 0.022 | 1.3 | 0.038 | 0.0028 | 0.006 | 0.1 | - | 0- | - |
| Example 3 | 0.22 | 1.6 | 1.0 | 0.018 | 0.8 | 0.062 | 0.0031 | 0.005 | 0.04 | 0.04 | - | |
| Example 4 | 0.28 | 1.4 | 1.32 | 0.031 | 1.1 | 0.048 | 0.0025 | 0.008 | - | - | 0.05 | 0.05 |
| Comparative example 1 | 0.24 | 0.24 | 1.32 | 0.031 | 0.13 | 0.031 | 0.0021 | - | - | - | - | |
| Comparative example 2 | 0.23 | 1.8 | 1.32 | 0.031 | 0.6 | 0.031 | 0.0021 | - | - | - | - |
Comparative example 1 is a composition of a typical commercially available 22MnB5 steel, and comparative example 2 is a composition of a steel to which Ce element is not added. The examples and comparative examples of the present invention were subjected to oxidation resistance tests and main mechanical property tests in accordance with the national standards. The oxidation resistance is detected according to the weight gain method in the national standard GB/T13303-1991 method for measuring oxidation resistance of steel, and the detection result is shown in Table 2.
TABLE 2 weight gain per unit area of hot stamping steel (heating temperature: 930 ℃ C.; holding time: 5min)
| Sample (I) | Before oxidation (g) | After oxidation (g) | Oxidative weight gain (g) | Weight gain per unit area (g/m)2) |
| Example 1 | 4.6329 | 4.6336 | 0.0007 | 0.92 |
| Example 2 | 4.7189 | 4.7196 | 0.0007 | 0.92 |
| Example 3 | 4.6895 | 4.6902 | 0.0007 | 0.92 |
| Example 4 | 4.7239 | 4.7246 | 0.0007 | 0.92 |
| Comparative example 1 | 12.1334 | 12.1374 | 0.004 | 3.29 |
| Comparative example 2 | 12.3063 | 12.9839 | 0.6776 | 1.83 |
As can be seen from Table 2, the weight gain per unit area is reduced by about 70% as compared with the comparative example, and is increased by 3.29g/m as compared with 22MnB5 steel2Down to 0.92g/m2And the Ce element is added to improve the oxide layer structure of the material, so that the thickness of the oxide layer is controlled, and the high-temperature oxidation resistance of the steel plate is greatly improved. The thickness of the oxide layer after the Ce element is added is less than 6.0 μm. Referring to fig. 2, the thickness of the oxide layer of the steel sheet of comparative example 2 to which Ce element is not added is 10.2 μm, and the thickness of the oxide layer of example 2 to which Ce element is added is 6.0 μm. After the element Ce is added, Cr is promoted2O3The film can be rapidly diffused to form a protective oxide film, and the oxide of Ce is in Cr2O3The crystal boundary dislocation is formed in the crystal boundary vacancy of the film, the compactness of the oxide film is improved, and the crystal grains are fine and uniform.
In the examples and the comparative examples in table 1, quenching treatment is carried out according to the following process method, the uncoated enhanced oxidation resistance hot stamping formed steel is heated to 930 ℃, heat preservation is carried out for 5min, after the steel plate is completely austenitized, the steel plate is sent into a die with a cooling system inside, pressure maintaining and rapid cooling quenching are carried out, and austenite is converted into martensite.
The mechanical properties such as yield strength, tensile strength, elongation, product of strength and elongation and the like of each example and each comparative example are detected according to national standards, and specific detection data are shown in table 3.
TABLE 3 comparison table of mechanical properties
| Sample (I) | Yield strength (Mpa) | Tensile strength (Mpa) | Elongation (%) | Product of strength and elongation (Gpa ·%) |
| Example 1 | 1052 | 1485 | 9.0 | 13.37 |
| Example 2 | 1120 | 1550 | 8.1 | 12.56 |
| Example 3 | 1080 | 1500 | 8.2 | 12.30 |
| Example 4 | 1232 | 1810 | 7.4 | 13.39 |
| Comparative example 1 | 1055 | 1500 | 5.7 | 8.55 |
| Comparative example 2 | 1060 | 1580 | 7.1 | 11.22 |
As can be seen from Table 3, after the hot stamping steel is heated at 930 ℃ for 5min and quenched, the yield strength is more than or equal to 1000MPa, the tensile strength is more than or equal to 1450MPa, the total elongation is more than or equal to 7.0 percent, and the product of strength and elongation is more than or equal to 12.0Gpa ·; in order to judge the performance of a material, the product of strength and elongation of the material is generally used as a judgment basis of comprehensive performance, and the 22MnB5 low-carbon hot-stamping formed steel generally has a smaller product of strength and elongation and is unstable. The invention is low-carbon hot stamping formed steel, and the product of strength and elongation is more stable. Ce is added, and the original austenite and martensite plate bundles are refined by expanding the equiaxed crystal area and inhibiting the growth of recrystallized grains in the solidification process, so that the strength and the toughness of the steel plate are improved.
