Emergency production method of φ50 specification steel bar

Abstract

The application discloses an emergency production method for a phi 50 steel bar, which comprises the following steps: S1, calculating the required billet length and section according to the available length of a large cooling bed and the size of a heating furnace; S2, feeding the billet into the heating furnace in a two-side feeding mode; S3, sequentially passing the billet through a rough rolling mill set, a medium rolling mill set and a finishing rolling mill set to form a rolled piece, and redesigning and matching rolling line passageways; and S4, clamping the rolled piece by pinch rolls for a certain time and then feeding the rolled piece to a cooling bed. The application has the advantages that the billet size mode is changed, the billet length is reduced, the double-length shearing is cancelled, the capital investment and time occupation can be reduced, and the existing production line can produce the phi 50 steel bar without modification through passageway optimization.

Description

Technical Field

[0001] This invention relates to the field of steel bar production technology, and in particular to an emergency production method for φ50 steel bars. Background Technology

[0002] Currently, with market development and changes in rebar applications, nuclear power projects, tunnel engineering projects, and cross-sea bridge projects have a certain demand for φ50 rebar. Domestic bar production lines, due to fewer orders for φ50 rebar, generally do not consider this specification when starting up production lines. Few lines can roll φ50 rebar, mainly due to insufficient shearing capacity of the multiple-length shears, which prevents normal shearing. Modifying to multiple-length shears requires significant investment and a considerable amount of time; equipment and civil engineering take about six months and cost over 8 million RMB, making the modification cost substantial. In recent years, the production lines and those under construction for bar production have large heating furnaces and long production lines. If there is insufficient force to move the rolled steel sheets forward, they will remain stuck in the roller conveyor. Summary of the Invention

[0003] The purpose of this invention is to provide an emergency production method for φ50 steel bars. By changing the billet size and reducing the billet length, and eliminating the need for multiple-length shearing, the capital investment and time consumption can be reduced. At the same time, by optimizing the hole shape, it can be ensured that existing production lines can produce φ50 steel bars without modification.

[0004] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0005] An emergency production method for φ50 steel bars, characterized by comprising the following steps:

[0006] S1. Calculate the required billet length and cross-section based on the available length of the large cooling bed and the size of the heating furnace;

[0007] S2, the steel billet enters the heating furnace using a two-sided feeding method;

[0008] S3, the steel billet passes through the roughing mill, intermediate mill and finishing mill in sequence to form a rolled piece, and the rolling line pass is redesigned and matched;

[0009] S4, the rolled piece exits the rolling mill and is held by the pinch rolls for a certain period of time before being placed on the cooling bed.

[0010] Preferably, in step S1, the required billet weight M is first calculated based on the available length L1 of the large cooling bed, as shown in equation (1):

[0011]

[0012] Where m is the weight per meter of φ50 steel bar (15.42 kg / m), c is the negative tolerance (1.5%), and T is the yield rate (97.5%).

[0013] Then, by calculating the required billet weight M, a relationship function is constructed between the required billet weight M and the required billet cross-sectional area S and length L2, as shown in equation (2):

[0014] M=S*ρ*L2 (2)

[0015] Where ρ is the density of the steel billet, 7.85 g / cm³. 3 .

[0016] Preferably, the required billet length in S1 meets the following conditions: the billet is 40cm away from the stationary beam on the side close to the rolling mill, and the other end of the billet does not scrape against the moving beam.

[0017] Preferably, the method of placing the billet on both sides of the heating furnace in S2 is as follows: the tail of the billet on the non-rolling mill side is positioned in the middle of the first cantilever roll head entering the furnace, 40cm away from the side wall of the rolling mill; the head of the billet on the rolling mill side is positioned in the middle of the fourth and fifth cantilever roll heads at the feeding end, 40cm away from the furnace wall.

[0018] Preferably, the finishing mill in S3 includes a first finishing mill and a second finishing mill in sequence, the roughing mill includes 6 mills, the intermediate mill includes 4 mills, the first finishing mill includes 6 mills, and the second finishing mill includes 4 mills.

[0019] Preferably, the tail stand of the intermediate rolling mill is 36m away from the head stand of the first finishing rolling mill, and the tail stand of the first finishing rolling mill is 70m away from the head stand of the second finishing rolling mill.

[0020] Preferably, the rolling pass types starting from the last stand in the roughing mill in S3 are sequentially set as: first round pass type, first elliptical pass type, second round pass type, third round pass type, fourth round pass type, second elliptical pass type and fifth round pass type.

[0021] Preferably, the first circular hole has a slot width of 90mm, a slot radius of 8mm, a slot bottom radius of 41mm, a roll gap of 12mm, a sidewall inclination angle of 35°, and a hole height of 81mm. The first elliptical hole has a hole height of 48mm, a slot width of 111mm, a slot radius of 5mm, a slot bottom radius of 90mm, and a roll gap of 10mm. The second, third, and fourth circular holes have the same dimensions, all with a slot width of 66mm. The first type of elliptical hole has a groove radius of 6mm, a groove bottom radius of 31mm, a roll gap of 10mm, a sidewall inclination angle of 33°, and a hole height of 61mm. The second type of elliptical hole has a hole height of 40mm, a groove width of 85mm, a groove radius of 5mm, a groove bottom radius of 65mm, and a roll gap of 8mm. The fifth type of circular hole has a groove width of 54mm, a groove radius of 5mm, a groove bottom radius of 25mm, a roll gap of 8mm, a sidewall inclination angle of 35°, and a hole height of 49mm.

