A wear-resistant surfacing method for annular high-temperature resistant stainless steel and its application

Abstract

The present invention relates to a wear-resistant surfacing method for annular high-temperature-resistant stainless steel and its application, and relates to the field of welding technology. The wear-resistant surfacing method comprises the following steps: welding a weld layer onto a substrate using a welding material, repeating the welding steps until the number of weld layers is ≤3, thereby obtaining a surfacing layer; the welding process also comprises the following steps: preheating, continuous welding, obtaining a weld layer, and directly post-heat treating and polishing the weld layer; the preheating temperature is 250-400°C. This method performs layer-by-layer wear-resistant surfacing on a substrate through four steps: preheating, welding, post-heating, and polishing, ultimately resolving the cracking problem of the surfacing layer welded onto the annular high-temperature-resistant stainless steel material. Furthermore, the penetration test, chemical composition content at predetermined locations, and hardness of the surfacing layer all meet standards.

Description

Technical Field

[0001] The present invention relates to the technical field of welding, in particular to a wear-resistant surfacing method for annular high-temperature resistant stainless steel and an application thereof. Background Art

[0002] The commonly used surfacing method in the production process is continuous multi-layer surfacing, which generally uses a higher preheating temperature and continuously surfacing three layers. However, when the base material for surfacing is annular stainless steel material, this commonly used surfacing method will cause continuous accumulation of stress and the inability to release it. When the number of surfacing layers increases, cracks will appear on the surface of the surfacing layer, cracking along the axial direction, or even directly cracking to the base material.

[0003] At the same time, in conventional surfacing methods, the welding current and voltage used are relatively large, and the number of surfacing layers is large. Therefore, the welding material has a large dilution rate, which has an adverse effect on the composition and quality of the surfacing layer and is difficult to meet the standards. Summary of the Invention

[0004] In response to the above problems, the present invention provides a wear-resistant surfacing method for annular high-temperature resistant stainless steel. The method performs wear-resistant surfacing layer by layer on a substrate through four steps: preheating, welding, post-heating, and polishing, ultimately solving the cracking problem of the surfacing layer welded on the annular high-temperature resistant stainless steel material. The penetration test, chemical composition content at the predetermined position, and hardness value of the surfacing layer all meet the standards.

[0005] In order to achieve the above object, the present invention provides a wear-resistant surfacing method for annular high-temperature resistant stainless steel, comprising the following steps: welding a weld layer on a substrate using a welding material, repeating the welding steps until the number of weld layers is ≤ 3 layers, thereby obtaining a surfacing layer;

[0006] The welding comprises the following steps: preheating, continuous welding, obtaining a weld layer, directly post-heat treating the weld layer, and grinding;

[0007] The preheating temperature is 250-400°C.

[0008] In the prior art, in order to avoid the rapid cooling of the preheating temperature during welding, a rapid continuous surfacing method is usually adopted to perform surfacing on the substrate. After welding is completed, the substrate is immediately put into the furnace for aging heat treatment, so that the hardness of the surfacing layer is ≥370HBW. However, the inventors found in their research that if the above method is used to perform surfacing on the substrate of annular high-temperature resistant stainless steel, the constraint stress ratio of the substrate in the circumferential direction and the axial direction will reach 2:1. The constraint stress of the annular substrate is relatively large. In addition, the welding material has the characteristics of high-temperature hardness, poor toughness, and a large tendency to cold cracking, which makes it very easy to produce cracks during the welding process, resulting in unqualified weld quality and a high possibility of cracking along the axial direction during the final welding process. Therefore, the inventors use the above-mentioned wear-resistant surfacing method to perform layer-by-layer wear-resistant surfacing on the substrate, which can solve the cracking problem of the surfacing layer welded on the annular high-temperature resistant stainless steel material, and the penetration test, chemical composition content at the predetermined position, and hardness value of the surfacing layer all meet the standards. The use of the above-mentioned low preheating temperature can reduce the dilution rate, which is conducive to ensuring the chemical composition requirements of the surfacing layer. Furthermore, the resulting weld layer, instead of undergoing aging heat treatment as in traditional processes, undergoes direct post-heat treatment. This utilizes the tempering effect between weld layers to appropriately reduce the surface hardness of the previous weld layer, thereby achieving a hardness value that meets the standard at a thickness of 4mm. This wear-resistant hardfacing method solves the problem of axial cracking on annular substrates when using traditional full-circle hardfacing techniques, and ensures that the chemical composition and hardness of the hardfacing layer at predetermined locations meet standard requirements.

