阅读说明：本技术 一种大规格窄缘h型钢的生产工艺 (Production process of large-size narrow-edge H-shaped steel ) 是由 刘春颖 魏振洲 王福良 刘瑞刚 李现富 李振华 杜鸿星 何力国 张年华 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种大规格窄缘H型钢的生产工艺,属于钢铁生产领域,生产工艺包括异型坯BD轧制、多道次连轧、冷却,其中：(1)异型坯BD轧制：采用扩腰轧制；(2)多道次连轧：采用X-H轧法；(3)冷却：采用分段冷却；总冷却时间的前三分之一阶段采用自然冷却,冷却速度在12～14℃/min；总冷却时间的后三分之二阶段采用强风冷却,冷却速度在25～30℃/min。与现有技术相比较,本工艺可以和中规格通用异型坯,减少了前期作业难度和成本,并且能够实现高尺寸精度控制。(The invention discloses a production process of large-size narrow-edge H-shaped steel, which belongs to the field of steel production and comprises the following steps of special-shaped blank BD rolling, multi-pass continuous rolling and cooling, wherein the production process comprises the following steps: (1) rolling a special-shaped blank BD: expanding waist for rolling; (2) multi-pass continuous rolling: adopting an X-H rolling method; (3) and (3) cooling: sectional cooling is adopted; natural cooling is adopted in the first third stage of the total cooling time, and the cooling speed is 12-14 ℃/min; and the last two thirds of the total cooling time is cooled by strong wind, and the cooling speed is 25-30 ℃/min. Compared with the prior art, the process can be used for the special-shaped blank with the medium specification, the early-stage operation difficulty and cost are reduced, and high-size precision control can be realized.)

1. A production process of large-size narrow-edge H-shaped steel is characterized by comprising the following steps: the production process comprises the steps of rolling the special-shaped blank BD, continuously rolling in multiple passes and cooling, wherein:

(1) rolling a special-shaped blank BD: the web plate is thinned and widened under high pressure by adopting waist expanding rolling, and the width of the flange is controlled to be increased;

(2) multi-pass continuous rolling: adopting an X-H rolling method, wherein the arrangement form of a reversible continuous rolling mill group is 5 or 7 times; the reduction coefficient of the flange is the proportional relation of the web reduction coefficients: the initial two passes are 1.04-1.05, the final pass is 1.02-1.03, and the rest amount is arranged in the middle pass;

(3) and (3) cooling: sectional cooling is adopted; natural cooling is adopted in the first third stage of the total cooling time, and the cooling speed is 12-14 ℃/min; and the last two thirds of the total cooling time is cooled by strong wind, and the cooling speed is 25-30 ℃/min.

2. The process of producing large format narrow edge H-section steel of claim 1, wherein: the width of the middle incoming material obtained after the BD rolling is 1.06-1.08 times of the width of the finished product, and the height of the flange of the middle incoming material is 1.2-1.5 times of the height of the finished product; the thickness ratio of the flange of the middle incoming material to the web is 2.2-2.8.

3. The process of producing large format narrow edge H-section steel of claim 1, wherein: the sectional cooling method comprises the following steps: the rolled piece rotates 90 degrees at the inlet of the cooling bed to form an I shape, then enters the constant-speed stepping cooling bed for vertical natural cooling, and is naturally cooled in the cooling bed and is cooled by strong wind when the rolled piece reaches 1/3.

4. A process for producing a large-gauge narrow-edged H-shaped steel as claimed in any one of claims 1 to 3, wherein: the 5-pass web reduction data: the deformation of 1-2 passes is 10-15%, the deformation of 3-4 passes is 10-15%, and the deformation of 5 passes is 2-3%.

5. The process for producing a large-specification narrow-edge H-shaped steel as claimed in any one of claims 1 to 3, wherein: and in the 7-pass rolling, the deformation of the front 4 webs is 6-10%, the deformation of the 5-6 passes is 6-7%, and the deformation of the 7 passes is 2-3%.

Technical Field

The invention relates to a steel production technology, in particular to a production process of large narrow-edge H-shaped steel based on a simulated extension balance method for producing the steel.

Background

The hot-rolled H-shaped steel is an economic section high-efficiency section with more optimized section area distribution and more reasonable strength-to-weight ratio. Compared with the traditional I-steel, the novel I-steel has the characteristics of good mechanical property and convenience in connection. Compared with the welding of H-shaped steel, the component has accurate size, no deformation and residual stress caused by welding and reduced welding workload. Compared with concrete, the concrete has the advantages of light dead weight, good earthquake resistance and the like. Because all parts of the H-shaped steel are arranged at right angles, the H-shaped steel has the advantages of strong bending resistance, simple construction, cost saving, light structure weight and the like in all directions and is widely applied.

