CN108397681A - Longitudinal special-shaped section steel plate and production method thereof - Google Patents

Abstract

The invention relates to a steel plate with a longitudinal special-shaped cross-section and a production method thereof. The steel plate with a longitudinal special-shaped cross-section includes a gradual change section 1, an equal-thickness section and a gradual change section 2 with a total length of L which are continuously formed by rolling, and the gradual change section 1 and the equal-thickness section The lower surface of the gradient section 2 is a plane, and the upper surface is a continuous and smooth transition surface; the upper surface of the equal thickness section is a plane, and the upper surfaces of the gradient section 1 and the gradient section 2 are curved surfaces. The present invention adopts a special structural shape, has a wide selection range of length and thickness, and has strong applicability. In actual engineering applications, it can reduce the processing and welding workload of structural steel beams such as extension beams, and can increase the strength of joints and improve Connection reliability; the production process is simple, the controllability is strong, the qualified rate of the finished plate is high, and the surface quality and mechanical properties meet the requirements of use.

Description

A kind of steel plate with special-shaped longitudinal section and its production method

technical field

The invention relates to the technical field of production of longitudinally variable thickness (LP) steel plates, in particular to a steel plate with longitudinal special-shaped cross-section and a production method thereof.

Background technique

Longitudinal variable thickness (LP) steel plate refers to a steel plate with a special longitudinal shape whose thickness changes continuously along the rolling direction. The longitudinal thickness of the steel plate is changed by continuously changing the opening of the roll during the rolling process. Since the longitudinally variable thickness steel plate can change its thickness according to the load bearing conditions, it can optimize the design of structural sections such as bridges, hulls, buildings, etc., which can not only reduce the amount of steel used, reduce the number of welding times, but also improve the thickness of the joints through equal thickness. Operability, such as omission of backing plate and taper processing, etc.

The paper "Engineering Application and Research Progress of Longitudinal Variable Thickness (LP) Steel Plates" written by Dr. Liu Xiaoling from Tsinghua University, disclosed the production and production of domestic and foreign enterprises including France, Japan, Germany Dillingen, the Czech Republic, Baosteel, Hebei Iron and Steel, Anshan Iron and Steel, etc. The main types of LP steel plates are designed, as shown in the table below:

However, the shape of these types of LP steel plates cannot fully meet the needs of actual engineering, and the range of thickness variation of the existing LP steel plates is small, which limits its application range.

The Chinese patent with the application number CN200910175208.6 discloses "a thickness control method for rolling wedge-shaped steel plates". The TDC controller controls the change of the oil column height of the hydraulic cylinder of the rolling mill, continuously changes the distance between the roll gaps, and realizes the continuous change of the longitudinal thickness of the steel plate. Since this method is to roll the transverse wedge-shaped steel plate at the last pass of rolling, that is, only one pass Rolling to complete the rolling of the wedge-shaped steel plate will inevitably lead to the problem that its thickness variation range is small and the steel plate shape is poor.

The Chinese patent with the application number CN201310227028.4 discloses "a production method of transverse wedge rolling variable thickness steel plate", including 1) transverse rolling: during the last pass of the transverse rolling stage, according to the steel plate head and 2) Longitudinal rolling; first, in the longitudinal rolling stage, carry out horizontal equal-proportion wedge rolling according to the longitudinal variable thickness value of the head and tail produced in the horizontal rolling stage; then, According to the distribution of the rolling schedule, the influence function method is used to determine the adjustment amount of the roll gap and the setting value of the roll bending force, so as to ensure that the transverse thickness distribution of the longitudinal rolling pass meets the requirement of equal proportion wedge shape. Since this method is to set the roll gap parameters in the last pass of transverse rolling to roll out transverse wedge-shaped steel plates, it will inevitably lead to a small range of thickness variation, poor plate shape and the inability to correct on the leveling machine, resulting in scrap rate. Increase.