[0009] In one embodiment, the continuous welding has a welding current of 100-130 A, a welding voltage of 22-28 V, a welding speed of 15-25 cm / min, and an overlap between welds of 50-60%.

[0010] The use of the above-mentioned lower welding current and relatively high overlap amount is conducive to ensuring the thickness of the cladding layer. By controlling the welding current and overlap amount, the thickness of a single layer of weld can be approximately 1-3mm. When the number of weld layers is 3, the thickness of the cladding layer can be guaranteed to reach 6-7mm. At the same time, the lower welding current and relatively fast welding speed are conducive to reducing the welding stress of the cladding layer.

[0011] In one embodiment, the temperature of the post-heat treatment is 250-400° C., and the holding time of the post-heat treatment is ≥4 h.

[0012] In conventional processes, the overlay layer obtained after continuous overlay welding is immediately placed in a furnace for aging heat treatment at a holding temperature of 600-850°C for 4-8 hours to improve the microstructure and properties of the overlay layer. However, the hardness of the overlay layer is ≥370 HBW, which is difficult to meet the required hardness of 270-390 HBW at the predetermined location. This has a negative impact on the stainless steel substrate and increases production costs. Therefore, the inventors eliminated the post-weld aging heat treatment step and subjected the weld layer preparation to a post-heat treatment. Through the post-heat treatment at the aforementioned temperature, the tempering effect between weld layers is utilized to appropriately reduce the surface hardness of the previous weld layer, bringing the hardness at the predetermined location to the standard.

[0013] In one embodiment, the thickness of the welding layer is 1-3 mm.

[0014] In one embodiment, the number of the welding layers is 3, and the thickness of the surfacing layer is 6-7 mm;

[0015] The predetermined position of the overlay layer has a C content of 0.10-0.18%, a Mn content of 1.00-2.00%, a Si content of 3.80-5.00%, a Cr content of 14.00-20.00%, a Ni content of 8.00-11.00%, a Mo content of 4.00-6.50%, a Nb content of 0.50-1.20%, a S content of ≤0.006%, a P content of ≤0.02%, a Co content of ≤0.05%, a B content of ≤0.0015%, an As content of ≤0.01%, a Sb content of ≤0.01%, a Bi content of ≤0.01%, a Pb content of ≤0.01%, a Sn content of ≤0.01%, an O content of ≤0.05%, and a H content of ≤0.0005%;

[0016] The hardness value of the predetermined position of the surfacing layer is 270-390 HBW.

[0017] The surfacing layer obtained by the above-mentioned wear-resistant surfacing method can ensure that the thickness of the surfacing layer is 6-7 mm, and at the same time can meet the standards of chemical composition content and hardness value at the above-mentioned predetermined position.

[0018] In one embodiment, the predetermined position is where the thickness of the surfacing layer is 4 mm.

[0019] In one embodiment, the welding further includes a flaw detection step after the grinding step, and the substrate is an annular high-temperature resistant stainless steel material.

[0020] In one embodiment, the preheating method is electric heating, and the post-heat treatment method is electric heating.

[0021] Conventional preheating and post-heat treatments use natural gas heating. However, due to the generally harsh welding operating environment and the need for uniform welding temperature for annular substrates, conventional gas heating can negatively impact the overall temperature uniformity of the substrate, leading to uneven temperatures in the desoldering layer, which in turn can cause fine cracks and PT readings. Therefore, the aforementioned electric heating method is used to mitigate the uneven temperature gradients that can occur during preheating and post-heat treatments, reducing thermal stress.