The series of H-shaped steel with the length of more than HN700 multiplied by 300 is close to the limit of equipment, the specification width of the series of H-shaped steel reaches 700-900 mm, and the series of H-shaped steel belongs to a large-specification narrow-flange H-shaped steel product in the standard. Due to the characteristics of large section, large width-to-height ratio and the like, the large-specification narrow-edge H-shaped steel has the following technical difficulties in the production and rolling process: firstly, a blank opening machine is used for rolling, the width of a web plate is limited to be expanded towards the width direction through a hole side wall, in order to realize the width of 700-900 mm at the later stage, the BD rolling link needs to calculate the specification of a deformed blank in a reverse mode according to the specification of a final product, for example, large-specification narrow-edge H-shaped steel with the specification of HN700 multiplied by 300 multiplied by 13 multiplied by 24mm (H multiplied by B multiplied by T multiplied by T, H height, B flange width, T web thickness and T flange 1/4 thickness) is produced, through multiple calculation, a special 1024 multiplied by 420 multiplied by 110 multiplied by 105mm deformed blank needs to be prepared, a universal 750 multiplied by 370 multiplied by 100 multiplied by 105mm deformed blank cannot be used, and the operation link and the; secondly, the area proportion of the web plate is large, the web plate plays a leading role in rolling deformation, and the extension of the web plate generates obvious drawing and shrinking effects on a flange, so that size fluctuation is easily caused; quality problems such as wave bending and the like caused by uneven cooling of the web during cooling of the rolled piece; fourthly, the size is large, and the temperature at the straightening inlet cannot be reduced; the development of large-scale series is severely restricted by the problems.

Disclosure of Invention

The technical task of the invention is to provide a production process of large-specification narrow-edge H-shaped steel aiming at the defects of the prior art, the process can reasonably distribute the rolling reduction of a web plate and a flange by using a simulation extension balance method based on the production section steel, so that the production process of the large-specification narrow-edge H-shaped steel is stable in production, high in dimensional precision control and capable of achieving the purpose of improving the yield and the efficiency.

The technical scheme for solving the technical problem is as follows: 1. a production process of large-size narrow-edge H-shaped steel is characterized by comprising the following steps: the production process comprises the steps of rolling the special-shaped blank BD, continuously rolling in multiple passes and cooling, wherein:

(1) rolling a special-shaped blank BD: the web plate is thinned and widened under high pressure by adopting waist expanding rolling, and the width of the flange is controlled to be increased;

(2) multi-pass continuous rolling: adopting an X-H rolling method, wherein the arrangement form of a reversible continuous rolling mill group is 5 or 7 times; the reduction coefficient of the flange is the proportional relation of the web reduction coefficients: the initial two passes are 1.04-1.05, the final pass is 1.02-1.03, and the rest amount is arranged in the middle pass;

(3) and (3) cooling: sectional cooling is adopted; natural cooling is adopted in the first third stage of the total cooling time, and the cooling speed is 12-14 ℃/min; and the last two thirds of the total cooling time is cooled by strong wind, and the cooling speed is 25-30 ℃/min.

The width of the middle incoming material obtained after the BD rolling is 1.06-1.08 times of the width of the finished product, and the height of the flange of the middle incoming material is 1.2-1.5 times of the height of the finished product; the thickness ratio of the flange of the middle incoming material to the web is 2.2-2.8.

The sectional cooling method comprises the following steps: the rolled piece rotates 90 degrees at the inlet of the cooling bed to form an I shape, then enters the constant-speed stepping cooling bed for vertical natural cooling, and is naturally cooled in the cooling bed and is cooled by strong wind when the rolled piece reaches 1/3.

The web reduction data of the above 5 passes: the deformation of 1-2 passes is 10-15%, the deformation of 3-4 passes is 10-15%, and the deformation of 5 passes is 2-3%.

And in the 7-pass rolling, the deformation of the front 4 webs is 6-10%, the deformation of the 5-6 passes is 6-7%, and the deformation of the 7 passes is 2-3%.

Compared with the prior art, the invention has the following outstanding beneficial effects:

1. the special-shaped blank can be universal with a medium specification, the early-stage operation difficulty and cost are reduced, and high-size precision control can be realized;

2. the product surface quality is high, and the quality problems of wave bending and the like caused by uneven cooling in the prior art are solved;

3. the existing process equipment and production technology are fully and effectively utilized, the economic benefit is remarkable, and the popularization value is high.

Drawings

FIG. 1 is a schematic drawing of the waist-expanding rolling of the present invention.

FIG. 2 is a schematic view of a prior art reduction rolling.

