CN114774751B

CN114774751B - Laser cladding high red hardness powder and hot stamping die cladding method

Info

Publication number: CN114774751B
Application number: CN202111226918.4A
Authority: CN
Inventors: 孙福臻; 姜波; 李岩; 刘希豪
Original assignee: Yantai Branch Of Beijing Machine Science Guochuang Lightweight Research Institute Co ltd; Beijing National Innovation Institute of Lightweight Ltd
Current assignee: Yantai Branch Of Beijing Machine Science Guochuang Lightweight Research Institute Co ltd; Beijing National Innovation Institute of Lightweight Ltd
Priority date: 2021-10-21
Filing date: 2021-10-21
Publication date: 2023-05-09
Anticipated expiration: 2041-10-21
Also published as: CN114774751A

Abstract

The utility model relates to laser cladding high red hardness powder and a hot stamping die cladding method, wherein the laser cladding high red hardness powder comprises the following components in parts by weight: 30-35 parts of Fe, 20-25 parts of Ni, 25-30 parts of Co, 0.5-1.0 part of C, 11-15 parts of Cr, 0.7-1.0 part of Si, 0.2-0.4 part of Mn, 2.5-2.8 parts of Mo, 0.8-1.0 part of Al, 0.3-0.6 part of V, 1.5-2 parts of W, 1.5-2 parts of Ti, 0.5-1.00 parts of B and 0.5-1.5 parts of graphene. The laser cladding method for the hot stamping die is provided, and high red hardness powder is adopted to carry out laser cladding repair reinforcement on the hot stamping die. According to the laser cladding high red hardness powder and the hot stamping die cladding method, the laser cladding high red hardness powder repairing and strengthening are carried out on the H13 steel hot stamping die surface with failure of thermal fatigue wear, the die surface after repairing and strengthening is high in hardness and excellent in wear resistance at high temperature, the friction coefficient of the die surface at high temperature is smaller, and the defects that a sheet metal part is easy to wrinkle, fold and the like due to larger friction in the hot stamping process are avoided.

Description

Laser cladding high red hardness powder and hot stamping die cladding method

Technical Field

The utility model relates to laser cladding high red hardness powder and a hot stamping die cladding method, and belongs to the technical fields of powder materials and laser processing.

Background

The Laser Cladding technology (Laser Cladding) is an advanced manufacturing technology that adopts a high-energy Laser beam as a heat source to heat a material so as to enable the material to be fused and deposited on the surface of a micro-melting substrate, thereby realizing additive manufacturing (AM, additive Manufacturing). As an advanced additive manufacturing technology, the laser cladding plays a significant role in the aspects of size recovery, surface strengthening, repair and remanufacturing; in particular to the preparation of a functional layer on the surface of a workpiece in a strengthening way.

At present, in order to realize the fuel economy of automobiles, some important automobile sheet metal parts are increasingly formed by adopting ultrahigh-strength steel hot stamping, and an ultrahigh-strength steel hot stamping die is generally manufactured by adopting H13 hot working die steel. H13 hot stamping die hardness is HRC50-HRC52 after heat treatment, and in the use process, cooling water is introduced into the die to keep the whole die in a low-temperature state, and the surface repeatedly bears the hot stamping impact influence of high-temperature ultra-high strength steel plate materials with the temperature of more than 900 ℃, so that the die surface can be worn, particularly the edges such as round corners are worn seriously, and the die is scrapped to a certain extent.

In order to realize the reuse of the hot stamping die after the high-temperature wear failure, the utility model provides laser cladding high red hardness powder and a laser cladding method of the hot stamping die, so as to solve the problem of laser cladding repair reinforcement of the hot stamping die of the ultra-high strength steel after the high-temperature fatigue wear failure, realize the reuse of the hot stamping die and prolong the service life of the hot stamping die.

