阅读说明：本技术 一种表面纳米化高能离子注渗复合处理方法 (Surface nanocrystallization high-energy ion injection and permeation composite treatment method ) 是由 *** 韩建波 徐德生 赵小辉 桑娜 于 2019-11-20 设计创作，主要内容包括：本发明涉及表面强化技术领域,具体为一种表面纳米化高能离子注渗复合处理方法,该方法包括样品表面滚压之前的预处理,先利用线切割将铁板切成圆柱；将样品放在磨床上固定,进行打磨,先对样品一面进行样品平整度打磨,直至表面平整,然后再对另一面也进行表面平整度的打磨,最后在该表面进行细磨处理降低滚压面的粗糙度；将机械表面改性强化技术与化学表面改性强化技术复合应用于金属模具表面,显著提高模具表面的硬度和耐磨性,而心部则保持原有钢基体的强韧性,并且在表层与心部之间还存在一个性能渐变的梯度过渡区,可以有效避免性能突变时可能引起的材料破坏,从而大大延长模具的使用寿命。(The invention relates to the technical field of surface strengthening, in particular to a surface nanocrystallization high-energy ion injection and permeation composite treatment method, which comprises the steps of pretreating the surface of a sample before rolling, firstly cutting an iron plate into cylinders by utilizing linear cutting; fixing a sample on a grinding machine, polishing, firstly polishing the sample flatness on one surface of the sample until the surface is flat, then polishing the surface flatness on the other surface, and finally performing fine grinding treatment on the surface to reduce the roughness of a rolled surface; the mechanical surface modification strengthening technology and the chemical surface modification strengthening technology are applied to the surface of the metal mold in a composite mode, the hardness and the wear resistance of the surface of the mold are obviously improved, the core part keeps the toughness of the original steel matrix, and a gradient transition area with gradually changed performance exists between the surface layer and the core part, so that material damage possibly caused by performance mutation can be effectively avoided, and the service life of the mold is greatly prolonged.)

1. A surface nanocrystallization high-energy ion injection-infiltration composite treatment method is characterized by comprising the following steps:

(1) pretreatment before rolling of sample surface

Firstly, cutting an iron plate into a cylinder with the diameter of 10mm and the thickness of 12mm by utilizing wire cutting;

fixing a sample on a grinding machine, polishing, firstly polishing the sample flatness on one surface of the sample until the surface is flat, then polishing the surface flatness on the other surface, and finally performing fine grinding treatment on the surface to reduce the roughness of a rolled surface;

(2) ultrasonic rolling treatment of sample surface

Fixing the sample treated in the step (1) on a machine tool, and adjusting the coaxiality and the flatness of the sample;

firstly, operating a machine tool to enable a sample to do rotary motion, then starting rolling equipment to set corresponding parameters, waiting for about 5 minutes to enable the vibration frequency of ultrasonic equipment to reach a positive sine wave form, and finally applying pressure to a rolling head, wherein the machine tool parameters are 2-10A, the rotating speed of a main shaft of the machine tool is 100r/min, the feeding speed of the machine tool is 0.1mm/r, the vibration frequency of the ultrasonic equipment is 20-27KHz, the amplitude is 6.5-7.5 mu m, and the pressure applied by the rolling head is 300N;

(3) preparation of tungsten carbide composite layer

Drilling the workpiece processed in the step (2), and suspending the workpiece in an injection infiltration furnace by using an iron wire to penetrate through the hollow hole;

the voltage is adjusted to 600V to keep the temperature in the furnace at the proper temperature of 470 ℃, so that not only can a good infiltration injection effect be achieved, but also the crystal grains of the workpiece can not be coarse;

the heat preservation time is 24 h.

Technical Field

The invention relates to the technical field of surface strengthening, in particular to a surface nanocrystallization high-energy ion injection and permeation composite treatment method.

Background

The mould is important technological equipment for production in industries such as machinery, electronics, light industry, national defense and the like, and the quality and benefit of a product and the development capability of a new product are determined to a great extent by the level of the production technology of the mould. The failure of the mold tends to start at the mold surface, and thus the quality of the mold surface performance directly affects the service and life of the mold. The surface modification technology is an important means for improving the surface performance of materials, and is widely applied to occasions requiring wear resistance, corrosion resistance and the like.

The metal surface nanocrystallization technology is characterized in that an external load is applied to the surface of a material repeatedly, the free energy of the surface of a polycrystalline metal material is increased, and the surface tissue generates strong plastic deformation in different directions to gradually thin the coarse-grained structure of the surface layer of the material to a nanometer level. After the nano-structure is formed, the hardness of the composite layer is further improved due to the existence of the gradient nano-structure, so that the friction performance of the material is obviously improved. The technology has the advantages of simple process, low cost and easy realization; the nano-layer structure is compact, and the chemical components are the same as those of the matrix; the nano layer has a gradient structure and is not easy to peel off. The prior successful material surface nanocrystallization method comprises the following steps: mechanical surface grinding (SMAT), ultrasonic shot blasting (USSP), pneumatic shot blasting (AB-SP), ultrasonic shot blasting (SFPB), rotational roll plastic deformation (CRPD), and ultrasonic impact technique (USRP).

