Process method for repairing hot work die steel based on multi-element composite alloy powder

Abstract

The present application relates to a process for repairing hot work die steel, and particularly relates to a process for repairing hot work die steel based on multi-element composite alloy powder. The process comprises the following steps: S1: pretreatment, turning the hot work die steel to be repaired to have no visible oxide layer; S2: configuring a control system to control the discharge amount of the multi-element composite alloy powder; the multi-element composite alloy powder comprises: Cr: 10-16%; Mo: 2-3.2%; V: 0.5-1.0%; C: 0.2-0.3%; Y2O3: 0.2-0.3%; Si: 0.3-0.6%; and the balance is Fe; the above multi-element composite alloy powder is mixed according to the proportion; S3: cladding, cladding the mixed multi-element composite alloy powder in S2 on the surface of the pretreated hot work die steel by means of laser cladding; S4: flaw detection; S5: finishing, turning the hot work die steel after cladding; and S6: marking and warehousing. The present application can improve the efficiency, save the cost, and achieve the effect of "one powder for multiple uses".

Description

TECHNICAL FIELD

[0001] The application relates to a hot work die steel repairing process method, in particular to a hot work die steel repairing process method based on a multi-element composite alloy powder. BACKGROUND

[0002] When the hot work die steel is damaged on the outer surface and appears a pull flower phenomenon, the hot work die steel needs to be repaired, so that high cost caused by re-manufacturing can be avoided and cost is reduced.

[0003] At present, when the hot work die steel is repaired, first, different powders need to be matched for repairing different types of steels in a cladding mode, the matching time is long, and the component matching process is complex: the base material needs to be analyzed, the proportion needs to be calculated, and the powder needs to be mixed every time a new steel type is repaired, and the matching period is long. Secondly, after being matched, in the cladding repairing process of the hot work die steel (hardness HRC 46-50) which has been subjected to vacuum quenching (heat treatment), although artificial observation and control can provide certain real-time feedback, due to the limitation of artificial observation, especially the influence of visual fatigue, the monitoring of product quality is not accurate enough. For example, in the cladding repairing process, the artificial observation may not discover problems such as a too wide molten pool, too high or too low temperature, poor combination of cladding powder and hot work die steel surface in time. These problems will directly affect the repairing quality, increase product defects, increase the number of rework, and thus reduce production efficiency.

[0004] Therefore, in view of the above technical problems and defects, the application provides a hot work die steel repairing process method based on a multi-element composite alloy powder, which can reduce cost, improve production efficiency, and make the surface hardness of the hot work die steel meet the use requirements. SUMMARY

[0005] The application aims at solving the problems in the prior art and provides a hot work die steel repairing process method based on a multi-element composite alloy powder.

[0006] In order to achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0007] A hot work die steel repairing process method based on a multi-element composite alloy powder, comprising the following steps:

[0008] S1: pretreatment, turning the hot work die steel to be repaired to no visible oxide layer;

[0009] S2: configuring a control system to control the discharging amount of the multi-element composite alloy powder, the multi-element composite alloy powder comprising:

[0010] Cr: 10-15%;

[0011] Mo: 2.1-2.6%;

[0012] V: 0.5-1.0%;

[0013] C: 0.21-0.3%;

[0014] Y2O3: 0.3-0.6%;

[0015] Si: 0.3-0.6%;

[0016] balance Fe;

[0017] The above powders are mixed according to the ratio;

[0018] S3: cladding, and a monitoring system is configured to monitor the cladding process;

[0019] The mixed multi-component composite alloy powder in S2 is cladded on the surface of the pretreated hot work die steel by laser cladding;

[0020] S4: flaw detection;

[0021] S5: finishing, turning the hot work die steel after cladding;

[0022] S6: labeling and warehousing.

[0023] Further, in S1, the hot work die steel includes round bar type, thick-walled pipe type and flat plate type.

[0024] Further, in S2, the control system includes a discharge control module, which controls the discharge amount of Cr, Mo, V, C, Y2O3, Si and Fe, and the Cr, Mo, V, C, Y2O3, Si and Fe are placed in the mixing and stirring tank according to the ratio and mechanically stirred.

