Al-containing directionally-solidified high-boron high-speed steel capable of resisting strong liquid zinc cavitation erosion and preparation method thereof

Abstract

The invention discloses Al-containing directionally solidified high-boron high-speed steel capable of resisting cavitation erosion of strong zinc liquid and a preparation method of the Al-containing directionally solidified high-boron high-speed steel, and the Al-containing directionally solidified high-boron high-speed steel comprises the following components in percentage by weight: 0.40%-0.48% of C, 3.10%-3.65% of B, 0.58%-0.72% of Mn, 1.18%-1.28% of W, 0.36%-0.54% of V, 4.60%-5.08% of Cr, 0.60%-0.68% of Mo, 0.05%-0.09% of Ti, 1.40%-2.78% of Si, 1.70%-2.54% of Al and the balance of Fe and inevitable trace impurities. The invention provides a new thought and approach for improving cavitation erosion damage of a zinc liquid resistant material, and lays a foundation for further use of directionally solidified high-boron high-speed steel.

Description

Technical Field

[0001] The invention belongs to the technical field of zinc liquid corrosion resistance of hot-dip galvanizing engineering equipment, and specifically relates to Al-containing directional solidified high-boron high-speed steel resistant to strong zinc liquid cavitation and a preparation method thereof. Background Art

[0002] Metal corrosion has caused serious economic losses and waste, and has also caused huge waste of metal materials. Hot-dip galvanized materials are widely used in the pillar fields of the national economy, but due to complex working conditions, they suffer from strong corrosion, which seriously affects the stability of roller operation and the surface quality of zinc plates, resulting in a great impact on processing cycles and production costs. Therefore, steel materials with strong resistance to zinc liquid corrosion are urgently needed.

[0003] After research, it was found that high-boron high-speed steel has good resistance to zinc liquid corrosion. FeB and Fe2B phases are not wetted by zinc liquid. Fe-B alloy has a unique network-like Fe2B phase + tough matrix structure. Fe2B phase can play a good "barrier effect", making Fe-B alloy have good resistance to static zinc liquid corrosion. The use of directional solidification process to prepare directionally solidified high-boron high-speed steel can obtain a directional structure with good orientation to improve the interface structure and improve the related properties of directional high-boron high-speed steel. The zinc corrosion products of directionally solidified high-boron high-speed steel form a unique interface effect. The Fe2B hard phase and ζ-FeZn 13 The corrosion products produce a strong "pinning effect", which greatly improves the corrosion resistance of high-boron high-speed steel under dynamic conditions. However, the corrosion and cavitation problems of hot-dip galvanizing production line engineering equipment are still prominent and need to be solved urgently.

[0004] Under the corrosion conditions of high-flow zinc liquid, cavitation is easy to occur, that is, when the local pressure of the high-flow corrosive liquid drops, the liquid vaporizes and produces bubbles. When the bubbles flow into the high-pressure area, high-speed microjets and shock waves are generated, causing pressure pulses to damage the surface of the material, greatly reducing the material's cavitation resistance. At present, in response to this phenomenon, it is a very effective process to improve the cavitation resistance of the alloy by adjusting the elemental composition of directionally solidified high-boron high-speed steel to obtain a good corrosion interface protection layer. Al is a silvery-white metal with light weight and good ductility, electrical conductivity, thermal conductivity, heat resistance and radiation resistance. Al will form a dense oxide film on its surface in the air, which makes Al have good corrosion resistance. Adding Al element to directionally solidified high-boron high-speed steel can greatly improve the alloy's resistance to high-temperature oxidation and high-temperature wear resistance, and can also improve the morphology of borides and carbides, greatly improving the corrosion resistance and other comprehensive mechanical properties of directional alloys. However, the problem of reasonable composition design of each element in Al-containing directionally solidified high-boron high-speed steel has not yet been solved, which poses a great challenge to the alloy's resistance to zinc liquid cavitation erosion. In addition, too high Al content in the alloy will lead to difficulties in the preparation process, and too low Al content will cause segregation and thus reduce the mechanical properties of the material. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation and a preparation method thereof in view of the deficiencies in the above-mentioned prior art, so as to solve the technical problem of the resistance of directionally solidified Fe-B alloy to zinc liquid cavitation under harsh working conditions.

