A hot-rolled weathering steel and a method for producing the same

Abstract

The application relates to the technical field of hot-rolled strip steel, in particular to a hot-rolled weather-resistant steel and a production method thereof. The weather-resistant steel comprises the following chemical components: C, Si, Mn, P, S, Ni, Cr, Cu, Al, N, Ti, the rest is Fe and inevitable impurities; the content of Ti is 0.40-0.60 wt%. Based on the weather-resistant performance of 09CuPCrNi, the low-carbon and low-manganese component design is adopted, on the basis of adding alloy elements Ni, Cr and Cu, by adding appropriate amount of alloy element Ti and through a proper process flow, the weather resistance and mechanical properties of the weather-resistant steel are further improved. The application solves the technical problem that the weather resistance and mechanical properties of the 09CuPCrNi weather-resistant steel in the prior art cannot be simultaneously considered.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hot-rolled strip steel, and particularly relates to a hot-rolled weathering steel and a production method thereof. BACKGROUND

[0002] Weathering steel is widely used in the industries of railway, vehicle, bridge and building, etc., and can protect the steel matrix by forming a protective rust layer and reducing the corrosion loss caused by the atmospheric environment. In particular, the weather resistance of 09CuPCrNi weathering steel is 2-8 times that of plain carbon steel.

[0003] However, the weather resistance of the 09CuPCrNi weathering steel in the prior art cannot meet the actual production requirements. At present, it is an urgent problem to be solved to produce a weathering steel which not only has good weather resistance but also has excellent mechanical properties. SUMMARY

[0004] The present application provides a hot-rolled weathering steel and a production method thereof, so as to solve the technical problem that the mechanical properties and weather resistance of the 09CuPCrNi weathering steel in the prior art cannot be considered simultaneously.

[0005] In a first aspect, the present application provides a hot-rolled weathering steel, which comprises the following chemical components:

[0006] C, Si, Mn, P, S, Ni, Cr, Cu, Al, N, Ti, the rest being Fe and unavoidable impurities.

[0007] The content of Ti is 0.40 wt% to 0.60 wt%.

[0008] Optionally, the content of Ti in the weathering steel is 0.50 wt% to 0.60 wt%.

[0009] Optionally, in the chemical components of the weathering steel, the content of C is 0.02 wt% to 0.05 wt%, the content of Si is 0.10 wt% to 0.30 wt%, the content of Mn is 0.30 wt% to 0.80 wt%, the content of P is ≤0.020 wt%, the content of S is ≤0.004 wt%, the content of Ni is 0.10 wt% to 0.30 wt%, the content of Cr is 0.30 wt% to 0.80 wt%, the content of Cu is 0.20 wt% to 0.80 wt%, the content of Al is ≤0.05 wt%, and the content of N is ≥0.0035 wt%.

[0010] Optionally, the microstructure of the weathering steel is ferrite, and the ferrite contains a large amount of spherical Ti-containing carbides and cubic carbonitrides.

[0011] In a second aspect, the present application provides a production method of a hot-rolled weathering steel, for producing the weathering steel of the first aspect, the method comprising:

[0012] performing first heating on the slab with the chemical composition under a condition of setting a first temperature;

[0013] performing rough rolling on the slab after the first heating under a condition of setting a total rolling deformation and a finish rolling temperature;

[0014] performing second heating on the slab after the rough rolling under a condition of setting a second temperature, and then performing finish rolling to obtain a hot-rolled plate;

[0015] performing cooling on the hot-rolled plate under a condition of setting a cooling speed, and then performing coiling to obtain the hot-rolled weathering steel.

[0016] Optionally, the total rolling deformation is ≥ 80%,

[0017] Optionally, the finish rolling temperature is 950-1100℃.

[0018] Optionally, the cooling speed is < 15℃ / s.

[0019] Optionally, the cooling speed is ≤ 10℃ / s.

[0020] Optionally, the first heating temperature is ≥ 1100℃.

[0021] Optionally, the second heating temperature is 1000-1200℃.