[0022] Preferably, the formula for calculating the delay time t in S4 is as shown in equation (3):

[0023]

[0024] Where L3 is the distance between the finished product frame and the pinch roller, V is the speed of the finished product frame, and t 设 The preset delay time is assumed to be 0.3s.

[0025] In summary, the beneficial effects of this invention are that by changing the billet size and reducing the billet length, eliminating the need for multiple-length shearing, it can reduce capital investment and time commitment. At the same time, through the optimization of the hole shape, it can ensure that existing production lines can produce φ50 specification steel bars without modification. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the first circular hole type in this invention;

[0027] Figure 2 This is a schematic diagram of the first elliptical hole type in this invention.

[0028] Figure 3 This is a schematic diagram of the structure of the second, third, and fourth circular hole types in this invention;

[0029] Figure 4 This is a schematic diagram of the second elliptical hole type in the present invention;

[0030] Figure 5 This is a schematic diagram of the fifth circular hole type in this invention. Detailed Implementation

[0031] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. These embodiments do not constitute a limitation on the present invention.

[0032] An emergency production method for φ50 steel bars includes the following steps:

[0033] S1. Calculate the required billet length and cross-section based on the available length of the large cooling bed and the size of the heating furnace.

[0034] S2, the steel billet enters the heating furnace by means of feeding from both sides.

[0035] S3, the steel billet passes through the roughing mill, intermediate mill and finishing mill in sequence to form a rolled piece, and the rolling line pass is redesigned and matched.

[0036] S4, the rolled piece exits the rolling mill and is held by the pinch rolls for a certain period of time before being placed on the cooling bed.

[0037] In S1, the required billet weight M is first calculated based on the available length L1 of the large cooling bed, as shown in formula (1):

[0038]

[0039] Where m represents the weight per meter of φ50 steel bar (15.42 kg / m), c represents the negative tolerance of 1.5%, and T represents the yield rate of 97.5%.

[0040] Then, by calculating the required billet weight M, a relationship function is constructed between the required billet weight M and the required billet cross-sectional area S and length L2, as shown in equation (2):

[0041] M=S*ρ*L2 (2)

[0042] Where ρ is the density of the steel billet, 7.85 g / cm³. 3 .

[0043] The required billet length in S1 meets the following conditions: the billet is 40cm away from the static beam on the side closest to the rolling mill, and the other end of the billet does not scrape against the moving beam.

[0044] The specific method of billet distribution on both sides of the heating furnace in S2 is as follows: the tail of the billet on the non-rolling mill side is positioned in the middle of the first cantilever roll head entering the furnace, 40cm away from the side wall of the rolling mill; the head of the billet on the rolling mill side is positioned in the middle of the fourth and fifth cantilever roll heads at the feeding end, 40cm away from the furnace wall. This method of distribution can ensure that the water beams in the furnace are subjected to uniform force, and the head and tail of the billet will not scrape against the furnace wall and water beams during the stepping process, causing equipment damage, deviation, or billet overturning, thereby causing major equipment accidents.

[0045] The S3 finishing mill unit includes the first finishing mill unit and the second finishing mill unit in sequence. The roughing mill unit includes 6 mill stands, the intermediate mill unit includes 4 mill stands, the first finishing mill unit includes 6 mill stands, and the second finishing mill unit includes 4 mill stands.

[0046] The tail stand of the intermediate rolling mill is 36m away from the head stand of the first finishing mill, and the tail stand of the first finishing mill is 70m away from the head stand of the second finishing mill.

[0047] like Figures 1 to 5 As shown, the rolling pass types starting from the last stand in the S3 roughing mill are sequentially set as follows: first round pass type, first elliptical pass type, second round pass type, third round pass type, fourth round pass type, second elliptical pass type, and fifth round pass type. The second, third, and fourth round pass types are the same based on the principle of equal flow rate per second. The function of the last two stands is to clamp the material without changing the material size. Since the flow rate per second is the same, the linear speed of the three mills should be equal. Due to the different speed ratios, the speed of the corresponding mills needs to be reset.

[0048] The first circular hole type has a slot width of 90mm, a slot radius of 8mm, a slot bottom radius of 41mm, a roll gap of 12mm, a sidewall inclination angle of 35°, and a hole height of 81mm. The first elliptical hole type has a hole height of 48mm, a slot width of 111mm, a slot radius of 5mm, a slot bottom radius of 90mm, and a roll gap of 10mm. The second, third, and fourth circular hole types have the same dimensions, all with a slot width of 66mm and a slot diameter of... The first elliptical hole has a corner radius of 6mm, a groove bottom radius of 31mm, a roll gap of 10mm, a side wall inclination angle of 33°, and a hole height of 61mm. The second elliptical hole has a hole height of 40mm, a groove width of 85mm, a groove corner radius of 5mm, a groove bottom radius of 65mm, and a roll gap of 8mm. The fifth circular hole has a groove width of 54mm, a groove corner radius of 5mm, a groove bottom radius of 25mm, a roll gap of 8mm, a side wall inclination angle of 35°, and a hole height of 49mm.

