Steel welding method, steel part and application of steel part

Abstract

The invention relates to a steel welding method. The steel welding method comprises the following steps that microalloyed steel is provided; laser surface alloying treatment is conducted on the area, to be welded, of the microalloyed steel, and an alloy layer is formed in the area to be welded; injecting nitrogen ions and titanium ions into the alloy layer through an ion injection process to obtain a to-be-welded layer; welding the microalloyed steel by taking the to-be-welded layer as a welding operation area, and obtaining a welded part after welding is completed; the welding workpiece is subjected to annealing treatment, and according to the mass percent of the microalloyed steel, the microalloyed steel comprises 0.05%-0.5% of neodymium, 0.05%-0.5% of lanthanum, 0.3%-1.5% of niobium and 0.3%-1.5% of molybdenum. According to the steel welding method provided by the embodiment of the invention, the material of the welding structure can have high tensile strength and impact toughness, and welding defects can be reduced.

Description

Technical Field

[0001] The present application relates to the field of steel materials, and in particular to the field of steel welding technology. Background Art

[0002] The welding process of steel structure of railway freight cars is one of the key processes in the manufacture of railway transportation equipment. This process involves welding steel into the freight car body and load-bearing structure to ensure the strength, stability and safety of the freight car during operation. The quality of the welding process directly affects the service life and operational reliability of the freight car. Therefore, how to improve the performance of steel structure welding has always been the focus of attention in the field of engineering technology.

[0003] The existing welding processes for railway freight car steel structures usually use traditional methods such as manual arc welding, gas shielded welding and automatic submerged arc welding. These methods melt the surface of steel at high temperature to form a strong weld joint after cooling, thereby achieving structural connection. Manual arc welding is widely used in the welding of complex structures due to its operational flexibility, gas shielded welding is used for its high welding quality and suitability for large-scale production, and automatic submerged arc welding has the characteristics of high efficiency and deep penetration. However, although these railway freight car steel structure welding processes have achieved certain results in improving the connection strength of steel and improving production efficiency, they still have significant deficiencies in dealing with high strength, long-term operation and harsh environmental conditions. Specifically, the tensile strength and impact toughness of the welded joints are not ideal, the corrosion resistance is poor, and the consistency of the welding quality is unstable, which is prone to defects such as cracks, pores and lack of fusion. These defects directly affect the safety and service life of the freight car. Summary of the invention

[0004] The present application provides a steel welding method, a steel part and applications thereof, so as to solve the technical problem of insufficient tensile strength and impact toughness of welded joints.

[0005] In a first aspect, an embodiment of the present application provides a steel welding method, the steel welding method comprising the following steps:

[0006] Provide micro-alloyed steel;

[0007] Performing laser surface alloying treatment on the area of ​​the microalloyed steel to be welded, so as to form an alloy layer in the area to be welded;

[0008] Implanting nitrogen ions and titanium ions into the alloy layer through an ion implantation process to obtain a layer to be welded;

[0009] Welding the microalloyed steel using the layer to be welded as the welding operation area, and obtaining a welded part after welding is completed;

[0010] The welded product is annealed.

[0011] Wherein, in terms of mass percentage of the microalloyed steel, the microalloyed steel includes 0.05% to 0.5% of neodymium, 0.05% to 0.5% of lanthanum, 0.3% to 1.5% of niobium, and 0.3% to 1.5% of molybdenum.

[0012] In some embodiments of the present application, the welding current is 200-500A; and / or,

[0013] The welding voltage is 25 to 50 V; and / or,

[0014] The welding speed is 150-600 mm / min; and / or,

[0015] The welding temperature is 300-400° C.; and / or,

[0016] The laser power of the laser surface alloying treatment is 1500-3000W; and / or,

[0017] The thickness of the alloy layer is 20 to 60 μm; and / or,

[0018] The ion energy range of the ion implantation process is 50-150 keV; and / or,

[0019] The annealing temperature is 550-700° C.; and / or,

[0020] The annealing duration is 1 to 5 hours.

[0021] In some embodiments of the present application, before welding the microalloyed steel, the steel welding method further comprises the following steps:

[0022] Nanoparticles are coated on the layer to be welded to form a nano protective layer.

