One-steel multi-material production method
By using the same composition design and optimizing hot rolling process parameters, the problem of increasing the number of billet grades when steel mills produce steel grades for different purposes has been solved, enabling the production of multiple materials of the same grade, reducing costs and improving production efficiency and product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-26
- Publication Date
- 2026-03-13
AI Technical Summary
When steel mills produce steel grades for different purposes, they need to design different composition systems to meet customer needs, which leads to an increase in the number of billet grades, inventory backlog, reduced production efficiency and increased costs.
Using the same composition design, and through reasonable composition matching and hot rolling process parameters, steel grades of the same level but different uses are produced, including beam steel 510L, wheel steel 490CL and bridge shell steel Q420QK. By combining precipitation strengthening and fine grain strengthening, the performance requirements of each steel grade are met.
The number of billet grades was reduced, inventory and production costs were lowered, and corporate efficiency was improved. Furthermore, by improving surface quality and low-temperature impact performance, the production of multiple products from a single steel billet was achieved.
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Figure CN121653322A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metallurgical technology, specifically relating to a method for producing multiple materials from a single steel source. Background Technology
[0002] With increasingly fierce market competition, steel mills are becoming more refined in their cost control. Since strip steel production is based on multiples of the weight per heat, sometimes orders are particularly low, resulting in excess slabs and unmanageable inventory buildup. To maintain product quality, this often leads to deterioration and subsequent losses for the company. Secondly, in traditional production processes, products of similar strength typically use different composition systems depending on the user's intended use and mechanical performance requirements. This is achieved through alloying and differentiation, which satisfies customer needs but increases steel mill costs.
[0003] Although they are of the same grade, different applications result in different technical specifications required by customers. For example, 510L beam steel requires an impact energy of >37J at -20℃, while 490CL wheel steel and Q420QK axle shell steel not only have requirements for low-temperature impact performance (requiring an impact energy of >37J at -20℃) but also for fatigue performance. Specifically, 490CL wheel steel requires a fatigue resistance of 3.75 tons to reach 1.6 million cycles (for wheel hubs to bear 3.75 tons and rotate 1.6 million times), and Q420QK axle shell steel requires a fatigue resistance of 2.5 times load to >800,000 cycles. This necessitates designing different composition systems to meet customer needs, increasing the number of billet grades, gradually increasing billet inventory, reducing steel mill production efficiency, and lowering enterprise costs. Currently, steel mills can only produce different grades of the same steel using the same composition of billets, but the same composition of billets cannot meet the production needs of different varieties and applications of steel.
[0004] Therefore, conducting a reasonable composition design and producing steel of the same grade but different uses through different rolling processes, thus realizing the production of multiple products from one steel, is of great practical significance for reducing steel smelting costs and improving the economic benefits of enterprises. Summary of the Invention
[0005] This invention provides a method for producing multiple steel products from a single steel. This method involves designing the composition of the product and is applicable to the same grade of beam steel 510L, wheel steel 490CL, and bridge shell steel Q420QK. This effectively reduces the number of billet grades, allows for effective control of inventory billets, improves the production efficiency of steel mills, and reduces enterprise costs.
[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a production method for multiple steel products, the production method including converter smelting, LF refining, slab continuous casting, heating, rolling, laminar flow cooling, and coiling processes, finally obtaining finished steel products, including beam steel 510L, wheel steel 490CL, and axle shell steel Q420QK; in the coiling process, the coiling temperature of beam steel 510L is 600-640℃, the coiling temperature of wheel steel 490CL is 560-590℃, and the coiling temperature of axle shell steel Q420QK is 580-620℃.
[0007] In the laminar flow cooling process described in this invention, the main beam steel 510L with a thickness of 5mm ≤ and 6mm adopts sparse cooling in the rear section, and the steel with a thickness ≥ 6mm adopts concentrated cooling in the rear-front section; the wheel steel 490CL and the axle shell steel Q420QK adopt concentrated cooling in the front section.
[0008] The 510L main beam steel described in this invention has a tensile strength ≥ 510 MPa, a yield strength ≥ 355 MPa, and an elongation ≥ 24%.
[0009] The wheel steel 490CL described in this invention has a tensile strength ≥490MPa, a yield strength ≥325MPa, and an elongation ≥24%.
[0010] The bridge shell steel Q420QK of the present invention has a tensile strength ≥520MPa, a yield strength ≥420MPa, and an elongation ≥22%.
[0011] The chemical composition and mass percentage of the finished steel described in this invention are as follows: C: 0.07%-0.09%, Mn: 1.20%-1.50%, Si: 0.05%-0.18%, S≤0.003%, P≤0.018%, Als: 0.015%-0.035%, Nb: 0.015%-0.35%, Ti: 0.015%-0.30%, N≤0.0060%, with the remainder being Fe and unavoidable residual elements.