Disclosure of Invention

The utility model provides laser cladding powder with higher hardness at high temperature and a laser cladding method for repairing and strengthening the molded surface of a hot stamping die by using the high-red hard powder aiming at the condition that the existing hot stamping die for ultra-high-strength steel fails due to high-frequency thermal fatigue wear.

The technical scheme for solving the technical problems is as follows:

the laser cladding high red hardness powder comprises the following components in parts by weight: 25-35 parts of Fe, 20-30 parts of Ni, 25-35 parts of Co, 0.5-1.0 part of C, 8-15 parts of Cr, 0.7-1.5 parts of Si, 0.2-0.5 part of Mn, 2.3-2.8 parts of Mo, 0.8-1.5 parts of Al, 0.3-0.6 part of V, 1.5-3 parts of W, 1.5-3 parts of Ti and 0.5-1.5 parts of B.

Further, the laser cladding high red hardness powder comprises the following components in parts by weight: 30-35 parts of Fe, 20-25 parts of Ni, 25-30 parts of Co, 0.5-1.0 part of C, 11-15 parts of Cr, 0.7-1.0 part of Si, 0.2-0.4 part of Mn, 2.5-2.8 parts of Mo, 0.8-1.0 part of Al, 0.3-0.6 part of V, 1.5-2 parts of W, 1.5-2 parts of Ti, 0.5-1.00 parts of B and 0.5-1.5 parts of graphene.

Further, fe, ni, co, C, cr, si, mn, mo, al, V, W, ti and B components are prepared into FeNiCo alloy by adopting an air atomization or water atomization method; uniformly mixing graphene and FeNiCo alloy in a mechanical mixing, ultrasonic mixing or ball milling mode; preferably, the graphene and the FeNiCo alloy are uniformly mixed by a mechanical mixing or ultrasonic mixing mode.

Furthermore, the graphene is one or more of single-layer, double-layer or few-layer graphene oxide, preferably few-layer graphene oxide is selected, the few-layer graphene oxide is stable in chemical property at high temperature, is not easy to burn or decompose in the laser cladding process, and can keep the characteristics of high strength, high hardness and high toughness of the graphene.

Further, the granularity of the FeNiCo alloy is 100-300 meshes.

The laser cladding high red hardness powder provided by the utility model lays a foundation for the overall high red hardness of the material by adding Co and Ni elements into the powder; meanwhile, the addition of W and Ti forms TiC and WC hard particles, the hardness is higher at high temperature, and Mn, si, mo, cr can form MnSi phase and MoCr phase, the MnSi phase and the MoCr phase have stable structure at high temperature, and the red hardness of the powder can be greatly improved; the element V can refine grains, the graphene is dispersed in the cladding layer in the laser cladding process, the overall strength of the cladding layer can be increased, and the graphene has better stability at a high temperature, so that the method is very beneficial to keeping the hardness, strength and stability of the cladding layer at a high temperature.

On the basis of the technical scheme, the utility model also provides a laser cladding method for the hot stamping die, and the laser cladding high red hardness powder is adopted to carry out laser cladding repair reinforcement on the hot stamping die.

Further, a laser cladding method of a hot stamping die comprises the following steps:

s1, machining: machining the molded surface of the hot stamping die, removing the fatigue layer, and forming a laser cladding reference surface by machining;

s2, sand blasting texturing: the processed hot stamping die profile is subjected to sand blasting roughening, so that the roughness of the profile is increased, the absorption of laser by the profile is facilitated, the surface of the profile is subjected to compressive stress, and the generation of laser cladding cracks is avoided;

s3, cleaning: removing dust on the molded surface of the hot stamping die by using compressed air, and then wiping the molded surface of the hot stamping die with alcohol or acetone to remove greasy dirt;

s4, laser cladding: carrying out laser cladding on the molded surface of the hot stamping die by adopting a coaxial powder feeding mode, and simultaneously adopting a paraxial feeding mode to feed graphene oxide into a molten pool or on the surface of the molten pool formed in the process of laser cladding of the high red hard powder;

s5, repeating the step S4 until the size of the hot stamping molded surface meets the requirement of subsequent machining;

s6, processing the molded surface: and machining the laser cladding surface to meet the drawing requirement of the hot stamping die.