Referring to the attached drawing 1, which is a topography of the surface oxide layer of the embodiment 1 and the comparative example 2, it can be seen that, compared with the comparative example, the Ce element is added to the invention to form the pinning effect on the surface of the oxide layer, mainly because: ce and oxides of Si and Cr are formed at an oxide skin-matrix interface, Ce blocks a short-circuit channel for outward diffusion of cations in the oxide skin, so that the cations are diffused inwards along the crystal boundary of the oxide skin and go deep into the matrix along the crystal boundary or in the crystal to form a pinning effect, the actual contact area of the oxide layer and matrix metal is increased, the adhesion force of the oxide skin and the matrix is increased, and the anti-stripping performance of an oxide film is improved. Meanwhile, the Ce oxide is used as a vacancy trap, so that a vacancy source for generating a cavity on an oxide skin/matrix interface is basically cut off, the adhesion of the oxide skin is fundamentally improved, the adhesive force is improved, and direct coating after hot forming can be realized.
The adhesion force of the steel plate after hot forming and direct coating is tested by an adhesion force tester, the adhesion force of each embodiment reaches 0 grade through detection, see figure 2, the average adhesion force of the steel plate without Ce element is only 3 grades, and the adhesion force distribution is very uneven.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-described embodiments. It will be understood by those skilled in the art that various changes, substitutions of equivalents, and alterations can be made without departing from the spirit and scope of the invention.
Claims (8)
1. The uncoated reinforced high-temperature oxidation resistant hot-stamping forming steel added with the Ce element is characterized by comprising the following alloy components in percentage by mass: c: 0.2-0.4%, Si: 1.3-2.0%, Mn: 1.0-1.8%, Al: less than or equal to 0.05 percent, Cr: 0.15-1.5%, Ti: 0.01-0.15%, B: 0.0008-0.004%, Ce: 0.0002-0.01%, S: less than or equal to 0.01 percent, P: less than or equal to 0.01 percent, and the balance of Fe and inevitable impurities.
2. The Ce-added uncoated enhanced high-temperature oxidation resistant hot-press-formed steel according to claim 1, wherein: the hot stamping steel also comprises Nb and/or V and/or W and/or Ni which are less than or equal to 1.0 percent.
3. The Ce-added uncoated enhanced high-temperature oxidation resistant hot-press-formed steel according to claim 1, wherein: the hot stamping forming steel also comprises Mo which is less than or equal to 1.0 percent.
4. The Ce-added uncoated enhanced high-temperature oxidation resistant hot-press-formed steel according to claim 1, wherein: the content of Mn is 1.2-1.5%.
5. The Ce-added uncoated enhanced high-temperature oxidation resistant hot-press-formed steel according to claim 1, wherein: the content of Ti is 0.01-0.05%.
6. The Ce element-added uncoated enhanced high-temperature oxidation resistant hot-press formed steel as claimed in any one of claims 1 to 5, wherein: after the high-adhesion steel is heated at 930 ℃ for 5min, the yield strength of the high-adhesion steel is more than or equal to 1000MPa, the tensile strength is more than or equal to 1450MPa, the total elongation is more than or equal to 7.0 percent, and the product of strength and elongation is more than or equal to 12.0 Gpa.
7. The Ce-added uncoated enhanced high-temperature oxidation resistant hot-press-formed steel according to claim 1, wherein: the preparation process of the hot stamping forming steel comprises the working procedures of steel making, continuous casting, hot rolling, pickling, cold rolling and annealing.
8. The Ce-added uncoated enhanced high-temperature oxidation resistant hot-press-formed steel according to claim 7, wherein: the hot rolling process comprises the following steps: heating the steel plate for hot stamping forming to 880-950 ℃, and preserving heat for 3-10 min to completely austenitize the steel plate; after the steel plate is completely austenitized, the steel plate is sent into a die with a cooling system inside for stamping and forming; and maintaining the pressure, rapidly cooling and quenching, controlling the cooling speed to be 15-200 ℃/s, converting austenite into martensite, and directly coating to obtain the hot-formed steel plate.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116200655A (en) * | 2022-12-09 | 2023-06-02 | 攀钢集团攀枝花钢铁研究院有限公司 | Antioxidant hot-forming steel and production method thereof |
| CN117265225A (en) * | 2023-09-19 | 2023-12-22 | 北京理工大学重庆创新中心 | Hot forming steel with super-strong antioxidation and preparation method thereof |
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