CN101886160B - Metal surface modification method through emulsion jet - Google Patents

Abstract

The invention discloses a metal surface modification method by emulsion jet, which belongs to the metal material surface processing technology. The metal surface modification method mainly includes preparing an emulsion that can produce effective cavitation bubbles and jet effects; immersing the parts to be processed in the emulsion, adjusting the jet nozzle, jet pressure and the relationship between the jet nozzle and the metal to be processed distance, jet machining of metal surfaces in an emulsion medium. Using the emulsion as the medium produced by the cavitation jet, the metal surface modification method of the emulsion jet is formed, and the fatigue strength of the strengthened test piece is increased by 56% and 11% respectively. The advantages are: it can generate effective cavitation bubbles, improve the processing efficiency of the metal surface, does not cause corrosion to the metal surface, has no pollution to the environment, is low in cost, and is not easy to cause damage to the metal surface. The residual emulsion has no corrosive effect on the metal surface. The investment cost and use cost are low, the use effect is good, and it is easy to promote and apply.

Description

Metal Surface Modification Method by Emulsion Jet

technical field

The invention relates to a metal material surface processing technology, in particular to an emulsion jet metal surface modification method.

Background technique

Introducing residual compressive stress on the surface can significantly improve the fatigue strength of metal materials. There are many mechanical methods for surface modification, such as shot peening, laser peening, ultrasonic shot peening, deep rolling and rolling, etc., which can lead to residual compressive stress on the surface of the material. The formation of stress. In order to improve the unfavorable effect of solid particle jet on crack initiation, in the 1990s, people put forward the idea of using liquid jet technology to process hardened metal surfaces, and continuously developed water jet and oil jet shot peening technology. In these techniques, high-speed liquid jets generated by high-pressure gas act on the metal surface, causing it to generate residual compressive stress. The size and depth of the residual stress on the surface of the sample depend on the jet pressure, jet time and material strength. Water jet cavitation spray strengthening is better than shot peening in improving the fatigue strength of metal, and it has a more obvious effect on prolonging fatigue crack initiation; Some substantive progress has been made in the research of chemical jet peening technology.

However, since water may cause certain corrosion on the components, although the process technology is simple and does not cause large water consumption, its strengthening effect is affected by the corrosion of water; the further development of oil jet shot peening can avoid corrosion However, the oil jet shot peening involves the cleaning of the sample and a large investment. Although the oil circulation method can be used, the consumption of oil is inevitable. These problems limit the application of water (oil) jet peening technology to a certain extent.

Contents of the invention

The object of the present invention is to provide a method for modifying the metal surface of an emulsion jet with weak protection to metal materials.

The object of the present invention is achieved like this: the metal surface modification method mainly includes the preparation of an emulsion capable of producing effective cavitation bubbles and jet effects; immersing the parts to be processed in the emulsion, adjusting the jet nozzle, jet The pressure and the distance between the jet nozzle and the metal to be processed are used to process the metal surface in the emulsion medium. The specific process is:

(1) Adopt emulsified liquid as the medium that produces jet flow, and emulsified liquid is the mixture of emulsified oil and water; Under room temperature, the mixing ratio of emulsified oil and water is 3% to 10% for emulsified oil and 97% to 90% for water, and then Add anhydrous sodium carbonate to adjust the pH value of the emulsion. The pH value of the emulsion is controlled at 7-10, the average viscosity is 1.0-1.5cSt, and the lower critical Reynolds coefficient is less than 2320;

(2) Submerge the parts to be processed in the emulsion, open the emulsion jet machine, and the emulsion jet will pass through the jet nozzle to generate the emulsion bubble flow, the jet pressure is 20-60MPa, and the emulsion jet diffusion angle is 25-5 °.

(3) Move the emulsion jet nozzle so that the jet is vertically aligned with the surface of the part to be processed, and the distance from the jet outlet of the jet nozzle to the surface of the part to be processed is 15 to 30 cm.

The appearance of the emulsified oil is transparent or translucent liquid, the pH value is 7-10, the kinematic viscosity is 35-50 at 40°C, and the corrosion of 45 steel is not more than 1 in 24 hours; the emulsified liquid is formed by mixing emulsified oil and water Oil-in-water (O/W) type emulsion; the water mixed with the emulsified oil is water softened by anhydrous sodium carbonate; the use temperature of the emulsion after preparation is 2-30°C.

Beneficial effects: Due to the adoption of the above scheme, the emulsified liquid is used as the medium generated by the cavitation jet to form a method for modifying the metal surface of the emulsified liquid jet. The fatigue strength of the metal is better than the shot peening method using water medium, and the effect on prolonging the initiation of fatigue cracks is particularly significant; compared with the jet peening method using oil as the medium, it solves the problem of cleaning the sample and greatly reduces The investment cost and the use cost are reduced; through the high-pressure water impact strengthening treatment of aluminum alloy, silicon-manganese alloy and carbon steel, the fatigue strength of the strengthened specimen can be increased by 56% and 11% respectively compared with the fatigue strength of the unstrengthened specimen. %, compared with the traditional shot peening, the fatigue strength increased by 4% to 36%, the surface roughness of the treated specimen did not change much, and the surface roughness value Ra of the treated specimen was greatly reduced; the jet produced by the jet nozzle The bubbles are uniform, and it is not easy to cause damage to the metal surface. The residual emulsion has no corrosive effect on the metal surface, and the processed metal surface will not cause secondary corrosion due to the jet medium; it has weak protection for metal materials, and the purpose of the present invention is achieved. .