[0022] The above technical solution provided by the embodiments of the present application has the following advantages compared with the prior art:

[0023] The hot-rolled weathering steel and the production method thereof provided by the embodiments of the present application are based on the fact that the weathering performance of 09CuPCrNi weathering steel is poor, and a low-carbon and low-manganese component design is adopted, and on the basis of adding alloy elements Ni, Cr and Cu, a proper amount of alloy element Ti is added to ensure the weathering performance; in the thermal mechanical rolling, the reduction in the rough rolling stage is controlled to be ≥ 80% to obtain refined austenite grains; and in the cooling stage, low cooling speed cooling is controlled to ensure the analysis and precipitation of Ti to take into account the impact toughness. In summary, the technical problem of simultaneously taking into account the mechanical properties and weathering performance of 09CuPCrNi weathering steel is solved. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and serve to explain the principles of the present application together with the specification.

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0026] Figure 1 A flowchart of a production method of a hot-rolled weathering steel provided in the embodiments of the present application is shown in the figure.

[0027] Figure 2 A microstructure diagram of the hot-rolled weathering steel provided in the embodiment 5 of the present application is shown in the figure.

[0028] Figure 3 A comparison diagram of corrosion rates of the hot-rolled weathering steel provided in the embodiments of the present application and the 09CuPCrNi steel is shown in the figure. DETAILED DESCRIPTION

[0029] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

[0030] The various embodiments of the present application can exist in the form of a range; it should be understood that the description in the form of a range is only for the convenience and brevity, and should not be understood as a hard limit to the scope of the present application; therefore, it should be considered that the described range has specifically disclosed all possible sub-ranges and single values in the range. For example, it should be considered that the range description from 1 to 6 has 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 in the described range, such as 1, 2, 3, 4, 5 and 6, which applies to any range. In addition, whenever a numerical range is indicated in this document, it refers to any cited number (fraction or integer) in the indicated range.

[0031] In the present application, the orientation words such as "upper" and "lower" are specifically the directions of the drawing surface in the drawings unless otherwise stated. In addition, in the description of the present application, the terms "include", "contain" and the like mean "including but not limited to". In the present text, the relational terms such as "first" and "second" are merely 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 the present text, "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent: the case of A alone, the case of A and B existing at the same time, and the case of B alone. Wherein A, B can be singular or plural. In the present text, "at least one" means one or more, and "multiple" means two or more. "At least one", "at least one of the following" or the like means any combination of these items, including any combination of single item or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can represent: a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0032] Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment used in the present application can be purchased on the market or can be prepared by existing methods.

[0033] In a first aspect, the present application provides a hot-rolled weathering steel, the weathering steel comprising the following chemical components:

[0034] C, Si, Mn, P, S, Ni, Cr, Cu, Al, N, Ti, the rest being Fe and unavoidable impurities;

[0035] The content of Ti is 0.40wt%-0.60wt%.

[0036] In the embodiments of the present application, Ti is added in an appropriate amount to improve the weather resistance of the 09CuPCrNi weather-resistant steel based on the poor weather resistance of the 09CuPCrNi weather-resistant steel. The positive effect of controlling the content of Ti to be 0.40 wt% to 0.60 wt% is that Ti is a weather resistance element, and a too low content of Ti may result in an insignificant improvement in the weather resistance of the steel, and a too high content of Ti may result in a difficult control of the grain boundary segregation of Ti and deterioration of the mechanical properties of the steel. In the embodiments of the present application, specifically, the content of Ti can be 0.40 wt%, 0.42 wt%, 0.44 wt%, 0.46 wt%, 0.48 wt%, 0.50 wt%, 0.52 wt%, 0.54 wt%, 0.56 wt%, 0.58 wt%, 0.60 wt%, etc.; preferably, the content of Ti is 0.45 wt%, 0.50 wt%, 0.60 wt%, etc.

[0037] In some embodiments, in the chemical composition of the weather-resistant steel, the content of C is 0.02 wt% to 0.05 wt%, the content of Si is 0.10 wt% to 0.30 wt%, the content of Mn is 0.30 wt% to 0.80 wt%, the content of P is ≤0.020 wt%, the content of S is ≤0.004 wt%, the content of Ni is 0.10 wt% to 0.30 wt%, the content of Cr is 0.30 wt% to 0.80 wt%, the content of Cu is 0.20 wt% to 0.80 wt%, the content of Al is ≤0.05 wt%, and the content of N is ≥0.0035 wt%.

