阅读说明：本技术 一种提高凸模寿命的激光强化和真空电弧复合处理方法 (Laser strengthening and vacuum arc composite treatment method for prolonging service life of male die ) 是由 *** 高峰 夏原 刘继红 周强 董玮 王晓秋 薛文涛 陈登鹤 马振海 于 2019-09-16 设计创作，主要内容包括：本发明公开了一种提高凸模寿命的激光强化和真空电弧复合处理方法,包括如下步骤：对氮化后的凸模表面进行激光强化处理,产生激光硬化层；对激光强化后的凸模进行真空电弧涂层的制备；本发明采用了激光相变硬化技术和多弧离子镀相结合的方式,在基材表面形成一种新的具有特殊力学性能的复合薄膜材料,以弥补基体所缺少的高性能；本发明可以在不破坏基体表面光洁度的同时,得到足够的激光相变硬化层深度；激光硬化层具有高度细化的组织,该特征将会对镀膜过程和膜组织及其性能发挥积极影响；同时又能保证复杂模具的精度要求,对提高凸模的使用寿命具有独特优势。(The invention discloses a laser strengthening and vacuum arc composite processing method for prolonging the service life of a male die, which comprises the following steps: carrying out laser strengthening treatment on the surface of the nitrided male die to generate a laser hardening layer; preparing a vacuum arc coating on the terrace die after laser strengthening; the invention adopts a mode of combining a laser phase change hardening technology and multi-arc ion plating to form a novel composite film material with special mechanical property on the surface of a base material so as to make up for the high performance lacked by a matrix; the invention can obtain enough depth of the laser phase change hardening layer without destroying the surface smoothness of the substrate; the laser hardening layer has a highly refined structure, and the characteristic can exert positive influence on the film coating process, the film structure and the performance of the film structure; meanwhile, the precision requirement of the complex die can be ensured, and the special advantage of prolonging the service life of the male die is achieved.)

1. A laser strengthening and vacuum arc composite processing method for prolonging the service life of a male die is characterized in that: the method comprises the following steps:

the method comprises the following steps: carrying out laser strengthening treatment on the surface of the nitrided male die to generate a laser hardening layer;

step two: and (4) preparing the vacuum arc coating on the terrace die after the laser strengthening.

2. The laser strengthening and vacuum arc composite processing method for prolonging the service life of the male die as claimed in claim 1, is characterized in that:

in the first step, the laser strengthening treatment of the nitrided surface of the male die comprises the following specific steps:

1.1 polishing and sand blasting the male die.

1.2, carrying out laser quenching hardening treatment on the surface of the male die by adopting an optical fiber coupling semiconductor laser with the maximum output power of 1000W, controlling the wavelength at 940nm and the scanning speed at 800 mm/min.

3. The laser strengthening and vacuum arc composite processing method for prolonging the service life of the male die as claimed in claim 1, is characterized in that:

the preparation of the vacuum arc coating on the laser-reinforced male die in the second step comprises the following specific steps:

2.1 sequentially carrying out cross grinding by using oilstones; grinding with sand paper, lightly coating grinding paste on the processed surface, cleaning in a pretreatment cleaning line, quickly drying, preheating, exhausting, and loading into a coating vacuum chamber;

2.2 starting heating in the vacuum chamber, the workpiece reaches 370 ℃ and 420 ℃, and the back bottom is vacuumized to less than 5.0 x 10^-3Keeping the temperature for 30-90 min after Pa; then introducing argon into the coating chamber, controlling the pressure to be 0.8-1.1 Pa, and applying-200 to-300V pulse bias on the workpiece; opening an ion source, adjusting the current to be 2.5-4A, performing bombardment cleaning on the surface of the substrate for 30-75 min by using argon plasma, and cleaning and activating the coated surface; then adjusting the pressure intensity to be 0.25-0.5 Pa, starting a Cr arc target, enabling the target current to be 60-75A, applying-850-950V pulse bias to the workpiece, and etching and activating the workpiece for 6-10 min by using Cr ions;

2.3 continuously introducing argon into the film coating chamber, adjusting the air pressure to be 0.7-1.0 Pa, applying-50-100V pulse bias on the workpiece, keeping the current of a Cr target arc at 60-75A, depositing a metal bonding layer Cr on the workpiece, and keeping the process for 2-5 min; closing argon and introducing nitrogen, keeping the air pressure and pulse bias in the original process, changing the Cr target arc flow to 85A, and depositing a transition layer CrN;

2.4 keeping the nitrogen pressure at 2.0-3.0 Pa, adjusting the pulse bias voltage to-100-50V, opening the AlCr alloy target, adjusting the arc current at 80-95A, and depositing for 45-75 min to obtain a functional layer AlCrN on the workpiece;

2.5 after the film coating is finished, introducing nitrogen for cooling, and opening the furnace to take the parts after the temperature in the furnace is reduced.