[0025] Further, in S3, the cladding adopts a coaxial powder feeding method, the cladding laser power is 9000-11000W, the scanning speed is 5-15mm / s, the powder feeding speed is 20-100g / min, the spot size is 26*3mm, and the overlap rate is 15-20%.

[0026] Further, in the cladding process, a monitoring system is configured to monitor the cladding process, the monitoring system includes an acquisition module, a processing module and an adjustment module, the acquisition module includes a temperature acquisition module and a topography acquisition module, the processing module processes the temperature and image collected by the acquisition module, the adjustment module adjusts the power, scanning speed and powder feeding speed of the cladding equipment according to the signal of the processing module, and the monitoring system is signal connected with the control system.

[0027] Further, the discharge control module comprises a Cr material bin, a Mo material bin, a V material bin, a C material bin, a Y2O3 material bin and a Si material bin, and the Cr material bin, the Mo material bin, the V material bin, the C material bin, the Y2O3 material bin, the Si material bin and the Fe material bin are provided with conical outlets at the bottom, and the conical outlets are connected with the inlet of the mixing and stirring tank.

[0028] Further, the Cr material bin, the Mo material bin, the V material bin, the C material bin, the Y2O3 material bin, the Si material bin and the Fe material bin are respectively provided with a weight sensor and a vibrator.

[0029] Further, the temperature acquisition module is an infrared thermal imager, and the temperature of the molten pool is collected in real time, and the appearance acquisition module is a high-speed camera and an acoustic emission sensor.

[0030] Further, the adjustment formula of the scanning speed adjustment of the cladding equipment is:

[0031] ,

[0032] wherein, represents the adjusted speed;

[0033] represents the initial speed;

[0034] β represents a weight coefficient;

[0035] tanh is a hyperbolic tangent function;

[0036] represents the viscosity of the molten pool metal;

[0037] represents the Laplace operator of the flow rate of the molten pool surface;

[0038] ρ represents the density of the hot work die steel;

[0039] L(t) represents the real-time length of the molten pool.

[0040] Further, based on the temperature change collected by the acquisition module, the adjustment formula of the real-time powder feeding speed m(t) of the adjustment module is:

[0041] ,

[0042] wherein, m0 represents the reference powder feeding speed;

[0043] K p represents a proportional gain coefficient;

[0044] T set represents a target temperature;

[0045] T actualrepresents the actual temperature, that is, the temperature of the molten pool measured by the infrared thermal imager in real time;

[0046] K i represents the integral gain coefficient;

[0047] represents the integral term, that is, the cumulative value of the temperature deviation between the target temperature T set and the actual temperature T actual with time.

[0048] Compared with the prior art, the present application has the advantages that:

[0049] 1. Cost saving. In the cladding process, the molten pool width is controlled within ±0.1 mm, the porosity is ≤0.3%, and the cladding thickness is 1-1.5 mm. The hardness of the hot work die steel repaired by the cladding method is HRC 30-45, which meets the standard value of the hardness of the hot work die steel and meets the use requirements. Compared with the traditional "scraping and remanufacturing", the cladding repair process reduces the waste rate through material reuse, and saves the comprehensive cost by 30%-50%. In addition, the service life of the hot work die steel is also prolonged.

[0050] 2. Efficiency improvement. Through the monitoring system, the temperature and geometric appearance of the molten pool are collected in real time by the collection module, and the cladding equipment parameters such as laser power and scanning speed are adjusted by the adjustment module to avoid rework caused by quality problems of the remanufactured hot work die steel, thereby improving the production efficiency.

