High-toughness and high-wear-resistance wire for additive manufacturing of hot working die and preparation method thereof

文档序号：147052 发布日期：2021-10-26 浏览：23次中文

阅读说明：本技术 一种高韧高耐磨性的热作模具增材制造用丝材及其制备方法 (High-toughness and high-wear-resistance wire for additive manufacturing of hot working die and preparation method thereof ) 是由易江龙邹晓东张雪莹潘琳琳牛犇范振华于 2021-06-29 设计创作，主要内容包括：本发明公开了一种高韧高耐磨性的热作模具增材制造用丝材及其制备方法,所述丝材为药芯焊丝,药芯粉末采用Cr、Mo、V为主体合金,联合添加Co和Nb,添加使用静电自组装工艺制备的纳米陶瓷颗粒均匀负载的雾化铁粉,制备纳米WC均匀分散的热作模具钢增材制造用丝材,解决了纳米陶瓷颗粒在制备过程容易团聚长大的问题,在增材制造过程中,弥散分布的WC颗粒不仅增强热作模具钢基体的耐磨性能,还能提升热作模具钢基体的韧性,尤其,在增材制造过程中,还能起到抑制柱状晶生成的作用,并能诱导等轴晶生成,进一步增强增材制造组织的综合性能,使得电弧熔丝增材制造热作模具钢组织兼具高韧性和高耐磨性能。(The invention discloses a high-toughness and high-wear-resistance wire for additive manufacturing of a hot-working die and a preparation method thereof, the wire material is a flux-cored wire, the flux-cored powder adopts Cr, Mo and V as main alloy, Co and Nb are jointly added, atomized iron powder which is uniformly loaded by nano ceramic particles and is prepared by using an electrostatic self-assembly process is added, the wire material for additive manufacturing of the hot-work die steel with uniformly dispersed nano WC is prepared, the problem that the nano ceramic particles are easy to agglomerate and grow in the preparation process is solved, in the additive manufacturing process, the dispersed WC particles not only enhance the wear resistance of the hot-work die steel matrix, but also improve the toughness of the hot-work die steel matrix, in particular, in the additive manufacturing process, the additive manufacturing method can also play a role in inhibiting the generation of columnar crystals, can induce the generation of equiaxial crystals, and further enhances the comprehensive performance of the additive manufacturing structure, so that the hot-work die steel structure manufactured by the arc fuse additive manufacturing has high toughness and high wear resistance.)

1. A wire for additive manufacturing of a high-toughness and high-wear-resistance hot-working die is characterized in that the wire is a flux-cored wire and consists of a steel strip with a sheath and internally-wrapped flux-cored powder, the steel strip is an H08A steel strip, the size of the steel strip is 0.7 x 14mm, the powder filling rate is 28.0-32.0%, the diameter range of the wire is 1.2-2.0mm, and the flux-cored powder comprises the following components in percentage by mass: 4.0-5.0% of Cr, 1.5-2.0% of Mo, 0.5-1.0% of V, 4.0-5.0% of Nb, 2.0-5.0% of Co, 0.5% of Zr, Si: 0.5%, Sc: 0.5%, nano WC: 1.5 to 5.0 percent of the total weight of the alloy, and the balance of iron powder, wherein the grain size range of the nano WC is 80 to 100nm, and the purity is 99.9 percent.

2. The high toughness and high wear resistance hot-work die additive manufacturing wire rod as claimed in claim 1, wherein the particle size range of the Cr, Mo, V, Nb, Co powders is 100-.

