Ultra-wide q500qd bridge plate and production process therefor

Abstract

The present invention relates to the technical field of metallurgy, and discloses an ultra-wide Q500qD bridge plate and a production process therefor. The ultra-wide Q500qD bridge plate comprises the following chemical components in percentages by mass: 0.09-0.11% of C, 1.60-1.65% of Mn, 0.55-0.70% of Cr, less than or equal to 0.012% of P, less than or equal to 0.010% of S, 0.035-0.045% of Nb, 0.001-0.007% of V, 0.020-0.035% of Ti, 0.05-0.09% of Mo, and the balance of Fe and inevitable impurities. In the present invention, by using a component design with a low C content, adding Nb, Ti, Cr and Mo for compounding, and using a special rolling and controlled-cooling mode, a steel plate having a multi-phase structure consisting of bainite, ferrite and an extremely small amount of martensite is obtained, ensuring that the strength, the extremely low yield ratio, the impact energy at a low temperature of -20°C, the percentage of fibers on an impact fracture surface and the aging impact energy meet the requirements. Moreover, the Q500qD steel plate produced by means of common normalizing or tempering has a high yield ratio and a relatively small margin in terms of impact toughness.

Description

Ultra-wide Q500qD bridge plate and production process thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of metallurgy, in particular to an ultra-wide Q500qD bridge plate and a production process thereof. BACKGROUND

[0002] At present, high-strength bridge steels are increasingly applied in national key projects, especially in the construction investment in western regions. The regions belong to remote regions with high altitudes and complex terrains, and the project steels for assembly design are complex and have high performance requirements. Large-width steel plates are needed to reduce the welding amount of butt welds and reduce the construction difficulty. At the same time, the environment in such regions is complex, and the safety of bridge construction should be fully considered in design. Therefore, a bridge plate with large width and high performance requirements needs to be developed to improve the fracture toughness and seismic performance of the steel.

[0003] SUMMARY

[0004] The present application solves the technical problems of overcoming the shortcomings of the prior art and providing an ultra-wide Q500qD bridge plate and a production process thereof.

[0005] In order to solve the above technical problems, the technical scheme of the present application is as follows:

[0006] An ultra-wide Q500qD bridge plate has the following chemical composition and mass percentage: C: 0.09-0.11%, Mn: 1.60-1.65%, Cr: 0.55-0.70%, P≤0.012%, S≤0.010%, Nb: 0.035-0.045%, V: 0.001-0.007%, Ti: 0.020-0.035%, Mo: 0.05-0.09%, and the rest is Fe and unavoidable impurities.

[0007] The present application also provides a production process of an ultra-wide Q500qD bridge plate, and the production process includes smelting, rolling, controlled cooling and heat treatment in sequence.

[0008] As a preferred scheme of the production process of the ultra-wide Q500qD bridge plate, the smelting process includes: using LF and RH refining processes to refine the blank, so that the hydrogen content in the blank is ≤1ppm and the nitrogen content is ≤40ppm.

[0009] As a preferred scheme of the production process of the ultra-wide Q500qD bridge plate, the rolling process has a opening rolling temperature of 760-780℃ and a water inlet temperature of 650-680℃.

[0010] As a preferred scheme of the production process of the ultra-wide Q500qD bridge plate, in the controlled cooling process, the red temperature is 400-500 DEG C.

[0011] As a preferred scheme of the production process of the ultra-wide Q500qD bridge plate, in the controlled cooling process, the red temperature is 400-500 DEG C.

[0012] As a preferred scheme of the production process of the ultra-wide Q500qD bridge plate, in the controlled cooling process, the red temperature is 400-500 DEG C.

[0013] As a preferred scheme of the production process of the ultra-wide Q500qD bridge plate, in the controlled cooling process, the red temperature is 400-500 DEG C.

[0014] As a preferred scheme of the production process of the ultra-wide Q500qD bridge plate, in the controlled cooling process, the red temperature is 400-500 DEG C.

[0015] The beneficial effects of the present application are:

[0016] The present application adopts a low C content component design, adds Nb, Ti, Cr and Mo in a composite manner, and adopts a special rolling and controlled cooling mode, so as to obtain a bainite + ferrite + a small amount of martensite multi-phase structure steel plate, which ensures that the strength, the low yield ratio, the low temperature impact at-20 DEG C, the impact fiber rate and the aging impact meet the requirements. At the same time, the Q500qD steel plate produced by ordinary normalizing or quenching and tempering has a high yield ratio and a small impact toughness. DETAILED DESCRIPTION

[0017] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to the specific embodiments and in combination with the drawings.

