[0012] The present invention will be described in further detail below with reference to the accompanying drawings and in conjunction with the embodiments. However, the invention is not limited to the examples given.
[0013] Embodiment 1 of the present invention is to perform rolling nano-crystallization on the surface of the outer cylindrical surface of the 20 steel annular workpiece.
[0014] Original state: Annealed state Average grain size 26um Workpiece size Φ200×20×50 Treatment process and control conditions: Clean the surface of the workpiece—the pressure of the rolling chamber is 6.67×10 -2 Pa——Three rolling die processing, pre-rolling processing process: two rolling die are distributed with protrusions with a diameter of 2mm, and the depth of their pressing into the workpiece is 0.02mm, and the other rolling die is distributed with a diameter of 20mm The protrusion, which is pressed into the workpiece to a depth of 0.005mm, has a plastic deformation rate of 7 × 10 per second. 3 , the time to complete a plastic deformation of 1 square meter of machined surface is 13 seconds, and this process takes 45 seconds (the actual workpiece surface area is 0.0314m 2 , the full surface rolling time is 0.4 seconds) - rolling treatment process: two rolling dies with 2mm diameter protrusions are pressed into the workpiece and the depth is increased to 0.1mm, and another rolling with 20mm diameter protrusions is distributed The depth of molding into the workpiece is still 0.005mm, and the plastic deformation rate of rolling is 2 × 10 per second. 4 , the time to complete a plastic deformation of 1 square meter of machined surface is 1 second, and this process is processed for 210 seconds - the rolling die is separated from the workpiece - the rolling chamber is vented to the atmosphere - 10 seconds of fast cooling - shutdown - A nanocrystalline layer with an average grain size of 48 nm and a depth of 0.1 mm was obtained.
[0015] Embodiment 2 of the present invention is to perform rolling nano-crystallization on the surface of the outer cylindrical surface of the Tu2 pure copper annular workpiece.
[0016] Original state: annealed average grain size 42um workpiece size Φ200×20×50 Treatment process and control conditions: clean workpiece surface - rolling chamber pressure 1Pa - three rolling die treatment, pre-rolling treatment process: two of them There are protrusions with a diameter of 2mm distributed on one rolling die, and the depth of their pressing into the workpiece is 0.02mm, and the other rolling die is distributed with protrusions with a diameter of 20mm, which is pressed into the workpiece with a depth of 0.005mm. Plastic deformation rate is 7 x 10 per second 3 , the time to complete a plastic deformation of 1 square meter of machined surface is 13 seconds, and this process is pre-rolled for 20 seconds - rolling process: two rolling dies with 2mm diameter protrusions are pressed into the workpiece and the depth is increased to 0.1 mm, another rolling die with 20mm diameter protrusions is still pressed into the workpiece at a depth of 0.005mm, and the plastic deformation rate of rolling is 2 × 10 per second. 1 , the time to complete a plastic deformation for 1 square meter of machined surface is 1 second (the actual workpiece surface area is 0.0314m 2 , its full surface rolling plastic deformation time is 0.031 seconds), and this process is rolled for 180 seconds - the rolling die with 2mm diameter protrusions is separated from the workpiece, and the rolling mold with 20mm diameter protrusions is pressed into the workpiece The depth was changed to 0.002 mm, and the rolling treatment was performed for 3 seconds—stopped—to obtain a nanocrystalline layer with an average grain size of 53 nm and a depth of 0.11 mm.
[0017] Examples 1 and 2 show that the nanocrystalline layer on the surface of the metal workpiece can be obtained by applying the method of the present invention, and the rolling treatment time range of the workpiece to prepare the nanocrystalline layer is 10-10 5 second.
[0018] The specific time required for the preparation of the nanocrystalline layer by the protrusion rolling treatment on the surface of the metal material should be determined by experiments according to the required average grain size, combined with the workpiece to be processed and the process characteristics of the treatment. Generally, the average grain size of the metal surface to be treated, without any temperature control measures, naturally changes with the treatment process in three time periods: first, the grain size rapidly decreases to nanocrystalline, which is a non-equiaxed Then the average grain size of nanocrystals decreased steadily, and the grains were equiaxed; after reaching the minimum average grain size, the average grain size of nanocrystals continued to increase.
[0019] Embodiment 3 of the present invention is to perform rolling nickel alloying treatment on the surface of the outer cylindrical surface of the Tu2 pure copper annular workpiece.
[0020] Original state: annealed Tu2 pure copper nickel-plated outer cylindrical surface, nickel-plated layer thickness 10um, workpiece size Φ200×20×50
[0021] Treatment process and control conditions: clean the surface of the workpiece - the pressure of the rolling chamber is 1Pa - three rolling dies are processed, two rolling dies are distributed with protrusions with a diameter of 2 mm, and the other rolling mold is distributed with protrusions with a diameter of 20 mm. Body - pre-rolling treatment process: the plastic deformation rate of rolling is 1 × 10 per second 4 , the time to complete a plastic deformation of 1 square meter of machined surface is 4 seconds, the depth of the two rolling dies with 2mm diameter protrusions is 0.05mm, and the other rolling die with 20mm diameter protrusions is pressed into the workpiece depth It is 0.005mm, and the pre-rolling treatment is 30 seconds—rolling treatment process: the depth of the two rolling dies with 2mm diameter protrusions is increased to 0.1mm, and the depth of the other rolling die is still 0.005mm. The plastic deformation rate of rolling is 2×10 per second 4 , the time to complete a plastic deformation of a 1 square meter machined surface is 1 second (the actual workpiece treatment surface is 0.031 seconds for a rolling plastic deformation), and the rolling treatment is 250 seconds - a rolling die and a workpiece with a 2mm diameter protrusion After separation, the rolling die with 20mm diameter protrusions was pressed into the workpiece with a depth of 0.002mm, and the rolling treatment was performed for 3 seconds—the rolling chamber was vented to the atmosphere—stopped—to obtain a copper-nickel alloy layer with a significant change in cross-sectional color.