3. A method for preparing a high-toughness and high-wear-resistance hot-working die additive manufacturing wire material according to claim 1, which comprises the following steps:

s1: firstly, adding atomized iron powder with the particle size of 450-; adding nano WC into a deionized water solution under the condition of an ice-water bath, stirring, adding sodium dodecyl benzene sulfonate, wherein the mass ratio of the nano WC to the deionized water solution is 1: 10-1: 30, the mass ratio of the sodium dodecyl benzene sulfonate to the nano WC is 1: 4-1: 6, continuously stirring for 1h to obtain a nano WC suspension liquid with negative charges on the surface, slowly adding atomized iron powder with positive charges on the surface into the nano WC suspension liquid with negative charges on the surface under the conditions of the ice-water bath and ultrasonic stirring, continuously stirring for 30min, carrying out vacuum filtration, and carrying out freeze drying to obtain atomized iron powder with uniform nano WC loaded on the surface;

s2: adding the atomized iron powder containing nano WC and Cr, Mo, V, Nb, Co, Zr, Si and Sc obtained in the step S1 into a V-shaped powder mixer, and mixing for 30min to obtain uniformly mixed flux-cored powder;

s3: and (3) ultrasonically cleaning an H08A steel strip on a strip unreeling machine, rolling and deforming the steel strip on a forming machine, changing the steel strip into a U-shaped groove, adding the flux-cored powder prepared by S2 according to the required filling rate, and carrying out multi-pass rolling, rough drawing and fine drawing to obtain the O-shaped slotted flux-cored wire with the required diameter.

The technical field is as follows:

the invention relates to a wire for repairing a hot-working die, in particular to a wire for manufacturing a high-toughness and high-wear-resistance hot-working die additive and a preparation method thereof.

Background art:

with the rapid development of the advanced manufacturing technology industry, the requirements on the service environment and the performance of the used materials are increasingly stringent, and the performance of the traditional metal materials cannot meet the multi-functional requirements of the development of the high-technology industry, so that the phenomena of failure such as abrasion, corrosion, fatigue, aging and the like often occur in the service process, and the development of special functional materials with multiple performances is urgently needed. At present, scholars at home and abroad adopt various technologies to improve the comprehensive performance of the surface of the traditional metal die material, such as nitriding, carburizing, vapor deposition, plasma spraying, supersonic spraying, laser cladding, plasma surfacing and the like. Compared with the traditional method of modifying the surface of the material by using single metal or alloy, the surface coating of the metal matrix composite material reinforced by the ceramic particles can obtain the comprehensive mechanical properties of high hardness, high strength, high modulus, high fracture toughness, high temperature oxidation resistance and excellent abrasion resistance, and is the most potential die reinforcing material at present.

In recent years, the hot-work die steel surface reinforcing material has been researched by adopting nano ceramic particles for reinforcement, so that the surface reinforcing material with high toughness and high wear resistance can be obtained. Based on Hall-Petch relationship, the nano ceramic particle reinforced metal matrix composite material has other comprehensive properties of high strength, high toughness, high wear resistance and the like. Taking the widely used high-temperature wear-resistant material WC/Co as an example, research shows that when the size of WC crystal grains is reduced to be below submicron, the hardness, toughness, strength and wear resistance of the material are all improved, and especially on the premise of improving the hardness, the toughness of the material can be obviously improved by the nano WC material. However, since the specific gravity phase difference between the nano ceramic particles and the metal matrix is large, it is difficult to uniformly add the nano particles to the metal matrix. Meanwhile, based on the higher surface energy of the nanoparticles, the adjacent nanoparticles are easy to agglomerate and grow in the preparation process, so that the dispersion effect is poor, the mechanical property of the material is reduced, and the performance improvement effect expected by theory cannot be achieved.