[0023] In some embodiments of the present application, the material of the nanoparticles is at least one of silicon dioxide or titanium dioxide; and / or,

[0024] The thickness of the nano protective layer is 3-15 μm.

[0025] In some embodiments of the present application, before welding the microalloyed steel, the steel welding method further comprises the following steps:

[0026] The layer to be welded is subjected to ultrasonic treatment.

[0027] In some embodiments of the present application, the ultrasonic frequency of the ultrasonic treatment is 15kHz to 45kHz.

[0028] In some embodiments of the present application, after the welded part is annealed, the steel welding method further comprises the following steps:

[0029] The weld of the welded part is ground.

[0030] In some embodiments of the present application, the weld of the welded component is polished to a surface roughness of Ra3.2 μm to Ra0.8 μm.

[0031] In a second aspect, an embodiment of the present application provides a steel part, which is welded by the steel welding method described in any embodiment of the first aspect.

[0032] In a third aspect, an embodiment of the present application provides a railway freight car, wherein the railway freight car comprises the steel parts described in any embodiment of the second aspect.

[0033] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0034] The steel welding method provided in the embodiment of the present application selects microalloyed steel as the welding material, performs laser surface alloying and ion implantation processes on the surface of the microalloyed steel, and forms a layer to be welded having high strength and toughness, so that the material of the welded structure has high tensile strength and impact toughness; in addition, the layer to be welded formed by the laser surface alloying and ion implantation processes has good uniformity, which makes the welded structure have good consistency, is beneficial to reducing welding defects such as cracks, pores and unfusion, and ensures the reliability and safety of the welded structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0037] Figure 1 A schematic flow chart of a steel welding method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0039] Unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. In the event of a conflict, this specification takes precedence.

[0040] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0041] The existing steel welding process has the technical problem of insufficient tensile strength and impact toughness of the welded joint.

[0042] The technical solution provided by the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0043] In a first aspect, an embodiment of the present application provides a steel welding method, the steel welding method comprising the following steps:

[0044] S1: Provides micro-alloyed steel;

[0045] S2: performing laser surface alloying treatment on the area to be welded of the microalloyed steel to form an alloy layer in the area to be welded;

[0046] S3: injecting nitrogen ions and titanium ions into the alloy layer through an ion implantation process to obtain a layer to be welded;

[0047] S4: welding the microalloyed steel with the layer to be welded as the welding operation area, and obtaining a welded part after the welding is completed;

[0048] S5: performing annealing treatment on the welded part.

[0049] Wherein, in terms of mass percentage of the microalloyed steel, the microalloyed steel includes 0.05% to 0.5% of neodymium, 0.05% to 0.5% of lanthanum, 0.3% to 1.5% of niobium, and 0.3% to 1.5% of molybdenum.

[0050] Microalloyed steel is a steel material with trace alloying elements added to the chemical composition of ordinary mild steel and ordinary high-strength low-alloy steel matrix. After adding trace alloying elements, one or several properties of the steel are significantly improved. Microalloyed steel usually has good cold and hot formability and weldability, especially at low carbon content and ultra-low carbon content. The alloying elements added to microalloyed steel are mainly titanium, vanadium, niobium, boron, aluminum, zirconium, tantalum, etc. These elements can form a variety of compounds with elements such as carbon, nitrogen, oxygen and sulfur in steel, which have a variety of effects on the properties of steel.

[0051] The present application selects microalloy steel including 0.05% to 0.5% neodymium, 0.05% to 0.5% lanthanum, 0.3% to 1.5% niobium, and 0.3% to 1.5% molybdenum. Neodymium and lanthanum are rare earth elements, which can effectively improve the microstructure and cleanliness of the steel after being added to the steel. These elements help to refine the structure of the steel, and enhance the toughness of the welding heat affected zone of the material by refining the grain size. Niobium and molybdenum are key microalloy elements for strengthening the performance of steel. They enhance the strength and hardness of the material by forming fine carbide and / or nitride particles. These particles are dispersed in the steel, effectively hindering the movement of dislocations, thereby improving the yield strength and fatigue resistance of the material, and making the railway freight car steel structure have higher safety and reliability under long-term fatigue loads and harsh environmental conditions. The above-mentioned trace metal elements can improve the purification effect and grain refinement of the steel, thereby enhancing the toughness of the welding heat affected zone, and can also improve the strength and toughness of the material, so that the welded structure has a higher load-bearing capacity and better fatigue resistance.