[0038] The positive effect of controlling the content of C to be 0.02 wt% to 0.05 wt% is that C, as a gap solid solution element, can improve the strength of the steel, and a too low content of C may result in an insufficient solid solution strength to some extent, and a too high content of C may result in pearlite phase transformation to some extent. Specifically, the content of C can be 0.02 wt%, 0.025 wt%, 0.03 wt%, 0.035 wt%, 0.04 wt%, 0.045 wt%, 0.05 wt%, etc.

[0039] The positive effect of controlling the content of Si to be 0.10 wt% to 0.30 wt% is that Si can promote the generation of fayalite phase and increase the adhesion between the rust layer and the substrate, and a too low content of Si may result in an insignificant adhesion effect between the rust layer and the substrate to some extent, and a too high content of Si may result in the generation of iron oxide scale during hot rolling and a difficult control of the surface quality to some extent. Specifically, the content of Si can be 0.10 wt%, 0.15 wt%, 0.20 wt%, 0.25 wt%, 0.30 wt%, etc.

[0040] The positive effect of controlling the content of Mn to be 0.30-0.80 wt% is that Mn, as a replacement solid solution element, can improve the strength of the steel. If the content of Mn is too low, it will lead to insufficient solid solution strength to some extent; if the content of Mn is too high, it will lead to segregation to some extent, which will deteriorate the mechanical properties of the steel. Specifically, the content of Mn can be 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, 0.70 wt%, 0.80 wt%, etc.

[0041] The positive effect of controlling the content of P to be ≤0.020 wt% is that P, as a weathering element, if the content of P is too high, it will lead to segregation to some extent, which will deteriorate the mechanical properties of the steel. Specifically, the content of P can be 0.020 wt%, 0.015 wt%, 0.010 wt%, etc.

[0042] The positive effect of controlling the content of S to be ≤0.004 wt% is that S is an impurity element, and if the content of S is too high, it will lead to difficulty in controlling inclusions to some extent. Specifically, the content of S can be 0.004 wt%, 0.003 wt%, 0.002 wt%, 0.001 wt%, etc.

[0043] The positive effect of controlling the content of Ni to be 0.10-0.30 wt% is that Ni is a weathering element, and if the content of Ni is too low, it will not be obvious to some extent; if the content of Ni is too high, it will lead to high alloy cost to some extent; specifically, the content of Ni can be 0.10 wt%, 0.15 wt%, 0.20 wt%, 0.30 wt%, etc.

[0044] The positive effect of controlling the content of Cr to be 0.30-0.80 wt% is that Cr, as a weathering element, if the content of Cr is too low, it will not be obvious to some extent; if the content of Cr is too high, it will be difficult to control the generation of large particles of Cr-containing carbides to some extent. Specifically, the content of Cr can be 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, 0.70 wt%, 0.80 wt%, etc.

[0045] The positive effect of controlling the content of Cu to be 0.20-0.80 wt% is that Cu, as a weathering element, if the content of Cu is too low, it will not be obvious to some extent; if the content of Cu is too high, it will lead to high alloy cost to some extent. Specifically, the content of Cu can be 0.20 wt%, 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, 0.70 wt%, 0.80 wt%, etc.

[0046] The positive effect of controlling the content of Al to be ≤0.05 wt%: Al as a deoxidizing element, if the content of Al is too high, it will affect the phase transformation to some extent. Specifically, the content of Al can be 0.05 wt%, 0.04 wt%, 0.03 wt%, 0.02 wt%, etc.

[0047] The positive effect of controlling the content of N to be ≥0.0035 wt%: N as a residual element, if the content of N is too low, it is not conducive to the precipitation of Ti nitrides to some extent. Specifically, the content of N can be 0.0035 wt%, 0.0040 wt%, etc.

[0048] In some embodiments, the microstructure of the weathering steel is ferrite, which contains a large amount of spherical Ti-containing carbides and cubic carbonitrides.

[0049] See Figure 2 , Figure 2 The microstructure schematic diagram of the hot-rolled weathering steel provided in Embodiment 5. The matrix structure is ferrite, and the black particles are Ti-containing carbides or carbonitrides. The addition of 0.6 wt% Ti to 09CuPCrNi expands the ferrite phase transformation temperature interval, and cooperates with low carbon and low Mn to inhibit pearlite phase transformation.

