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I. Wear-resistant steel plate NM360: The main feature of the wear-resistant steel plate NM360 is its high resistance to wear; its wear resistance is 3–5 times that of ordinary low-alloy steel plates. It also has high strength, a low alloy content, and is easy to weld as well as to process (cut, drill, bend, shape)； It is primarily used as a lining in mechanical devices in areas where friction occurs, **helping to extend the equipment’s service life, ensure its proper operation, and reduce losses resulting from maintenance downtime. It is also often used as high-strength structural steel with a yield strength of ≥700 MPa. The NM360 grade specifies the structure, applications, and hardness; it is commonly referred to as Wear-Resistant 360 ； N represents the first letter of \" tolerance \", and M represents the first letter of \" grind \". It is mainly used in equipment manufacturing enterprises in the coal mines, mining, cement, environmental protection, construction machinery and other industries. Such as scraper conveyors, crushers, vibrating screens, mining dump trucks, excavator buckets, cement mixing equipment, etc. Wear-resistant steel plates with high wear resistance are widely used in coal mining machinery, mining equipment, environmental protection machinery, cement machinery, and construction machinery. Construction machinery: bulldozer buckets, backhoe buckets, rotary drilling rigs, mining dump trucks, pavers, material loaders. Coal mine machinery: mining scraper conveyors, screw conveyors, shield machines, coal grinders, ball mills. Mining machinery: crushers, vibrating screens. Cement machinery: cement mixing plants, cement mixers, concrete mixers/vehicles. Ventilation and dust removal: large fan blades, complete dust removal systems. New application areas: silos, coal conveyors. Origin: Wugang, Wugang Iron and Steel, Baosteel, Nanjing Iron and Steel, Xingang Iron and Steel, Xiangtan Iron and Steel, Taiyuan Iron and Steel. II. NM400 high-strength wear-resistant steel plate. In NM, N stands for the first letter of “Nai”, and M stands for the first letter of “Mo”; NM thus refers to “wear-resistant”” ； 400 is the Brinell hardness value, HB. (The 400 hardness value is a general term; the hardness range for the domestic NM400 material is 360–420.) The delivery conditions of wear-resistant steel plates are as follows: 1. Tempered state; 2. Quenched and tempered state (quenching + tempering). Relatively speaking, the quality of the quenched and tempered state is better! III. Bimetallic cladded wear-resistant steel plates: These are steel plate products designed for use in situations involving extensive wear. They are created by depositing, via welding, a layer of material with high hardness and excellent wear resistance onto the surface of ordinary low-carbon steel or low-alloy steel, which possesses good toughness and plasticity. Bimetallic composite wear-resistant steel plates consist of a low-carbon steel base and an alloy wear-resistant layer, with the wear-resistant layer typically accounting for 1/3 to 1/2 of the total thickness. During operation, the matrix provides comprehensive properties such as strength, toughness, and plasticity to resist external forces, while the wear-resistant layer offers the wear resistance required for specific operating conditions. There is a metallurgical bond between the wear-resistant layer and the matrix of the wear-resistant steel plate alloy. Using specialized equipment and an automatic welding process, high-hardness self-shielding alloy wires are evenly welded onto the base material, resulting in one to two or even multiple composite layers. During the compounding process, uniform transverse cracks appear due to the different contraction rates of the alloys, and this is a distinctive feature of wear-resistant steel plates. The wear-resistant layer is primarily composed of chromium alloys, with additional alloying elements such as manganese, molybdenum, niobium, and nickel also included. In the microstructure, the carbides are distributed in a fibrous pattern, with the direction of these fibers being perpendicular to the surface. The microhardness of carbides can reach over HV1700-2000, while the surface hardness can reach HRc58-62. Alloy carbides exhibit strong stability at high temperatures, maintaining high hardness; they also have excellent oxidation resistance, allowing them to function properly up to 500°C. Wear-resistant steel plates possess high wear resistance as well as good impact resistance. They can be cut, bent, and welded, and can be connected to other structures using methods such as welding, plug welding, or bolt connections. They offer time