4. The laser strengthening and vacuum arc composite processing method for prolonging the service life of the male die as claimed in claim 3, characterized in that:

in the step 2.1, the oilstone is 240#320#400# and is subjected to cross grinding with 70-degree angle position balance; after the oilstone is primarily treated, grinding the oilstone by using abrasive paper in a crossed manner at an angle of 70 degrees in cooperation with a polished rod like oilstone operation, wherein the grinding times of the abrasive paper on one surface are about 10-15 times; after the sand paper is ground, lightly coating a layer of No. 5 grinding paste on the processed surface, and carrying out high-speed rotary grinding on the surface of the workpiece by using a polishing machine with a wool head until the processed surface has a mirror surface; polishing the substrate, cleaning in a pre-treatment cleaning line to remove oil stain, polishing wax and adsorbed particles on the surface of the substrate, quickly drying, preheating, exhausting, loading in a vacuum coating chamber, and vacuumizing to less than 5.0 × 10^-3Pa。

5. The laser strengthening and vacuum arc composite processing method for prolonging the service life of the male die as claimed in claim 3, characterized in that:

and 2.5, after the film coating in the step 2.5 is finished, introducing nitrogen gas, cooling for at least 90min, and opening the furnace to take the workpiece after the temperature in the furnace is reduced to 100 ℃.

Technical Field

The invention relates to the technical field of surface composite coatings after nitriding treatment of a gear male die of a gearbox, relates to a preparation process for combining metal surface laser strengthening and a vacuum arc composite coating, and particularly relates to a laser strengthening and vacuum arc composite treatment method for prolonging the service life of the male die.

Background

With the development of modern industry, more and more products need to be processed by molds, and the mold industry becomes the basis of industrial development. More than 80% of the failures of the die are caused by surface damage, and because the stress on the surface of the die is the most complex, most of the stress caused by factors such as the structure of parts, working conditions and the like is concentrated on the surface, so that the surface of the die is damaged early. Particularly, the working environment of a forging die is severe, the forging die bears thermal load and mechanical load in the forging process, and under the combined action of the thermal load and the mechanical load, the forging die is easy to form various damages, including abrasion, mechanical cracks, thermal cracks, plastic deformation and the like, which seriously affect the service life of the forging die. Therefore, thermal and mechanical loads are considered to be the most fundamental cause affecting the life of the forging dies.

At present, domestic forging dies are generally subjected to TD surface treatment or surface nitriding strengthening treatment. However, the TD surface treatment technique not only softens and eventually deforms and fails the mold base material due to the absorption of C atoms of the mold base material, but also causes a great environmental pollution due to the subsequent treatment problem of salt bath waste liquid.

The surface hardness of the matrix of the die after nitriding treatment is 950HV (about 67HRC), but the working requirement of the hot forging die is still difficult to meet, and the problems are difficult to realize through the integral heat treatment of the material or the die. The surface vacuum arc coating technology can greatly improve and enhance the surface properties of the die, such as hardness, wear resistance, friction resistance, oxidation resistance and the like. Vacuum arc coating technology has become an effective means for most molds to increase their life and efficiency.

However, the film on the surface of the hot forging die can be peeled off and cracked in the using process. The reason is that the film hardness is 3200HV, the body hardness after nitriding is 950HV, even if the film is harder and the surface lubricity is better, the film is a layer of film with very thin thickness on the body surface, if the supporting force on the die surface is insufficient, the film begins to crack and peel after a large force, and the wear-resistant and lubricating effects are not achieved.

Disclosure of Invention

In order to overcome the situation that the surface supporting force of a forging die is insufficient, a laser hardening technology is applied to the surface of the nitrided die and is combined with a multi-arc ion plating technology, after the laser hardening, the hardness of the surface of a die base body is improved by HV100-300 after relative nitriding treatment, the highest hardness exceeds HV1200, and meanwhile, a high-density dislocation type tissue structure is obtained after the laser hardening treatment of a nitriding layer, so that the nitriding layer has higher toughness. The visible laser hardening technology can improve the mechanical properties such as surface hardness, wear resistance, thermal stability, fatigue resistance, toughness and the like, and the multi-arc ion plating technology can improve the high-temperature oxidation resistance of the surface of the die and slow down and reduce the generation of thermal fatigue cracks. The two technologies supplement each other to make up for the shortage of materials, and the service life of the die is obviously prolonged.