[0022] In one embodiment, the electric heating includes: fixing a heater inside or outside the substrate to rotate the substrate around an axis.

[0023] In one embodiment, the electric heating further includes the following steps: fixing a heater inside or outside the substrate, causing the substrate to rotate about an axis, using the heater to increase the temperature of the substrate, and measuring the temperature of the substrate until the temperature of the substrate meets the requirements; the measurement includes: dividing the substrate into 8 temperature measurement areas along the circumferential direction, and measuring the temperatures of the temperature measurement areas; the temperature of the substrate meeting the requirements includes: the difference between the temperature of the temperature measurement area and the temperature of the preheating or post-heat treatment is ≤40°C.

[0024] The present invention also provides an intermediate heat exchanger prepared by the wear-resistant surfacing method.

[0025] In one embodiment, the raw material of the substrate is high temperature resistant austenitic stainless steel 316H, and the welding material is EDCrNi-B-15.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a wear-resistant surfacing method for annular high-temperature resistant stainless steel and its application. The wear-resistant surfacing method performs wear-resistant surfacing layer by layer on a substrate through four steps of preheating, welding, post-heating, and polishing, ultimately solving the cracking problem of the surfacing layer welded on the annular high-temperature resistant stainless steel material. In addition, the penetration test, chemical composition content at a predetermined position, and hardness value of the surfacing layer all meet the standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of welding requirements for the surface of the annular forging in Example 1;

[0029] Figure 2 Schematic diagram of the surfacing layer in Example 1;

[0030] Figure 3 This is a schematic diagram of the process stages of (4) arranging the surfacing welding station and (5) preheating in Example 1;

[0031] Figure 4Schematic diagram of the process stages of layer-by-layer wear-resistant surfacing welding in Example 1;

[0032] Figure 5 This is a schematic diagram of the surfacing layer of the three-layer weld layer completed in Example 1;

[0033] Figure 6 Schematic diagram of the process stages of grinding and penetrant testing the weld overlay layer in Example 1;

[0034] Among them, 1 is the base material, 2 is the surfacing layer;

[0035] Figure 7 This is a diagram showing the nondestructive testing results of the cladding layer of comparative example 1 in experimental example 1;

[0036] Figure 8 This is the non-destructive testing result diagram of the weld overlay layer of Example 1 in Experimental Example 1. DETAILED DESCRIPTION

[0037] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0039] definition:

[0040] Post-weld heat treatment (PWHT) is a welding heat treatment process in which the weldment is heated to a certain temperature, held at that temperature for a certain period of time, and then slowly cooled to improve the metallographic structure and properties of the weld joint or eliminate residual stress. PWHT generally involves three steps: heating, holding, and cooling, which are interconnected and cannot be interrupted.

[0041] PT (Penetrant Testing): Also known as penetrant testing, it involves applying a penetrant, removing excess with a detergent, and, if necessary, applying a developer to obtain an indication of certain surface defects on a part.

[0042] Weld layer: Each layer in multi-layer welding. Each weld layer can be composed of one weld bead or several weld beads overlapping side by side.

[0043] Weld bead: A single weld formed each time metal is deposited during welding.

[0044] Weld overlay: refers to the metal cladding used to protect the surface of the component from corrosion or other damage.

[0045] Intermediate heat exchanger: refers to one of the key equipment of high-temperature gas-cooled reactors that carry out indirect gas turbine cycle or high-temperature process heat utilization.

[0046] Unless otherwise specified, the reagents, materials, and equipment used in this example are all commercially available; and the experimental methods, unless otherwise specified, are all conventional experimental methods in the art.

[0047] Example 1

[0048] 1. Preliminary research

[0049] In the process of preparing the intermediate heat exchanger, a ring-shaped high-temperature resistant austenitic stainless steel 316H forging is used as the base material, and then the surface of the ring forging needs to be subjected to a full circle of wear-resistant surfacing welding. The welding material is EDCrNi-B-15, and the specification is Ф4.0. The welding requirements for the surface of the ring forging are as follows: Figure 1 As shown, Figure 2 Schematic diagram of the weld overlay layer.

