Top-Quality Back up roll Supplier

Extra large back up roll

In the field of large-scale back up rolls, as early as the 1980s, LMM GROUP Roll Manufacturing Plant successfully developed and produced large-scale back up rolls weighing more than 100 tons.

At the beginning of the 21st century, Cr2 and Cr3 series of large-scale back up roll materials with independent intellectual property rights were developed, which met the requirements of rolling technology for back up rolls and are still used today.

Number

Steel grade

Technical conditions

EBR21

Special technical conditions

0.50

0.60

0.10

0.30

1.0

1.50

≤

0.025

≤

0.020

1.50

2.50

—

0.40

0.60

0.04

0.10

—

≤

0.15

EBR32

（3%CrMoV）

EZB1867

-2012

0.40

0.50

0.40

0.70

0.50

0.70

≤

0.025

≤

0.025

3.00

3.50

≤

0.60

0.30

0.60

≤

0.15

—

Manufacturing Process

Raw materials – crude water – ladle refining – pouring – ingot – forging – forging heat treatment – rough machining – preliminary heat treatment – surface quenching – finishing – finished product

Smelting and pouring process

Electric furnace smelting water – Ladle furnace vacuum refining – Vacuum pouring

Smelting
Electric furnace smelting and ladle furnace vacuum refining ensure the chemical composition of molten steel and improve the purity of molten steel.

The main tasks of electric furnace smelting are: melting steel materials, dephosphorization, and heating;

The main tasks of ladle furnace are: deoxidation, desulfurization, degassing, alloying, purifying molten steel, and adjusting temperature.

Main equipment: 60t electric arc furnace, 80t electric arc furnace, 40t, 150t ladle refining furnace.

Casting:
The vacuum casting method is used to reduce the gas content in the molten steel and prevent white spots and hydrogen embrittlement cracks in forgings.
Main equipment: 600t, 400t, 200t vacuum ingot casting chambers.

Forging process

Pressing pliers handle – Main deformation of upsetting and drawing refining – Material division and forging of finished products

A large press is used to upset and elongate the steel ingots to achieve the shape and size of the forgings required by the process.

The main function is to reduce and eliminate the inherent defects in the steel ingots (cast structure, loose holes, etc.) as much as possible, and obtain a dense forging structure, so that the forgings have good mechanical properties and performance.

Main equipment: 160MN open forging hydraulic press, 125MN open forging hydraulic press.

Heat treatment process

Post-forging heat treatment: dehydrogenation, adjustment of forged structure, grain refinement, and ensuring ultrasonic flaw detection penetration.

Preparatory heat treatment: ensure the hardness of the roll neck and the mechanical properties of the matrix, and prepare the structure for surface quenching. During surface quenching, the transition between the roll body and the roll neck is cooled to ensure the hardness and strength of this part.

Surface quenching treatment: ensure the hardness, uniformity of hardness and depth of the hardened layer of the roll body. Surface quenching treatment is the most important process to ensure the hardness of the roll body of the support roll and determine the quality of the support roll. Equipment: Large horizontal differential temperature furnace

Heat treatment example: Large support roller out of furnace, quenching

Main achievements of wide and thick plate mill back up roll

Serial number	Rolling mill model	Material	Unit weight (tons)	Quantity (pieces)
1	5000 Wide and thick plates	Cr 2	226	6
2	5000 Wide and thick plates	Cr 2	226	6
3	5000 Wide and thick plates	Cr 2	201	4
4	5500 Wide and thick plates	Cr 2	226	1
5	5000 Wide and thick plates	Cr 2	226	4
6	4200 Wide and thick plates	Cr 2、Cr3	165	12
7	4200 Wide and thick plates	Cr 2、Cr3	165	6
8	4200 Wide and thick plates	Cr4 sleeve	101.6	5
9	4300 Wide and thick plates	Cr 3	168	6
10	4300 Wide and thick plates	Cr 3	195.3	2

Serial number	Rolling mill model	Material	Unit weight (tons)	Quantity (pieces)
11	5000 Wide and thick plates	Cr3	206.7	2
12	4300 Wide and thick plates	Cr3	168	1
13	4300 Wide and thick plates	Cr3	168	3
14	3800 Wide and thick plates	Cr3	151.4	12
15	3800 Wide and thick plates	Cr3	151.4	12
16	5000 Wide and thick plates	Cr2	225	1
17	5000 Wide and thick plates	Cr2	227.5	2
18	5000 Wide and thick plates	Cr2	227.5	2

Main achievements of plate mill back up roll

Serial number	Rolling mill model	Material	Unit weight (tons)	Quantity (pieces)
1	2800 Steckel	Cr3	100	4
2	φ2000	Cr3	108	2
3	3500 Medium and thick plates	Cr3	124	2
4	3500 Medium and thick plates	Cr3	122	8
5	φ1700	Cr3	70	6
6	2800 Medium and thick plates	Cr3	76	8
7	3000 Medium and thick plates	Cr3	80.995	8
8	3000 Medium and thick plates	Cr3	80	6
9	2800 Medium and thick plates	Cr3	75.35	2
10	3100 Medium and thick plates	Cr3	81	8
11	2800 Medium and thick plates	Cr3	76	2
12	3500 Medium and thick plates	Cr3	108	4
13	3000 Medium and thick plates	Cr3	82.5	2

Serial number	Rolling mill model	Material	Unit weight (tons)	Quantity (pieces)
14	3500 Medium and thick plates	Cr3	129	2
15	3500 Medium and thick plates	Cr3	108	8
16	2800 Medium and thick plates	Cr3	100.715	4
17	3500 Medium and thick plates	Cr3	124	7
18	3800 Medium and thick plates	Cr3	129	1
19	2800 Medium and thick plates	Cr3	80	5
20	3500 Medium and thick plates	Cr3	122	12
21	3500 Medium and thick plates	Cr3	139	6
22	3500 Medium and thick plates	Cr3	115.5	1
23	3000 Medium and thick plates	Cr3	101.7	2
24	3500 Medium and thick plates	Cr3	131.3	6
25	3500 Medium and thick plates	Cr3	125.5	1
23	3500 Medium and thick plates	Cr3	138	6