[0018] The present application provides an ultra-wide Q500qD bridge plate, and the chemical components and mass percentages are as follows: C: 0.09-0.11%, Mn: 1.60-1.65%, Cr: 0.55-0.70%, P≤0.012%, S≤0.010%, Nb: 0.035-0.045%, V: 0.001-0.007%, Ti: 0.020-0.035%, Mo: 0.05-0.09%, and the rest is Fe and inevitable impurities.

[0019] The application also provides a production process of the ultra-wide Q500qD bridge plate, which comprises smelting, rolling, controlled cooling and heat treatment in sequence.

[0020] The smelting process comprises: refining the blank by using LF and RH refining processes, so that the hydrogen content in the blank is ≤1 ppm and the nitrogen content is ≤40 ppm. The rolling temperature is 760-780 DEG C, and the water inlet temperature is 650-680 DEG C. The red temperature in the controlled cooling process is 400-500 DEG C. The tempering temperature in the heat treatment process is 480-510 DEG C.

[0021] The application is described below by means of specific embodiments.

[0022] Embodiment 1: The embodiment provides a production method of an ultra-wide Q500qD bridge plate, which has a thickness of 8 mm and a width of 4200 mm, and the chemical component composition and mass percentage content are shown in Table 1.

[0023] The embodiment also provides a production method of an ultra-wide Q500qD bridge plate, which adopts LF and RH refining technologies in smelting to ensure that the gas H content of the steel plate is 0.8 ppm and the N content is 35 ppm.

[0024] In addition, the production method of the ultra-wide Q500qD bridge plate provided by the embodiment comprises rolling, controlled cooling and heat treatment in sequence, and the specific process steps are as follows:

[0025] (1) Rolling process: the steel plate rolling temperature is 780 DEG C, and the water inlet temperature is 650 DEG C.

[0026] (2) Controlled cooling process: the red temperature of the steel plate is limited to 400 DEG C.

[0027] (3) Heat treatment process: tempering at 480 DEG C is adopted to eliminate the surface stress of the steel plate.

[0028] The mechanical properties of the ultra-wide Q500qD bridge plate obtained by the embodiment are shown in Table 2.

[0029] Embodiment 2: The embodiment provides a production method of an ultra-wide Q500qD bridge plate, which has a thickness of 16 mm and a width of 4500 mm, and the chemical component composition and mass percentage content are shown in Table 1.

[0030] The embodiment also provides a production method of an ultra-wide Q500qD bridge plate, which adopts LF and RH refining technologies in smelting to ensure that the gas H content of the steel plate is 0.7 ppm and the N content is 37 ppm.

[0031] In addition, the production method of the ultra-wide Q500qD bridge plate provided by the embodiment comprises rolling, controlled cooling and heat treatment in sequence, and the specific process steps are as follows:

[0032] (1) Rolling process: steel plate open rolling temperature 770°C, water temperature 660°C.

[0033] (2) Controlled cooling process: steel plate red temperature is limited to 420°C

[0034] (3) Heat treatment process: tempering at 485°C to eliminate the surface stress of the steel plate.

[0035] The mechanical properties of the super-wide Q500qD bridge plate obtained in the embodiment are shown in Table 2.

[0036] In the embodiment, a production method of a super-wide Q500qD bridge plate is provided, the thickness of which is 22 mm and the width of which is 4550 mm, the chemical component composition and mass percentage content of which are shown in Table 1.

[0037] In the embodiment, a production method of a super-wide Q500qD bridge plate is also provided, in which LF and RH refining technologies are used in smelting to ensure that the gas H content of the steel plate is 0.8 ppm and the N content is 31 ppm.

[0038] In addition, the production method of the super-wide Q500qD bridge plate provided in the embodiment sequentially comprises rolling, controlled cooling process and heat treatment process, and the specific process steps are as follows:

[0039] (1) Rolling process: steel plate open rolling temperature 760°C, water temperature 670°C.

[0040] (2) Controlled cooling process: steel plate red temperature is limited to 435°C

[0041] (3) Heat treatment process: tempering at 490°C to eliminate the surface stress of the steel plate.

[0042] The mechanical properties of the super-wide Q500qD bridge plate obtained in the embodiment are shown in Table 2.