Further, in S2, sand blasting and texturing are performed by adopting one of iron sand, quartz sand or corundum sand, and the shape of the sand is spherical or spheroidic, and the grain size of the sand is 50-200 microns.

Further, the laser cladding process in S4 is as follows: laser power 1500W-2000W, coaxial powder feeding amount 5g/min-25g/min, laser scanning speed 5mm/s-20mm/s and lap joint rate 30-60%

The feeding amount of the graphene oxide in the paraxial feeding mode in the S4 is 0.01g/min-0.15g/min;

nitrogen is adopted as carrier gas for coaxial powder feeding and paraxial feeding and protective gas for laser cladding; nitrogen is used as carrier gas and shielding gas, and the nitrogen and B element in the powder can form BN, so that the high red hardness of the cladding layer is further improved.

Further, the thickness of a single-layer cladding layer formed by laser cladding in a coaxial powder feeding mode in the S4 is not more than 0.3mm, and the spot diameter of laser in laser cladding is 3mm or 4.2mm.

The utility model has the advantages that: 1. the high-red hard powder material takes Fe, ni and Co as main components, fe can lead the material to be well fused with steel matrixes (matrixes such as hot-work die steel and the like) in the laser cladding process, and the laser cladding layer is well combined with the matrixes; the Co and Ni elements lay a foundation for the overall high red hardness of the material; 2. w, ti, C, mn, si, mo, cr the powder can form TiC and WC hard particles, and MnSi phase and MoCr phase, the TiC and WC hard particles have higher hardness at high temperature, and the MnSi phase and the MoCr phase have stable structure at high temperature, so that the red hardness of the powder can be greatly improved; 3. the graphene oxide is added, and the graphene is dispersed in the cladding layer in the laser cladding process, so that the overall strength of the cladding layer can be improved, and the graphene has better stability at high temperature, so that the hardness, strength and stability of the cladding layer at high temperature are very beneficial to maintaining; 4. nitrogen is adopted in the laser cladding process, BN can be formed, and the high red hardness of the cladding layer is further improved; 5. in the laser cladding process, graphene oxide is additionally added to the surface of a molten pool in a paraxial feeding mode, the graphene oxide is deposited on the surface of the molten pool which is not solidified yet, and the graphene diffuses and permeates into the molten pool at high temperature, so that a wear-resistant layer is formed on the surface of a cladding layer, and the wear resistance of the cladding layer can be greatly improved.

According to the laser cladding high red hardness powder and the hot stamping die cladding method, the laser cladding high red hardness powder repairing and strengthening are carried out on the H13 steel hot stamping die surface with thermal fatigue wear failure, the die surface after repairing and strengthening is high in hardness and excellent in high-temperature performance, the wear resistance is excellent at high temperature, the friction coefficient of the die surface at high temperature is smaller, the hot stamping forming of an automobile sheet metal part is facilitated, and the defects that the sheet metal part is easy to wrinkle, fold and the like due to larger friction in the hot stamping process are avoided.

Drawings

FIG. 1 is a schematic diagram of a process route of a laser cladding method for cladding high red hardness powder and a hot stamping die;

FIG. 2 is a schematic diagram of a laser cladding process of a laser cladding high red hardness powder and a hot stamping die cladding method of the present utility model;

FIG. 3 is a graph showing the friction coefficient of example 2 of the laser cladding method for cladding high red hardness powder and hot stamping die of the present utility model.

The reference numerals are recorded as follows: 1-coaxial powder feeding laser cladding head 2-high red hardness powder beam, 3-laser beam, 4-hot stamping surface, 5-molten pool, 6-paraxial material feeding pipe and 7-graphene oxide.

