Light reduction method for continuous casting of bloom plain-barrelled roll-roller combination

Patent metadata

Field	Value
Publication number	US-11207729-B2
Application number	US-201917271041-A
Country	US
Kind code	B2
Filing date	Aug 16, 2019
Priority date	Aug 31, 2018
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

Disclosed is a light reduction method for continuous casting of a bloom plain-barrelled roll-roll combination. The method comprises: firstly obtaining three-dimensional temperature field profile, a two-phase region, solid-phase region thickness, and solid-phase fraction of a billet, determining positions of start and end rolls of the reduction, and setting a reduction amount of each tensioner roll according to the volume shrinkage of the billet; in an interval f s =0.9-1.0 of the solid-phase fraction of the billet, performing a heavy reduction working mode; and in an interval f s =0.25-0.80 of the solid-phase fraction of the billet, performing a light reduction working mode.

First claim

What is claimed is:

1. A soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll, comprising sequentially arranging a plurality of tension levelers on a continuous casting line to compression cast a casting bloom, characterized by:
acquiring model data of solidification heat transfer and liquid phase cavity in continuous casting of the casting bloom according to steel grades, drawing speeds, cooling conditions, and superheat degrees for casting molding, wherein the model data include a three-dimensional temperature field profile, a two-phase region thickness, a solid-phase region thickness and a solid fraction f s along a casting direction;
determining positions of rolls starting and ending reduction based on the model data, and associating the model data with each tension leveler on the continuous casting line;
acquiring a volume shrinkage of the casting bloom, setting a reduction for each tension leveler roll based on the volume shrinkage, and implementing a heavy reduction operation mode on the casting bloom in a zone of the casting bloom having a solid fraction of f s =0.9 to 1.0, wherein the corresponding tension levelers each achieve a reduction with a single-roll reduction rate of 1%-10%;
implementing a soft reduction operation mode on the casting bloom in a zone of the casting bloom having a solid fraction of f s =0.25 to 0.80, wherein the corresponding tension levelers each achieve a reduction with a single-roll reduction rate of no more than 2%;
wherein the plurality of tension levelers are grouped into upstream tension levelers and downstream tension levelers, wherein the downstream tension levelers are closer to a solidification end of the casting bloom than the upstream tension levelers, wherein the downstream tension levelers are convex roll tension levelers, and the upstream tension levelers are flat roll tension levelers.

2. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 1 , wherein when the solid fraction is f s ≤0.5, the flat roll tension leveler is used to perform compression casting on the casting bloom; and when the solid fraction is f s >0.5, the convex roll tension leveler is used to perform compression casting on the casting bloom.

3. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 1 , wherein an upper roll of the convex roll tension leveler is a convex roll which can be raised or lowered to adjust the roll gap, and the convex roll is connected to a motor and a speed reducer;
a lower roll of the convex roll tension leveler is a flat roll;
the upper roll and the lower roll are connected by a frame, and a reduction force is applied to the casting bloom therebetween through four pairs of driving hydraulic cylinders.

4. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 3 , wherein the upper roll is a convex roll, and it is a driving roll.

5. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 3 , wherein the lower roll is a flat roll, and it is a fixed driven roll.

6. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 3 , wherein a working part of a body of the convex roll has a profile curve consisting of a first straight line section (AB), a first transition curve section (BC), a second straight line section (CD), a second transition curve section (DE), and a third straight line section (EF) connected in sequence,
wherein the first straight line section (AB) and the third straight line section (EF) are arranged coaxially or coplanarly; the second straight line section (CD) and the first straight line section (AB) or the third straight line section (EF) are arranged in parallel;
wherein the first transition curve section (BC) and the second transition curve section (DE) are each composed of a sine curve, or composed of two arc lines, one inwardly concave, and the other outwardly convex, wherein the two arcs have equal or unequal radii;
wherein for a longitudinal section of the convex roll in an axial direction, the first transition curve section (BC), the second straight line section (CD) and the second transition curve section (DE) form a protruding structure in the form of a protuberance on a surface of the convex roll.

7. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 6 , wherein when the first transition curve section (BC) of the protuberance is a sine curve, the sine curve has an equation:
y=H sin( x*π/ 2 nH );
wherein H is a height of the protuberance; n is a projection length of the first transition curve section (BC) of the protuberance on the axis x.

8. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 6 , wherein the second transition curve (DE) is mirror-symmetrical to the first transition curve (BC), and a mirror-symmetrical centerline is a straight line that passes through a midpoint of the second straight line section (CD) and is perpendicular to the second straight line section (CD).

9. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 6 , wherein in the zone where the casting bloom has a solid fraction f s =0.25 to 0.80, for each tension leveler, an opening of an indentation profile generated on an upper surface of the casting bloom is equal to a length of the second straight line section (CD) of the body of the convex roll.

10. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 6 , wherein a length of the second straight line section (CD) of the body of the convex roll of each tension leveler depends on a width (D) of the unsolidified two-phase region of the casting bloom when it arrives at a position corresponding to each tension leveler.

11. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 10 , wherein the length of the second straight line section (CD) of the body of the convex roll of each tension leveler is ≥D+40 mm.

12. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 1 , wherein the model data are acquired by performing model calculation on the solidification heat transfer and liquid phase cavity in the continuous casting of the bloom according to theories of continuous casting and casting molding, wherein the three-dimensional temperature field profile, the two-phase region thickness, the solid-phase region thickness and the solid fraction f s are calculated from various steel grades, drawing speeds, cooling conditions, and superheat degrees when the casting bloom arrives at a position corresponding to each tension leveler.

13. The soft reduction method for a continuous casting bloom with a combination of a flat roll and a convex roll according to claim 1 , wherein a maximum single-roll reduction is 10 mm for each of the tension levelers implementing a heavy reduction operation mode on the casting bloom; and a single-roll reduction is no more than 5 mm for each of the tension levelers implementing a soft reduction operation mode on the casting bloom.

Assignees

• Baoshan Iron & Steel

Inventors

• Xu Rongjun
• Liu Junjiang
• Wan Genjie
• Li Chengbin
• Liu Xiangchun
• Meng Qingyu

Classifications

• B22D11/1206 Primary

  for plastic shaping of strands (rolling mills B21B1/46) · CPC title

• B21B1/46 Primary

  for rolling metal immediately subsequent to continuous casting (metal-rolling stands B21B13/22; continuous casting B22D11/00, e.g. into moulds with rolls B22D11/06) · CPC title

• B22D11/207

  responsive to thickness of solidified shell · CPC title

• B22D11/16 Primary

  Controlling or regulating processes or operations · CPC title

• B22D11/1287

  Rolls; Lubricating, cooling or heating rolls while in use · CPC title