savings and convenience during maintenance operations, and are widely used in industries such as metallurgy, coal, cement, power generation, glass manufacturing, mining, building materials, and brick production. Compared to other materials, they offer an excellent cost-performance ratio, which has led to their increasing popularity among various industries and manufacturers. IV. W wear-resistant plate: The W wear-resistant plate is a wear-resistant plate produced by Wuyang Steel Plant. Grade WNM360, WNM400, WNM450, WNM500. The excellent properties of Wugang wear-resistant steel plates meet the strict requirements for high strength, high wear resistance, stability, flatness, and surface quality. The combination of high hardness, high strength, and excellent impact toughness makes these wear-resistant steel plates an ideal material for a wide range of applications. Since the development of wear-resistant steel in 1999, Wuyang Iron and Steel Company has utilized its long-term research efforts and years of production experience to develop steel plates of various quality grades that meet market demands, including product series such as ordinary wear-resistant steel plates, high-grade wear-resistant steel plates, and wear-resistant steel plates with excellent impact toughness. Currently, the production thickness of Wugang’s wear-resistant steel plates ranges from 8 to 150 mm, with a maximum hardness of 500 HBW. It can fully meet the requirements for thin plates and ultra-wide wear-resistant plates. Wugang wear-resistant steel plates are used for wear-resistant components in equipment across various industries, including underground mines, the cement industry, road construction, ore mining and open-pit mines, as well as the metallurgical industry. 1. Classification of W wear-resistant plates: Wuhan Iron and Steel’s wear-resistant plates come in 2 standard series and 4 high-grade series. The high-grade series include more than a dozen types such as ordinary wear resistance, ultra-high wear resistance, and high toughness, enabling them to meet the requirements of various application areas. Standard wear-resistant steel plates: This series of steel plates can be manufactured to a maximum thickness of 100 mm, while still maintaining the desired hardness. At the same time, ensure a certain impact toughness. The representative steel grades include the WNM360 and WNM400 series, along with 6 grades in quality levels A, B, and C. Ultra-wear-resistant steel plates: This series of steel plates is designed to offer a longer service life, thereby reducing overall operating costs. Without making further sacrifices to welding and forming properties, it offers extremely high wear resistance; the corresponding steel grades include the WNM450 and WNM500 series, as well as six grades with quality levels A, B, and C. High-toughness wear-resistant plates: Below -20 degrees Celsius, it is difficult to ensure the toughness of wear-resistant steel plates; however, Wugang has successfully developed such plates that can meet the requirements for toughness under the harshest conditions, including temperatures as low as -40 degrees Celsius. The relevant steel grades include the WNM360 and WNM400 series, along with four quality grades labeled D and E. High-weldability steel plates: This series of steel plates is designed to maintain weldability comparable to that of ordinary materials under severe welding conditions (where pre-treatment prior to welding is not possible). Without compromising wear resistance, it achieves the lowest possible carbon equivalent of the steel plate, exhibiting excellent weldability; representative grades include WNM360L. Clad composite wear-resistant steel plates, welded wear-resistant steel plates, bimetallic wear-resistant steel plates, composite wear-resistant plates, welded wear-resistant plates, bimetallic wear-resistant plates. Bimetallic composite wear-resistant steel plates have been widely used in the heavy industry sector, providing important wear-resistant protection for industrial equipment and workpieces in China. They significantly extend the service life of such equipment and workpieces, thereby contributing to improved production efficiency and reduced production costs for enterprises. The dual-metal composite wear-resistant steel plate is produced using an arc-shielded, fully automatic surfacing process to deposit a layer of high-alloy material with high hardness and excellent wear resistance on the surface of ordinary steel or stainless steel plates. This wear-resistant steel plate possesses the advantages of both metals: the high wear resistance of the working layer and the high plasticity and toughness of the base layer. It provides convenient conditions for mechanical joining and welding in industrial applications, and can be processed through methods such as coiling, welding, plasma cutting, and mechanical joining. 