[0051] 3. The powders are placed in the hoppers respectively, and the appropriate proportion is weighed by the weight sensor, which can adapt to most hot work die steels and achieve the effect of "one powder for multiple uses". BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 is a process flowchart of the present application;

[0053] Figure 2 is a control system framework schematic diagram of the present application;

[0054] Figure 3 is an adjustment module framework diagram of the present application;

[0055] Figure 4 is a change diagram of the repaired workpiece of the present application. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0057] Embodiment 1, taking 5CrNiMo steel as an example, referring to Figure 1 Process flow chart, including the following steps:

[0058] S1: Pretreatment, turning the hot work die steel (5CrNiMo steel) to be repaired to no visible oxide layer;

[0059] S2: Configure a control system to control the discharge amount of the multi-element composite alloy powder, which includes:

[0060] Cr: 12-13%;

[0061] Mo: 2.3-2.9%;

[0062] V: 0.6-0.7%;

[0063] C: 0.21-0.26%;

[0064] Y2O3: 0.3-0.5%;

[0065] Si: 0.4-0.5%;

[0066] The balance is Fe;

[0067] Mix the above powders according to the proportion;

[0068] S3: Cladding, and configure a monitoring system to monitor the cladding process:

[0069] The mixed multi-element composite alloy powder in S2 is cladded on the surface of the pretreated hot work die steel by laser cladding;

[0070] S4: Inspection;

[0071] S5: Finishing, turning the cladding layer;

[0072] S6: Marking and warehousing.

[0073] The hot work die steel (5CrNiMo steel) after the pull flower in the above embodiment is repaired by cladding, so that the hardness of the repaired hot work die steel reaches HRC 54-57, meeting the use standard. The configured powder can realize "one powder for multiple uses", that is, the above powder can repair hot work die steels such as 5CrMn, 5CrNiMo, 3Cr2W8V, 8Cr3, 5Cr4MO3SiMnVAl, 3Cr3MO3W2V, 5Cr4W5Mo2V, 4CrMnSiMoV, 4Cr3Mo3SiV (H10), 4Cr5MoSiV (H11), 4Cr5MoSiV1 (H13) and 4Cr5W2VSi (W2) and the like, because these steels all contain the same chemical composition, the key elements in the multi-element composite alloy powder are fully covered, and they are suitable for different substrates. For example, when repairing low-Cr steel (such as 5CrNiMo, Cr ≈ 0.8%), the Cr content in the cladding layer is reduced to 5-8% due to substrate dilution, still meeting the corrosion resistance requirements; when repairing high-Cr steel (such as 8Cr3, Cr ≈ 3.5%), the Cr content in the cladding layer is close to that of the substrate, ensuring performance matching. Cr, Mo and V can replace or supplement functional elements such as W and Ni in different steel grades.

[0074] Add 0.3%-0.6% of Si, which preferentially reacts with oxygen to form SiO2, reducing CO porosity, low cost, suitable for large-scale application, add Y2O3 (yttrium oxide), which can adsorb residual oxygen, refine the grain, and form a composite oxide with SiO2, enhancing the effect of molten pool purification.

[0075] In S1, the types of repaired hot work die steels include round bar, thick-walled pipe and flat plate.

[0076] In S1, the pretreatment is processed by machine tool turning, and the hot work die steel (5CrNiMo steel) is clamped and turned on the machine tool to turn the outer surface of the hot work die steel pull flower damage to no visible oxide layer.

[0077] In S2, as shown in Figure 2 The control system includes a discharge control module, which controls the discharge amount of Cr, Mo, V, C, Y2O3, Si and Fe, and the Cr, Mo, V, C, Y2O3, Si and Fe are placed in the mixing and stirring tank in proportion and mechanically stirred. In this embodiment, the control system further includes a human-machine interface HMI and a PLC controller, the human-machine interface HMI is in communication connection with the PLC controller, the PLC controller is a prior art, a logic control program can be written, and the PLC controller is in signal connection with the discharge control module.

[0078] The discharge control module further comprises a Cr bin, a Mo bin, a V bin, a C bin, a Y2O3 bin, a Si bin and a Fe bin, the Cr bin, the Mo bin, the V bin, the C bin, the Y2O3 bin and the Si bin are provided with a conical outlet at the bottom, and the conical outlets are connected with the inlet of the mixing and stirring tank respectively. The Cr bin, the Mo bin, the V bin, the C bin, the Y2O3 bin, the Si bin and the Fe bin are respectively provided with a weight sensor and a vibrator.