[0050] In a second aspect, based on the same overall inventive concept, the present application also provides a production method of a hot-rolled weathering steel, see Figure 1 , for producing the weathering steel of the first aspect, the method comprising:

[0051] S1, under the condition of setting a first temperature, first heating a slab having the chemical composition;

[0052] S2, under the condition of setting a total rolling deformation amount and a set finish rolling temperature, rough rolling the first-heated slab;

[0053] S3, under the condition of setting a second temperature, second heating the rough-rolled slab, and then finish rolling to obtain a hot-rolled plate;

[0054] S4, under the condition of setting a cooling speed, cooling the hot-rolled plate, and then coiling to obtain a hot-rolled weathering steel.

[0055] In some embodiments, the set total rolling deformation amount is ≥80%.

[0056] The positive effect of controlling the total rough rolling deformation amount to be ≥80%: Ti in high-Ti steel is prone to segregate at grain boundaries, and the main purpose of large rough rolling reduction is to eliminate the segregation of Ti at grain boundaries in the slab; if the deformation amount is too low, it is difficult to eliminate the segregation of Ti at the grain boundaries of the slab to some extent. Specifically, the total rough rolling deformation amount can be 80%, 82%, 84%, 86%, 90%, etc.

[0057] In some embodiments, the finishing temperature is set to 950-1100℃.

[0058] The positive effect of controlling the finishing temperature of rough rolling to be 950-1100℃ is to ensure the finishing temperature, which is too low to cause excessive reheating energy consumption. In the rough rolling stage, 3 passes are adopted for rolling, and dephosphorization is performed in each pass, which aims to ensure the surface quality of the billet. Specifically, the outlet temperature of rough rolling can be 950℃, 980℃, 1030℃, 1060℃, 1090℃, 1100℃, etc.

[0059] In some embodiments, the cooling speed is set to be <15℃ / s.

[0060] The positive effect of controlling the cooling speed to be <15℃ / s is that high Ti steel will cause Ti to exist in the form of solid solution in the steel to some extent, which will cause the deterioration of impact performance. Specifically, the cooling speed can be 14℃ / s, 13℃ / s, 12℃ / s, 11℃ / s, 10℃ / s, 9℃ / s, 8℃ / s, 7℃ / s, 6℃ / s, 5℃ / s, etc.

[0061] In some embodiments, the cooling speed is set to be ≤10℃ / s.

[0062] In some embodiments, the first heating temperature is set to be ≥1100℃.

[0063] In the embodiments of the present application, a short process equipment is adopted, and after steelmaking, continuous casting is performed to obtain a slab; then the slab directly enters a tunnel furnace for heating. The positive effect of controlling the first heating temperature to be ≥1100℃ is that the tunnel furnace has a slight heating effect for heat preservation of the cast slab, and the highest temperature of the tunnel furnace can reach 1150℃; which is too low to be unfavorable for recrystallization in the rough rolling stage. Specifically, the first heating temperature can be 1100℃, 1130℃, 1150℃, 1170℃, 1190℃, etc.

[0064] In some embodiments, the second heating temperature is set to be 1000-1200℃.

[0065] After rough rolling, the slab enters reheating, and an online induction heating mode is adopted, and the positive effect of controlling the second heating temperature to be 1000-1200℃ is that the induction heating temperature ensures that the finishing rolling outlet temperature is above 900℃, so as to ensure that the ferrite phase change does not occur in the finishing rolling stage; if the temperature exceeds the range, it is easy to cause unstable finishing rolling. Specifically, the second heating temperature can be 1000℃, 1020℃, 1040℃, 1060℃, 1080℃, 1100℃, 1120℃, 1140℃, 1160℃, 1180℃, 1200℃, etc.

[0066] The weathering steel is realized based on the production method of the weathering steel, and specific steps of the production method of the weathering steel can refer to the above-mentioned embodiments. Since the weathering steel adopts part or all of the technical solutions of the above-mentioned embodiments, at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments are possessed, and here, all the beneficial effects will not be described one by one.

[0067] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not used to limit the scope of the present application. The experimental methods in the following examples without specific conditions are generally determined according to national standards. If there is no corresponding national standard, the international standard, the conventional condition or the condition suggested by the manufacturer is used.