The advantages are: it can generate effective cavitation bubbles, improve the processing efficiency of the metal surface, does not cause corrosion to the metal surface, has no pollution to the environment, is low in cost, and is not easy to cause damage to the metal surface. The residual emulsion has no corrosive effect on the metal surface. The investment cost and use cost are low, the use effect is good, and it is easy to promote and apply.

Detailed ways

Example 1: Surface modification of ordinary carbon steel. Translucent emulsified oil is used, its pH value is 10, its kinematic viscosity is 50 at 40°C, and it is not more than 1 when corroding 45 steel for 24 hours. At room temperature, according to the ratio of 10% emulsified oil and 90% water, the emulsion is prepared, and the pH value of the emulsion is adjusted to 10 with anhydrous sodium carbonate, the average viscosity is 1.5cSt, and the lower critical Reynolds coefficient is less than 2320; Turn on the emulsion jet machine, control the jet pressure to 50MPa, the diffusion angle of the cavitation bubbles generated by the jet is 6°, the distance from the jet outlet of the nozzle to the surface to be processed is 30cm, and the hardness and fatigue life of the processed surface are significantly improved.

The emulsion jet machine is a hydraulic pump; the emulsified oil is a commercially available product.

Example 2: Surface modification of SiMn alloy steel. Translucent emulsified oil is used, its pH value is 8, its kinematic viscosity is 45 at 40°C, and it is not more than 1 when corroding 45 steel for 24 hours. At room temperature, the emulsified oil is 6%, and the ratio of water is 94%. Prepare the emulsion, use anhydrous sodium carbonate to adjust the pH value of the emulsion to 8, and the average viscosity is 1.1cSt. Turn on the emulsion jet machine and control the jet flow The pressure is 60MPa, the diffusion angle of the cavitation bubbles generated by the jet is 5°, and the distance from the jet outlet of the nozzle to the surface to be processed is 25cm, and the hardness and fatigue life of the processed surface are significantly improved. Others are the same as in Example 1.

Example 3: Surface modification of ordinary carbon steel. Translucent emulsified oil is used, its pH value is 7, its kinematic viscosity is 35 at 40°C, and it is not more than 1 when corroding 45 steel for 24 hours. At room temperature, the emulsified oil is 3%, water is 97% ratio, the emulsified liquid is prepared, the pH value of the emulsified liquid is adjusted to 7 with anhydrous sodium carbonate, and the average viscosity is 1.0cSt. Open the emulsified liquid jet machine, control The jet pressure is 20MPa, the diffusion angle of the cavitation bubbles generated by the jet is 25°, the distance from the jet outlet of the nozzle to the surface of the part to be processed is 15cm, the hardness of the processed surface is improved, and the rust layer is removed. Others are the same as in Example 1.

Embodiment 4: Modification of the bottom of the keyway of the steel part. Translucent emulsified oil is used, its pH value is 8, its kinematic viscosity is 45 at 40°C, and it is not more than 1 when corroding 45 steel for 24 hours. At room temperature, the ratio of emulsified oil to water is 5%, and the ratio of water to 95% is used to prepare an emulsion, and the pH value of the emulsion is adjusted to 9 with anhydrous sodium carbonate, and the average viscosity is 1.4cSt; open the emulsion jet Machine, control the jet pressure to 40MPa, the diffusion angle of the cavitation bubbles generated by the jet is 11°, the distance from the jet outlet of the nozzle to the surface to be processed is 25cm, and the hardness of the processed surface is significantly improved. Others are the same as in Example 1.

Claims (1)

1. metal surface modification method through emulsion jet, it is characterized in that: this metal surface modification method comprises that mainly preparation can produce the emulsion of effective cavitation bubble and jet effect; Part to be processed is immersed in the described emulsion, adjusts the distance of ejector nozzle, jet pressure and ejector nozzle and work metal, in emulsifiable solution medium jet processing is carried out in the metallic surface, specific embodiment is:

(1) adopt emulsion as producing the effusive medium, emulsion is the mixture of oil in water emulsion and water; The ratio that cooperates of oil in water emulsion and water under the room temperature, oil in water emulsion is 3%～10%, water is 97%～90%, adds the pH value that anhydrous sodium carbonate is regulated emulsion then, and the pH value of emulsion is controlled at 7-10, viscosity average 1.0～1.5cSt, lower critical Reynolds coefficient is less than 2320;

(2) part to be processed is immersed in the described emulsion, opens emulsion jet machine emulsion jet and produce the emulsion bubble flow by ejector nozzle, jet pressure is 20～60MPa, and the emulsion spread angle of jet is 25～5 °;

(3) mobile emulsion ejector nozzle makes jet perpendicular alignmnet part work surface, and the jet exit of ejector nozzle is 15～30cm to the distance of part work surface;

The outward appearance of described oil in water emulsion is transparent or semitransparent liquid, pH value 7-10, and kinematic viscosity is 35-50 in the time of 40 ℃, corrodes 45 steel 24h and is not more than 1; Described emulsion is that oil in water emulsion mixes back formation oil-in-water (O/W) type emulsion with water; Described and oil in water emulsion blended water is anhydrous sodium carbonate remollescent water; Use temperature after the described emulsion preparation is 2～30 ℃.