[0052] Laser surface alloying is an advanced material surface treatment technology. It uses the rapid heating and melting characteristics of a high-energy-density laser beam to melt and mix the surface layer of the substrate and the added alloying elements, thereby forming a new surface alloy layer based on the original substrate. The laser beam can precisely control the treated area to achieve local strengthening of the material surface. Through laser treatment, the alloying elements and the substrate can achieve good metallurgical bonding to form an alloy layer with excellent performance. Compared with traditional surface treatment technologies, laser surface alloying treatment is faster and greatly improves production efficiency. The strengthening mechanism of laser surface alloying is a comprehensive strengthening result of phase transformation hardening, solid solution strengthening and carbide strengthening. Among them, carbide second phase strengthening is the most important strengthening mechanism, which can enable the alloy layer to obtain a hardness exceeding that of the substrate material and greatly improve wear resistance. The high energy of the laser not only ensures rapid alloying, but also achieves rapid cooling to prevent excessive oxidation and annealing of the alloy layer. This rapid solidification process results in the alloy layer having a very fine grain structure, which greatly enhances its wear resistance and corrosion resistance, improves the wear resistance and corrosion resistance of the steel surface, and by precisely controlling the thickness and uniformity of the alloy layer, not only the hardness of the material surface is increased, but also its ability to resist fatigue cracking is improved, making the steel structure more resistant to performance degradation caused by wear and corrosion in long-term service, thereby extending the service life of railway freight cars and reducing operational interruptions caused by maintenance and repairs.

[0053] The basic principle of ion implantation is to accelerate charged impurity ions so that they enter the matrix of solid materials (such as semiconductors, metals, etc.) with high energy. In this process, the doped ions are accelerated and hit the surface of the solid material at a very high speed, and penetrate to a certain depth. By controlling the energy and implantation dose of the ions, the depth and concentration of the impurity ion distribution can be accurately controlled. The present application implants nitrogen ions and titanium ions into the alloy layer, which replace the original atoms in the lattice of the material or form a solid solution in the lattice gap, causing lattice distortion. This distortion significantly improves the hardness and wear resistance of the material, because the tighter lattice structure increases the interaction force between atoms, thereby increasing the difficulty of dislocation movement. Through ion implantation treatment, the hardness of the steel surface is improved. In addition, the improvement of hardness also brings better corrosion resistance, because the harder surface is more difficult to be eroded or penetrated. Ultimately, this surface modification technology extends the service life of the steel structure, reduces long-term maintenance and replacement costs, and improves the reliability and efficiency of railway freight cars in operation.

[0054] In addition, it is easy to understand that the laser surface alloying and ion implantation processes are both stable and uniform processing processes, which makes the material uniformity of the layer to be welded good, thereby improving the consistency of the welding structure, which is beneficial to reducing welding defects such as cracks, pores and unfusion, and ensuring the reliability and safety of the welding structure.

[0055] The present application selects microalloyed steel as welding material, performs laser surface alloying and ion implantation processes on the surface of the microalloyed steel, and forms a layer to be welded having high strength and toughness, so that the material of the welded structure has high tensile strength and impact toughness; in addition, the layer to be welded formed by the laser surface alloying and ion implantation processes has good uniformity, which makes the welded structure have good consistency, is conducive to reducing welding defects such as cracks, pores and unfusion, and ensures the reliability and safety of the welded structure.

[0056] In some embodiments of the present application, the welding current is 200-500A; and / or,

[0057] The welding voltage is 25 to 50 V; and / or,

[0058] The welding speed is 150-600 mm / min; and / or,

[0059] The welding temperature is 300-400° C.; and / or,

[0060] The laser power of the laser surface alloying treatment is 1500-3000W; and / or,

[0061] The thickness of the alloy layer is 20 to 60 μm; and / or,

[0062] The ion energy range of the ion implantation process is 50-150 keV; and / or,

[0063] The annealing temperature is 550-700° C.; and / or,

[0064] The annealing duration is 1 to 5 hours.