[0079] In the powder processing flow, the Cr, Mo, V, C, Y2O3, Si and Fe solid powders are pretreated (such as drying and sieving) to ensure the uniformity of particle size and fluidity and reduce errors caused by powder caking or moisture absorption. The powders can be dried by a dryer, and the powder storage environment is dry, and the relative humidity is ≤60%. In this embodiment, the treated Cr, Mo, V, C, Y2O3, Si and Fe are respectively stored in the Cr bin, the Mo bin, the V bin, the C bin, the Y2O3 bin, the Si bin and the Fe bin. The discharge outlets of the bins are all conical outlets. The contact area between the conical wall and the powder is reduced, which can significantly reduce the friction between the powder and the bin wall and promote the smooth flow of the powder. The symmetrical structure of the conical outlet enables the powder to be evenly discharged along the central axis, avoids uneven discharge caused by flow deviation, improves the powder fluidity, reduces clogging and bridging, and improves the discharge uniformity and controllability.

[0080] The vibrator is installed at the bottom of each bin or the side wall near the discharge outlet and is fixed by bolts. Different vibration frequencies (20-60 Hz) and amplitudes (0.1-2 mm) are set according to the characteristics of the respective powders to ensure that the vibration energy of the vibrator directly acts on the powder accumulation area and prevents bridging or mouse hole phenomenon. The vibrator is signal connected with the PLC controller, and the PLC controller controls and adjusts the vibration parameters.

[0081] The weight sensor is connected with the PLC controller, and the PLC controller controls the discharge amount of various powders. When used, the weight parameter values of various powders are output on the human-machine interface HMI, the PLC controller reads the weight values of the sensor, and then adjusts the opening degree of the valve of each bin.

[0082] When various powders are placed in the stirring tank according to the proportioning, the mixed powders are stirred uniformly and connected to the discharge mechanism of the cladding equipment. Argon protection is adopted during cladding to reduce oxidation and other gas inclusions.

[0083] In the S3 cladding, the coaxial powder feeding mode is adopted, the cladding laser power is 9000-11000 W, the scanning speed is 5-15 mm / s, the powder feeding speed is 20-100 g / min, the spot size is 26*3 mm, and the overlap rate is 15-20%.

[0084] As shown in Figures 2-3 During the cladding process, a monitoring system is configured to monitor the cladding process, the monitoring system comprising a collection module, a processing module, and an adjustment module, the collection module comprising a temperature collection module and a topography collection module, the processing module processing the temperature and image collected by the collection module, the adjustment module adjusting the power, scanning speed, and powder feeding speed of the cladding equipment according to the signal of the processing module, and the monitoring system being signal-connected with a PLC controller. The PLC controller is built-in with a PID algorithm to form a self-adaptive closed-loop control.

[0085] In the present embodiment, the temperature collection module is an infrared thermal imager, and multiple infrared thermal imagers can be arranged to collect the temperature of the molten pool in real time and display the temperature on a human-machine interface (HMI) in real time. The infrared thermal imager is installed obliquely (at an installation angle of 30°-45°) to avoid laser reflection interference, and has a wavelength of 3-5 μm. The collected temperature value is transmitted to the processing module in the control system in real time.

[0086] The topography collection module comprises a high-speed camera and an acoustic emission sensor. The high-speed camera collects the geometric topography of the molten pool surface, has a resolution of 1024×1024 pixels, can ensure the clarity of the molten pool edge, has a frame rate of ≥10000 fps, and can capture the width, depth, and flow state of the molten pool. After the high-speed camera collects the geometric topography of the molten pool surface, the collected data are transmitted to the processing module, and the image gray scale, edge, shape, and other features are calculated to identify defects by relying on an image processing algorithm.

[0087] In the present embodiment, the image gray scale, edge, shape, and other features can be calculated by using an algorithm in the prior art. For example, the image gray scale can be converted into a gray scale image by using a weighted average method, and the image edge can be detected by using a Sobel operator or a Canny operator.