[0012] In the hot rolling process described in this invention, the finishing rolling inlet temperature is 980-1030℃, and the final rolling temperature is 840-880℃.
[0013] The heating process described in this invention uses a heating temperature of 1170-1230℃.
[0014] The finished steel of the present invention has a thickness of 5.0-12.0 mm and a low-temperature impact energy of -20℃ ≥60J.
[0015] The wheel steel 490CL described in this invention is required to have fatigue resistance so that the wheel hub can bear a load of 3.75 tons and rotate ≥ 1.8 million times. The axle shell steel Q420QK is required to have fatigue resistance of 2.5 times load > 900,000 times.
[0016] The design concept of this invention is as follows: Generally, the strengthening mechanisms of beam steel, wheel steel, and axle shell steel differ, resulting in different compositions. This invention uses only one component, rationally combined with hot rolling process parameters, employing a reasonable combination of precipitation strengthening and grain refinement strengthening to achieve the production of steel grades for different applications. For example, for beam steel, by controlling the hot rolling process, the precipitation strengthening ratio is 70%-80%, and the grain refinement strengthening ratio is 20%-30%, ensuring that the product performance meets standard requirements. For wheel steel, by controlling the hot rolling process, the precipitation strengthening ratio is 60%-70%, and the grain refinement strengthening ratio is 30%-40%, ensuring that the product performance meets standard requirements. For axle shell steel, by controlling the hot rolling process, the precipitation strengthening ratio is 50%-60%, and the grain refinement strengthening ratio is 40%-50%, ensuring that the product performance meets standard requirements.
[0017] The beneficial effects of adopting the above technical solution are as follows: 1. This invention can produce beam steel 510L, wheel steel 490CL, and bridge shell steel Q420QK from steel billets with the same chemical composition, which to a certain extent reduces the number of steel billet grades and lowers the cost increase for steel companies due to the independent casting of different steel grades and the increase in inventory billets. At the same time, this invention can enhance order-taking capacity, eliminate the drawback of not being able to take orders if there is not enough heat, and improve enterprise efficiency. 2. This invention adopts a lower finishing mill inlet temperature, which not only improves the surface quality of the strip steel, but also improves the low-temperature impact performance of the strip steel; by adopting different cooling modes and coiling temperatures, it realizes the production of strip steel of multiple products from one steel. Attached Figure Description
[0018] Figure 1 Here is a metallographic diagram of the main beam steel in Example 1; Figure 2 Here is a metallographic diagram of the wheel steel from Example 1; Figure 3 The image shows the metallographic structure of the bridge shell steel in Example 1. Detailed Implementation
[0019] The present invention will now be described in further detail with reference to specific embodiments. Example 1
[0020] A method for producing multiple steel products from a single steel source includes converter smelting, LF refining, slab continuous casting, heating, rolling, laminar flow cooling, and coiling processes to finally obtain finished steel. The chemical composition and mass percentage of the finished steel are shown in Table 1. The finished steel includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel. The specific production process control is as follows: The heating process involves a heating temperature of 1230℃. In the hot rolling process, the entry temperature for finishing rolling is 1030℃, and the final rolling temperature is 880℃. In the laminar flow cooling process, the finished steel thickness is 5mm. The main beam steel 510L adopts the rear-stage sparse cooling; the wheel steel 490CL and the axle shell steel Q420QK adopt the front-stage centralized cooling. In the coiling process, the coiling temperature of 510L beam steel is 640℃, the coiling temperature of 490CL wheel steel is 560℃, and the coiling temperature of Q420QK axle shell steel is 580℃, finally obtaining the finished steel, which includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel.
[0021] The tensile strength, yield strength, elongation, and -20℃ low-temperature impact energy of the main beam steel 510L, wheel steel 490CL, and axle shell steel Q420QK produced in this embodiment are shown in Table 2-5.