[0022] Example 4 of the present invention uses foreign phase Al 2 O 3 The surface of the outer cylindrical surface of the annular workpiece is rolled and alloyed by infiltrating DT3 pure iron.
[0023] Original state: the outer cylindrical surface is coated with Al 2 O 3 Granular Annealed Pure Iron Al 2 O 3 Particle size≤50nm Workpiece size Φ200×20×50
[0024]Treatment process and control conditions: Coated with Al 2 O 3 The outer cylindrical surface of the workpiece of the particles - the air pressure of the rolling chamber is 3 × 10 -2 Pa——Three rolling dies, two rolling dies are distributed with protrusions with a diameter of 2mm, and the other rolling mold is distributed with protrusions with a diameter of 20mm - pre-rolling process: the plastic deformation rate of rolling is 4×10 per second 2 , the time to complete a plastic deformation of 1 square meter of machined surface is 240 seconds, the depth of the two rolling dies distributed with 2mm diameter protrusions is 0.05mm, and the other rolling die with 20mm diameter protrusions is pressed into the workpiece depth It is 0.005mm, and the pre-rolling treatment is 2400 seconds—rolling treatment process: the depth of the two rolling dies with 2mm diameter protrusions is increased to 0.1mm, and the depth of the other rolling wheel is still 0.005mm. The plastic deformation rate of rolling is 2×10 per second 4 , the time to complete a plastic deformation on a 1 square meter machined surface is 1 second (the actual workpiece treatment surface is 0.031 seconds for a rolling plastic deformation), and the rolling treatment is 180 seconds - a rolling die and a workpiece with a 2mm diameter protrusion Detach, the rolling die with 20mm diameter protrusions is pressed into the workpiece and the depth is changed to 0.002mm, and the rolling treatment is performed for 10 seconds—the rolling chamber is vented to the atmosphere—stopped—the surface layer is dispersed and distributed nano-Al 2 O 3 alloy layer.
[0025] Examples 3 and 4 show that there is a specific substance required for self-alloying between the relatively moving rolling die and the surface of the workpiece, which can be a coating layer (such as nickel plating, coating Al 2 O 3 In the form of self-surface alloying components or foreign phases, they enter the workpiece surface layer during the rolling process of the present invention to form an alloying layer. The rolling treatment time range for preparing the alloyed layer on the workpiece surface is 5-10 5 second.
[0026] In the processing method of the present invention, one workpiece may correspond to one or more rolling dies, or one rolling die may correspond to one or more workpieces. In the former case, within the overall process conditions, the size of the protrusions between two or more rolling dies can be the same or different, and the depth of the protrusions pressing into the surface of the workpiece can be the same or different. The above rolling dies can be rolled at the same time, or can be rolled sequentially, or alternately rolled at the same time and sequentially.
[0027] In the treatment method of the present invention, the temperature of the surface of the metal workpiece is also an important parameter. It is determined by the time to complete a rolling plastic deformation of 1 square meter of machined surface, the rate of rolling plastic deformation, the rolling treatment time, additional heating conditions, and the cooling conditions of conduction and heat conduction. Although the low surface temperature can also achieve the purpose of forming the surface nanocrystalline layer and surface alloying by the protrusion rolling, in order to help reduce the cracking tendency of the metal material during rolling and make the existing crack forging welding and hot pressing welding. , usually choose a higher surface treatment temperature. In the method of rolling nanometer processing of protrusions on the surface of metal materials, the sharp growth of grains is the most important factor that restricts the use of higher rolling surface temperature. There are many factors that affect the temperature of rapid grain growth, including the type of metal material, the composition of the material, the time to complete the plastic deformation of 1 square meter of surface during the processing, the deformation rate of the rolling treatment, and the rolling process. The depth of pressing, the cooling ability of the treated surface after the end of rolling, etc., and it is difficult to accurately measure the surface temperature of the workpiece moving in a vacuum (such as room temperature to 700 ℃) in engineering, so the comprehensive process control is used to achieve indirect control of the workpiece surface temperature. Therefore, in order to prevent the final grain size from being uncontrollable due to the excessively high temperature, the temperature of the workpiece surface during the treatment process should be controlled below the temperature at which the metal grains grow rapidly.
[0028] In the method of self-alloying treatment of metal material surface by rolling, it is emphasized to maintain a high surface temperature because it is conducive to the smooth and rapid progress of the alloying process. Its high temperature limiting factor is mainly the undesired transformation of the self-alloyed skin or the service life of the roll-molded material.