[0065] The selection of the above range of the process parameters of the welding is conducive to obtaining a welded structure with optimal tensile strength and impact toughness. Appropriate current and voltage levels can ensure the stability of the arc and sufficient heat input, which is essential for melting steel and forming a uniform weld. The welding speed of 150 to 600 mm / min helps to control the formation rate of the weld and the size of the heat-affected zone. By controlling the welding speed, the heat-affected zone and the penetration depth of the weld can be affected, thereby affecting the microstructure and mechanical properties of the welded structure. The welding temperature of 300 to 400 ° C can ensure the best welding quality, optimize the heat input and cooling rate to prevent the weld from overheating or cooling too fast, because too high a temperature can cause weld defects such as burn-through, while too low a temperature may cause incomplete welding. The annealing temperature of 550 to 700 ° C and the annealing duration of 1 to 5 hours can rearrange the atoms in the steel, thereby eliminating the uneven lattice distortion formed during the welding process. Maintaining the above temperature for the above time allows new grain boundaries to form, thereby enhancing the overall toughness and strength of the material. Through the above annealing treatment, the welded structure can obtain significantly improved mechanical properties, including enhanced tensile strength, improved fatigue life and better crack resistance.

[0066] As an example, the welding current may be 200A, 300A, 400A, or 500A.

[0067] As an example, the welding voltage may be 25V, 30V, 35V, 40V, 45V, or 50V.

[0068] As an example, the welding speed may be 150 mm / min, 300 mm / min, 450 mm / min, or 600 mm / min.

[0069] As an example, the welding temperature may be 300°C, 320°C, 340°C, 360°C, 380°C, or 400°C.

[0070] As an example, the laser power of the laser surface alloying treatment may be 1500W, 2000W, 2500W, or 3000W.

[0071] As an example, the thickness of the alloy layer may be 20 μm, 30 μm, 40 μm, 50 μm, or 60 μm.

[0072] As an example, the ion energy range of the ion implantation process may be 50 keV, 70 keV, 100 keV, 80 keV, or 150 keV.

[0073] As an example, the annealing temperature may be 550°C, 600°C, 650°C, or 700°C.

[0074] As an example, the annealing may last for 1 h, 2 h, 3 h, 4 h, or 5 h.

[0075] In some embodiments of the present application, before welding the microalloyed steel, the steel welding method further comprises the following steps:

[0076] S31: coating nanoparticles on the layer to be welded to form a nano protective layer.

[0077] It is easy to understand that the purpose of preparing the nano protective layer is to increase the corrosion resistance of the welded structure. The nanoparticles form a high-density nano protective layer on the surface of the steel, which effectively blocks the direct contact of moisture and oxygen with the metal surface, thereby enhancing the corrosion resistance of the welded structure, especially in rainy or humid environments, effectively extending the service life of the welded structure and reducing maintenance requirements. In addition, the nano coating can also absorb and disperse the oxidation stress transmitted through the coating to a certain extent, thereby reducing the oxidation rate, thereby enhancing the corrosion and oxidation resistance of the steel, especially in harsh external environments such as high humidity or salt spray environments.

[0078] In some embodiments of the present application, the material of the nanoparticles is at least one of silicon dioxide or titanium dioxide; and / or,

[0079] The thickness of the nano protective layer is 3-15 μm.

[0080] It is easy to understand that the main function of the nano protective layer is to isolate water and oxygen, so the material can be selected from nanoparticles with relatively stable chemical properties, which are not limited to silicon dioxide and titanium dioxide. For example, tin dioxide can also be used. Silicon dioxide nanoparticles and titanium dioxide nanoparticles are cheap and readily available nanomaterials on the market with stable chemical properties.

[0081] As an example, the thickness of the nano protective layer may be 3 μm, 6 μm, 9 μm, 12 μm, or 15 μm.

