StE500N steel for engineering machinery axle and preparation method of StE500N steel

Abstract

The invention discloses StE500N steel for an engineering machinery axle and a preparation method of the StE500N steel, and relates to the technical field of steel production, and the StE500N steel comprises the following chemical components in percentage by mass: 0.12 < = C < = 0.20%; mn: 1.5 to 1.8%; 0.2 to 0.4 percent of Si; less than or equal to 0.015% of P; s is less than or equal to 0.010%; 0.005% to 0.20% of Al; 0.10% to 0.25% of Ni; 0.10% to 0.25% of Cr; 0.010% to 0.025% of Nb; 0.13% to 0.20% of V; 100 to 200 ppm of N, and the balance being Fe and inevitable impurities. Through the V-N composite microalloying process technology, uniform and dispersed V (C, N) second-phase particulate matter precipitation is formed on a ferrite and pearlite steel matrix, two strengthening mechanisms of precipitation strengthening and grain refinement are exerted, and strength and toughness matching of the steel plate is achieved through the combined action.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel production, in particular to a StE500N steel for engineering machinery axle and a preparation method thereof. BACKGROUND

[0002] Engineering machinery axle is a core component of engineering machinery (such as excavator, loader, crane, etc.), mainly including drive axle, steering axle, support axle, etc. At present, domestic engineering machinery axle manufacturing generally adopts casting form production, which has the characteristics of low cost, high material utilization rate, etc. However, there are still some shortcomings in the machining precision, surface quality, service life and carrying capacity of the current axle products.

[0003] Invention patent CN111893385A discloses a steel plate for automobile axle housing and a preparation method. The invention is characterized by the composite addition of alloy elements such as Nb, V and Ti, the reasonable design of Si and Mn content, and the implementation of 4300mm double rack rolling, controlled cooling and other process technologies. The automobile axle housing steel obtained has a banded structure less than 3 levels, a lower yield strength greater than 490MPa, a tensile strength greater than 610MPa, an elongation after fracture greater than 17%, and a 0 degree impact energy greater than 47J. The thickness specification of the steel plate is 11-17mm. The alloy cost is relatively low, and the smelting process is relatively simple. However, the thickness specification range is relatively narrow, and the steel does not have good low temperature impact toughness.

[0004] Invention patent CN113201689A discloses a steel for medium truck front axle and a production method thereof. The invention belongs to the technical field of alloy steel, and precisely controls the content of Mo, Ni, Cu and other elements in the steel, refines the grain size of the steel, and improves the impact toughness of the steel, which is beneficial to improving the fatigue life of the automobile front axle. The steel for medium truck front axle produced by the method has a high alloy content, and the alloy cost is high.

[0005] Invention patent CN119287263A discloses a high-performance low-cost microalloy steel for automobile I-beam axle and a preparation method thereof. The invention is characterized by directly performing heat treatment after casting. The above composition control helps to promote the dispersion precipitation of nano-sized TiC on the original austenite grain boundary, effectively pins the austenite grains, and obtains a microstructure with uniform and fine grain size. The martensite structure is obtained by quenching, and the uniform dispersion precipitation of TiC carbide in the martensite structure is realized through subsequent tempering process, which ensures that the mechanical strength and toughness of the automobile I-beam axle are optimally matched. The method not only has a high alloy content, but also adopts quenching + tempering heat treatment, which is a complex process and has a high cost. SUMMARY

[0006] The technical problem solved by the present application is to overcome the defects of the prior art and provide a StE500N steel for an engineering machinery axle and a preparation method thereof.

[0007] To solve the above technical problems, the technical solutions of the present application are as follows: A StE500N steel for an engineering machinery axle, which has the following chemical components and mass percentages: 0.12≤C≤0.20%; Mn: 1.5~1.8%; Si: 0.2~0.4%; P≤0.015%; S≤0.010%; Al: 0.005~0.20%; Ni: 0.10~0.25%; Cr: 0.10~0.25%; Nb: 0.010~0.025%; V: 0.13~0.20%; N: 100~200ppm, and the balance being Fe and inevitable impurities.

