Sink roll bush structure improvements(3)

Link above

-Sink roll bush structure improvements 3

c. Considering the material expansion coefficient of Sellite6 alloy and 00Cr17Ni14Mo2 is not the same. The proper clearance retained between part 2 and part 4. And to prevent zinc adhesion between part 2 and part 4 causes applied force to part 2. That is because sink roll bush returned to normal temperature after bush off lined.  Similarly the graphite gaskets installed in the gap between part 2 and the part 4.

d. After rollers mounted the gap between the shaft end and the bush inner end is less than the gap between the roll end and the roll arm stopper. Consequently the actual use of the process it could easily lead to shaft end wear at first then the roller head was worn after. Therefore Sellite6 alloy part (part 2) put to the bush in the middle in order to increase the gap between the inner roll arm and sink roll shaft end.

 

3. Conclusion

Through the four improvements of optimizing the bush structure we resolve the problem of the stall and crack in the production. It greatly extended its working life.

After Improved structure of the liner – Figure 4.
After Improved structure of the liner – Figure 4.

 

END

Sink roll bush structure improvements (2)

Link above

The cracks were found on Stellite6 alloy block part after the structure put into use a period. After analysis the cause of cracks is the welded structure of Stellite6 alloy block and sink roll bush body. In the production the line is under high temperature environment of greater than 600 ℃.The state returns to normal temperature after the offline. In this process of expansion and contraction, Since Stellite6 alloy material is different with bush body material 00Cr17Ni14Mo2, the thermal expansion coefficient is different, so that Stellite6 alloy subjected to tension and pressing force, thus cracks even breaks were found at weld position. See figure2.

 Fig2 sink roller bush after use

Figure 2 sink roller bush after use offline

From whole assembly drawings (Figure 3) The clearance between carbide block and sink roll sleeve end is 13 mm, while the spacing between sink roll head and stopper block is 15mm. That means actually the head did not play the effect of reducing friction area.

2. Improved sleeve

In order to avoid recurrence of the above two cases, the bush re- designed and the assembly form changed. See figure4 Improved bush structure

a. Due to the action in the course of the strip steel, the actual contact surface of the roll sleeve and the bush is in the upper part of the bush. Therefore, the Sellite6 alloy blocks changes to one unit which can still meet the requirements and also reduces the manufacturing cost.

b. As for Sellite6 alloy part (part 2) installation, two stoppers (part 3) welded at two sides and 2 semicircle with material 00Cr17Ni14Mo2 (part 4) welded at the lower half of the body to support. Not to weld Sellite6 alloy directly with 00Cr17Ni14Mo2 body which reduce the difficulty of construction and potentially dangerous.

 

Figure 3 original bush assembly drawing
Figure 3 original bush assembly drawing

Link below

Sink roll bush structure improvements (1)

The CGL unit annual output 250000 ton, produce width of 800 ~ 1 300 mm, thickness of 0. 3 5 ~ 2. 0 mm. The product varieties are full of hard grade, commercial-grade, high-strength steel. The application are mainly household appliances industry and the construction industry and other fields.

Sink roll is located just above the zinc pan. when unit continuous product, strip steel is imported into zinc pot , the strip steel is immersed in liquid zinc by the sink roll and changed direction. that is, from entering into the zinc pot, dip into zinc pot, galvanized layer solidification & cooling. And  also to be entering the air knife, the strip steel remains stable and flat. With the movement of the strip steel rotating, sink roll bush supported by the bracket of both sides. The bush acts as a sliding bearing.

1. Bush problems in production

CGL unit sink roll and stabilizing roll off the line after use we found Stellite 6 alloy block had cracks on semicircle parts of the bush. Even alloy block broken. Consequently which affect the normal use of the bushing and resulting in stall phenomenon of stable roll and correction rollers. After analysis and research of the structure and also working condition the structure of bush has more improved to avoid cracks.

  •  The original design structure using a semicircle and a 1 / 4 circle, two Stellite6 alloy blocks are welded with bush body, shown in Figure 1.
sink roll bush

Figure1  original design structure diagram

 Link…..

Centrifugal casting stainless steel products

 

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Radiant tubes type:

U-type, W-Type, 0-Type, P-type, L-Type, S-Type. Similarly straight-type and also electric radiant tubes.

Application:

One of centrifugal casting stainless steel products. The radiant tubes are working at high temperature environment on average: 800-1200° C. Therefore most of them are used for indirect heating to furnace like CAL (continuous annealing line). Similarly CGL (continuous galvanizing line).

Process:

One of centrifugal casting stainless steel products. First of all centrifugal/spun casting method for tube sections. Furthermore investment casting or sand casting for the bends, hangers. Then welding and finally machining.

Material:

High Nickel and high Chrome heat resistant alloys, Cobalt base alloys. The material like HU, HT, HK, HP, HW, 24/24NbTiZr, 50Cr/50Ni (2.4813), 1.4865, 1.4849, 1.4848, 1.4410, 1.4059, 1.4841, 1.4845, 1.4852, 2.4879 or as per customer’s requirements.

Standard:

ANSI, ASTM, ASME, DIN, GB etc.

20101119102810346

 

 

Stainless steel

roller —Immersion roller, Sink roll, Furnace roller, Bottom roller, Heat resistant roller:

1. Furnace roller

2. Hearth roll

3. immersion roller

4. Heat resistant roller

Application:
One of centrifugal casting stainless steel products.Centrifugal casting stainless steel roll are of good heat, corrosion, wear resistant properties. Almost all working at high temperature environment on average: 800 to 1, 200° C. As a result which are used in the steel mills. Like continuous annealing line, continuous galvanizing line.

Process of centrifugal casting stainless steel products of roll. First of all centrifugal casting for barrel/tube. Furthermore forging for journal/shaft. And static /investment or sand casting for cone/turnings. Then welding and machining and finally grinding.

Material of centrifugal casting stainless steel products of roll: High nickel and high chrome heat resistant alloys, cobalt base alloys. The material like HU, HT, HK, HP, HW, 24/24NbTiZr, 50Cr/50Ni (2.4813), 1.4865, 1.4849, 1.4848, 1.4410, 1.4059, 1.4841, 1.4845, 1.4852, 2.4879 or as per customer’s requirements.