The invention is realized by adopting the following technical scheme, which is described by combining the accompanying drawings as follows:

a laser strengthening and vacuum arc composite processing method for prolonging the service life of a male die is characterized in that: the method comprises the following steps:

the method comprises the following steps: carrying out laser strengthening treatment on the surface of the nitrided male die to generate a laser hardening layer;

step two: and (4) preparing the vacuum arc coating on the terrace die after the laser strengthening.

In the first step of the technical scheme, the laser strengthening treatment of the nitrided surface of the male die comprises the following specific steps:

1.1 polishing and sand blasting the male die.

1.2, carrying out laser quenching hardening treatment on the surface of the male die by adopting an optical fiber coupling semiconductor laser with the maximum output power of 1000W, controlling the wavelength at 940nm and the scanning speed at 800 mm/min.

The preparation of the vacuum arc coating on the laser-reinforced male die in the step two of the technical scheme comprises the following specific steps:

2.1 sequentially carrying out cross grinding by using oilstones; grinding with sand paper, lightly coating grinding paste on the processed surface, cleaning in a pretreatment cleaning line, quickly drying, preheating, exhausting, and loading into a coating vacuum chamber;

2.2 starting heating in the vacuum chamber, the workpiece reaches 370 ℃ and 420 ℃, and the back bottom is vacuumized to less than 5.0 x 10^-3Keeping the temperature for 30-90 min after Pa; then introducing argon into the coating chamber, controlling the pressure to be 0.8-1.1 Pa, and applying-200 to-300V pulse bias on the workpiece; opening an ion source, adjusting the current to be 2.5-4A, performing bombardment cleaning on the surface of the substrate for 30-75 min by using argon plasma, and cleaning and activating the coated surface; then adjusting the pressure intensity to be 0.25-0.5 Pa, starting a Cr arc target, enabling the target current to be 60-75A, applying-850-950V pulse bias to the workpiece, and etching and activating the workpiece for 6-10 min by using Cr ions;

2.3 continuously introducing argon into the film coating chamber, adjusting the air pressure to be 0.7-1.0 Pa, applying-50-100V pulse bias on the workpiece, keeping the current of a Cr target arc at 60-75A, depositing a metal bonding layer Cr on the workpiece, and keeping the process for 2-5 min; closing argon and introducing nitrogen, keeping the air pressure and pulse bias in the original process, changing the Cr target arc flow to 85A, and depositing a transition layer CrN;

2.4 keeping the nitrogen pressure at 2.0-3.0 Pa, adjusting the pulse bias voltage to-100-50V, opening the AlCr alloy target, adjusting the arc current at 80-95A, and depositing for 45-75 min to obtain a functional layer AlCrN on the workpiece;

2.5 after the film coating is finished, introducing nitrogen for cooling, and opening the furnace to take the parts after the temperature in the furnace is reduced.

In the step 2.1 of the technical scheme, the oilstone is 240#320#400# and is subjected to cross grinding with 70-degree angle position balance; after the oilstone is primarily treated, grinding the oilstone by using abrasive paper in a crossed manner at an angle of 70 degrees in cooperation with a polished rod like oilstone operation, wherein the grinding times of the abrasive paper on one surface are about 10-15 times; after the sand paper is ground, lightly coating a layer of No. 5 grinding paste on the processed surface, and carrying out high-speed rotary grinding on the surface of the workpiece by using a polishing machine with a wool head until the processed surface has a mirror surface; polishing the substrate, cleaning in a pre-treatment cleaning line to remove oil stain, polishing wax and adsorbed particles on the surface of the substrate, quickly drying, preheating, exhausting, loading in a vacuum coating chamber, and vacuumizing to less than 5.0 × 10^-3Pa。

According to the technical scheme, after the film coating in the step 2.5 is finished, nitrogen is introduced for cooling for at least 90min, and the workpiece is taken out after the temperature in the furnace is reduced to 100 ℃.

Compared with the prior art, the invention has the beneficial effects that:

the invention adopts a mode of combining a laser phase change hardening technology and multi-arc ion plating to form a novel composite film material with special mechanical property on the surface of a base material so as to make up for the high performance lacking in a matrix. By applying the technology, the sufficient depth of the laser phase change hardening layer can be obtained without damaging the surface smoothness of the substrate. The laser hardened layer has a highly refined structure, which will positively influence the coating process and the membrane structure and its performance. Meanwhile, the precision requirement of the complex die can be ensured, and the special advantage of prolonging the service life of the male die is achieved.