[0049] The formula for calculating the delay time t in S4 is shown in equation (3):

[0050]

[0051] Where L3 is the distance between the finished product frame and the pinch roller, V is the speed of the finished product frame, and t 设 The preset delay time is 0.3s. Setting the delay time manually can prevent the pinch roller from clamping the material before the head of the material passes the pinch roller.

[0052] The beneficial effects of this invention are that by changing the billet size and reducing the billet length, the multiple-length shearing is eliminated, which can reduce capital investment and time occupation. At the same time, by optimizing the hole shape, it can ensure that the existing production line can produce φ50 specification steel bars without modification.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within the scope of its essence and protection. Such modifications or equivalent substitutions should also be considered to fall within the protection scope of the present invention.

Claims

1. An emergency production method for φ50 steel bars, characterized in that, Includes the following steps: S1. Calculate the required billet length and cross-section based on the available length of the large cooling bed and the size of the heating furnace; S2, the steel billet enters the heating furnace using a two-sided feeding method; S3, the steel billet passes through the roughing mill, intermediate mill and finishing mill in sequence to form a rolled piece, and the rolling line pass is redesigned and matched; S4, the rolled piece exits the rolling mill and is held by the pinch rolls for a certain time before being placed on the cooling bed; In S1, the required billet weight M is first calculated based on the available length L1 of the large cooling bed, as shown in formula (1): （1） Where m represents the weight per meter of φ50 steel bar (15.42 kg / m), c represents the negative tolerance of 1.5%, and T represents the yield rate of 97.5%. Then, by calculating the required billet weight M, a relationship function is constructed between the required billet weight M and the required billet cross-sectional area S and length L2, as shown in equation (2): （2） Where ρ is the density of the steel billet, 7.85 g / cm³; The rolling pass types starting from the last stand in the roughing mill of S3 are sequentially set as follows: first circular pass type, first elliptical pass type, second circular pass type, third circular pass type, fourth circular pass type, second elliptical pass type, and fifth circular pass type; The first circular hole has a slot width of 90mm, a corner radius of 8mm, a bottom radius of 41mm, a roll gap of 12mm, a sidewall inclination angle of 35°, and a hole height of 81mm. The first elliptical hole has a hole height of 48mm, a slot width of 111mm, a corner radius of 5mm, a bottom radius of 90mm, and a roll gap of 10mm. The second, third, and fourth circular holes have the same dimensions, all with a slot width of 66mm. The first type of circular hole has a fillet radius of 6mm, a groove bottom radius of 31mm, a roll gap of 10mm, a sidewall inclination angle of 33°, and a hole height of 61mm. The second type of elliptical hole has a hole height of 40mm, a groove width of 85mm, a groove fillet radius of 5mm, a groove bottom radius of 65mm, and a roll gap of 8mm. The fifth type of circular hole has a groove width of 54mm, a groove fillet radius of 5mm, a groove bottom radius of 25mm, a roll gap of 8mm, a sidewall inclination angle of 35°, and a hole height of 49mm.

2. The emergency production method for φ50 steel bars according to claim 1, characterized in that: The required billet length in S1 meets the following conditions: the billet is 40cm away from the stationary beam on the side closest to the rolling mill, and the other end of the billet does not scrape against the moving beam.

3. The emergency production method for φ50 steel bars according to claim 1, characterized in that: The specific method of billet distribution on both sides of the heating furnace in S2 is as follows: the tail of the billet on the non-rolling mill side is positioned in the middle of the first cantilever roll head entering the furnace, 40cm away from the side wall of the rolling mill; the head of the billet on the rolling mill side is positioned in the middle of the fourth and fifth cantilever roll heads at the feeding end, 40cm away from the furnace wall.

4. The emergency production method for φ50 steel bars according to claim 1, characterized in that: The S3 finishing mill unit includes a first finishing mill unit and a second finishing mill unit in sequence. The roughing mill unit includes 6 mill stands, the intermediate mill unit includes 4 mill stands, the first finishing mill unit includes 6 mill stands, and the second finishing mill unit includes 4 mill stands.

5. The emergency production method for φ50 steel bars according to claim 4, characterized in that: The tail stand of the intermediate rolling mill is 36m away from the head stand of the first finishing mill, and the tail stand of the first finishing mill is 70m away from the head stand of the second finishing mill.

6. The emergency production method for φ50 steel bars according to claim 1, characterized in that: The formula for calculating the delay time t in S4 is shown in equation (3): （3） Where L3 is the distance between the finished product frame and the pinch roller, V is the speed of the finished product frame, and t 设 The preset delay time is assumed to be 0.3s.

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