1. Excellent wear resistance: The alloy’s wear-resistant layer contains 4–5% carbon and as much as 25–30% chromium in its chemical composition. In its microstructure, the volume fraction of Cr7C3 carbides is over 50%, with a macroscopic hardness of HRC56–62; the hardness of chromium carbides is HV1400–1800. Since the carbides are distributed perpendicular to the direction of wear, its wear resistance is more than doubled even when compared with cast alloys of the same composition and hardness. A comparison of wear resistance with several typical materials is as follows: (1) Compared with low-carbon steel ； 20–25:1 (2) vs. as-cast high-chromium cast iron ； 1.5～2.5:1 2. Good impact resistance; the base material of the wear-resistant composite steel plate is low-carbon steel or low-alloy steel. Ductile materials such as stainless steel demonstrate the advantages of bimetallic structures: the wear-resistant layer protects against wear caused by abrasive agents, while the base material bears the loads exerted by these agents, resulting in excellent impact resistance. It can withstand the impacts and wear caused by hoppers and the like under high drop conditions in material conveying systems. 3. Good heat resistance: The alloy wear-resistant layer is recommended for use in conditions of ≤600°C; by adding alloys such as vanadium and molybdenum to this layer, it becomes capable of withstanding high-temperature wear at ≤800°C. The recommended temperature range is as follows: For ordinary carbon steel substrates, it is recommended to use them in environments where the temperature does not exceed 380°C ； For low-alloy heat-resistant steel plates (15CrMo, 12Cr1MOV, etc.), it is recommended to use them in conditions where the temperature does not exceed 540°C ； The heat-resistant stainless steel substrate is recommended for use in environments at temperatures not exceeding 800°C. 4. Good corrosion resistance: The alloy layer of the wear-resistant composite steel plate contains a high percentage of chromium, which gives it certain rust- and corrosion-resistant properties. It can be used in coal drop tubes and funnels to prevent coal sticking. 5. Complete range of varieties and specifications: There is a wide variety of wear-resistant steel plates in different specifications, which have been organized into standardized product series. The thickness of the wear-resistant alloy layer is 3–20 mm. The minimum thickness of composite steel plates is 6mm; there is no upper limit on thickness. Currently, standard wear-resistant steel plates are available in sizes of 1200 or 1450×2000 mm. They can also be custom-made according to customer requirements and specified dimensions. Wear-resistant steel plates are now divided into three types: ordinary, impact-resistant, and high-temperature. When ordering high-temperature wear-resistant and impact-resistant composite steel plates, it is necessary to specify this. 6. Easy processing properties Wear-resistant steel plates can be cut, bent or curled, welded, and drilled; they can be processed into various components that can be made from ordinary steel plates. The cut wear-resistant steel plates can be welded together to form various engineering structural components or parts. 7. Functions and features: Weldable, with good wear resistance. V. Weldability of non-quenched and tempered NM400 grade high-strength wear-resistant steel plates: The weldability of non-quenched and tempered NM400 grade high-strength wear-resistant steel plates was studied using manual arc welding. The results showed that the weld structure consisted mainly of granular ferrite along with a small amount of pearlite, while the heat-affected zone had a new type of bainitic structure. The fusion zone exhibited good bonding, with relatively fine grains; thus, the welded joints of non-quenched HB400 wear-resistant plates possess good strength and toughness. VI. Properties and Applications of Highly Wear-Resistant Composite Steel Plates In the field of industrial production, wear and tear on mechanical parts is one of the main causes of equipment failure. Early damage to mechanical equipment caused by wear from media such as sediment, dust, and ore is a prominent issue encountered in production. Currently, traditional wear-resistant materials are generally integrally cast wear-resistant materials such as high-manganese steel and chromium-based wear-resistant cast irons. Although the use of such materials can improve the wear resistance of machine components, they still have shortcomings. Materials such as