[0022] Figure 1 Here is a metallographic diagram of the main beam steel in Example 1; Figure 2 Here is a metallographic diagram of the wheel steel from Example 1; Figure 3 The image shows the metallographic structure of the bridge shell steel in Example 1 (the images for other examples are similar and therefore omitted). Figure 1 It can be seen that the microstructure of the beam steel is ferrite plus pearlite, with a grain size of grade 9. The grains are uniform, and the pearlite is distributed in a fine and uniform lamellar or granular carbide morphology. Some grains contain granular carbides and a high density of dislocations. This microstructure is achieved by the high cooling rate after hot rolling, which can simultaneously ensure the steel's high strength and good toughness. Figure 2 It can be seen that the microstructure of wheel steel is ferrite + pearlite. The grain size is grade 10.5, indicating fine grain size and good overall uniformity. This structure balances the required strength, plasticity, and weldability of wheel steel, meeting the needs of wheel processing and service. Figure 3 It can be seen that the metallographic structure of the bridge shell steel is ferrite + pearlite, with a grain size of grade 11. The grain size is small and uniform, with good cold formability, weldability and load-bearing toughness, making it suitable for the complex processing and stress scenarios of bridge shells. Example 2
[0023] A method for producing multiple steel products from a single steel source includes converter smelting, LF refining, slab continuous casting, heating, rolling, laminar flow cooling, and coiling processes to finally obtain finished steel. The chemical composition and mass percentage of the finished steel are shown in Table 1. The finished steel includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel. The specific production process control is as follows: The heating process involves a heating temperature of 1220℃. In the hot rolling process, the entry temperature for finishing rolling is 1030℃, and the final rolling temperature is 880℃. The laminar flow cooling process is used for finished steel with a thickness of 6mm. The main beam steel 510L adopts front-stage centralized cooling; the wheel steel 490CL and the axle shell steel Q420QK adopt front-stage centralized cooling. In the coiling process, the coiling temperature of the main beam steel 510L is 620℃, the coiling temperature of the wheel steel 490CL is 570℃, and the coiling temperature of the axle shell steel Q420QK is 590℃, finally obtaining the finished steel, which includes the main beam steel 510L, the wheel steel 490CL, and the axle shell steel Q420QK.
[0024] The tensile strength, yield strength, elongation, and -20℃ low-temperature impact energy of the main beam steel 510L, wheel steel 490CL, and axle shell steel Q420QK produced in this embodiment are shown in Table 2-5. Example 3
[0025] A method for producing multiple steel products from a single steel source includes converter smelting, LF refining, slab continuous casting, heating, rolling, laminar flow cooling, and coiling processes to finally obtain finished steel. The chemical composition and mass percentage of the finished steel are shown in Table 1. The finished steel includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel. The specific production process control is as follows: The heating process involves a heating temperature of 1210℃. In the hot rolling process, the entry temperature of the finishing mill is 1010℃, and the final rolling temperature is 880℃. The laminar flow cooling process is used for finished steel with a thickness of 8mm. The main beam steel 510L adopts front-stage centralized cooling; the wheel steel 490CL and the axle shell steel Q420QK adopt front-stage centralized cooling. In the coiling process, the coiling temperature of 510L beam steel is 635℃, the coiling temperature of 490CL wheel steel is 580℃, and the coiling temperature of Q420QK axle shell steel is 600℃, finally obtaining the finished steel, which includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel.
[0026] The tensile strength, yield strength, elongation, and -20℃ low-temperature impact energy of the main beam steel 510L, wheel steel 490CL, and axle shell steel Q420QK produced in this embodiment are shown in Table 2-5. Example 4
[0027] A method for producing multiple steel products from a single steel source includes converter smelting, LF refining, slab continuous casting, heating, rolling, laminar flow cooling, and coiling processes to finally obtain finished steel. The chemical composition and mass percentage of the finished steel are shown in Table 1. The finished steel includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel. The specific production process control is as follows: The heating process involves a heating temperature of 1200℃. In the hot rolling process, the entry temperature of the finishing mill is 1010℃, and the final rolling temperature is 860℃. In the laminar flow cooling process, the finished steel thickness is 10mm. The main beam steel 510L adopts front-stage centralized cooling; the wheel steel 490CL and the axle shell steel Q420QK adopt front-stage centralized cooling. In the coiling process, the coiling temperature of the main beam steel 510L is 610℃, the coiling temperature of the wheel steel 490CL is 590℃, and the coiling temperature of the axle shell steel Q420QK is 620℃, finally obtaining the finished steel, which includes the main beam steel 510L, the wheel steel 490CL, and the axle shell steel Q420QK.
[0028] The tensile strength, yield strength, elongation, and -20℃ low-temperature impact energy of the main beam steel 510L, wheel steel 490CL, and axle shell steel Q420QK produced in this embodiment are shown in Table 2-5. Example 5
[0029] A method for producing multiple steel products from a single steel source includes converter smelting, LF refining, slab continuous casting, heating, rolling, laminar flow cooling, and coiling processes to finally obtain finished steel. The chemical composition and mass percentage of the finished steel are shown in Table 1. The finished steel includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel. The specific production process control is as follows: The heating process involves a heating temperature of 1180℃. In the hot rolling process, the entry temperature for finishing rolling is 980℃, and the final rolling temperature is 860℃. In the laminar flow cooling process, the finished steel thickness is 11mm. The main beam steel 510L adopts front-stage centralized cooling; the wheel steel 490CL and the axle shell steel Q420QK adopt front-stage centralized cooling. In the coiling process, the coiling temperature of 510L beam steel is 600℃, the coiling temperature of 490CL wheel steel is 560℃, and the coiling temperature of Q420QK axle shell steel is 610℃, finally obtaining the finished steel, which includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel.