Detailed Description

The principles and features of the present utility model are described below with reference to the drawings, the examples are illustrated for the purpose of illustrating the utility model and are not to be construed as limiting the scope of the utility model.

Example 1

The components with the following parts by weight are taken: 32 parts of Fe, 20 parts of Ni, 30 parts of Co, 0.6 part of C, 13 parts of Cr, 0.8 part of Si, 0.3 part of Mn, 2.6 parts of Mo, 0.9 part of Al, 0.4 part of V, 1.6 parts of W, 1.6 parts of Ti and 0.6 part of B are fully melted and mixed, feNiCo alloy with the grain size of 100-300 meshes is prepared by adopting gas atomization, and then 0.7 part of single-layer and double-layer graphene oxide is uniformly mixed with the prepared FeNiCo alloy by adopting a ball milling mode, so that a laser cladding high red hardness powder material is obtained.

The powder material obtained by mixing is adopted to carry out laser cladding reinforcement on a hot stamping H13 steel die with the abrasion loss of 1.0mm, and the repairing and reinforcing steps are as follows:

s1, machining: machining the molded surface of the hot stamping die to remove the fatigue layer, wherein the machining is performed to form a laser cladding reference surface, and the machining amount is 0.5mm;

s2, sand blasting texturing: adopting corundum sand with the grain diameter of 100 microns to carry out sand blasting roughening on the processed hot stamping die molded surface, increasing the roughness of the molded surface, facilitating the absorption of laser by the molded surface, generating compressive stress on the surface of the molded surface, and avoiding the generation of laser cladding cracks;

s4, laser cladding: carrying out laser cladding on the molded surface of the hot stamping die by adopting a coaxial powder feeding mode, and simultaneously adopting a paraxial feeding mode to feed graphene oxide into a molten pool or on the surface of the molten pool formed in the process of laser cladding of the high red hard powder; as shown in fig. 2, which is a schematic diagram of a laser cladding process, the high red hardness powder prepared above is conveyed by a coaxial powder conveying laser cladding head 1, a high red hardness powder beam 2 is melted and deposited on the surface of a hot stamping molded surface 4 under the irradiation of a laser beam 3 to form a molten pool 5, and meanwhile, graphene oxide 7 is conveyed to the molten pool through a paraxial conveying pipe 6 until cladding is completed to form a single-layer cladding layer;

the technological parameters adopted by the laser cladding are as follows: the spot diameter of the laser beam is 3mm, the laser power is 2000W, the coaxial powder feeding amount is 22g/min, the laser scanning speed is 8mm/s, the lap joint rate is 50%, and the feeding amount of the paraxial feeding pipe 6 for feeding the graphene oxide 7 to the molten pool is 0.08g/min;

nitrogen is adopted as carrier gas for coaxial powder feeding and paraxial feeding and protective gas for laser cladding;

s5, repeating the step S4 until the size of the hot stamping molded surface meets the requirement of subsequent machining, and forming 5 layers of laser cladding layers;

s6, processing the molded surface: machining the laser cladding surface to the drawing requirement of the hot stamping die

Example 2

The components with the following parts by weight are taken: 30 parts of Fe, 25 parts of Ni, 30 parts of Co, 0.8 part of C, 15 parts of Cr, 0.8 part of Si, 0.3 part of Mn, 2.6 parts of Mo, 0.9 part of Al, 0.4 part of V, 1.8 parts of W, 1.8 parts of Ti and 0.6 part of B are fully melted and mixed, feNiCo alloy with the particle size of 100-300 meshes is prepared by adopting gas atomization, and then 1.3 parts of single-layer and double-layer graphene oxide are mixed with the prepared FeNiCo alloy by adopting an ultrasonic mixing mode (ultrasonic mixing is that FeNiCo alloy powder and graphene are put into a container filled with absolute ethyl alcohol, the container is put into ultrasonic equipment for ultrasonic treatment, and the container is stirred in the ultrasonic process), so that the laser cladding high red hardness powder material is obtained.