[0006] The present invention adopts the following technical solutions: The invention discloses an Al-containing directionally solidified high-boron high-speed steel resistant to cavitation erosion by strong zinc liquid. The steel comprises, by weight percentage, 0.40%-0.48% C, 3.10%-3.65% B, 0.58%-0.72% Mn, 1.18%-1.28% W, 0.36%-0.54% V, 4.60%-5.08% Cr, 0.60%-0.68% Mo, 0.05%-0.09% Ti, 1.40%-2.78% Si, 1.70%-2.54% Al, and the remainder is Fe and inevitable trace impurities.

[0007] Preferably, by weight percentage, it includes C: 0.44%, B: 3.50%, Mn: 0.61%, W: 1.22%, V: 0.45%, Cr: 4.92%, Mo: 0.65%, Ti: 0.07%, Si: 2.12%, Al: 2.13%, and the rest is Fe and inevitable trace impurities.

[0008] Preferably, after corrosion at a temperature of 455-465° C. for 9-11 hours, the cavitation-erosion rate of the Al-containing directionally solidified high-boron high-speed steel against zinc liquid is 2.8-3.5 μm / h.

[0009] Preferably, after corrosion at 460° C. for 10 hours, the cavitation-erosion rate of the Al-containing directionally solidified high-boron high-speed steel against zinc liquid is 3.1 μm / h.

[0010] Preferably, the Al-containing directionally solidified high-boron high-speed steel has a layered alternating structure of soft matrix and hard phase.

[0011] Another technical solution of the present invention is a method for preparing Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation erosion, wherein the Al-containing directionally solidified high-boron high-speed steel is prepared by a directional solidification process.

[0012] Preferably, the melting temperature of the directional solidification process is 1645-1680°C.

[0013] More preferably, the pouring temperature of the directional solidification process is 1455~1475℃.

[0014] Preferably, the cooling rate of the directional solidification process is 12.6-13.8°C / s.

[0015] Preferably, the directionally oriented structure of the Al-containing directionally solidified high-boron high-speed steel grows straight and is embedded in the corrosion layer in a wedge shape, and a continuous and dense Fe2Al5 inhibition layer is formed on the corrosion interface.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: A high-boron high-speed steel containing Al and directionally solidified, which is resistant to strong zinc liquid cavitation. The content of B in the high-boron high-speed steel containing Al and directionally solidified is 3.10-3.65%, which is close to the eutectic point of B in the Fe-B alloy phase diagram of 3.8wt.%, which greatly improves the casting performance of the alloy, and the fluidity of the alloy is good, which prevents defects such as pores, shrinkage, looseness and segregation during pouring. The Al content is 1.70-2.54%, which can not only refine the grains, improve the morphology of borides and carbides, and improve the impact toughness, high-temperature oxidation and wear resistance of the high-boron high-speed steel, but also form a continuous and dense Fe2Al5 inhibition layer at the interface under the erosion of zinc liquid corrosion, which can inhibit the diffusion of zinc atoms, separate liquid zinc from the alloy matrix, resist micromechanical erosion, and inhibit the occurrence of cavitation. The Si content is 1.40-2.78%, which can further refine Fe2B, improve the hardness, strength and toughness of high-boron high-speed steel, and Si can promote the corrosion interface Γ-Fe3Zn in zinc liquid corrosion. 10 and δ-FeZn 10Combination makes the corrosion interface denser and more compact, improves the adhesion effect of the interface, prevents the penetration of zinc liquid and interface peeling, maintains the density and bonding strength of the corrosion interface, and improves the alloy's resistance to zinc liquid cavitation.

[0017] Furthermore, by adjusting the element composition design and optimizing the element content, the cavitation erosion resistance of the Al-containing directionally solidified high-boron high-speed steel in zinc liquid was greatly improved. The cavitation-erosion rate against zinc liquid was 2.8~3.5μm / h at a temperature of 455-465℃ and a corrosion time of 9-11h.