[0082] In some embodiments of the present application, before welding the microalloyed steel, the steel welding method further comprises the following steps:

[0083] S32: performing ultrasonic treatment on the layer to be welded.

[0084] Ultrasonic treatment of the layer to be welded can improve the material uniformity of the layer to be welded, increase the reliability during welding, and reduce welding defects. The energy of ultrasonic waves can interrupt the original grain boundaries and promote the formation of new grain boundaries. These newly formed fine grains have higher interface energy, which helps to enhance the overall mechanical properties of the material, thereby improving the microstructure of the steel, making the fusion of materials more uniform during welding, reducing the occurrence of welding defects such as pores and lack of fusion, and improving the quality and consistency of the weld, thereby increasing the static and fatigue strength of the welded structure, and effectively extending the service life of the freight car structure, reducing maintenance costs, and improving the operating efficiency of railway freight cars.

[0085] In some embodiments of the present application, the ultrasonic frequency of the ultrasonic treatment is 15kHz to 45kHz.

[0086] As an example, the ultrasonic wave frequency of the ultrasonic treatment may be 15 kHz, 25 kHz, 35 kHz, or 45 kHz.

[0087] In some embodiments of the present application, after the welded part is annealed, the steel welding method further comprises the following steps:

[0088] S51: grinding the weld of the welded part.

[0089] It is easy to understand that the grinding can be performed by a device such as a grinding wheel or a grinding belt. Grinding the weld of the welded part is beneficial to improving the flatness and aesthetics of the welded structure surface, and removing high points and irregular structures on the welded structure surface by mechanical grinding, smoothing the weld surface, and improving the surface quality. The grinding process not only removes surface defects, but also locally anneals the weld area through the tiny heat generated by grinding, which helps to release welding stress and improve the microstructure of the material, thereby improving the surface smoothness and appearance quality of the welded structure, and also enhancing its corrosion resistance and fatigue life; in addition, the smooth surface reduces the formation of eddies and turbulence, which is particularly important for railway freight cars when transporting liquid or gas products, and can reduce fluid power losses.

[0090] In some embodiments of the present application, the weld of the welded component is polished to a surface roughness of Ra3.2 μm to Ra0.8 μm.

[0091] As an example, the surface roughness of the weld can be polished to Ra3.2 μm, Ra2.4 μm, Ra1.6 μm, or Ra0.8 μm.

[0092] In a second aspect, an embodiment of the present application provides a steel part, which is welded by the steel welding method described in any embodiment of the first aspect.

[0093] The steel parts are realized based on the above-mentioned steel welding method. The specific implementation methods of the steel parts can refer to the above-mentioned embodiments and the common knowledge in the field. Since the steel parts adopt part or all of the technical solutions of the above-mentioned embodiments, they at least have all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0094] In a third aspect, an embodiment of the present application provides a railway freight car, wherein the railway freight car comprises the steel parts described in any embodiment of the second aspect.

[0095] The railway freight car is realized based on the above-mentioned steel parts. The specific implementation of the railway freight car can refer to the above-mentioned embodiments and the common knowledge in the field. Since the railway freight car adopts part or all of the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0096] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.

[0097] Example 1

[0098] This embodiment provides a steel welding method, which includes the following steps:

[0099] Provide micro-alloyed steel;

[0100] Performing laser surface alloying treatment on the area of ​​the microalloyed steel to be welded, so as to form an alloy layer in the area to be welded;

[0101] Implanting nitrogen ions and titanium ions into the alloy layer through an ion implantation process to obtain a layer to be welded;

[0102] Coating silicon dioxide nanoparticles on the layer to be welded to form a nano protective layer;

[0103] Performing ultrasonic treatment on the layer to be welded;

[0104] Welding the microalloyed steel using the layer to be welded as the welding operation area, and obtaining a welded part after welding is completed;

[0105] The welded product is annealed.

[0106] The weld of the welded part is ground.

[0107] Wherein, in terms of mass percentage of the microalloyed steel, the microalloyed steel comprises 0.1% of neodymium, 0.1% of lanthanum, 0.5% of niobium, and 0.5% of molybdenum.