the technological parameters adopted by the laser cladding are as follows: the spot diameter of the laser beam is 3mm, the laser power is 1600W, the coaxial powder feeding amount is 13g/min, the laser scanning speed is 10mm/s, the lap joint rate is 50%, and the feeding amount of the paraxial feeding pipe 6 for feeding the graphene oxide 7 to the molten pool is 0.12g/min;

Example 3

The components with the following parts by weight are taken: 35 parts of Fe, 25 parts of Ni, 25 parts of Co, 0.75 part of C, 13 parts of Cr, 0.6 part of Si, 0.3 part of Mn, 2.6 parts of Mo, 0.8 part of Al, 0.3 part of V, 1.6 parts of W, 1.6 parts of Ti and 0.6 part of B are fully melted and mixed, feNiCo alloy with the grain size of 100-300 meshes is prepared by adopting gas atomization, and then 1.0 part of single-layer and double-layer graphene oxide is mixed with the prepared FeNiCo alloy uniformly by adopting a mechanical mixing (V-type powder mixer) mode, so that the laser cladding high red hardness powder material is obtained.

the technological parameters adopted by the laser cladding are as follows: the spot diameter of the laser beam is 3mm, the laser power is 1500W, the coaxial powder feeding amount is 8g/min, the laser scanning speed is 10mm/s, the lap joint rate is 50%, and the feeding amount of the paraxial feeding pipe 6 for feeding the graphene oxide 7 to the molten pool is 0.08g/min; nitrogen is adopted as carrier gas for coaxial powder feeding and paraxial feeding and as protective gas for laser cladding.

In order to illustrate the beneficial effects of the present utility model, the laser cladding reinforced H13 steel hot stamping die and the H13 steel hot stamping die body of the embodiment of the present utility model were subjected to the following performance tests, and the test results are shown in table 1, table 2, table 3 and fig. 3, respectively.

TABLE 1 Vickers microhardness as a property of the matrix of the hot stamping die for H13 steel in accordance with the examples of the present utility model

Performance of	Example 1	Example 2	Example 3	H13 steel hot stamping die matrix
					Vickers hardness/HV	623-637	645-659	635-648	551-569

Note that: the Vickers hardness test load is 300g, the loading time is 15 seconds, the number of test points of each sample is 6, and the test temperature is room temperature.

The above results illustrate: the hardness of the rear surface of the high red hardness powder of the hot stamping die after laser cladding is increased by more than 70HV compared with the hardness of the H13 steel matrix before cladding at room temperature, and the hardness of the high red hardness powder provided by the utility model is higher than that of the hot stamping die at room temperature.

TABLE 2 high temperature hardness, performance of the inventive examples and H13 Steel Hot stamping die matrix

Performance of	Example 1	Example 2	Example 3	H13 steel hot stamping die matrix
					High temperature hardness/HV	571-587	592-607	583-596	434-451

Note that: the Vickers hardness test load was 5000g, the loading time was 15 seconds, the number of test points per sample was 6, and the test temperature was 600 ℃.

The above results illustrate: the hardness of the laser cladding layer is reduced to a small extent at a high temperature (600 ℃), the hardness at the high temperature can be kept above 570HV, the hardness of the die matrix is reduced to a large extent, the hardness can be reduced to 135HV at the highest, and the hardness at the high temperature is reduced to 434HV.

TABLE 3 high temperature wear of the performance of the inventive example and H13 steel hot stamping die matrix

Performance of	Example 1	Example 2	Example 3	H13 steel hot stamping die matrix
					Wear amount/mg	5.4mg	4.3mg	4.8mg	10.3mg

Note that: the high-temperature abrasion loss is tested by a high-temperature frictional abrasion tester and an analytical balance, the high-temperature frictional abrasion is tested by a test force of 50N, the test time is 15 minutes, the abrasion test temperature is 600 ℃, and the weight before and after abrasion is measured by using the analytical balance.