[0088] The acoustic emission sensor can collect signals of cracking or incomplete fusion of the cladding layer, has a frequency response of 50 kHz-1 MHz, and a sampling rate of 500 kS / s. The acoustic emission sensor is installed at a distance of 20-50 mm from the edge of the molten pool, is fixed on a waveguide rod by a bolt, and is integrated on a laser head to maintain long-term stability. The acoustic emission sensor collects the crack propagation, incomplete fusion state, or pore formation of the cladding layer, which will trigger an elastic wave. The elastic wave is converted into an electrical signal, and the characteristics of the electrical signal are directly related to the type of defect. For example, if the acoustic emission sensor detects crack propagation during the cladding process, the crack tip rapidly expands to trigger a high-frequency elastic wave, the signal characteristics are steep pulses, and the frequency energy is concentrated in 200-400 kHz. If incomplete fusion occurs, the cladding layer and the base material or the interlayer are not fully fused to form an interface defect, the signal characteristics are a slowly varying envelope in the time domain, and the main peak in the frequency domain is about 150 kHz with harmonic components. The acoustic emission sensor transmits the collected defects of the cladding layer to the processing module for processing.

[0089] The processing module processes the information collected by the collection module and transmits the information to the adjustment module, which adjusts the corresponding parameters of the cladding equipment according to the information. First, input parameters such as temperature parameter range, molten pool width parameter range, and laser power range in the processing module.

[0090] The collection module, the processing module, and the adjustment module exchange data through a communication protocol such as Modbus / TCP.

[0091] Based on the molten pool length collected by the collection module and processed by the processing module, the adjustment module adjusts the scanning speed adjustment formula of the cladding equipment as follows:

[0092]

[0093] wherein, represents the adjusted speed;

[0094] represents the initial speed;

[0095] β represents the weight coefficient;

[0096] tanh is the hyperbolic tangent function;

[0097] represents the molten pool metal viscosity;

[0098] Laplacian of the molten pool surface flow rate;

[0099] ρ represents the density of the hot work die steel;

[0100] L(t) represents the real-time length of the molten pool.

[0101] In some embodiments, such as when the molten pool temperature rises sharply, the scanning speed needs to be increased to avoid overburning; when the molten pool length L(t) exceeds the set value (1.2 mm-1.8 mm), the scanning speed needs to be increased to reduce energy accumulation; otherwise, the speed is reduced to enhance the penetration. When the acoustic emission sensor detects cracks, the scanning speed of the cladding equipment can be reduced.

[0102] Based on the PID algorithm control of the molten pool temperature feedback, the real-time powder feeding speed m(t) calculation formula is as follows:

[0103]

[0104] wherein, m0 represents the reference powder feeding speed;

[0105] K p represents the proportional gain coefficient;

[0106] T set represents the target temperature;​​

[0107] T actual represents the actual temperature, i.e. the temperature of the molten pool measured by the infrared thermal imager in real time;

[0108] K i represents the integral gain coefficient;

[0109] represents the integral term, i.e. the cumulative value of the temperature deviation between the target temperature T set and the actual temperature T actual over time.

[0110] According to the temperature deviation between the target temperature T set and the actual temperature T actual collected by the infrared thermal imager, the powder feeding speed of the cladding equipment can be adjusted in real time. If the adjustment module receives information from the processing module, for example, when the temperature is too high, the powder feeding speed can be increased to reduce heat consumption, and when the temperature is too low, the powder feeding speed can be reduced.

[0111] In some embodiments, the target temperature is T set = 1500℃, the reference powder feeding speed m0= 10g / min, the proportional gain coefficient K p = 0.1 (g / min) / ℃, the actual temperature T actual = 1450℃, the gain coefficient K i = 0.01, and the error duration t = 0.1 min,

[0112] Assuming that the temperature deviation remains constant within 10 seconds, the formula is substituted:

[0113] ,

[0114] The final powder feeding speed is calculated to be 4.95g / min, which is lower than the reference value of 10g / min, in line with the process logic of reducing the powder feeding speed to concentrate heat when the actual temperature is lower than the target temperature.

[0115] Through the control of the monitoring system, the entire cladding process can be effectively controlled, so that the hot work die steel after cladding reaches a usable state, meets the use standard, the porosity is greatly reduced to ≤0.3%, the cladding layer is free of cracks and un-melted state, the molten pool width fluctuates within ±0.1mm, and the interface bonding strength is 550-600MPa.