[0050] Because the intermediate heat exchanger is placed in a vertical position in the cold pool, and the cladding layer is mainly located in the central tube assembly and piping assembly of the intermediate heat exchanger, it serves as a thermal expansion fulcrum between equipment components to improve the equipment's vibration resistance. Therefore, the wear resistance of the cladding layer is crucial to the stability of the equipment.

[0051] The welding material EDCrNi-B-15 is a stainless steel electrode for high-temperature wear-resistant surfacing. The microstructure after welding is austenite and a small amount of ferrite, accompanied by the precipitation of alloy strengthening phase. It is mainly used for high-temperature and high-pressure valve surfacing. The conventional surfacing method is to use a high preheating temperature (preheating temperature ≥400℃) for surfacing. At the same time, in order to avoid the preheating temperature cooling too quickly during the welding process, a rapid continuous surfacing method is usually adopted. After welding is completed, it is immediately put into the furnace for aging heat treatment. The hardness of the final surfacing layer is usually ≥370HBW.

[0052] However, the welding material EDCrNi-B-15 also has the characteristics of high-temperature hardness, poor toughness, and a high tendency to cold cracking. Therefore, cracks are very likely to occur during the welding process, resulting in unsatisfactory weld quality. Furthermore, the substrate is a ring-shaped high-temperature austenitic stainless steel 316H. If the above-mentioned conventional cladding method is used, the axial stress to circumferential stress ratio of the substrate is approximately 2:1, resulting in a large restraining stress in the ring-shaped substrate. The stress accumulates continuously and cannot be released. As the number of weld layers increases, cracks will appear on the surface of the cladding layer. It is very likely that cracks will occur in the axial direction during welding and directly crack into the substrate.

[0053] Furthermore, the conventional cladding methods mentioned above use high welding currents and voltages, resulting in a large number of weld layers. This results in a significant dilution rate for the welding material, adversely affecting the composition and quality of the cladding layer. Using conventional cladding methods, it is difficult to achieve the chemical composition and hardness values that meet the assessment requirements at a 4mm thickness.

[0054] In this embodiment, the assessment indicators when the thickness of the cladding layer is 4 mm are as follows:

[0055] C content is 0.10-0.18%, Mn content is 1.00-2.00%, Si content is 3.80-5.00%, Cr content is 14.00-20.00%, Ni content is 8.00-11.00%, Mo content is 4.00-6.50%, Nb content is 0.50-1.20%, S content is ≤0.006%, P content is ≤0.02%, Co content is ≤0.05%, B content is ≤0.0015%, As content is ≤0.01%, Sb content is ≤0.01%, Bi content is ≤0.01%, Pb content is ≤0.01%, Sn is ≤0.01%, O content is ≤0.05%, H content is ≤0.0005%;

[0056] The hardness value is Brinell hardness 270-390HBW.

[0057] The hardness of the surfacing layer obtained by conventional surfacing methods is usually ≥370HBW. Therefore, in order to better meet the assessment index requirements, the hardness needs to be appropriately reduced.

[0058] 2. A wear-resistant surfacing method for annular high-temperature resistant stainless steel.

[0059] 1. Based on the above reasons, when the inventors perform surfacing welding on the annular substrate of this embodiment, they adopt the method of preheating layer by layer, continuous welding, post-heat treatment, grinding, and flaw detection to perform wear-resistant surfacing welding. The welding process of each layer is not allowed to be interrupted, which breaks the conventional surfacing process that uses a relatively high preheating temperature and continuously surfacing three layers to prevent cracks. In the process of performing wear-resistant surfacing welding layer by layer, the inventors use a relatively low preheating temperature. After each layer of continuous welding is completed, the obtained weld layer is directly post-heat treated, and then slowly cooled to room temperature, ground, and passed the PT test before the next layer of wear-resistant surfacing is performed and preheating is started. This is repeated until the number of weld layers reaches 3. The specific operation method is as follows:

[0060] (1) Clean the surface of the substrate to be welded. In this embodiment, the substrate is an annular high-temperature resistant austenitic stainless steel 316H forging.