Drawings

The invention is further described with reference to the accompanying drawings in which:

FIG. 1 is a schematic structural diagram of a male die composite coating;

FIG. 2 is a schematic view of a male die with a laser and PVD composite coating deposited on the surface;

in the figure:

1. a laser hardening layer; 2. forging the die base body after laser strengthening; 3. a bonding layer Cr; 4. a transition layer CrN; 5. a functional layer AlCrN; 6. laser and PVD composite coatings; 7. and (3) a male die base body.

Detailed Description

The invention is described in detail below with reference to the attached drawing figures:

a laser strengthening and vacuum arc composite processing method for prolonging the service life of a male die comprises the following steps:

1. and carrying out laser strengthening treatment on the surface of the nitrided male die to generate a laser hardening layer.

1.1 polishing and sand blasting the male die.

1.2, carrying out laser quenching hardening treatment on the male die surface by adopting an optical fiber coupling semiconductor laser surface device with the maximum output power of 1000W, controlling the wavelength at 940nm and the scanning speed at 800 mm/min.

2. Referring to fig. 1 and 2, the laser-strengthened male die is subjected to vacuum arc coating preparation.

2.1 sequentially using oilstones 240#320#400# to perform cross grinding with 70-degree angular position balance; after the oilstone is primarily treated, grinding the oilstone by using abrasive paper in a crossed manner at an angle of 70 degrees in cooperation with a polished rod like oilstone operation, wherein the grinding times of the abrasive paper on one surface are about 10-15 times; after the sand paper is ground, a layer of grinding paste (No. 5) is lightly coated on the processed surface, and the processed surface is rotationally ground on the surface of a workpiece at a high speed by a polishing machine provided with a wool head until the processed surface has a mirror surface. Polishing the substrate, cleaning in a pre-treatment cleaning line to remove oil stain, polishing wax and adsorbed particles on the surface of the substrate, quickly drying, preheating, exhausting, loading in a vacuum coating chamber, and vacuumizing to less than 5.0 × 10^-3Pa。

2.2 starting heating in the vacuum chamber, the workpiece reaches 370 ℃ and 420 ℃, and the back bottom is vacuumized to less than 5.0 x 10^-3And keeping the temperature for 30-90 min after Pa. Then introducing argon into the coating chamber, controlling the pressure to be 0.8-1.1 Pa, and applying-200 to-300V pulse bias on the workpiece; and opening an ion source, adjusting the current to be 2.5-4A, performing bombardment cleaning on the surface of the substrate for 30-75 min by using argon plasma, and cleaning and activating the coated surface. And then adjusting the pressure intensity to be 0.25-0.5 Pa, starting a Cr arc target, enabling the target current to be 60-75A, applying-850-950V pulse bias to the workpiece, and etching and activating the workpiece by using Cr ions for 6-10 min.

2.3 continuously introducing argon into the film coating chamber, adjusting the air pressure to be 0.7-1.0 Pa, applying-50-100V pulse bias on the workpiece, keeping the current of a Cr target arc at 60-75A, depositing a metal bonding layer Cr on the workpiece, and keeping the process for 2-5 min; closing argon and introducing nitrogen, keeping the air pressure and pulse bias in the original process, changing the Cr target arc flow to 85A, and depositing a transition layer CrN;

2.4 keeping the nitrogen pressure at 2.0-3.0 Pa, adjusting the pulse bias voltage to-100-50V, opening the AlCr alloy target, adjusting the arc current at 80-95A, and depositing for 45-75 min to obtain a functional layer AlCrN on the workpiece.

2.5 after the film coating is finished, introducing nitrogen gas to cool for at least 90min, and opening the furnace to take the parts after the temperature in the furnace is reduced to 100 ℃.

The experimental demonstration shows that the coating has the binding force of 72-75N, the hardness of 35-38GPa and the oxidation resistance temperature of 850-.

The male die without composite treatment has oxidation wear and cracks after 5000 times of processing, and can not work continuously; and the terrace die adopting the laser-arc composite treatment has fine cracks after 20000 times of processing, but can be continuously used. According to the detection, the laser-arc composite treatment coating greatly increases the high-temperature-resistant hardness of the surface of the male die, slows down the high-temperature oxidation wear of the die and reduces the generation of thermal fatigue cracks of the die.