The Chinese patent with the application number CN200610046457.1 discloses "a continuous rolling method for steel plates with variable thickness". Pre-calculate the plastic curve of the piece, and then combine the rolling mill bounce curve to determine the roll gap of the roll, and then roll under the roll gap; calculate the rolling length during the head rolling process until the rolling length is equal to L; the head transition stage After the rolling is completed, the variable thickness rolling is continued; according to the change of the variable thickness rolling length, the roll gap is adjusted accordingly; the above rolling process continues until the rolling length of the variable thickness section is equal to L, at this time the rolled piece The thickness has transitioned to the maximum thickness, and then the tail rolling is carried out. Based on the deviation between the pre-calculated plastic curve and the actual plastic curve, in the tail rolling process, according to the difference in the actual calculation of the exit thickness, the tail is eliminated by adjusting the position of the roll gap. Thickness deviation until tail rolling is complete. Adopting the method of the invention can continuously roll variable-thickness steel plates in a convenient and fast process. This method adopts segmental rolling, which will lead to the disadvantages of low production efficiency and poor control stability in actual mass production.

Contents of the invention

The invention provides a steel plate with longitudinal special-shaped cross-section and its production method. The steel plate with special-shaped longitudinal cross-section adopts a unique structural shape, the length and thickness of which can be selected in a large range, and has strong applicability. In actual engineering applications, extension beams, etc. can be reduced. The processing and welding workload of structural steel beams can increase the strength of joints and improve the reliability of connections; the production process is simple, the controllability is strong, the qualified rate of the finished plate is high, and the surface quality and mechanical properties meet the requirements of use.

In order to achieve the above object, the present invention adopts the following technical solutions to realize:

A steel plate with a longitudinal special-shaped cross-section, comprising a gradual transition section 1, an equal thickness section and a transition section 2 which are continuously formed by rolling and have a total length of L, the lower surfaces of the transition section 1, the equal thickness section and the transition section 2 are a plane, The upper surface is a continuous and smooth transition surface; the upper surface of the equal-thickness section is a plane, and the upper surfaces of the first and second gradient sections are curved surfaces; the length of the equal-thickness section is L ₀ , and the thickness is H ₀ ; The length is L ₁ , and its thickness transitions uniformly from H ₁ to H ₀ , H ₁ >H ₀ ; the length of the second transition section is L ₂ , and its thickness transitions uniformly from H ₀ to H ₂ , H ₂ >H ₀ .

The total length L=2000-50000mm.

Said H ₀ =8-100mm.

Said H ₁ =50-150 mm, H ₂ =50-150 mm.

The production method of a kind of vertical special-shaped section steel plate, comprises the following steps:

1) Steel billet heating process: the steel billet heating temperature range is controlled at 1120-1180°C, and the upper surface temperature is 20-30°C higher than the lower surface temperature;

2) After the billet is out of the furnace, it is descaled by high-pressure water with a pressure ≥ 20MPa;

3) Rolling process: the starting rolling temperature is controlled at 1020-1080°C, and the final rolling temperature is controlled at 980-1020°C; the total rolling reduction rate is ≥40%, and the single-pass reduction rate is ≥5%;; steel plate rolling The speed is controlled at 3.5~5.0m/s;

At the beginning of rolling, the self-learning coefficient of the mathematical model is adjusted according to the actual thickness of the steel plate; specifically, the actual thickness of the steel plate is measured by a thickness gauge, and then the measured actual thickness is compared with the theoretical thickness to obtain the self-learning coefficient, and the self-learning coefficient is used The learning coefficient corrects the zero point in the rolling force preset model of the rolling mill; the value range of the self-learning coefficient is:

When the steel plate thickness is 5<t≤50mm, the self-learning coefficient is 0.05~0.15;

When the steel plate thickness is 50<t≤120mm, the self-learning coefficient is 0.16~0.35;

When the steel plate thickness t>120mm, the self-learning coefficient is 0.4;

4) Cooling process: the cooling start temperature is 890-920°C, the redness temperature is 550-650°C; the cooling speed is 5-10°C/s.

Compared with prior art, the beneficial effect of the present invention is:

1) The steel plate with longitudinal special-shaped section adopts a unique structural shape, and the length and thickness dimensions can be selected in a wide range, and the applicability is strong;

2) In actual engineering applications, it can reduce the processing and welding workload of steel beams such as extension beams, and can increase the strength of nodes and improve the reliability of connections;

3) The production process of the steel plate with longitudinal special-shaped cross-section is simple, the controllability is strong, the qualified rate of the finished plate shape is high, and the surface quality and mechanical properties meet the requirements for use.