[0068] Example 1

[0069] The molten steel with components as described in example 1 in table 1 is cast into slab, then enters the tunnel furnace, the temperature of the tunnel furnace is controlled at 1180℃, then the finishing temperature of rough rolling is controlled at 1100℃, the rough rolling is rolled for 3 passes, the total deformation of the rough rolling stage is 85%; the strip steel after rough rolling enters the induction heating equipment, the induction heating temperature is controlled at 1200℃; then enters the finishing rolling, the finishing rolling is rolled for 5 passes, the total deformation of the finishing rolling stage is 15%; the strip steel after finishing rolling enters air cooling, the air cooling rate is 10℃ / s, direct coiling, the final thickness of the hot-rolled plate is 1.6mm.

[0070] Example 2

[0071] The molten steel with components as described in example 2 in table 1 is cast into slab, then enters the tunnel furnace, the temperature of the tunnel furnace is controlled at 1150℃; then the finishing temperature of rough rolling is controlled at 1080℃, the rough rolling is rolled for 3 passes, the total deformation of the rough rolling stage is 83%; the strip steel after rough rolling enters the induction heating equipment, the induction heating temperature is controlled at 1180℃; then enters the finishing rolling, the finishing rolling is rolled for 5 passes, the total deformation of the finishing rolling stage is 17%; the strip steel after finishing rolling enters air cooling, the air cooling rate is 8℃ / s, direct coiling, the final thickness of the hot-rolled plate is 1.8mm.

[0072] Example 3

[0073] The molten steel with components as described in example 1 in table 1 is cast into slab, then enters the tunnel furnace, the temperature of the tunnel furnace is controlled at 1150℃; then the finishing temperature of rough rolling is controlled at 1080℃, the rough rolling is rolled for 3 passes, the total deformation of the rough rolling stage is 83%; the strip steel after rough rolling enters the induction heating equipment, the induction heating temperature is controlled at 1180℃; then enters the finishing rolling, the finishing rolling is rolled for 5 passes, the total deformation of the finishing rolling stage is 17%; the strip steel after finishing rolling enters air cooling, the air cooling rate is 8℃ / s, direct coiling, the final thickness of the hot-rolled plate is 1.8mm.

[0074] Example 4

[0075] The molten steel with the components as described in Example 4 of Table 1 was cast into a slab, then entered a tunnel furnace, the temperature of which was controlled at 1100℃, and then the finishing temperature of rough rolling was controlled at 950℃, the rough rolling was rolled for 3 passes, and the total deformation in the rough rolling stage was 82%; after the rough rolling, the strip steel entered an induction heating equipment, the induction heating temperature was controlled at 1000℃; then it entered the finishing rolling, the finishing rolling was rolled for 5 passes, and the total deformation in the finishing rolling stage was 18%; after the rolling was completed, the strip steel entered air cooling, the air cooling rate was 12℃ / s, and it was directly coiled, and the final thickness of the hot-rolled plate was 1.9mm.

[0076] Example 5

[0077] The molten steel with the components as described in Example 1 of Table 1 was cast into a slab, then entered a tunnel furnace, the temperature of which was controlled at 1100℃, and then the finishing temperature of rough rolling was controlled at 1050℃, the rough rolling was rolled for 3 passes, and the total deformation in the rough rolling stage was 82%; after the rough rolling, the strip steel entered an induction heating equipment, the induction heating temperature was controlled at 1140℃; then it entered the finishing rolling, the finishing rolling was rolled for 5 passes, and the total deformation in the finishing rolling stage was 18%; after the rolling was completed, the strip steel entered air cooling, the air cooling rate was 6℃ / s, and it was directly coiled, and the final thickness of the hot-rolled plate was 2.0mm.

[0078] Figure 2 The microstructure schematic diagram of the hot-rolled weathering steel provided by Example 5 of the present application is shown in the figure. As can be seen from the figure, the microstructure of the weathering steel is mainly ferrite, and the black particles are Ti-containing carbides or carbonitrides. The addition of 0.6% Ti to 09CuPCrNi expands the ferrite phase transformation temperature interval, and cooperates with low C and low Mn to inhibit pearlite phase transformation.

[0079] The chemical composition content of the hot-rolled weathering steel is shown in Table 1; the mechanical properties of yield strength (Rp0.2), tensile strength (Rm), and elongation (A) are shown in Table 2.

[0080] Table 1 Chemical composition content of the hot-rolled weathering steel wt%, the balance is Fe and unavoidable impurities.