[0108] The welding current is 350A, the welding voltage is 30V, the welding speed is 300mm / min, the welding temperature is 350°C, the laser power of the laser surface alloying treatment is 2000W, the thickness of the alloy layer is 40μm, the ion energy range of the ion implantation process is 100keV, the annealing temperature is 600°C, and the annealing duration is 3h. The thickness of the nano protective layer is 10μm. The ultrasonic frequency of the ultrasonic treatment is 30kHz.

[0109] The weld of the welded part is polished to a surface roughness of Ra 1.0 μm.

[0110] Example 2

[0111] This embodiment provides a steel welding method, which includes the following steps:

[0112] Provide micro-alloyed steel;

[0113] Performing laser surface alloying treatment on the area of ​​the microalloyed steel to be welded, so as to form an alloy layer in the area to be welded;

[0114] Implanting nitrogen ions and titanium ions into the alloy layer through an ion implantation process to obtain a layer to be welded;

[0115] Coating silicon dioxide nanoparticles on the layer to be welded to form a nano protective layer;

[0116] Performing ultrasonic treatment on the layer to be welded;

[0117] Welding the microalloyed steel using the layer to be welded as the welding operation area, and obtaining a welded part after welding is completed;

[0118] The welded product is annealed.

[0119] The weld of the welded part is ground.

[0120] Wherein, in terms of mass percentage of the microalloyed steel, the microalloyed steel comprises 0.3% of neodymium, 0.3% of lanthanum, 1.0% of niobium, and 1.0% of molybdenum.

[0121] The welding current is 500A, the welding voltage is 50V, the welding speed is 150mm / min, the welding temperature is 400°C, the laser power of the laser surface alloying treatment is 3000W, the thickness of the alloy layer is 60μm, the ion energy range of the ion implantation process is 150keV, the annealing temperature is 700°C, and the annealing duration is 3h. The thickness of the nano protective layer is 10μm. The ultrasonic frequency of the ultrasonic treatment is 30kHz.

[0122] The weld of the welded part is polished to a surface roughness of Ra0.8 μm.

[0123] Example 3

[0124] This embodiment provides a steel welding method, which includes the following steps:

[0125] Provide micro-alloyed steel;

[0126] Performing laser surface alloying treatment on the area of ​​the microalloyed steel to be welded, so as to form an alloy layer in the area to be welded;

[0127] Implanting nitrogen ions and titanium ions into the alloy layer through an ion implantation process to obtain a layer to be welded;

[0128] Coating silicon dioxide nanoparticles on the layer to be welded to form a nano protective layer;

[0129] Performing ultrasonic treatment on the layer to be welded;

[0130] Welding the microalloyed steel using the layer to be welded as the welding operation area, and obtaining a welded part after welding is completed;

[0131] The welded product is annealed.

[0132] The weld of the welded part is ground.

[0133] Wherein, in terms of mass percentage of the microalloyed steel, the microalloyed steel comprises 0.5% of neodymium, 0.5% of lanthanum, 1.5% of niobium, and 1.5% of molybdenum.

[0134] The welding current is 450A, the welding voltage is 45V, the welding speed is 600mm / min, the welding temperature is 350°C, the laser power of the laser surface alloying treatment is 2500W, the thickness of the alloy layer is 50μm, the ion energy range of the ion implantation process is 150keV, the annealing temperature is 650°C, and the annealing duration is 4h. The thickness of the nano protective layer is 10μm. The ultrasonic frequency of the ultrasonic treatment is 30kHz.

[0135] The weld of the welded part is polished to a surface roughness of Ra0.8 μm.

[0136] Comparative Example 1

[0137] This comparative example provides the same microalloyed steel as in Example 1, but without surface treatment, and directly obtains a welded product under the same welding conditions as in Example 1. The details are as follows:

[0138] Provide micro-alloyed steel;

[0139] Welding the microalloyed steel to obtain a welded product;

[0140] The welded product is annealed.

[0141] The weld of the welded part is ground.

[0142] Wherein, in terms of mass percentage of the microalloyed steel, the microalloyed steel comprises 0.1% of neodymium, 0.1% of lanthanum, 0.5% of niobium, and 0.5% of molybdenum.