[0008] As a preferred scheme of the StE500N steel for an engineering machinery axle, the thickness of the StE500N steel for an engineering machinery axle is less than or equal to 85mm.

[0009] As a preferred scheme of the StE500N steel for an engineering machinery axle, the mechanical properties of the StE500N steel for an engineering machinery axle satisfy: When the thickness of the steel plate is less than or equal to 16mm, the yield strength of the steel plate is greater than or equal to 500 Mpa; When the thickness of the steel plate is greater than 16mm and less than or equal to 35mm, the yield strength of the steel plate is greater than or equal to 480 Mpa; When the thickness of the steel plate is greater than 35mm and less than or equal to 50mm, the yield strength of the steel plate is greater than or equal to 470 Mpa; When the thickness of the steel plate is greater than 50mm and less than or equal to 60mm, the yield strength of the steel plate is greater than or equal to 460 Mpa, and the tensile strength is 610~780Mpa; When the thickness of the steel plate is greater than 60mm and less than or equal to 70mm, the yield strength of the steel plate is greater than or equal to 450 Mpa, and the tensile strength is 610~780Mpa; When the thickness of the steel plate is greater than 70mm and less than or equal to 85mm, the yield strength of the steel plate is greater than or equal to 440 Mpa, the tensile strength is 600~770Mpa, the elongation is greater than or equal to 16%, and the transverse impact energy at-20℃ is greater than or equal to 21J.

[0010] The present application also provides a preparation method of the StE500N steel for an engineering machinery axle, which comprises the following steps in sequence: heating, hot rolling, cooling and heat treatment.

[0011] As a preferred scheme of the preparation method of the StE500N steel for the engineering machinery axle of the application, in the heating process, the heating temperature of the billet is 1180-1220 DEG C.

[0012] As a preferred scheme of the preparation method of the StE500N steel for the engineering machinery axle of the application, in the heating process, the heating temperature of the billet is 1180-1220 DEG C.

[0013] As a preferred scheme of the preparation method of the StE500N steel for the engineering machinery axle of the application, in the heating process, the heating temperature of the billet is 1180-1220 DEG C.

[0014] As a preferred scheme of the preparation method of the StE500N steel for the engineering machinery axle of the application, in the heating process, the heating temperature of the billet is 1180-1220 DEG C.

[0015] The beneficial effects of the application are: (1) The application forms uniform and dispersed V(C, N) second phase particle precipitation on the ferrite + pearlite steel matrix through the V-N composite micro-alloying process, and plays the two strengthening mechanisms of precipitation strengthening and grain refinement, and realizes the matching of the strength and toughness of the steel plate.

[0016] (2) The StE500N steel plate for the engineering machinery axle prepared by the application has good low-temperature toughness, stable performance, and the preparation method provided by the application has low comprehensive cost. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 The metallographic structure morphology schematic view of the StE500N steel for the engineering machinery axle prepared for example 1 at 1 / 4. DETAILED DESCRIPTION

[0019] In order to make the content of the application more easily understood, the application will be further described in detail according to the specific embodiments and in combination with the drawings.

[0020] The embodiment of the application provides a kind of engineering machinery axle StE500N steel, its chemical composition and mass percentage are C:0.14%;Mn:1.55%;Si:0.24%;P:0.008%;S:0.004%;Al:0.018%;Ni:0.14%;Cr:0.15%;Nb:0.015%;V:0.15%;N:128ppm, the balance is Fe and inevitable impurities.

[0021] The preparation method of the engineering machinery axle StE500N steel includes the following steps: Step S1: heating process: billet is heated using a heating furnace, and the heating section temperature is controlled at 1200±20℃, and the total furnace time is (0.9~1.5)H (H-steel plate thickness); Step S2: hot rolling process: after the continuous casting billet is heated and discharged, two-stage controlled rolling is used, and the warm billet thickness is greater than or equal to 2.2H (H-steel plate thickness), and the rolling temperature is controlled at 780℃~810℃ in the finishing rolling stage; Step S3: cooling process: water cooling or air cooling is used to cool to room temperature, and the re-red temperature is 600~680℃.