The invention patent of publication No. CN 112680690A discloses a method for preparing a WC/Fe iron-based composite cladding layer modified by nano beta-SiC, which comprises the steps of cladding pretreated iron-based WC powder in a plasma cladding mode, adding nano beta-SiC particle powder into water glass, fully stirring and mixing to prepare a thick state, uniformly coating the surface of the iron-based WC plasma cladding layer, and cladding the nano beta-SiC into the iron-based WC plasma cladding layer in a laser remelting mode to obtain the cladding layer with less pores and cracks and better wear resistance. CN 108103387A discloses a nano WC particle reinforced high-chromium iron-based powder metallurgy material, which is prepared into a high-performance powder metallurgy high-chromium iron-based composite material reinforced by nano WC particles through a high-energy ball milling combined hot-pressing sintering technology. When the sintering temperature is 1000 ℃, a nearly fully dense sintered sample can be obtained, and the hardness and the bending strength of the sample respectively reach 47.7HRC and 1952 MPa. CN 105861905A discloses a nano-particle modified titanium carbide-based hard alloy and a preparation method thereof, wherein the addition amount of nano-titanium carbide is 2-8%, the nano-particle modified titanium carbide-based hard alloy is prepared by adopting the processes of ultrasonic mixing, hot press forming and vacuum sintering, and has the advantages of high hardness, good wear resistance and corrosion resistance, low porosity and high cost performance. The invention patent of CN 107475548A discloses a method for preparing nano toughened ultra-fine grain WC-Co hard alloy, wherein the nano rare earth metal mixed additive is prepared by adopting a vacuum arc melting ingot casting and a rapid-in-situ packaging plasma arc method. The nano metal mixed additive has the functions of refining hard alloy grains, improving material wettability, reducing porosity and enhancing local grain boundary strength of the alloy, thereby greatly improving the macroscopic properties of the alloy, such as hardness, bending strength, fracture toughness and the like. The invention patent of CN 11471908A discloses a TiCx-bonded nanocrystalline WC-based hard alloy composite material and a preparation method thereof, the raw materials for preparing the composite material comprise nano tungsten carbide powder and nano TiCx powder, and the TiCx-bonded nanocrystalline WC-based hard alloy composite material is prepared by hot-pressing sintering, so that the problem of high sintering temperature of a ceramic bonding agent tungsten carbide hard alloy is solved, and the hardness and fracture toughness of the tungsten carbide hard alloy composite material are improved.

In summary, the materials for strengthening by using nano-ceramic particles disclosed at present mostly adopt a mixing mode of mechanical mixing, high-energy ball milling, ultrasound and hot pressing, and the direct mechanical mixing method has the advantages of low cost and wide application range, but because no additional energy is used for improving the binding force between the ceramic particles and the matrix, the nano-ceramic particles in the composite powder prepared by the mechanical mixing method have certain agglomeration tendency. The high-energy ball milling method is a common preparation method of nano-particle reinforced composite powder, can improve the binding force between ceramic particles and a matrix to a certain extent, but the higher energy in the ball milling process can change the surface quality and the sphericity of matrix powder and reduce the flowability of a powder material. The ultrasonic vibration dispersion mixing method combines the advantages of ultrasonic vibration and mechanical mixing, can effectively improve the problem of powder agglomeration, but also has the defects of long time consumption of the preparation process and complex process.

The invention content is as follows:

the invention aims to provide a wire for hot-work die additive manufacturing with high toughness and high wear resistance and a preparation method thereof, wherein the wire is a flux-cored wire and consists of a steel belt of an outer skin and flux-cored powder of an inner package, the flux-cored powder adopts Cr, Mo and V as main body alloys, Co and Nb are jointly added to obtain ultrahigh strength and good comprehensive mechanical property, atomized iron powder uniformly loaded with nano ceramic particles prepared by using an electrostatic self-assembly process is added to prepare the wire for hot-work die steel additive manufacturing with uniformly dispersed nano WC, the problem that the nano ceramic particles are easy to agglomerate and grow in the preparation process is solved, in the additive manufacturing process, the dispersed WC particles not only enhance the wear resistance of a hot-work die steel matrix, but also can refine the matrix structure to play a fine grain strengthening role and improve the toughness of the hot-work die steel matrix, in particular, in the additive manufacturing process, the alloy can also play a role in inhibiting columnar crystal generation, can induce equiaxial crystal generation, further enhances the comprehensive performance of an additive manufacturing structure, obtains excellent comprehensive performance which is not possessed by micron WC, and enables the arc fuse additive manufacturing hot-work die steel structure to have high toughness and high wear resistance.