[0116] After the cladding is completed, a colored penetrant inspection agent is used. The colored penetrant inspection agent mainly uses capillary phenomenon to make the penetrant liquid penetrate into the defects. After cleaning with a cleaning agent, the surface penetrant liquid is removed, and the penetrant liquid remaining in the defects is adsorbed by the capillary action of the developing agent to achieve the purpose of inspecting the defects. After the inspection is completed, the cladding layer of the workpiece is turned, the turning thickness is 0.5-1mm, and the hardness after turning meets the use requirements. Then, the workpiece is marked and stored.

[0117] Example 2, different from example 1, the proportion of the multi-element composite alloy powder is different, including the following steps:

[0118] S1: pretreatment, turning the 5CrMnMo steel to be repaired to no visible oxide layer;

[0119] S2: configure a control system to control the discharge amount of the multi-element composite alloy powder; the multi-element composite alloy powder comprises:

[0120] Cr: 10-11%;

[0121] Mo: 2.1-2.3%;

[0122] V: 0.5-0.6%;

[0123] C: 0.19-0.2%;

[0124] Y2O3: 0.3-0.4%;

[0125] Si: 0.3-0.4%;

[0126] the balance is Fe;

[0127] mix the above powders according to the proportion;

[0128] S3: cladding, and configure a monitoring system to monitor the cladding process:

[0129] the mixed multi-element composite alloy powder in S2 is cladded on the surface of the pretreated hot work die steel by laser cladding;

[0130] S4: inspection;

[0131] S5: finishing, turning the hot work die steel after cladding;

[0132] S6: mark and store.

[0133] Example 3, different from example 1, the proportion of the multi-element composite alloy powder is different, including the following steps:

[0134] S1: pretreatment, turning the 5CrMnMo steel to be repaired to no visible oxide layer;

[0135] S2: configuring a control system to control the discharging amount of the multi-element composite alloy powder; the multi-element composite alloy powder comprises:

[0136] Cr: 14-15%;

[0137] Mo: 2.7-2.9%;

[0138] V: 0.7-1.0%;

[0139] C: 0.27-0.3%;

[0140] Y2O3: 0.26-0.3%;

[0141] Si: 0.51-0.6%;

[0142] the balance being Fe; the above powders are mixed according to the proportion;

[0143] S3: cladding, and configuring a monitoring system to monitor the cladding process:

[0144] the mixed multi-element composite alloy powder in S2 is cladded on the surface of the pretreated hot work die steel by laser cladding;

[0145] S4: flaw detection;

[0146] S5: finishing, turning the hot work die steel after cladding;

[0147] S6: marking and warehousing.

[0148] Comparative Example 1, which is different from Example 1 in that the proportion of the multi-element composite alloy powder is different, comprises the following steps:

[0149] S1: pretreatment, turning the 5CrMnMo steel to be repaired to no visible oxide layer;

[0150] S2: configuring a control system to control the discharging amount of the multi-element composite alloy powder; the multi-element composite alloy powder comprises:

[0151] Cr: 8-9%;

[0152] Mo: 1.0-2.0%;

[0153] V: 0.1-0.5%;

[0154] C: 0.01-0.2%;

[0155] Y2O3: 0.1-0.3%;

[0156] Si: 0.1-0.2%;

[0157] the balance being Fe;

[0158] Mix the above powders according to the ratio;

[0159] S3: cladding, and a monitoring system is configured to monitor the cladding process:

[0160] The mixed multi-element composite alloy powder in S2 is cladded on the surface of the pretreated hot work die steel by laser cladding;

[0161] S4: flaw detection;

[0162] S5: finishing, turning the cladded hot work die steel;

[0163] S6: labeling and warehousing.