The above results illustrate: in a high temperature state (600 ℃), the abrasion loss of the laser cladding layer is between 4.3mg and 5.4mg, and the abrasion loss of the hot stamping die matrix is up to 10.3mg, namely the abrasion loss of the hot stamping die after the hot stamping die is subjected to laser cladding of high red hardness powder is only about 50% of the abrasion loss of the original die matrix, and the abrasion resistance is doubled.

Fig. 3 is a graph of the friction coefficient between the laser cladding layer and the mold matrix at a high temperature (600 ℃), in which the friction coefficient is increased with time to a dynamic balance state, fig. 3 illustrates that the friction coefficient of the laser cladding layer is maintained at about 0.15, and the friction coefficient of the matrix is between 0.35 and 0.4, and the friction coefficient of the cladding layer is greatly reduced, because graphene oxide is added to the surface of the cladding layer during the cladding process (step S5), the lubricity of the surface of the cladding layer is increased, and the friction coefficient is greatly reduced.

The foregoing description of the preferred embodiments of the utility model is not intended to limit the utility model to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the utility model are intended to be included within the scope of the utility model.

Claims

1. The laser cladding high red hardness powder is characterized by comprising the following components in parts by weight: 30-35 parts of Fe, 20-25 parts of Ni, 25-30 parts of Co, 0.5-1.0 part of C, 11-15 parts of Cr, 0.7-1.0 part of Si, 0.2-0.4 part of Mn, 2.5-2.8 parts of Mo, 0.8-1.0 part of Al, 0.3-0.6 part of V, 1.5-2 parts of W, 1.5-2 parts of Ti, 0.5-1.00 parts of B and 0.5-1.5 parts of graphene.

2. The laser cladding high red hardness powder according to claim 1, wherein Fe, ni, co, C, cr, si, mn, mo, al, V, W, ti and B components are prepared into FeNiCo alloy by adopting an air atomization or water atomization method; and uniformly mixing the graphene and the FeNiCo alloy in a mechanical mixing, ultrasonic mixing or ball milling mode.

3. The laser cladding high red hardness powder according to claim 2, wherein the graphene and the FeNiCo alloy are uniformly mixed by a mechanical or ultrasonic mixing mode.

4. The laser cladding high red hardness powder according to claim 1, wherein the graphene is one or a mixture of two of single-layer and double-layer graphene oxide.

5. The laser cladding high red hardness powder according to claim 2, wherein the particle size of the FeNiCo alloy is 100 mesh to 300 mesh.

6. A method for laser cladding a hot stamping die, which is characterized in that the laser cladding high red hardness powder in any one of claims 1-5 is adopted to carry out laser cladding repair reinforcement on the hot stamping die.

7. The method for laser cladding a hot stamping die according to claim 6, comprising the steps of:

8. The laser cladding method for hot stamping die according to claim 7, wherein the sand blasting texturing in S2 is one of iron sand, quartz sand or corundum sand, and has a spherical or spheroidic shape and a particle size of 50-200 μm.

9. The laser cladding method of the hot stamping die according to claim 7, wherein the laser cladding process in S4 is as follows: the laser power is 1500W-2000W, the coaxial powder feeding amount is 5g/min-25g/min, the laser scanning speed is 5mm/s-20mm/s, and the lap joint rate is 30% -60%;

nitrogen is adopted as carrier gas for coaxial powder feeding and paraxial feeding and as protective gas for laser cladding.

10. The laser cladding method of the hot stamping die according to claim 8, wherein the thickness of a single-layer cladding layer formed by laser cladding in a coaxial powder feeding mode in the step S4 is not more than 0.3mm, and the spot diameter of laser in laser cladding is 3mm or 4.2mm.