[0081]

[0082]

[0083] Table 2 Mechanical property results of the hot-rolled weathering steel, yield strength (Rp0.2), tensile strength (Rm), and elongation (A). 0.2

[0084] Example [Rp 0.2 (MPa)]]> Rm (MPa) A，％ Example 1 556 752 28 Example 2 541 735 28 Example 3 533 720 32 Example 4 543 730 32 Example 5 600 780 28 Comparative Example 1 360 520 35 Comparative Example 2 355 510 36 Comparative Example 3 612 740 24

[0085] ​As can be seen from the data in Table 2, the mechanical properties of the hot-rolled weathering steel provided by the embodiments of the present application include: yield strength of 533 MPa to 600 MPa, tensile strength of 720 MPa to 780 MPa, and elongation of 28% to 32%. The hot-rolled weathering steel in the embodiments of the present application has excellent yield strength, tensile strength and ductility. The addition of an appropriate amount of Ti can improve the yield strength and tensile strength of the 09CuPCrNi weathering steel. However, the addition of excessive Ti can cause the elongation of the 09CuPCrNi weathering steel to decrease to some extent.

[0086] Figure 3 A comparison chart of the corrosion rates of the hot-rolled weathering steels provided by the embodiments and the comparative examples and the 09CuPCrNi steel is shown. The corrosion experiment was performed according to TB / T 2375-53, the experimental medium was 0.01 mol / L NaHSO3 solution, the experimental temperature was controlled at (45±2) °C, the humidity was controlled at (70±5) %, and one cycle period was 60 min, including immersion for 12 min and drying for 48 min. The duration of the entire experiment was 504 h, and the samples were taken at 48 h, 120 h, 216 h, 360 h and 504 h during the experiment to measure the corrosion rate. As can be seen from the chart, the corrosion rate of the conventional 09CuPCrNi steel of Comparative Example 1-2 is obviously higher than that of the weathering steel of the embodiments, indicating that the weather resistance of the weathering steel of the embodiments is better than that of Comparative Example 1-2. Although Comparative Example 3 increases the Ti content and slows down the corrosion rate of the weathering steel, it causes the elongation of the weathering steel to decrease to some extent. Therefore, the addition of an appropriate amount of Ti can not only ensure the yield strength, tensile strength and elongation of the weathering steel, but also improve its weather resistance. Controlling the Ti content in the range of 0.4% to 0.6% can simultaneously take into account the mechanical properties and weather resistance of the 09CuPCrNi steel.

[0087] The above description is merely one specific implementation of the present application, which enables those skilled in the art to 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 scope consistent with the principles and novel features disclosed herein.​

Claims

1. A hot-rolled weathering steel, characterized in that, The chemical composition of the weathering steel comprises: C 0.02 wt%-0.05 wt%; Si 0.10 wt%-0.30 wt%; Mn 0.30 wt%-0.80 wt%; P ≤0.020 wt%; S ≤0.004 wt%; Ni 0.10 wt%-0.30 wt%; Cr 0.30 wt%-0.80 wt%; Cu 0.20 wt%-0.80 wt%; Al ≤0.05 wt%; N ≥0.0035 wt%; and Ti 0. The composition is 40%-0.60% by weight, with the remainder being Fe and unavoidable impurities; the microstructure of the weathering steel is ferrite, containing a large number of spherical Ti-containing carbides and cubic carbonitrides; the mechanical properties of the hot-rolled weathering steel include: yield strength of 533MPa-600MPa, tensile strength of 720MPa-780MPa, and elongation of 28%-32%; the preparation process of the hot-rolled weathering steel includes rough rolling of the heated slab under the condition that the total rolling deformation is ≥80%, and cooling of the hot-rolled plate under the condition of a set cooling rate of ≤10℃ / s.

2. A method for producing hot-rolled weathering steel, used to produce the weathering steel of claim 1, the method comprising: Under a set first temperature, a slab having the aforementioned chemical composition is subjected to a first heating. Under the conditions of setting the total rolling deformation and setting the final rolling temperature, the slab after the first heating is rough rolled; Under a set second temperature, the slab after rough rolling is subjected to a second heating, followed by finish rolling to obtain a hot-rolled plate; Under a set cooling rate, the hot-rolled plate is cooled and then coiled to obtain hot-rolled weathering steel. The set total rolling deformation is ≥80%, the set cooling rate is ≤10℃ / s, the set first temperature is ≥1100℃, and the set second temperature is 1000℃-1200℃.

3. The method according to claim 2, characterized in that, The set final rolling temperature is 950℃-1100℃.

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