[0043] In the embodiment, a production method of a super-wide Q500qD bridge plate is provided, the thickness of which is 28 mm and the width of which is 4620 mm, the chemical component composition and mass percentage content of which are shown in Table 1.

[0044] In the embodiment, a production method of a super-wide Q500qD bridge plate is also provided, in which LF and RH refining technologies are used in smelting to ensure that the gas H content of the steel plate is 0.5 ppm and the N content is 30 ppm.

[0045] In addition, the production method of the super-wide Q500qD bridge plate provided in the embodiment sequentially comprises rolling, controlled cooling process and heat treatment process, and the specific process steps are as follows:

[0046] (1) Rolling process: steel plate open rolling temperature 765℃, water temperature 670℃.

[0047] (2) Controlled cooling process: steel plate red temperature is limited to 470℃

[0048] (3) Heat treatment process: tempering at 490℃ to eliminate the surface stress of the steel plate.

[0049] The mechanical properties of the super-wide Q500qD bridge plate obtained in the embodiment are shown in Table 2.

[0050] In the embodiment, a production method of a super-wide Q500qD bridge plate is provided, the thickness of which is 32mm and the width of which is 4600mm, the chemical composition and mass percentage content of which are shown in Table 1.

[0051] In the embodiment, a production method of a super-wide Q500qD bridge plate is provided, the thickness of which is 32mm and the width of which is 4600mm, the chemical composition and mass percentage content of which are shown in Table 1.

[0052] In addition, the production method of the super-wide Q500qD bridge plate provided in the embodiment sequentially comprises a rolling process, a controlled cooling process and a heat treatment process, and the specific process steps are as follows:

[0053] (1) Rolling process: steel plate open rolling temperature 755℃, water temperature 680℃.

[0054] (2) Controlled cooling process: steel plate red temperature is limited to 480℃

[0055] (3) Heat treatment process: tempering at 500℃ to eliminate the surface stress of the steel plate.

[0056] The mechanical properties of the super-wide Q500qD bridge plate obtained in the embodiment are shown in Table 2.

[0057] In the embodiment, a production method of a super-wide Q500qD bridge plate is provided, the thickness of which is 44mm and the width of which is 4650mm, the chemical composition and mass percentage content of which are shown in Table 1.

[0058] In the embodiment, a production method of a super-wide Q500qD bridge plate is provided, the thickness of which is 44mm and the width of which is 4650mm, the chemical composition and mass percentage content of which are shown in Table 1.

[0059] In addition, the production method of the super-wide Q500qD bridge plate provided in the embodiment sequentially comprises a rolling process, a controlled cooling process and a heat treatment process, and the specific process steps are as follows:

[0060] (1) Rolling process: steel plate open rolling temperature 760℃, water temperature 660℃.

[0061] (2) Controlled cooling process: the red temperature of the steel plate is limited to 480°C

[0062] (3) Heat treatment process: tempering at 500°C is adopted to eliminate the surface stress of the steel plate.

[0063] The mechanical properties of the super-wide Q500qD bridge plate obtained in the embodiment are shown in Table 2.

[0064] In the embodiment, a production method of a super-wide Q500qD bridge plate with a thickness of 48 mm and a width of 4700 mm is provided, and the chemical composition and mass percentage content are shown in Table 1.

[0065] The embodiment also provides a production method of a super-wide Q500qD bridge plate, and LF and RH refining technologies are adopted during smelting to ensure that the gas H content of the steel plate is 0.6 ppm and the N content is 38 ppm.

[0066] In addition, the production method of the super-wide Q500qD bridge plate provided in the embodiment sequentially includes rolling, a controlled cooling process and a heat treatment process, and the specific process steps are as follows:

[0067] (1) Rolling process: the opening rolling temperature of the steel plate is 780°C, and the water inlet temperature is 670°C.

[0068] (2) Controlled cooling process: the red temperature of the steel plate is limited to 490°C

[0069] (3) Heat treatment process: tempering at 490°C is adopted to eliminate the surface stress of the steel plate.

[0070] The mechanical properties of the super-wide Q500qD bridge plate obtained in the embodiment are shown in Table 2.

[0071] In the embodiment, a production method of a super-wide Q500qD bridge plate with a thickness of 48 mm and a width of 4700 mm is provided, and the chemical composition and mass percentage content are shown in Table 1.