[0018] Furthermore, the microstructure of the oriented high-boron high-speed steel presents a layered alternating structure of soft matrix + hard phase. The hard phase protects the soft matrix, and the soft matrix supports the hard phase, which greatly improves the strength and toughness of the material and improves the material's resistance to high-velocity zinc liquid cavitation.

[0019] A method for preparing Al-containing directional solidification high-boron high-speed steel resistant to strong zinc liquid cavitation erosion, adopting a directional solidification process to prepare Al-containing high-boron high-speed steel, so that the alloy maintains a directional state, Fe2B maintains long rod-shaped growth, and a well-directional oriented structure grows straight and is embedded in the corrosion layer in a wedge shape, thereby increasing the bonding area between the corrosion product and the alloy structure. The corrosion product and the Fe2B hard phase produce a strong pinning bonding effect, which greatly improves the adhesion between the corrosion layer and the alloy structure, prevents the corrosion layer from peeling off, thereby blocking the infiltration of zinc liquid and greatly reducing the number of cavitation pits on the corrosion interface.

[0020] Furthermore, the melting temperature of directional solidification is 1645~1680℃, and the pouring temperature is 1455~1475℃, so that the metal pouring liquid is fully integrated, ensuring the pouring quality and good filling performance during molding, avoiding defects such as pores and slag inclusions, and improving the comprehensive performance of directionally solidified high-boron high-speed steel.

[0021] Furthermore, the directional solidification cooling rate is 12.6~13.8℃ / s, which ensures good molten metal filling capacity, smooth cooling gradient of the casting, and ensures a good directional effect.

[0022] In summary, the Al-containing directionally solidified high-boron high-speed steel with strong zinc liquid cavitation resistance of the present invention has greatly improved zinc liquid cavitation resistance, can adapt to harsh working conditions, and has 70 to 93 times higher zinc liquid cavitation resistance than 316L stainless steel.

[0023] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the SEM analysis morphology of the corrosion interface after 10 hours. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the present invention, unless otherwise specified, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0027] In the present invention, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0028] In the present invention, unless otherwise specified, percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0029] In the present invention, unless otherwise specified, the components or preferred components involved can be combined with each other to form a new technical solution.

[0030] In the present invention, unless otherwise specified, the numerical range "a-b" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "6-22" represents that all real numbers between "6-22" are listed in this document, and "6-22" is just an abbreviation of these numerical combinations.

[0031] The “range” disclosed in the present invention is in the form of a lower limit and an upper limit, which can be one or more lower limits, and one or more upper limits, respectively.

[0032] In the present invention, the term "and / or" used herein refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0033] In the present invention, unless otherwise specified, each reaction or operation step can be carried out sequentially or in accordance with the sequence. Preferably, the reaction method herein is carried out sequentially.

[0034] Unless otherwise specified, the professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content may also be applied to the present invention.

[0035] The invention provides an Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation erosion and a preparation method thereof. On the basis of the zinc liquid corrosion resistance of the previous directionally solidified high-boron high-speed steel, the element composition of the alloy is adjusted, and the composition design is reasonably optimized. The Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation erosion and a preparation method thereof are provided, which greatly improves the zinc liquid cavitation erosion resistance of the directionally solidified high-boron high-speed steel, and the zinc liquid cavitation erosion resistance of the directionally solidified high-boron high-speed steel is improved by 70 to 93 times compared with 316L stainless steel, reduces the economic cost of the material, is more adaptable to actual working conditions and environments, provides new ideas and approaches for improving the cavitation erosion damage of zinc liquid resistant materials, and lays a foundation for the further use of the directionally solidified high-boron high-speed steel.

[0036] The invention discloses an Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation erosion. The steel comprises, by weight percentage, 0.40%-0.48% of C, 3.10%-3.65% of B, 0.58%-0.72% of Mn, 1.18%-1.28% of W, 0.36%-0.54% of V, 4.60%-5.08% of Cr, 0.60%-0.68% of Mo, 0.05%-0.09% of Ti, 1.40%-2.78% of Si, 1.70%-2.54% of Al, and the remainder is Fe and inevitable trace impurities.