[0030] The tensile strength, yield strength, elongation, and -20℃ low-temperature impact energy of the main beam steel 510L, wheel steel 490CL, and axle shell steel Q420QK produced in this embodiment are shown in Table 2-5. Example 6
[0031] A method for producing multiple steel products from a single steel source includes converter smelting, LF refining, slab continuous casting, heating, rolling, laminar flow cooling, and coiling processes to finally obtain finished steel. The chemical composition and mass percentage of the finished steel are shown in Table 1. The finished steel includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel. The specific production process control is as follows: The heating process involves a heating temperature of 1170℃. In the hot rolling process, the entry temperature for finishing rolling is 980℃, and the final rolling temperature is 840℃. The laminar flow cooling process is used for finished steel with a thickness of 12mm. The main beam steel 510L adopts front-stage centralized cooling; the wheel steel 490CL and the axle shell steel Q420QK adopt front-stage centralized cooling. In the coiling process, the coiling temperature of 510L beam steel is 600℃, the coiling temperature of 490CL wheel steel is 560℃, and the coiling temperature of Q420QK axle shell steel is 580℃, finally obtaining the finished steel, which includes 510L beam steel, 490CL wheel steel, and Q420QK axle shell steel.
[0032] The tensile strength, yield strength, elongation, and -20℃ low-temperature impact energy of the main beam steel 510L, wheel steel 490CL, and axle shell steel Q420QK produced in this embodiment are shown in Table 2-5.
[0033] Table 1 Chemical composition and mass percentage of the finished steel products from Examples 1-6
[0034] Table 2 Mechanical and impact properties of 510L steel strip for beams in Examples 1-6
[0035] Table 3 Mechanical and impact properties of 490CL wheel steel strips (Examples 1-6)
[0036] Table 4 Mechanical and impact properties of bridge shell steel Q420QK strip (Examples 1-6)
[0037] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for producing multiple materials from a single steel source, characterized in that, The production method includes converter smelting, LF refining, slab continuous casting, heating, rolling, laminar flow cooling, and coiling processes to finally obtain finished steel, including beam steel 510L, wheel steel 490CL, and axle shell steel Q420QK; in the coiling process, the coiling temperature of beam steel 510L is 600-640℃, the coiling temperature of wheel steel 490CL is 560-590℃, and the coiling temperature of axle shell steel Q420QK is 580-620℃.
2. The method for producing multiple materials from a single steel source according to claim 1, characterized in that, In the laminar flow cooling process, the main beam steel 510L with a thickness of 5mm ≤ and 6mm adopts the rear sparse cooling, and the steel with a thickness ≥ 6mm adopts the rear front concentrated cooling; the wheel steel 490CL and the axle shell steel Q420QK adopt the front concentrated cooling.
3. The method for producing multiple materials from a single steel source according to claim 1, characterized in that, The tensile strength of the 510L main beam steel is ≥510MPa, the yield strength is ≥355MPa, and the elongation is ≥24%.
4. The method for producing multiple materials from a single steel source according to claim 1, characterized in that, The wheel steel 490CL has a tensile strength ≥490MPa, a yield strength ≥325MPa, and an elongation ≥24%.
5. The method for producing multiple materials from a single steel source according to claim 1, characterized in that, The bridge shell steel Q420QK has a tensile strength ≥520MPa, a yield strength ≥420MPa, and an elongation ≥22%.
6. A method for producing multiple materials from a single steel source according to any one of claims 1-5, characterized in that, The finished steel has the following chemical composition and mass percentage: C: 0.07%-0.09%, Mn: 1.20%-1.50%, Si: 0.05%-0.18%, S≤0.003%, P≤0.018%, Als: 0.015%-0.035%, Nb: 0.015%-0.35%, Ti: 0.015%-0.30%, N≤0.0060%, with the remainder being Fe and unavoidable residual elements.
7. A method for producing multiple materials from a single steel source according to any one of claims 1-5, characterized in that, The hot rolling process has a finishing rolling inlet temperature of 980-1030℃ and a final rolling temperature of 840-880℃.
8. A method for producing multiple materials from a single steel source according to any one of claims 1-5, characterized in that, The heating process involves heating at a temperature of 1170-1230℃.
9. A method for producing multiple materials from a single steel source according to any one of claims 1-5, characterized in that, The thickness of the finished steel is 5.0-12.0 mm, and the low-temperature impact energy of the finished steel at -20℃ is ≥60 J.
10. A method for producing multiple materials from a single steel source according to any one of claims 1-5, characterized in that, The wheel steel 490CL is required to have fatigue resistance so that the wheel hub can bear a load of 3.75 tons and rotate ≥ 1.8 million times. The axle shell steel Q420QK is required to have fatigue resistance of 2.5 times load > 900,000 times.