Description of drawings

Fig. 1 is a structural schematic diagram of a steel plate with a longitudinal special-shaped section according to the present invention.

In the figure: 1. Gradient section 1 2. Equal thickness section 3. Gradient section 2

Detailed ways

The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing:

As shown in Figure 1, a steel plate with a longitudinal special-shaped cross-section according to the present invention includes a gradual transition section 1, an equal-thickness section 2, and a transition section 2 3 that are continuously formed by rolling and have a total length of L. The transition section 1, The lower surface of the equal-thickness section 2 and the transition section 2 3 is a plane, and the upper surface is a continuous and smooth transition surface; the upper surface of the equal-thickness section 2 is a plane, and the upper surfaces of the transition section 1 and the transition section 2 3 are curved surfaces ; The length of equal-thickness section 2 is L ₀ , and the thickness is H ₀ ; the length of gradient section 1 is L ₁ , and its thickness transitions from H ₁ to H ₀ evenly, H ₁ >H ₀ ; the length of gradient section 2 3 is L ₂ , its thickness transitions uniformly from H ₀ to H ₂ , H ₂ >H ₀ .

The total length L=2000-50000mm.

Said H ₀ =8-100mm.

H ₁ =50-150 mm, H ₂ =50-150 mm.

The production method of a kind of vertical special-shaped section steel plate, comprises the following steps:

1) Steel billet heating process: the steel billet heating temperature range is controlled at 1120-1180°C, and the upper surface temperature is 20-30°C higher than the lower surface temperature;

2) After the billet is out of the furnace, it is descaled by high-pressure water with a pressure ≥ 20MPa;

3) Rolling process: the starting rolling temperature is controlled at 1020-1080°C, and the final rolling temperature is controlled at 980-1020°C; the total rolling reduction rate is ≥40%, and the single-pass reduction rate is ≥5%;; steel plate rolling The speed is controlled at 3.5~5.0m/s;

At the beginning of rolling, the self-learning coefficient of the mathematical model is adjusted according to the actual thickness of the steel plate; specifically, the actual thickness of the steel plate is measured by a thickness gauge, and then the measured actual thickness is compared with the theoretical thickness to obtain the self-learning coefficient, and the self-learning coefficient is used The learning coefficient corrects the zero point in the rolling force preset model of the rolling mill; the value range of the self-learning coefficient is:

When the steel plate thickness is 5<t≤50mm, the self-learning coefficient is 0.05~0.15;

When the steel plate thickness is 50<t≤120mm, the self-learning coefficient is 0.16~0.35;

When the steel plate thickness t>120mm, the self-learning coefficient is 0.4;

4) Cooling process: the cooling start temperature is 890-920°C, the redness temperature is 550-650°C; the cooling speed is 5-10°C/s.

The following examples are carried out on the premise of the technical solutions of the present invention, and detailed implementation methods and specific operation processes are provided, but the protection scope of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

【Example 1】

A 5500mm medium and thick plate rolling mill is used to roll a steel plate with a longitudinal special-shaped section of Q345B. The shape of the longitudinal section is shown in Figure 1, and the specific dimensions are:

H ₀ =8mm, H ₁ =40mm, H ₂ =50mm, the total length of the steel plate L=50000mm, in which the length of transition section 1 is L ₁ =8000mm, and the length of transition section 2 3 is L ₂ =8500mm.

In the present embodiment, the production method of the longitudinal special-shaped section steel plate is as follows:

1) Steel billet heating process: the steel billet heating temperature range is controlled at 1120-1150 °C, and the upper surface temperature is 30 °C higher than the lower surface temperature;

2) After the billet is out of the furnace, it is descaled by high-pressure water with a pressure ≥ 20MPa;

3) Rolling process: the starting rolling temperature is controlled at 1020°C, and the final rolling temperature is controlled at 980°C; the total rolling reduction rate is 40%, and the single pass reduction rate is 5%; the steel plate rolling speed is controlled at 3.5m /s;

At the beginning of rolling, the actual thickness of the steel plate is measured by the thickness measuring instrument, and then the measured actual thickness is compared with the theoretical thickness to obtain the self-learning coefficient, and the zero point in the rolling force preset model of the rolling mill is corrected with the self-learning coefficient ;The self-learning coefficient is 0.05～0.15;

4) Cooling process: the cooling start temperature is 890°C, and the redness temperature is 550°C; the cooling speed is 5°C/s.