The high-energy ion implantation technology (HEII) is to implant high-energy ions into the surface of a material to obtain a new alloy phase beneficial to improving the performance, so that the physical, chemical and mechanical properties of the surface layer of the material are changed. It has been found that the hardness, wear resistance and corrosion resistance of certain metal materials can be significantly improved by High Energy Ion Implantation (HEII). Although the surface modification technology is various, after the surface modification is carried out by high-energy ion implantation, a new alloy phase which cannot be obtained by other methods can be obtained, and the new alloy phase is firmly combined with a substrate without obvious interface and shedding phenomena, so that the problems of adhesion and mismatch of thermal expansion coefficients in a plurality of coating technologies are solved, and certain defects exist in the thickness and uniformity of an impregnation layer.

Disclosure of Invention

In order to solve the problems, the invention provides a surface nano high-energy ion injection-infiltration composite treatment method based on ultrasonic surface rolling and high-energy ion injection-infiltration of tungsten carbide.

The technical problem to be solved by the invention is realized by adopting the following technical scheme:

a surface nano high-energy ion injection-infiltration composite treatment method comprises the following steps:

(1) pretreatment before rolling of sample surface

Firstly, cutting an iron plate into a cylinder with the diameter of 10mm and the thickness of 12mm by utilizing wire cutting;

fixing a sample on a grinding machine, polishing, firstly polishing the sample flatness on one surface of the sample until the surface is flat, then polishing the surface flatness on the other surface, and finally performing fine grinding treatment on the surface to reduce the roughness of a rolled surface;

(2) ultrasonic rolling treatment of sample surface

Fixing the sample treated in the step (1) on a machine tool, and adjusting the coaxiality and the flatness of the sample;

firstly, operating a machine tool to enable a sample to do rotary motion, then starting rolling equipment to set corresponding parameters, waiting for about 5 minutes to enable the vibration frequency of ultrasonic equipment to reach a positive sine wave form, and finally applying pressure to a rolling head, wherein the machine tool parameters are 2-10A, the rotating speed of a main shaft of the machine tool is 100r/min, the feeding speed of the machine tool is 0.1mm/r, the vibration frequency of the ultrasonic equipment is 20-27KHz, the amplitude is 6.5-7.5 mu m, and the pressure applied by the rolling head is 300N;

(3) preparation of tungsten carbide composite layer

Drilling the workpiece processed in the step (2), and suspending the workpiece in an injection infiltration furnace by using an iron wire to penetrate through the hollow hole;

the voltage is adjusted to 600V to keep the temperature in the furnace at the proper temperature of 470 ℃, so that not only can a good infiltration injection effect be achieved, but also the crystal grains of the workpiece can not be coarse;

the heat preservation time is 24 h.

Compared with the prior art, the invention has the beneficial effects that: the invention relates to a surface nano high-energy ion injection-permeation composite treatment method,

(1) the ultrasonic impact treatment can refine crystal grains, and after the nano treatment, the hardness of a composite layer is further improved due to the existence of a gradient nano structure, so that the friction performance of the material is obviously improved.

(2) Researches show that after the ultrasonic rolling pretreatment and the high-energy ion tungsten carbide impregnation, the obtained surface composite layer has thicker hardness and better uniformity and hardness.

(3) The mechanical surface modification strengthening technology and the chemical surface modification strengthening technology are applied to the surface of the metal mold in a composite mode, the hardness and the wear resistance of the surface of the mold are obviously improved, the core part keeps the toughness of the original steel matrix, and a gradient transition area with gradually changed performance exists between the surface layer and the core part, so that material damage possibly caused by performance mutation can be effectively avoided, and the service life of the mold is greatly prolonged.

Drawings

FIG. 1 is a simplified schematic diagram of the ultrasonic surface rolling principle;

FIG. 2(a) is a surface SEM photograph of a sample of example 1;

FIG. 2(b) is a surface SEM image of a sample of example 2;

FIG. 3(a) is a sectional SEM photograph of a sample of example 1;

FIG. 3(b) is a cross-sectional SEM image of a sample of example 2;

fig. 4 is a cross-sectional hardness plot for the example 1 sample and the example 2 sample.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The material selected in the test is Dievar hot work die steel, and the microstructure of the material is hypereutectoid steel ledeburite phase. The main chemical components are Cr, Mo and V.

The alloy components and the basic mechanical properties of the material are shown in tables 1 and 2, respectively.

Table 1 alloy composition of materials

TABLE 2 mechanical Properties of Dievar Hot work die steels