wear-resistant white cast iron and chromium-based wear-resistant cast iron are quite brittle and not resistant to impact ； Manganese steel has poor resistance to abrasive wear, and cast wear-resistant materials are bulky in structure with significant material waste, which prevents them from meeting the requirements for wear-resistant materials in industrial production. High-wear-resistant composite steel plate is a wear-resistant composite material produced using advanced composite manufacturing techniques; its base layer is made of ordinary carbon steel, while the wear-resistant layer is composed of high-grade wear-resistant alloys. This material is widely used in industrially developed countries. Wear-resistant composite steel plate is a wear-resistant composite material produced using advanced composite manufacturing techniques; its wear-resistant layer is made from high-grade wear-resistant alloys, making it an advanced wear-resistant composite material in the industrial sector. VII. Performance characteristics of high-wear-resistant composite steel plates: 1. High wear resistance: Utilizing the alloy system commonly used in international high-wear-resistant composite steel plates, these plates exhibit excellent resistance to abrasive wear; their wear resistance is **higher than that of heat-treated wear-resistant steels and cast wear-resistant irons, and their ability to resist wear is also **greater than that achieved through spray welding or thermal spraying methods. 2. Impact resistance: Since the base material of the wear-resistant composite steel plate is low-carbon steel with excellent plasticity, it can absorb energy during impacts; as a result, the wear-resistant composite steel plate possesses strong impact resistance and crack resistance, making it suitable for use in conditions with high vibration and impact forces. 3. Easy to process: Wear-resistant composite steel plates can be made into sheets of standard sizes; they are lightweight and easy to work with. Thanks to the use of a soft substrate, they can be bent inward, and they can be cut using heat sources such as plasma arcs or carbon arcs. It can be formed by tack welding, making on-site welding work faster and more convenient. 4. High cost-performance ratio: Taking into account maintenance costs, spare parts costs, and downtime losses, the performance-to-price ratio of components made from wear-resistant composite steel plates is 2 to 3 times higher than that of ordinary materials. 5. Technical analysis: On the wear-resistant layer of the wear-resistant composite steel plate, stress is released through the formation of fine and uniform cracks. This helps maintain the flatness of the entire plate surface and prevents stress concentration. These cracks remain confined within the hard layer; they do not propagate into the substrate, which has excellent toughness, during use. Below 600°C, under conditions involving high levels of erosive wear and abrasive wear, it exhibits excellent wear resistance, impact resistance, and oxidation resistance, making it suitable for various wear conditions. In addition, the tensile and impact resistance of the wear-resistant composite steel plate is no lower than that of welded joints of Q235 steel plates. (1) Hardness of the wear-resistant layer: HRC54–60; thickness of the wear-resistant layer: 3.5–12 mm. The dimensions of the composite plate are ≤1×2M. (2) The matrix of the wear-resistant layer in the composite steel plate consists of alloyed martensite, carbides, and residual austenite. A large number of hard, wear-resistant particles are distributed within this matrix, and the optimal combination of this matrix with these hard, wear-resistant particles gives the material high wear resistance. Its wear resistance is 5 to 6 times that of heat-treated wear-resistant steel ； 5 times that of stainless steel ； 5–6 times that of high-manganese steel ； 18 times that of low-carbon steel (grit wear experiment data at room temperature). (3) The tensile and impact resistance of the composite steel plate shall be no lower than those of the welded joints of Q235 steel plates. (4) Workability of the composite steel plate: It can be cut and drilled using air arc or plasma arc. It can be cold-formed or rolled into a round shape. During cold rolling, the minimum radius of curvature is 600 mm; it can be connected to the workpiece that requires strengthening using plug welding, end face welding, or bolted connections. (5) The surface wear-resistant composite layer of composite steel plates can be manufactured using different alloy systems to meet the needs of various users. VIII. Applications of wear-resistant composite steel plates Wear-resistant composite steel plates can be used for surface strengthening of various wear-prone equipment components in industries such as metallurgical machinery, building materials machinery, power machinery, and mining machinery. Typical applications include: 1. Using the composite sheet directly for cutting, rolling, and welding to create various wear-resistant conveyor pipes, such as those used in powder air conveying systems and blast furnace slag handling systems. 