The longitudinal variable thickness steel plate produced according to the above-mentioned production process and technical parameters has a plate shape pass rate of 96.7%, a performance pass rate of 99.2%, and a good surface quality.

[Example 2]

A 5500mm medium and thick plate rolling mill is used to roll a steel plate with a longitudinal special-shaped section of Q345B. The shape of the longitudinal section is shown in Figure 1, and the specific dimensions are:

H ₀ =120mm, H ₁ =150mm, H ₂ =150mm, the total length of the steel plate L=12000mm, where the length of transition section 1 is L ₁ =2500mm, and the length of transition section 2 3 is L ₂ =2500mm.

In the present embodiment, the production method of the longitudinal special-shaped section steel plate is as follows:

1) Steel billet heating process: the steel billet heating temperature range is controlled at 1130-1170°C, and the upper surface temperature is 30°C higher than the lower surface temperature;

2) After the billet is out of the furnace, it is descaled by high-pressure water with a pressure ≥ 20MPa;

3) Rolling process: the starting rolling temperature is controlled at 1030°C, and the final rolling temperature is controlled at 990°C; the total rolling reduction rate is 45%, and the single pass reduction rate is 5%; the steel plate rolling speed is controlled at 4.0m/s ;

At the beginning of rolling, the actual thickness of the steel plate is measured by the thickness measuring instrument, and then the measured actual thickness is compared with the theoretical thickness to obtain the self-learning coefficient, and the zero point in the rolling force preset model of the rolling mill is corrected with the self-learning coefficient ;The self-learning coefficient is 0.4;

4) Cooling process: the cooling start temperature is 900°C, and the redness temperature is 580°C; the cooling speed is 6°C/s.

The longitudinal variable thickness steel plate produced according to the above-mentioned production process and technical parameters has a plate shape pass rate of 96.6%, a performance pass rate of 99.4%, and a good surface quality.

[Example 3]

A 5500mm medium and thick plate rolling mill is used to roll a steel plate with a longitudinal special-shaped section of Q345B. The shape of the longitudinal section is shown in Figure 1, and the specific dimensions are:

H ₀ =52mm, H ₁ =72mm, H ₂ =80mm, the total length of the steel plate L=20000mm, in which the length of transition section 1 is L ₁ =3000mm, and the length of transition section 23 is L ₂ =3500mm.

In the present embodiment, the production method of the longitudinal special-shaped section steel plate is as follows:

1) Steel billet heating process: the steel billet heating temperature range is controlled at 1130-1150 °C, and the upper surface temperature is 30 °C higher than the lower surface temperature;

2) After the billet is out of the furnace, it is descaled by high-pressure water with a pressure ≥ 20MPa;

3) Rolling process: the starting rolling temperature is controlled at 1040°C, and the final rolling temperature is controlled at 1000°C; the total rolling reduction rate is 50%, and the single pass reduction rate is 5%; the steel plate rolling speed is controlled at 4.5m/ s;

At the beginning of rolling, the actual thickness of the steel plate is measured by the thickness measuring instrument, and then the measured actual thickness is compared with the theoretical thickness to obtain the self-learning coefficient, and the zero point in the rolling force preset model of the rolling mill is corrected with the self-learning coefficient ;The self-learning coefficient is 0.16～0.35;

4) Cooling process: the cooling start temperature is 900°C, the redness temperature is 600°C; the cooling speed is 8°C/s.

The longitudinally variable thickness steel plate produced according to the above-mentioned production process and technical parameters has a plate shape pass rate of 97.2%, a performance pass rate of 99.5%, and a good surface quality.