[0061] (2) Visually inspect the substrate surface.

[0062] (3) Perform penetrant testing on the substrate surface.

[0063] (4) Arrange the surfacing station: install the base material on the positioner, install the electric heater inside or outside the annular base material, and when heating, drive the base material to rotate along the axis through the positioner, while the electric heater remains fixed.

[0064] (5) Preheating: The substrate is heated using an electric heater and rotated along the axis of the substrate by a positioner. During this process, the electric heater remains fixed and heated, and then the substrate temperature is measured. The preheating temperature is 250-400°C. The temperature measurement method is: the annular substrate is divided into 8 temperature measurement areas along the circumference for temperature measurement. When the temperature difference between each temperature measurement area and the preheating temperature is ≤40°C, it is judged that the preheating temperature has been reached.

[0065] This electric heating method achieves uniform temperature throughout the substrate, leaving the surface to be welded exposed during welding. Furthermore, using electric heating throughout the substrate reduces uneven temperature gradients that can occur during preheating, reduces thermal stress, and avoids cracking in the weld overlay caused by large temperature differences in the substrate due to uneven heating temperatures. It also prevents the influence of the heated atmosphere on the weld pool, improving the welder's operating environment and enhancing weld quality.

[0066] (6) Welding: The welding current is 100-130A, the welding voltage is 22-28V, the welding speed is 15-25cm / min, and the overlap between welds is 50-60%. The welding process of a single layer must be completed continuously, which is called continuous welding.

[0067] If the preheating temperature is too high or the welding current is too large, the dilution rate of the stainless steel base material will increase, the weld width will be too wide, the weld thickness will be too thin, and the chemical composition of the weld overlay will be diluted;

[0068] If the overlap is too small and the welding current is too high, the weld thickness will be insufficient and will not meet the final thickness processing requirements of the cladding layer after welding three layers;

[0069] Slow welding speed will lead to excessive welding stress in the cladding layer, which may easily cause cracking of the cladding layer;

[0070] The use of the above welding parameters can ensure that the welding material can be effectively melted, while obtaining a suitable dilution rate and a suitable thickness of the cladding layer. The probability of welding defects and welding cracks is greatly reduced, and the thickness, chemical composition content and welding quality of the cladding layer are guaranteed.

[0071] At the same time, because continuous operation is required during the welding process of each layer, preheating and welding after post-heat treatment are not allowed, which reduces the temperature gradient of the base material and the deposited metal, reduces the number of thermal cycles during the continuous welding process of each layer, and reduces welding stress and thermal stress.

[0072] (7) Post-heat treatment: The weld layer obtained after welding is immediately subjected to post-heat treatment. The heating and temperature measurement methods for post-heat treatment are the same as those for the preheating step in this embodiment. The post-heat treatment temperature is 250-400°C, and the minimum holding temperature is 4 hours. After the heat preservation step in the post-heat treatment step is completed, the substrate is slowly cooled to room temperature by gradually reducing the power.

[0073] After the welding step, the aging heat treatment process in the conventional cladding method is cancelled. Instead, the weld layer obtained after welding is immediately subjected to polarity post-heat treatment, and the tempering effect between weld layers is used to appropriately reduce the surface hardness, welding residual stress and thermal stress of the previous weld layer.

[0074] At the same time, the above-mentioned post-heat treatment step can further reduce the temperature gradient between the substrate and the deposited metal, reduce the thermal stress of the substrate and the welding residual stress, and reduce the risk of cracks in the workpiece, thereby ensuring that the hardness of the workpiece meets the technical requirements and the quality of the weld is guaranteed without adopting post-weld aging heat treatment measures.

[0075] (8) Grind the weld layer.

