2032mm Hot Continuous Rolling Production Line

This paper introduces the main projects and technical parameters of the technical transformation of the 2032mm -hand hot continuous rolling production line completed by Steel Group Corporation in 2008 , including adding 2 walking beam heating furnaces, 1 Ro strong roughing mill, 1 A set of coreless transfer type hot coil box, 2# coiler, 3 cross-cutting lines and 1 leveling and splitting line. After the transformation, billets with a thickness of 250mm can be used, and the designed annual output is increased from 1.5 million tons to 3.6 million tons.

Key words: hot rolling mill; technological transformation; product quality; output
Iron and Steel Group Corporation's 2032mm hot rolling production line was completed and put into operation at the end of 2005 , with an original designed production capacity of 1.5 million t/a . The main equipment of this production line is a complete set of second-hand equipment purchased from British CORUS company in 2003 , which belongs to the second generation of semi-continuous hot strip rolling mill. Although during the construction period and commissioning of the project

( 1 ) When using the welding seam on the short side of the welded pipe, it is recommended to add more than 2 forming passes, or use the downhill method, so as to reduce the internal stress of the long side by reducing the forming amount of the pass, thereby eliminating side waves;
( 2) When using the welding seam on the long side of the welded pipe, it is recommended to pay attention to making the four corners of the welded pipe start empty bending at the same time during the radiation distribution, so as to eliminate the upward bending trend of the welded pipe in the longitudinal direction. If conditions permit, the forming passes or Use the downhill method.
Since the pass pattern has been fixed on site, and the cost of re-opening the pass pattern is too high, the downhill method can be used to optimize the radial bending process. After optimization, the edge wave defect rate is significantly reduced.
2 Main technical transformation projects
Art layout , the main renovation project includes three parts : heating furnace area, main rolling area and finishing area .
The transformation of the hot rolling production line was carried out in the original factory building, and the process layout was severely restricted by the site .

2.1 Furnace zone
line, the original 1 walking beam heating furnace on the production line shortened the renovation period as much as possible, and newly built 2** and 3* heating furnaces on the east side of the original 1* heating furnace , and used the shutdown period for maintenance Complete the docking work of the pipeline. The walking beam heating furnace can provide rollable steel slabs with uniform temperature, less watermark and no scratch deformation, and has short heating time, less burning loss of slabs, good comprehensive performance and low annual comprehensive consumption index. The main technical parameters of the new heating furnace are shown in Table 1 .

Table 1 Main technical parameters of newly built 2* and 3* heating furnaces
the project	parameter
Rated heating capacity /t・hi	300( cold billet)
Effective length of heating furnace /mm	51500
Inner width of heating furnace /mm	10200
fuel	mixed gas

2.2 Main rolling line area
The original roughing mill of the 2032mm hot continuous rolling production line is a second-hand equipment purchased from CORUS company and manufactured by the former British DA -VY company . The Ro roughing mill has high rigidity, high transmission power, and has the functions of electric APC and hydraulic AGC . in R. _ The entrance side of the four-spoke rolling mill is equipped with a reversible vertical-spoke rolling mill, which forms a compact arrangement. The vertical-spoke rolling mill is reserved with automatic width control (AWC) and short-stroke (SSC) automatic control functions. AWC and SSC can effectively control the width of the strip. Steel width and head and tail shape. The R rough rolling mill can be used alone, and can also form reversible continuous rolling with the R rough rolling mill. In order to match the rough rolling capacity, the two main drive motors of the original F 2 and F 3 finishing mills of the hot continuous rolling production line were replaced , and their power was increased from the original 4474kW to 6500kW o
In order to reduce the temperature drop of the strip and reduce the temperature difference between the head and the tail of the slab, a set of coreless transfer hot coil box is added between the flying shears of the R. rough rolling mill and the finishing mill. The use of hot coil boxes can not only increase the production capacity and yield of the rolling line, but also help to reduce scale and improve thickness control.
the original 1* coiler , a new 2# coiler is added. It adopts a three-assist spoke type downcoiler. The reel is a stepless expansion and contraction type . The inner layer steel coil is squeezed by the head of the strip under the pressure of the auxiliary coil to form indentations, so as to ensure the coiling quality.
The steel coils in the hot rolling mill were originally transported in the form of vertical coils. After adding a weighing and turning device, the vertical coils can be turned into horizontal coils, which is convenient for loading and unloading by driving. At the same time, a strapping machine is installed on the newly added saddle-type chain conveyor, which is convenient for bundling steel coils again.
The technical parameters of the newly added main equipment in the main rolling line area of the hot continuous rolling production line are shown in Table 2 .
2.3 Finishing area
3 cross-cutting lines and 1 flattening coiling line were added in this transformation. ; Among them, the leveling and slitting line is transformed by using the original second-hand equipment of CORUS company. Through leveling, the surface quality and shape of the plate can be improved, and the mechanical properties of the plate can be improved. It can also be used as a coil slitting line . See Table 3 for the technical parameters of the newly added equipment in the finishing area .

table 2		The technical parameters of the main equipment newly added in the main rolling line area
	device name	the project	parameters
		Maximum rolling force /kN	5500
		Rolling speed /m・st	0 ~ ±6.05 '
		Rod diameter /mm	Spoke groove ① 1200/ ① 1100mm
	vertical spoke mill	Radial body length /mm	650, slot height 250
		Rolling mill opening /mm	650 ~ 2150
		Main motor power /kW	2X 1200 AC
		Main motor speed /r • min -1	0±150/400
Ro roughing mill		Mill type	Four-spoke reversible
		Maximum rolling force /kN	45000
		Rolling speed /m • s _1	0 ~ ± 3* 01/6. 54
	Four Tsuki rough rolling mill	Working spoke size /m mXmm	① 1250/61150X2032
		Support spoke size /m mXmm	① 1600/61450X 1982
		Rolling mill opening /mm	300 (max)
		Main motor power /kW	2X7000
		Main motor speed /r・minT	0±50/100
		type	Steel coil coreless transfer type
		Coiling intermediate billet thickness /mm	25 ~ 40
		Intermediate billet width /mm	1000 ~ 1840
Hot coil box		Intermediate billet temperature /°c	950 ~ 1150
		Threading speed /m- s- 1	2. 0 ~ 2. 5
		Coiling speed /m • s _1	5. 0( max)
		Unwinding speed /m • si	0 ~ 2. 0
		type	Full-hydraulic three-assist roller horizontal
		Strip thickness /mm	2~25
2# Coiler		Strip width /mm	600 ~ 1850
		Roll type	Four-sided spindle connecting rod type
		Roll nominal diameter /mm	① 762 ( pre-expansion diameter ① 745/ reduction diameter ① 727)
		Coiling speed /m • s 1	0 ~ 25. 1

the 2032mm hot continuous rolling production line was carried out without affecting production, and all transformations were completed in 2008 . Through the transformation, the output of the hot rolling mill has been greatly increased, and the level of technical equipment has been further improved. It is mainly reflected in the fact that after the capacity of the rolling mill is enhanced, billets with a thickness of 250mm can be used, thereby improving the weight of finished coils and the dimensional accuracy and surface of steel coils . Quality has enhanced the market competitiveness of Iron and Steel Hot Rolling Plant.

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