Fig. 3 is a schematic view of the structure of the reversible continuous rolling mill train of the present invention.

Fig. 4 is a schematic view of the arrangement of the 5-pass train of the reversible continuous rolling mill train of the present invention.

Figure 5 is a schematic comparison of prior art and inventive roll fillets.

Detailed Description

The invention is further described with reference to the drawings and the detailed description.

The invention provides a method for manufacturing stable and large narrow-edge H-shaped steel, which can stably produce HN 700X 300, HN 800X 300 and HN 900X 300 series specifications with high dimensional accuracy and meet the requirements of stable product performance and high dimensional accuracy.

The production process comprises the following steps: the special-shaped blank → BD (blank opener) rolling → multi-pass continuous rolling → cooling.

1. Rolling of beam blank BD

The special-shaped blank BD rolling adopts a waist expanding rolling process. In the so-called pinch-off rolling, as shown in fig. 1, when the web of the preform is pressed down, the web is freely widened, and the web height (H) of the formed intermediate incoming material 2 is larger than that of the billet 1, so that the billet can be used in common with specifications of 700mm or less, and a preform of 750 × 370 × 100 × 105mm (hxb × T, H height, B flange width, T web thickness, T flange 1/4 thickness) is used.

The prior art is a reduction rolling, as shown in fig. 2, a profiled blank web is reduced, the transverse widening of the web is limited by a groove-shaped side wall, and the height dimension of the formed middle incoming material 2' web is smaller than the dimension of a blank 1. The used blank is 1024X 420X 110X 105mm with single specification, and the existing general-purpose blank can not be used.

In the BD rolling process, the pass system is controlled to adjust the web reduction and the flange reduction to make the web thinner and wider at a high reduction and to control the flange width to increase.

In order to realize that: the width of the middle incoming material obtained after BD rolling is 1.06-1.08 times of the width of the finished product, and the height of the flange of the middle incoming material is 1.2-1.5 times of the height of the finished product. The thickness ratio of the flange of the middle incoming material to the web is 2.2-2.8.

The proportional relation can ensure the balance of the extension of the web and the flange during the subsequent reversible X-H continuous rolling, overcomes the defect of irregular flange shape caused by waist expanding rolling, and plays a role in the regularity of the later flange shape.

2. Multiple pass continuous rolling

The invention adopts an X-H rolling method to realize the balance of the elongation of the web and the flange.

Particularly adopt U_REU_FReversible continuous rolling mill train, said U_REU_FUr rolling mill, E rolling mill and U of reversible continuous rolling unit_FThe rolling mill is shown in figure 3.

And the multiple passes are rolling for 5 or 7.

As shown in fig. 4, U_REU_FThe arrangement form of the reversible continuous rolling mill group is 5 passes, each pass participates in rough rolling and ensures the surface quality of finished products in finish rolling passes. 5-pass web reduction data: the deformation of 1-2 passes is 10-15%, the deformation of 3-4 passes is 10-15%, and the deformation of 5 passes is 2-3%.

U_REU_FThe method can also be reversible 7-pass rolling, the deformation of the front 4 webs is 6-10%, and the deformation of the 5-6 passes is 6-7%And 7, 2-3% of each pass, rolling by adopting multi-pass small deformation, and ensuring the dimensional precision of the finished product.

In addition, the large-size narrow flange H-shaped steel web is wide and occupies a large area proportion, deformation of the web plays a leading role in subsequent X-H reversible connection, and extension of the web generates an obvious stretching and shrinking effect on the flange. Therefore, the flange and web reduction rules are distributed, namely, the reduction coefficients of the flanges are in a certain proportional relation with the reduction coefficients of the web, the ratio is 1.04-1.05 in the first two passes, and the final pass is 1.02-1.03. The remaining amounts are arranged in intermediate passes, as specified in the table of the example reduction parameters.

The thickness T of the flange is one quarter of the thickness of the flange. And the rolling reduction coefficient is the thickness of the last pass divided by the thickness of the next pass.

By means of X-H technology, with X-shaped frame U_RThe intersection of the roller fillet and the side wall straight line section is seriously bonded with steel, and the U-shaped frame of the H-shaped frame_FThe abrasion of the round corners of the roller is quite serious, the rolling reduction of the round corners is relatively large, the metal flow is relatively large, and the round corners are easily abraded.

The invention improves the roller from single round angle (figure 5-a) to double round angle (figure 5-b) to avoid the surface pit problem at the R corner.