The invention is realized by the following technical scheme:

a wire for additive manufacturing of a hot-working die with high toughness and high wear resistance is a flux-cored wire and comprises a steel strip with an outer skin and flux-cored powder wrapped inside, wherein the steel strip is an H08A steel strip, the size of the steel strip is 0.7 x 14mm, the powder filling rate is 28.0-32.0%, the diameter range of the wire is 1.2-2.0mm, and the flux-cored powder comprises the following components in percentage by mass: 4.0-5.0% of Cr, 1.5-2.0% of Mo, 0.5-1.0% of V, 4.0-5.0% of Nb, 2.0-5.0% of Co, 0.5% of Zr, Si: 0.5%, Sc: 0.5%, nano WC: 1.5 to 5.0 percent of the total weight of the alloy, and the balance of iron powder, wherein the grain size range of the nano WC is 80 to 100nm, and the purity is 99.9 percent.

Wherein Cr, Mo, V, Nb and Co form alloy powder, the grain diameter range of the alloy powder is 100-150 μm, and Zr, Si and Sc form a combined deoxidizer.

The preparation method of the wire for the additive manufacturing of the hot-working die with high toughness and high wear resistance comprises the following steps:

The invention has the following beneficial effects:

1) co added into the flux-cored powder can improve the high-temperature hardness and improve the service temperature of hot-work die steel; the addition of Nb can play a role in solid solution strengthening and can also refine crystal grains, improve the impact toughness of the hot-work die steel and reduce the brittle transition temperature of the hot-work die steel;

2) the added small amount of nano WC can be dispersed and distributed in the matrix alloy, and simultaneously can perform a two-phase diffusion reaction with elements of a hot-working die steel matrix based on the surface activity of the nano WC to obtain a high-toughness interface structure with high bonding strength, so that the wear resistance of the matrix is improved, a brittle intermediate phase is not generated, and the toughness of the matrix is deteriorated; on the other hand, the nano WC which is dispersed and distributed can further refine the matrix structure, play a role in fine grain strengthening, improve the toughness of the hot work die steel matrix, particularly prevent the columnar crystal structure generated by the multiple heat cycle accumulation of additive manufacturing in the additive manufacturing process, and induce the generation of isometric crystal, so that excellent comprehensive performance which cannot be achieved by adding the micron WC is obtained;

3) based on the flexibility of adding flux-cored powder in the flux-cored wire, the adding amount of the nano WC and the required strengthening elements can be adjusted based on the use requirement; 4) the Sc and Si combined deoxidizer can effectively clean the welding line, has good effects of degassing, purifying and refining grains, and can reduce the non-metallic inclusions of the deoxidation product by adding the rare earth Sc, so that the matrix structure is compact and pure.

4) The invention adopts the electrostatic self-assembly process which is relatively simple, the reaction process is easy to control, the surface charge of different nano ceramic particles can be modified by the optimized selection of the surface charge modifier, high-quality raw materials with good interface bonding force and fluidity can be obtained, and the invention is suitable for preparing metal-based composite materials containing different nano particles, and is particularly suitable for preparing special composite materials with the requirements of both wear resistance and high toughness.

Description of the drawings:

FIG. 1 is a microstructure diagram of nano WC dispersion distribution and atomized iron powder prepared in example 5;

FIG. 2 is a structural diagram of additive manufacturing of hot work die steel of example 5 with the addition of 5% wt. nano WC;

FIG. 3 is a structural diagram of additive manufacturing of hot-work die steel with 5 wt% of WC micron added in comparative example 1.

The specific implementation mode is as follows:

the following is a further description of the invention and is not intended to be limiting.

Example 1:

a wire suitable for hot-working die additive manufacturing adopts an H08A steel belt as a sheath, the size of the steel belt is 0.7 multiplied by 14mm, the powder filling rate is 28.0%, and the diameter of the wire is 1.2 mm. The flux core powder comprises the following components in percentage by mass: alloy powder: 4.0 percent of Cr, 1.5 percent of Mo, 0.5 percent of V and 4.0 percent of Nb; co:2.0 percent; combined deoxidizing agent: zr: 0.5%, Si: 0.5 percent; and (C) Sc: 0.5 percent; nano WC: 1.5 percent and the balance of iron powder. The grain size range of the alloy powder is 100-150 mu m, the grain size range of the nanometer WC is 80-100nm, and the purity is 99.9%.