[0143] The welding current is 350A, the welding voltage is 30V, the welding speed is 300mm / min, the welding temperature is 350°C, the annealing temperature is 600°C, and the annealing duration is 3h. The weld of the welded part is polished to a surface roughness of Ra1.0μm.

[0144] Comparative Example 2

[0145] This comparative example provides ordinary commercial steel without surface treatment, and directly obtains welded parts under the same welding conditions as Example 1. The details are as follows:

[0146] Provide steel;

[0147] Welding the steel material to obtain a welded product;

[0148] The welded product is annealed.

[0149] The weld of the welded part is ground.

[0150] The welding current is 350A, the welding voltage is 30V, the welding speed is 300mm / min, the welding temperature is 350°C, the annealing temperature is 600°C, and the annealing duration is 3h. The weld of the welded part is polished to a surface roughness of Ra1.0μm.

[0151] Related experiments and effect data:

[0152] Three groups of samples of welded parts of Example 1, Comparative Example 1 and Comparative Example 2 were provided, each group of samples included at least five samples, and a tensile test was performed on each sample using a universal material testing machine to record the fracture strength; a Charpy impact test was performed using an impact testing machine to record the absorbed energy. All test data were collected, and the average value and standard deviation were calculated. Results Table 1.

[0153] Table 1

[0154] Sample grouping Sample type Tensile strength(MPa) Standard deviation(MPa) Impact energy(J) Standard Deviation(J) Group 1 Example 1 620 15 35 2 Group 2 Example 1 615 20 36 1.5 Group 3 Example 1 630 18 37 3 Group 4 Comparative Example 1 590 22 30 2.5 Group 5 Comparative Example 1 595 19 31 2 Group 6 Comparative Example 1 580 20 29 2.2 Group 7 Comparative Example 2 550 25 25 3 Group 8 Comparative Example 2 560 30 24 3.5 Group 9 Comparative Example 2 555 28 26 2.8

[0155] The tensile strength and impact energy of Example 1 are higher than those of Comparative Examples 1 and 2, indicating that due to the use of laser surface alloying and ion implantation, the tensile strength and impact toughness of the welded structure are significantly better than those of untreated microalloyed steel and conventional commercial steel. These treatment methods improve the mechanical properties of the welded structure, showing higher tensile strength and toughness.

[0156] Three groups of samples of welded parts of Example 1, Comparative Example 1, and Comparative Example 2 were provided, each group of samples included at least five samples, all samples were placed in a salt spray test chamber, and a salt spray corrosion test was performed for 240 hours continuously; then all samples were placed in a salt spray test chamber again, and a salt spray corrosion test was performed for 240 hours continuously. All test data were collected and the average value was calculated. The results are shown in Table 2.

[0157] Table 2

[0158]

[0159]

[0160] Example 1, after laser surface alloying, ion implantation and nanotechnology coating treatment, exhibits excellent corrosion resistance, and the corrosion rate is significantly lower than that of the untreated comparative example 1 and the traditional steel comparative example 2. Although the comparative example 1 material has a certain corrosion resistance, it is still not comparable to the treated example 1.

[0161] Three groups of samples of welded parts of Example 1, Comparative Example 1, and Comparative Example 2 were provided, each group of samples included at least five samples, all samples were placed in a wear tester, the same load and speed were set, and 10,000 cycles of wear test were performed; the mass of the samples before and after wear was measured using a weighing device, and the wear amount was recorded. All test data were collected, and the average value and standard deviation were calculated. The results are shown in Table 3.

[0162] Table 3

[0163]

[0164] After laser surface alloying and ion implantation treatment, Example 1 shows significantly improved surface hardness and wear resistance. The hardness and wear rate are significantly better than those of the untreated Example 1 and the traditional steel Example 2. Although the hardness and wear resistance of the Example 1 material have been improved to a certain extent, they are still inferior to those of the experimental group material, indicating a significant effect of surface treatment on material properties.