[0076] After each layer of welding and post-heat treatment is completed, grinding is carried out to promptly release and eliminate the welding stress of the weld layer and reduce the risk of cracks in the workpiece.

[0077] (9) Perform a visual inspection of the solder layer.

[0078] (10) Check the dimensions of the weld layer.

[0079] (11) Perform penetrant testing on the weld layer.

[0080] Repeat the above steps (5)-(11) until the number of weld layers is 3, to obtain a surfacing layer with a thickness of 6-7 mm.

[0081] By using this layer-by-layer welding and polishing method, the welding stress of each layer is promptly released, reducing the probability of weld defects such as cracks and PT indications in the cladding layer, and improving the welding quality of the cladding layer. At the same time, tempering between weld layers is used to reduce the hardness of the cladding layer, which not only reduces manufacturing costs and prevents degradation of stainless steel wood properties, but also ensures the quality and performance of the weld.

[0082] The number of welding layers is controlled at 3 layers. On the basis of meeting the requirements of the cladding layer thickness in the design drawings and the requirements of product use, the amount of deposited metal is reduced, the welding stress is reduced, the manufacturing cost is saved, and the production efficiency is improved.

[0083] (12) Remove the surfacing welding station.

[0084] (13) Machine the EDCrNi-B-15 cladding layer to a thickness of 4 mm.

[0085] (14) Perform a visual inspection of the weld overlay.

[0086] (15) Check the dimensions of the weld overlay layer.

[0087] (16) Perform penetrant testing on the weld overlay layer.

[0088] (17) Destructive testing.

[0089] The above-mentioned (4) arrangement of surfacing stations and (5) preheating process stages are as follows: Figure 3 As shown, the process stages of layer-by-layer wear-resistant surfacing are as follows Figure 4 As shown, the three-layer cladding layer is completed as shown in Figure 5 As shown in the figure, the process stages of grinding and penetrant testing the weld overlay layer are as follows: Figure 6 shown.

[0090] 2. Test the hardness and chemical composition of the final surfacing layer surface.

[0091] Assessment indicators: chemical composition content standard and hardness value requirements of the 4mm thickness of the cladding layer.

[0092] The chemical composition content standards are: C content 0.10-0.18%, Mn content 1.00-2.00%, Si content 3.80-5.00%, Cr content 14.00-20.00%, Ni content 8.00-11.00%, Mo content 4.00-6.50%, Nb content 0.50-1.20%, S content ≤0.006%, P content ≤0.02%, Co content ≤0.05%, B content ≤0.0015%, As content ≤0.01%, Sb content ≤0.01%, Bi content ≤0.01%, Pb content ≤0.01%, Sn ≤0.01%, O content ≤0.05%, and H content ≤0.0005%. The chemical analysis standard test is carried out according to standard ASTM A751-2014A to test the above chemical composition contents.

[0093] Hardness requirement: 270-390 HBW; Brinell hardness measurement is performed according to standard ASTM E10-2018, and the hardness value of the above-mentioned weld overlay layer with a thickness of 4 mm is tested.

[0094] The test results are as follows:

[0095] Table 1 Hardness value and chemical composition test results of cladding layer

[0096]

[0097] As can be seen from the above table, the minimum hardness value of the 4mm thick cladding layer is 353HBW, and the average value is 364HBW, which meets the hardness value requirements, and the chemical composition content meets the assessment index requirements. The wear-resistant cladding method of this embodiment has completed 1 process test and 2 welding process assessments. In this embodiment, the above process tests and welding process assessments include cladding process performance tests, non-destructive testing tests (including visual inspection, penetrant testing), and mechanical properties tests (including hardness value testing and chemical composition testing); the post-weld chemical composition test results and hardness values fully meet the requirements, the penetrant testing of the cladding layer is qualified in one go, and the welding quality is greatly improved. At the same time, the chemical composition is not diluted, meeting the technical requirements, which is beneficial to the overall wear resistance of the cladding layer. On the basis of meeting the design and product use requirements, the service life of the product is greatly improved. Subsequently, this wear-resistant cladding method will be implemented on 20 cylinder sections of 4 intermediate heat exchangers.