[0164] Comparative Example 2, which is different from Comparative Example 1 in that the ratio of the multi-element composite alloy powder is different, comprises the following steps:

[0165] S1: pretreatment, turning the 5CrMnMo steel to be repaired to no visible oxide layer;

[0166] S2: a control system is configured to control the discharge amount of the multi-element composite alloy powder; the multi-element composite alloy powder comprises:

[0167] Cr: 16-17%;

[0168] Mo: 3.0-4.0%;

[0169] V: 1.0-2.0%;

[0170] C: 0.3-0.35%;

[0171] Y2O3: 0.3-0.4%;

[0172] Si: 0.61-0.75%;

[0173] the balance is Fe;

[0174] Mix the above powders according to the ratio;

[0175] S3: cladding, and a monitoring system is configured to monitor the cladding process:

[0176] The mixed multi-element composite alloy powder in S2 is cladded on the surface of the pretreated hot work die steel by laser cladding;

[0177] S4: flaw detection;

[0178] S5: finishing, turning the cladded hot work die steel;

[0179] S6: labeling and warehousing.

[0180] The above examples and comparative examples are tested for 650 hours in salt spray test, and the results are shown in the following table, content (%)

[0181] Experimental group Cr Mo V C [Y2O3] Si Fe Results Example 1 12-13 2.3-2.9 0.6-0.7 0.19-0.2 0.3-0.26 0.4-0.5 Residual Performance optimal Example 2 10-11 2.1-2.3 0.5-0.6 0.19-0.2 0.3-0.4 0.3-0.4 Residual Performance meets standards, low cost Example 3 14-15 2.7-2.9 0.7-1.0 0.27-0.3 0.26-0.3 0.51-0.6 Residual Performance meets standards Comparative Example 1 8-9 1.0-2.0 0.1-0.5 0.01-0.2 0.1-0.3 0.1-0.2 Residual Not resistant to corrosion Comparative Example 2 16-17 3.0-4.0 1.0-2.0 0.3-0.35 0.3-0.4 0.61-0.75 Residual Brittle failure

[0182] Examples 1, 2 and 3, according to the requirements of the workpiece to be cladded, the relevant example parameters can be selected on the human-machine interface HML, and the control system can control the corresponding example to discharge the corresponding powder content. Then, according to the requirements, the repair is carried out by mixing multi-element alloy powder in different proportions, for example, only the material or product needs to meet the pre-set minimum performance requirements, the parameters in example 3 can be selected for cladding, if the hardness, wear resistance, corrosion resistance and other indicators all need to reach the best performance, the parameters in example 1 can be selected for cladding, and if both low cost and performance standards are required, the cladding parameters in example 2 can be selected.

[0183] Comparative example 1, the test result is not corrosion resistant, the Cr content is lower than the corrosion resistant threshold (<10.5%), a continuous oxide film cannot be formed, the Mo and V alloying elements are insufficient, and the corrosion resistance and strength are further weakened. Comparative example 2, the test result is brittle failure, the C carbon content is too high, which promotes the precipitation of carbides and reduces the toughness.

[0184] The present application takes the upper die assembly of a forging die as an example to illustrate the principle of repairing the hot work die steel (H13) according to the present application: as shown in Figure 4As shown, the change diagram of the surface of the upper die assembly during the repair process is shown, the hardness of the pull flower surface of the upper die assembly is detected, the detection result is HRC47.4, the outer diameter of the upper die assembly before turning is Φ104mm, the upper die assembly is first pretreated, the upper die assembly is clamped on the lathe, the outer surface of the upper die assembly is turned to no visible oxide layer, the outer diameter size is turned to Φ103mm, and the hardness after turning is HRC47.4; the ratio of each powder is input through the man-machine interface, the opening of the Cr bin, Mo bin, V bin, C bin, Y2O3 bin, Si bin and Fe bin valve is controlled through the PLC controller, Cr, Mo, V, C, Y2O3, Si and Fe are placed in the stirring tank and stirred uniformly, and then transported into the laser cladding equipment, the mixed powder is cladded on the outer surface of the upper die assembly through the powder feeding mechanism. In the cladding process, the monitoring system monitors the geometry of the molten pool surface, if it does not match the set value, the adjustment module in the monitoring system adjusts the cladding equipment parameters in time to form self-adaptive adjustment, if it matches the set value, it continues to run according to the original parameters to ensure the stability of the molten pool state and reduce the generation of pores. After cladding is completed, the cladding layer thickness is 1.0mm-1.5mm, then the coloring penetration flaw detection agent is used for detection, the upper die assembly cladding layer is free of cracks and un-melted state, the porosity is ≤0.3%, the interface bonding strength between the upper die assembly and the cladding layer is 550-600MPa; then finish machining is carried out, the cladded upper die assembly is clamped on the lathe, the cladding layer is turned, the outer diameter of the upper die assembly is turned to Φ104mm, the hard layer reserved depth is ±0.6mm, the hardness after turning is HRC54-57, which meets the use standard. Finally, the parts are cleaned, marked and stored.