[0165] Three groups of samples of welded parts of Example 1, Comparative Example 1, and Comparative Example 2 were provided, each group of samples included at least five samples, ultrasonic testing was performed on each welded sample, and the number and type of defects detected were recorded; X-ray testing was performed on each welded sample, and the number and type of defects detected were confirmed and recorded. All test data were collected, and the number and defect rate of each sample were calculated. The results are shown in Table 4.

[0166] Table 4

[0167]

[0168] Example 1, after laser surface alloying, ion implantation and nanotechnology coating treatment, showed the best welding quality consistency, and the number and type of defects were significantly less than those of the untreated comparative example 1 and the traditional steel comparative example 2. Although the comparative example 1 material was better than the comparative example 2 in the number and type of defects, it was still far less than the experimental group material, indicating that surface treatment has a significant impact on the consistency of welding quality.

[0169] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0170] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "including", "comprising", etc. refer to "including but not limited to". Moreover, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "including..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. For the association relationship of more than three associated objects described by "and / or", it means that any one of these three associated objects can exist alone, or any at least two of them exist at the same time. For example, for A, and / or B, and / or C, it can be represented that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single items (individuals) or plural items (individuals). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, c can be single or multiple respectively. The "number of parts" involved in this application, such as weight parts, mass parts, etc., represent the proportional relationship between each component. In the proportional relationship involved in the present application, the parameters that need to be described by proportion should be understood as the first term of the proportional formula in the order of description, and the proportional numbers should be understood as the second term of the proportional formula. For example, if the mass ratio of substance A, substance B and substance C is 1:2:3, then substance A, substance B and substance C should correspond one-to-one with the proportional numbers in the proportional formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0171] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A steel welding method, characterized in that: The steel welding method comprises the following steps: Provide micro-alloyed steel; Performing laser surface alloying treatment on the area of ​​the microalloyed steel to be welded, so as to form an alloy layer in the area to be welded; Implanting nitrogen ions and titanium ions into the alloy layer through an ion implantation process to obtain a layer to be welded; Welding the microalloyed steel using the layer to be welded as the welding operation area, and obtaining a welded part after welding is completed; The welded product is annealed. Wherein, in terms of mass percentage of the microalloyed steel, the microalloyed steel includes 0.05% to 0.5% of neodymium, 0.05% to 0.5% of lanthanum, 0.3% to 1.5% of niobium, and 0.3% to 1.5% of molybdenum.

2. The steel welding method according to claim 1, characterized in that: The welding current is 200-500A; and / or, The welding voltage is 25 to 50 V; and / or, The welding speed is 150-600 mm / min; and / or, The welding temperature is 300-400° C.; and / or, The laser power of the laser surface alloying treatment is 1500-3000W; and / or, The thickness of the alloy layer is 20 to 60 μm; and / or, The ion energy range of the ion implantation process is 50-150 keV; and / or, The annealing temperature is 550-700° C.; and / or, The annealing duration is 1 to 5 hours.

3. The steel material welding method according to claim 1 or 2, characterized in that: Before welding the microalloyed steel, the steel welding method further comprises the following steps: Nanoparticles are coated on the layer to be welded to form a nano protective layer.

4. The steel welding method according to claim 3, characterized in that: The material of the nanoparticles is at least one of silicon dioxide or titanium dioxide; and / or, The thickness of the nano protective layer is 3-15 μm.

5. The steel welding method according to claim 1 or 2, characterized in that: Before welding the microalloyed steel, the steel welding method further comprises the following steps: The layer to be welded is subjected to ultrasonic treatment.

6. The steel welding method according to claim 5, characterized in that: The ultrasonic frequency of the ultrasonic treatment is 15kHz to 45kHz.

7. The steel material welding method according to claim 1 or 2, characterized in that: After the welded part is annealed, the steel welding method further comprises the following steps: The weld of the welded part is ground.

8. The steel material welding method according to claim 7, characterized in that: The weld of the welded part is polished to a surface roughness of Ra3.2 μm to Ra0.8 μm.

9. A steel part, characterized in that: The steel part is welded by the steel welding method according to any one of claims 1 to 8.

10. A railway freight car, characterized in that: The railway freight car comprises the steel member of claim 9.

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