【Example 4】

A 5500mm medium and thick plate rolling mill is used to roll a steel plate with a longitudinal special-shaped section of Q345B. The shape of the longitudinal section is shown in Figure 1, and the specific dimensions are:

H ₀ =60mm, H ₁ =80mm, H ₂ =80mm, the total length of the steel plate L=25000mm, in which the length of transition section 1 is L ₁ =2000mm, and the length of transition section 2 3 is L ₂ =3000mm.

In the present embodiment, the production method of the longitudinal special-shaped section steel plate is as follows:

1) Steel billet heating process: the steel billet heating temperature range is controlled at 1150-1180°C, and the upper surface temperature is 30°C higher than the lower surface temperature;

2) After the billet is out of the furnace, it is descaled by high-pressure water with a pressure ≥ 20MPa;

3) Rolling process: the starting rolling temperature is controlled at 1080°C, and the final rolling temperature is controlled at 1020°C; the total rolling reduction rate is 42%, and the single pass reduction rate is ≥6%; the steel plate rolling speed is controlled at 5.0m/ s;

At the beginning of rolling, the actual thickness of the steel plate is measured by the thickness measuring instrument, and then the measured actual thickness is compared with the theoretical thickness to obtain the self-learning coefficient, and the zero point in the rolling force preset model of the rolling mill is corrected with the self-learning coefficient ;The self-learning coefficient is 0.16～0.35;

4) Cooling process: the cooling start temperature is 920°C, the redness temperature is 650°C; the cooling speed is 10°C/s.

The longitudinal variable thickness steel plate produced according to the above-mentioned production process and technical parameters has a plate shape pass rate of 96.8%, a performance pass rate of 99.2%, and a good surface quality.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Equivalent replacements or changes to the concepts thereof shall fall within the protection scope of the present invention.

Claims (5)

1. a kind of longitudinal direction odd-shaped cross section steel plate, which is characterized in that include through roll transition one that continuously shaped and overall length is L, Uniform thickness section and transition two, the lower surface of the transition one, uniform thickness section and transition two are a flat surface, upper surface be it is continuous and Smooth transition surface；Wherein the upper surface of uniform thickness section is plane, and the upper surface of transition one and transition two is curved surface；Uniform thickness section Length be L₀, thickness H₀；The length of transition one is L₁, thickness is by H₁To H₀Even transition, H₁＞ H₀；Transition two Length is L₂, thickness is by H₀To H₂Even transition, H₂＞ H₀。

2. a kind of longitudinal odd-shaped cross section steel plate according to claim 1, which is characterized in that the overall length L=2000~ 50000mm。

3. a kind of longitudinal odd-shaped cross section steel plate according to claim 1, which is characterized in that the H₀=8~100mm.

4. a kind of longitudinal odd-shaped cross section steel plate according to claim 1, which is characterized in that the H₁=50~150mm, H₂ =50~150mm.

5. a kind of production method of longitudinal section steel plate as described in claim 1, which is characterized in that include the following steps：

1) heating steel billet technique：Billet heating temperature scope control is at 1120~1180 DEG C, and upper surface temperature is than lower surface temperature It spends 20~30 DEG C high；

2) after steel billet is come out of the stove, the high-pressure water descaling through pressure >=20MPa；

3) rolling mill practice：Start rolling temperature is controlled at 1020~1080 DEG C, and finishing temperature control is at 980~1020 DEG C；Roll stagnation pressure Lower rate >=40%, single pass reduction ratio >=5%；；Steel plate rolling speed control is in 3.5~5.0m/s；

When rolling starts, the self study coefficient of mathematical model is adjusted according to the actual (real) thickness of steel plate；Specially：Pass through thickness measure Instrument measures the actual (real) thickness of steel plate, then measured actual (real) thickness is compared with theoretic throat to obtain self study coefficient, use Self study coefficient is modified the zero in mill rolling force preset model；The value range of self study coefficient is：

When steel plate thickness is 5 ＜ t≤50mm, self study coefficient is 0.05~0.15；

When steel plate thickness is 50 ＜ t≤120mm, self study coefficient is 0.16~0.35；

When steel plate thickness t ＞ 120mm, self study coefficient is 0.4；

4) cooling technique：The beginning of cooling temperature is 890~920 DEG C, and red temperature is 550~650 DEG C；Cooling velocity is 5~10 ℃/s。