The double round corner means that two straight line sides of the roller are connected in sequence through two arcs with different radiuses, for example, in the prior art, the two straight line sides of the roller are connected through an arc of R36 in a single round corner mode, and the two straight line sides of the roller with the double round corners are connected through arcs of R200 and R36. The radian of the X-shaped frame is excessive, so that the arc can be improved_RThe steel is stuck at the intersection of the straight line sections of the upper wall and the lower wall. And in the H-shaped frame U_FAnd the radians are different, especially when the upper radian is larger than the lower radian, the metal flow is not in the middle point of a single impact arc, and the fillet abrasion condition is improved.

In addition, heat preservation treatment is required in the rolling process, such as: and a heat insulation cover is added to prevent the temperature of the web from dropping faster than that of the flange to cause cooling bending.

3. Cooling down

In the prior art, a natural cooling method is mostly adopted, and the temperature at a straightening inlet can not be reduced due to large specification, so that the cooling time has to be prolonged, otherwise, the normal production rhythm is influenced.

Some technologies adopt strong air cooling or super cooling technologies for cooling, but the web temperature is cooled faster than the flange due to the overlarge area of the web of the H-shaped steel, so that the cooling and bending problems are easily caused by the strong cooling mode.

In addition, due to air convection, the upper temperature difference and the lower temperature difference of the H-shaped steel web are different, so that the deformation is more easily aggravated.

Therefore, the technology of the invention adopts the technology of sectional cooling.

The total cooling time is 32-36 min.

And naturally cooling the first third stage of the total cooling time at a cooling speed of 12-14 ℃/min.

And the last two thirds of the total cooling time is cooled by strong wind, and the cooling speed is 25-30 ℃/min.

The method specifically comprises the following steps: the rolled piece rotates 90 degrees at the inlet of the cooling bed to form an I shape, then enters the constant-speed stepping cooling bed for vertical natural cooling, and is naturally cooled in the cooling bed and is cooled by strong wind when the rolled piece reaches 1/3.

The cooling bed adopts a deep foundation, air inlets are arranged at the inlet and the outlet of the cooling bed, and a ventilator is arranged above the cooling bed to meet the requirement of good air convection cooling effect.

And a strong cooling fan is arranged below the middle and rear two thirds of the cooling bed, the cooling force of the strong cooling fan improves the cooling rate, the temperature of the rolled piece out of the cooling bed is less than 80 ℃, the rolled piece is turned over for 90 degrees again at the outlet of the cooling bed after being cooled, and is restored to an H shape, and the problem of web cooling waves is effectively solved through the above cooling means.

For better description, the rolling process will be described by taking the HN 700X 300X 13X 24mm (H X B X T X T) specification as an example.

Practice proves that: when the 750 × 370 × 100 × 105mm beam blank is used for traditional reduction rolling, the flange B of the intermediate blank cannot be increased, reasonable extension cannot be realized in the continuous rolling stage, and the HN700 × 300 × 13 × 24mm specification cannot be produced.

Comparative example

In the prior art, the beam blank → BD rolling → multi-pass reversible tandem rolling → cooling.

1. Rolling of beam blank BD

Comparative example a specific stock of 1024X 420X 110X 105mm gauge was rolled down. The dimensions of the resulting intermediate charge were 850X 322X 47X 107 mm.

2. Multiple pass reversible continuous rolling

By X-H rolling, using U_REU_FThe data of the reversible continuous rolling unit and 5 passes of the web plate reduction amount are shown in a continuous rolling parameter table of an embodiment.

3. Cooling down

Naturally cooling in the whole process, wherein the cooling speed is 12-14 ℃/min.

Group of embodiments

The production process of each embodiment group comprises the following steps: the special-shaped blank → BD expanding rolling → multi-pass reversible continuous rolling → combined cooling. The dimensions of the profiled blank used in the examples were 750X 370X 100X 105 mm.

1. BD waist expanding rolling of special-shaped blank

The specifications of the final intermediate stock are given in the following table:

2. multiple pass reversible continuous rolling

By X-H rolling, using U_REU_FThe specific pass reduction schedule for the reversing tandem mill train is shown in the following table.

3. Combined cooling

The results of the comparison of the control and the examples are shown in the following table:

from the above results, it can be seen that the narrow-edge H-shaped steel with HN 700X 300X 13X 24 specification manufactured by the process of the present invention has the size capable of meeting the size requirement of the finished product, the surface quality of the product is high, the wave bending occurrence is obviously reduced compared with the comparative example, in addition, the double circular arcs at the R corners effectively reduce the generation of pits, and the shortage of the X-H technology is improved. The comparative examples using the prior art production method had to be carried out using a single blank, and could not share blanks with the HN600 × 300, HN600 × 200, and HN650 × 300 series.

It should be noted that while the invention has been described in detail with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various obvious changes can be made therein without departing from the spirit and scope of the invention.