2. Provide users with wear-resistant spare parts made of composite materials, such as mill linings, mixer blades, fan blades, etc., in accordance with design requirements. 3. Provide composite steel plates directly to the user, who then cuts the materials as needed and carries out welding to complete on-site construction projects such as silos and chutes. 4. Depending on the extent of wear on the user’s components, pre-fabricated units are provided for on-site welding repairs, thereby reducing the amount of welding work required on site. Examples include the buckets of construction machinery and the digging buckets of dredgers. 5. The arc welding method with wire feeding can be used to apply wear-resistant layers directly to large-scale worn components, which significantly improves production efficiency. Examples include various types of large crushers, the drums and rollers of grinding mills, etc. 9. Imported Swedish wear-resistant plates such as Hardox 400/Hardox 500: Although HARDOX wear-resistant steel plates possess high hardness and toughness, they can still be processed using conventional methods to create the desired components or structures. 1. Bending and shearing: Thanks to its high purity and low thickness tolerance, HARDOX wear-resistant steel plate is easy to bend into shape. The gas cutting method can be applied to HARDOX wear-resistant steel plates of any grade. 2. The alloy element content in welded HARDOX wear-resistant steel plates is very low, and their carbon equivalent is also quite low. Therefore, HARDOX wear-resistant steel plates can be welded using conventional welding methods, and they can also be welded to other ordinary structural steel plates. 3. Machining: Machining includes drilling, countersinking, end milling, tapping, or milling. HARDOX wear-resistant steel plates can be machined using high-speed steel (HSS) or cemented carbide (CC) tools. Experimental techniques such as SEM, TEM, and EDS were used to study the variations in the microstructure, surface hardness, and wear amount of NM400 steel plates after tempering at 200–600°C for 1 hour, as a function of the tempering temperature. The results show that the hardness and wear resistance of NM400 steel plates decrease as the tempering temperature increases. Between 400–450°C, the decline is relatively gradual due to the strengthening effect of the precipitation of alloy elements. The microstructure in the quenched state is martensite, and it transforms into tempered martensite after tempering at temperatures below 450°C. As the tempering temperature rises, the merging of adjacent martensite laths becomes more apparent, leading to a decrease in the surface hardness of the steel plate. The microstructure, mechanical properties, and weldability of carbide-free bainitic wear-resistant steel plates were studied. The results show that, based on low-carbon bainite steel, by adding a certain amount of silicon and utilizing its ability to inhibit the precipitation of carbides during the bainite transformation process, a carbide-free bainite structure can be obtained. This structure consists of non-equiaxed ferrite along with martensite and residual austenite (M-A) islands, or of lath-like ferrite along with residual austenite (Ar) films in between the laths. Such a structure confers high strength and hardness, as well as good low-temperature impact toughness, alongside excellent weldability. The effects of different heat treatment processes, including hot rolling, low-temperature tempering, as well as hot rolling followed by normalizing, low-temperature tempering, and tempering at various temperatures in the as-rolled state, on the microstructure, mechanical properties, and wear resistance of the new HB400 grade high-strength quasi-bainitic wear-resistant steel plate were studied. The results show that in both conditions, the microstructure of the wear-resistant plate consists of bainite ferrite (BF) and residual austenite (AR), granting it good strength, toughness, and wear resistance. Low-temperature tempering can improve the toughness of wear-resistant steel plates. The new type of wear-resistant steel plate has strong temper resistance. Producing high-strength wear-resistant plates using quasibainite steel features a simple production process and low costs.