[0185] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A process for repairing hot work die steel including round bar type, thick wall pipe type and flat plate type based on a multi-component composite alloy powder, characterized in that, The method comprises the following steps: S1: preprocessing, turning the hot work die steel to be repaired to no visible oxide layer; S2: configuring a control system to control the discharge amount of the multi-element composite alloy powder, the multi-element composite alloy powder comprising: Cr：10-15%； Mo: 2.1-2.6%; V：0 .5-1 .0%； C：0 .21-0 .3%； Y2O3: 0.3-0.6%; Si: 0.3-0.6%; the balance being Fe; mixing the above powders according to the proportion; S3: cladding, and configuring a monitoring system to monitor the cladding process: the mixed multi-element composite alloy powder in S2 is cladded on the surface of the preprocessed hot work die steel by laser cladding; S4: flaw detection; S5: finishing, turning the cladded hot work die steel; S6: marking and warehousing.

2. A process for repairing hot work die steel based on multi-component composite alloy powder according to claim 1, characterized in that, In S2, the control system comprises a discharge control module, the discharge control module controls the discharge amount of Cr, Mo, V, C, Y2O3, Si and Fe, and the Cr, Mo, V, C, Y2O3, Si and Fe are placed in a mixing and stirring tank according to the proportion and mechanically stirred; the discharge control module comprises a Cr bin, a Mo bin, a V bin, a C bin, a Y2O3 bin and a Si bin, the bottom of the Cr bin, the Mo bin, the V bin, the C bin, the Y2O3 bin, the Fe bin and the Si bin is provided with a conical outlet, and the conical outlets are connected with the inlet of the mixing and stirring tank respectively; the Cr bin, the Mo bin, the V bin, the C bin, the Y2O3 bin, the Si bin and the Fe bin are respectively provided with a weight sensor and a vibrator.

3. The process for repairing hot work die steel based on multi-element composite alloy powder according to claim 1, characterized in that, In S3, the cladding method adopts a coaxial powder feeding method, the cladding laser power is 9000-11000W, the scanning speed is 5-15mm / s, the powder feeding speed is 20-100g / min, the spot size is 26*3mm, and the overlap rate is 15-20%.

4. The process for repairing hot work die steel based on multi-element composite alloy powder according to claim 1, characterized in that, The monitoring system in S3 comprises a collection module, a processing module and an adjustment module, the collection module comprises a temperature collection module and a topography collection module, the processing module processes the temperature and image collected by the collection module, the adjustment module adjusts the power, scanning speed and powder feeding speed of the cladding equipment according to the signal of the processing module, and the monitoring system is signal connected with the control system; the temperature collection module is an infrared thermal imager, which collects the temperature of the molten pool in real time, and the topography collection module is a high-speed camera and an acoustic emission sensor; the scanning speed adjustment formula of the adjustment module is: wherein, denotes the adjusted speed; denotes the initial velocity; β represents the weight coefficient; tanh is the hyperbolic tangent function; represents the bath metal viscosity; Laplace operator representing the surface flow velocity of the melt pool; ρ represents the density of the hot work die steel; L(t) represents the real-time length of the molten pool.

5. A process for repairing a workpiece based on a multi-component composite alloy powder according to claim 4, characterized in that Based on the temperature change collected by the collection module, the adjustment module adjusts the real-time powder feeding speed m(t) calculation formula: , Wherein, m0 represents the reference powder feeding speed; K p represents a proportional gain coefficient; T set represents the target temperature; T actual represents the actual temperature, i.e. the temperature of the molten bath as measured in real time by the infrared thermal camera; K i represents an integral gain coefficient; represents the integral term, i.e. the accumulated value of the temperature deviation between the target temperature T set and the actual temperature T actual over time.

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