[0022] The specific rolling process parameters of examples 1-5 are shown in Table 1.

[0023] Table 1 rolling process parameters of examples 1-5

[0024] The product properties obtained in examples 1-5 are shown in Table 2.

[0025] Table 2 product properties obtained in examples 1-5

[0026] The metallographic structure morphology at 1 / 4 of the steel plate obtained in example 1 is shown in Figure 1 , which is mainly ferrite+pearlite structure, and the grain size is about 10~20um.

[0027] According to the above performance results, it can be seen that the steel plate prepared by the method has good low-temperature toughness. And the engineering machinery axle StE500N steel plate prepared by the method has stable performance and low comprehensive cost.

[0028] In addition to the above embodiments, the application can also have other implementation manners; any technical solution formed by equivalent substitution or equivalent transformation falls within the protection scope required by the application.

Claims

1. A StE500N steel for construction machinery axles, characterized by: Its chemical composition and mass percentage are: 0.12≤C≤0.20%; Mn:1.5~1.8%; Si:0.2~0.4%; P≤0.015%; S≤0.010%; Al:0.005~0.20%; Ni:0.10~0.25%; Cr:0.10~0.25%; Nb:0.010~0.025%; V:0.13~0.20%; N:100~200ppm, the balance is Fe and unavoidable impurities.

2. The StE500N steel for construction machinery axles according to claim 1, characterized in that: The thickness of the StE500N steel for the engineering machinery axle is less than or equal to 85 mm.

3. The StE500N steel for construction machinery axles according to claim 1, characterized in that: The mechanical properties of the StE500N steel for construction machinery axles meet the following requirements: When the thickness of the steel plate is less than or equal to 16mm, the yield strength of the steel plate is greater than or equal to 500 MPa; When the thickness of the steel plate is greater than 16 mm and less than or equal to 35 mm, the yield strength of the steel plate is greater than or equal to 480 MPa; When the thickness of the steel plate is greater than 35mm and less than or equal to 50mm, the yield strength of the steel plate is greater than or equal to 470 MPa; When the thickness of the steel plate is greater than 50mm and less than or equal to 60mm, the yield strength of the steel plate is greater than or equal to 460Mpa, and the tensile strength is 610~780Mpa; When the thickness of the steel plate is greater than 60mm and less than or equal to 70mm, the yield strength of the steel plate is greater than or equal to 450Mpa, and the tensile strength is 610~780Mpa; When the thickness of the steel plate is greater than 70mm and less than or equal to 85mm, the yield strength of the steel plate is greater than or equal to 440 MPa, the tensile strength is 600~770 MPa, the elongation is greater than or equal to 16%, and the transverse impact absorption energy at -20℃ is greater than or equal to 21J.

4. A method for preparing StE500N steel for construction machinery axles according to any one of claims 1 to 3, characterized in that: The process includes the following steps in sequence: heating, hot rolling, cooling and heat treatment.

5. The method for preparing StE500N steel for construction machinery axles according to claim 4, characterized in that: The heating temperature of the steel billet in the heating process is 1180°C to 1220°C.

6. The method for preparing StE500N steel for construction machinery axles according to claim 4, characterized in that: The hot rolling process adopts two-stage controlled rolling, and the thickness of the warm billet is greater than or equal to 2.2 times the thickness of the steel plate, and the rolling temperature of the finishing rolling stage is controlled to be 780°C~810°C.

7. The method for preparing StE500N steel for construction machinery axles according to claim 4, characterized in that: The cooling process adopts water cooling, and the final cooling temperature is 600~680℃.

8. The method for preparing StE500N steel for construction machinery axles according to claim 4, characterized in that: In the heat treatment process, the normalizing temperature is controlled to be Ac3+(20-40)°C, the holding time of the steel plate after reaching the temperature is controlled to be 30-45 minutes, and the steel plate is air-cooled to room temperature after being taken out of the furnace.

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