[0037] The microstructure of directionally solidified high-boron high-speed steel presents a layered alternating structure of soft matrix + hard phase. The directionally oriented microstructure of high-boron high-speed steel grows straight and is embedded in the corrosion layer in a wedge shape, increasing the bonding area between the corrosion products and the alloy microstructure. The corrosion products and the Fe2B hard phase produce a strong bonding effect, and a continuous and dense Fe2Al5 inhibition layer is formed on the corrosion interface, which inhibits the occurrence of cavitation erosion.

[0038] After Al-containing directionally solidified high-boron high-speed steel was corroded at 455~465℃ for 9~11h, the cavitation-erosion rate of zinc liquid resistance was 2.8~3.5μm / h. The zinc liquid cavitation erosion resistance was greatly improved, and it can better adapt to harsh working conditions. Compared with 316L stainless steel, the zinc liquid corrosion cavitation erosion resistance is improved by 70~93 times.

[0039] The present invention discloses a method for preparing Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation, comprising the following steps: Directional solidification process is adopted to control the melting temperature at 1645~1680℃ to melt the Al-containing directionally solidified high-boron high-speed steel; then pouring is carried out at 1455~1475℃; After pouring, the cooling rate was controlled at 12.6-13.8°C / s for natural cooling; finally, Al-containing high-boron high-speed steel samples with good directional properties were obtained.

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] Example 1 A directionally solidified high-boron high-speed steel containing Al and resistant to strong zinc liquid erosion comprises, by weight percentage, 0.40% C, 3.10% B, 0.58% Mn, 1.18% W, 0.36% V, 4.60% Cr, 0.60% Mo, 0.05% Ti, 1.40% Si, 1.70% Al, and the rest is Fe and inevitable trace impurities.

[0042] The melting temperature of Al-containing directionally solidified high-boron high-speed steel is 1645°C, and then it is poured at 1455°C. The cooling rate after pouring is 12.6°C / s, and finally an Al-containing high-boron high-speed steel sample with good directional performance is obtained.

[0043] The cavitation-erosion rate of Al-containing directionally solidified high-boron high-speed steel in zinc liquid corrosion at 455℃ for 9h is 3.5μm / h, and the rotation speed of the corrosion sample in the zinc liquid is 288r•min -1 Compared with 316L stainless steel, its corrosion resistance to zinc liquid cavitation is improved by 70 times. The specific corrosion rate comparison is shown in Table 1.

[0044] Table 1 Comparison results of 9h corrosion rate

[0045] Example 2 The invention discloses an Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation erosion, which comprises, by weight percentage, 0.44% C, 3.50% B, 0.61% Mn, 1.22% W, 0.45% V, 4.92% Cr, 0.65% Mo, 0.07% Ti, 2.12% Si, 2.13% Al, and the rest is Fe and inevitable trace impurities.

[0046] The melting temperature of Al-containing directionally solidified high-boron high-speed steel is 1668°C, and then it is poured at 1462°C. The cooling rate after pouring is 13.2°C / s, and finally an Al-containing high-boron high-speed steel sample with good directional performance is obtained.

[0047] The cavitation-erosion rate of Al-containing directionally solidified high-boron high-speed steel in zinc liquid is 3.1 μm / h when it is corroded at 460℃ for 10 h. The rotation speed of the corrosion sample in the zinc liquid is 300 r•min. -1 Compared with 316L stainless steel, its corrosion resistance to zinc liquid cavitation is improved by 82 times. The specific corrosion rate comparison is shown in Table 2.

[0048] Table 2 Comparison of 10h corrosion rate

[0049] Figure 1 This is the SEM analysis morphology of the corrosion interface after 10 hours. It can be seen that the directional structure of the Al-containing directionally solidified high-boron high-speed steel grows straight at the corrosion interface and is embedded with the corrosion layer. A continuous and dense Fe2Al5 inhibition layer is formed on the corrosion interface. The mutual embedding effect of the directional structure and the corrosion inhibition layer at the interface improves the adhesion between the corrosion layer and the alloy structure, prevents the corrosion layer from peeling off, and prevents further penetration and corrosion of the zinc liquid, greatly improving the zinc liquid cavitation resistance of the Al-containing directionally solidified high-boron high-speed steel.