[0072] The embodiment also provides a production method of a super-wide Q500qD bridge plate, and LF and RH refining technologies are adopted during smelting to ensure that the gas H content of the steel plate is 0.9 ppm and the N content is 37 ppm.

[0073] In addition, the production method of the super-wide Q500qD bridge plate provided in the embodiment sequentially includes rolling, a controlled cooling process and a heat treatment process, and the specific process steps are as follows:

[0074] (1) Rolling process: the opening rolling temperature of the steel plate is 780°C, and the water inlet temperature is 650°C.

[0075] (2) Controlled cooling process: the red temperature of the steel plate is limited to 500°C

[0076] (3) heat treatment process: tempering at 490℃ to eliminate surface stress of the steel plate.

[0077] The mechanical properties of the super-wide Q500qD bridge plate obtained in the embodiment are shown in Table 2.

[0078] Table 1 Chemical composition of the steel plate of Examples 1-8

[0079] Table 2 Mechanical property data of the steel plate of Examples 1-8

[0080] It can be seen from the above examples that: first, the width of the steel plate is 4200-4700mm, which is much higher than the design width of the ordinary bridge plate. Second, the elongation of the steel plate is ≥18%, the impact at -20℃ is ≥250J, the yield ratio is ≤0.84, the fiber ratio of the impact fracture is ≥95%, and the aging impact performance at 5% deformation is ≥150J. These indexes can well improve the welding and assembly characteristics of the steel plate to adapt to the characteristics of high altitude and complex laying environment in the western region. In addition, the low-carbon and multi-phase structure design effectively improves the seismic safety factor.

[0081] Therefore, the technical scheme of the present application adopts a low-C content composition design, adds Nb, Ti, Cr and Mo in a composite manner, and adopts a special rolling and controlled cooling mode, thereby obtaining a bainite + ferrite + very small amount of martensite multi-phase structure steel plate, which ensures that the strength, very low yield ratio, -20℃ low temperature impact, impact fiber ratio and aging impact meet the requirements. At the same time, the Q500qD steel plate produced by ordinary normalizing or quenching and tempering has high yield ratio and small impact toughness surplus.

[0082] In addition to the above examples, the present application can have other implementation manners; any technical scheme formed by equivalent substitution or equivalent transformation falls within the protection scope required by the present application.

Claims

1. An ultra-wide Q500qD bridge deck plate characterized by: The chemical composition and mass percentage are as follows: C: 0.09-0.11%, Mn: 1.60-1.65%, Cr: 0.55-0.70%, P≤0.012%, S≤0.010%, Nb: 0.035-0.045%, V: 0.001-0.007%, Ti: 0.020-0.035%, Mo: 0.05-0.09%, and the rest is Fe and inevitable impurities.

2. A production process of the ultra-wide Q500qD bridge deck slab based on the claim 1, characterized by: The production process comprises smelting, rolling, controlled cooling and heat treatment in sequence.

3. The process for producing an ultra-wide Q500qD bridge deck slab as claimed in claim 2, wherein: The smelting process comprises: refining the blank by using LF and RH refining process, so that the hydrogen content in the blank is ≤1ppm and the nitrogen content is ≤40ppm.

4. The process for producing an ultra-wide Q500qD bridge deck slab as claimed in claim 2, wherein: The rolling temperature of the rolling process is 760-780℃, and the water inlet temperature is 650-680℃.

5. The process for producing an ultra-wide Q500qD bridge deck slab as claimed in claim 2, wherein: The red temperature in the controlled cooling process is 400-500℃.

6. The process for producing an ultra-wide Q500qD bridge deck slab as claimed in claim 2, wherein: The tempering temperature in the heat treatment process is 480-510℃.

7. The process for producing an ultra-wide Q500qD bridge deck slab as claimed in claim 2, wherein: The yield strength of the steel plate is ≥500Mpa, the tensile strength is 630-750Mpa, the elongation is ≥18%, the impact at-20℃ is ≥250J, and the yield strength ratio is ≤0.

84.

8. The process for producing an ultra-wide Q500qD bridge deck slab as claimed in claim 2, wherein: The impact fracture fiber ratio of the steel plate is ≥95%, and the aging impact performance at 5% deformation is ≥150J.

9. The process for producing an ultra-wide Q500 qD bridge deck slab as claimed in claim 2 wherein: The thickness of the steel plate is 8-50mm, and the width is 4200-4700mm.

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