[0098] Comparative Example 1

[0099] A wear-resistant surfacing method.

[0100] The wear-resistant surfacing method of this comparative example is basically the same as that of Example 1, except that a higher welding current is used, specifically a welding current of 140-160A.

[0101] Experimental Example 1

[0102] Nondestructive testing experiments were performed on the weld overlay layers obtained in the examples and comparative examples.

[0103] 1. Non-destructive testing: using the method of penetrant testing.

[0104] Specific steps: Spray or apply a penetrant containing pigment or fluorescent powder onto the weld surface to be inspected. Using the capillary action of the liquid, it penetrates into any open surface defects. Excess liquid is then cleaned off the surface. After drying, a developer is applied to absorb the liquid from the defect onto the weld surface, where the defect is observed. This method is primarily used for surface inspection of welds or for root defect detection after gouging.

[0105] 2. Test results such as Figure 7 、 Figure 8 As shown, Figure 7 For the surfacing layer of Comparative Example 1, Figure 8 This is the surfacing layer of Example 1.

[0106] Result analysis: When the wear-resistant surfacing method of Example 1 is used, when the number of weld layers is 3, the thickness of the surfacing layer can reach 6-7mm, while when the comparative example 1 uses a higher welding current, the number of weld layers needs to be 4 to achieve the same surfacing layer thickness as that of Example 1. Figure 7 、 Figure 8The results of penetrant testing show that the cladding layer of comparative example 1 has cracking problems. Figure 7 The colored penetrant traces in the middle are the cracking locations, while the surfacing layer of Example 1 has no cracks and is qualified.

[0107] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A wear-resistant surfacing method for annular high-temperature resistant stainless steel material, characterized in that: The following steps are involved: The welding material is used to weld layer by layer on the substrate. After each layer is welded, the obtained weld layer is directly subjected to post-heat treatment and polished, and then the next layer is welded until the number of weld layers is 3, thereby obtaining a surfacing layer. The thickness of the surfacing layer is 6-7 mm. The C content of the predetermined position of the surfacing layer is 0.10-0.18%, the Mn content is 1.00-2.00%, the Si content is 3.80-5.00%, the Cr content is 14.00-20.00%, the Ni content is 8.00-11.00%, and the Mo content is 4.00-6 0.50%, Nb content is 0.50-1.20%, S content ≤0.006%, P content ≤0.02%, Co content ≤0.05%, B content ≤0.0015%, As content ≤0.01%, Sb content ≤0.01%, Bi content ≤0.01%, Pb content ≤0.01%, Sn ≤0.01%, O content ≤0.05%, H content ≤0.0005%; the hardness value of the predetermined position of the cladding layer is 270-390 HBW; the predetermined position is where the thickness of the cladding layer is 4 mm; The welding comprises the following steps: preheating, continuous welding, and obtaining a weld layer; the continuous welding has a welding current of 100-130A, a welding voltage of 22-28V, a welding speed of 15-25cm / min, and an overlap between welds of 50-60%; the post-heat treatment temperature is 250-400°C, and the holding time of the post-heat treatment is ≥4h; the preheating temperature is 250-400°C.

2. The wear-resistant surfacing method according to claim 1, characterized in that: The thickness of the welding layer is 1-3 mm.

3. The wear-resistant surfacing method according to any one of claims 1 to 2, characterized in that: The wear-resistant surfacing method further includes a flaw detection step after the grinding step, and the substrate is an annular high-temperature resistant stainless steel material.

4. The wear-resistant surfacing method according to claim 3, characterized in that: The heating method of the preheating is electric heating, and the heating method of the post-heat treatment is electric heating.

5. The wear-resistant surfacing method according to claim 4, characterized in that: The electric heating comprises: fixing a heater inside or outside the substrate to make the substrate rotate around an axis.

6. An intermediate heat exchanger prepared by the wear-resistant surfacing method according to any one of claims 1 to 5.

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