[0050] Example 3 The invention discloses an Al-containing directionally solidified high-boron high-speed steel resistant to cavitation erosion by strong zinc liquid, which comprises, by weight percentage, 0.48% C, 3.65% B, 0.72% Mn, 1.28% W, 0.54% V, 5.08% Cr, 0.68% Mo, 0.09% Ti, 2.78% Si, 2.54% Al, and the rest is Fe and inevitable trace impurities.

[0051] The melting temperature of Al-containing directionally solidified high-boron high-speed steel is 1680°C, and then it is poured at 1475°C. The cooling rate after pouring is 13.8°C / s, and finally an Al-containing high-boron high-speed steel sample with good directional performance is obtained.

[0052] The cavitation-erosion rate of Al-containing directionally solidified high-boron high-speed steel in zinc liquid is 2.8 μm / h when it is corroded at 465℃ for 11 hours. The rotation speed of the corrosion sample in zinc liquid is 320 r•min. -1 Compared with 316L stainless steel, its corrosion resistance to zinc liquid cavitation is improved by 93 times. The specific corrosion rate comparison is shown in Table 3.

[0053] Table 3 Comparison results of 11h corrosion rate

[0054] In summary, the present invention provides an Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation erosion and a preparation method thereof, which provides a new idea and approach for improving the cavitation erosion damage of zinc liquid resistant materials and lays a foundation for the further use of directionally solidified high-boron high-speed steel.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A directionally solidified high-boron high-speed steel containing Al and resistant to strong zinc liquid cavitation, characterized in that: Calculated by weight percentage, it includes C: 0.40%~0.48%, B: 3.10%~3.65%, Mn: 0.58%~0.72%, W: 1.18%~1.28%, V: 0.36%~0.54%, Cr: 4.60%~5.08%, Mo: 0.60%~0.68%, Ti: 0.05%~0.09%, Si: 1.40%~2.78%, Al: 1.70%~2.54%, and the rest is Fe and inevitable trace impurities.

2. The Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation according to claim 1, characterized in that: Calculated by weight percentage, it includes C: 0.44%, B: 3.50%, Mn: 0.61%, W: 1.22%, V: 0.45%, Cr: 4.92%, Mo: 0.65%, Ti: 0.07%, Si: 2.12%, Al: 2.13%, and the rest is Fe and inevitable trace impurities.

3. The Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation according to claim 1, characterized in that: After corrosion at 455~465℃ for 9~11h, the cavitation-erosion rate of Al-containing directionally solidified high-boron high-speed steel against zinc liquid is 2.8~3.5μm / h.

4. The Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation according to claim 1, characterized in that: After corrosion at 460℃ for 10h, the cavitation-erosion rate of Al-containing directionally solidified high-boron high-speed steel against zinc liquid is 3.1μm / h.

5. The Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation according to any one of claims 1 to 4, characterized in that: The microstructure of Al-containing directionally solidified high-boron high-speed steel presents a layered alternating structure of soft matrix + hard phase.

6. A method for preparing the Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation according to any one of claims 1 to 5, characterized in that: Al-containing directionally solidified high-boron high-speed steel was prepared by directional solidification process.

7. The method for preparing Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation according to claim 6, characterized in that: The melting temperature of the directional solidification process is 1645~1680℃.

8. The Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation and the preparation method thereof according to claim 7, characterized in that: The pouring temperature of the directional solidification process is 1455~1475℃.

9. The Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation and the preparation method thereof according to claim 6, characterized in that: The cooling rate of the directional solidification process is 12.6~13.8℃ / s.

10. The Al-containing directionally solidified high-boron high-speed steel resistant to strong zinc liquid cavitation and the preparation method thereof according to claim 6, characterized in that: The directional oriented structure of Al-containing directionally solidified high-boron high-speed steel grows straight and is embedded in the corrosion layer in a wedge shape, and a continuous and dense Fe2Al5 inhibition layer is formed on the corrosion interface.

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