JPS6284891A - Repairing method for slag pot - Google Patents

Abstract

PURPOSE:To reduce repairing cost by cutting a slag pot at a specified height position from a bottom part, and subsequently, welding a bottom member having an inside diameter which is larger by a prescribed size than inside diameter of a cutting line of a body, to a cutting part of the body. CONSTITUTION:A marking-off line is put on the inner surface of a shell of a position of 700-1,400mm height from the bottom part of a slag pot S, and a bottom member in which a crack, errosion, and variation of deformation are remarkable is removed. Subsequently, the upper end part of a new bottom member 5 having an inside diameter D2, 7 which is larger by 10-100mm than an inside diameter D1 of a cutting line of an upstream side body 1, and a cutting part of the body 1 are welded. Also, local parts 8, 9 of the inner surface of the body, and the outer surface of the bottom member 5 are finished by fusing cutting and build up welding, respectively. According to this repairing method, a term of work of repair can be shortened and the cost of material required can be curtailed, therefore, the repairing cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a slag pot repair method, and more specifically, it relates to a slag pot repair method, and more specifically, a method for repairing molten slag generated or remaining in hot metal or molten steel pretreatment, ingot making, continuous casting, etc. , relates to a method for repairing slag pots transported to slow treatment plants.

[Prior art 1] Conventionally, when a crack occurs in a slag pot, or relatively minor erosion or deformation occurs, the affected part is repaired by backward Il welding after cleaning the slag pot. However, if large holes were created due to sudden meltdown accidents, large deformations, or severe local material deterioration occurred, repairs were impossible. Therefore, slag pots are disposed of after being used for about 3 to 4 years and new slag pots are used.

In addition, when using a slag pot with an internal volume of 9 m' class, it is often seen that nearly 3 tons of molten metal called bullion is mixed with the slag and poured into the slag pot, and for this reason, it is difficult to use the slag pot after it has been used for about a year. In some cases, the equipment becomes inoperable and extremely difficult to repair, and is left outdoors.

[Problem to be solved by the invention 1 'The present invention solves the problems in repairing slag pots as explained above, and as a result of the inventor's research, it was determined that the repair was impossible. By cutting and removing the unrepairable parts of slag pots that are unusable due to extremely large cracks, melting damage, deformation, metal welding, or holes, weld new parts to the cut and removed parts.
We have developed a method for repairing slag pots.

[Means for Solving Problems J] A feature of the slag pot repair method according to the present invention is that when repairing a slag pot that has become unusable due to cracks, melting damage, deformation, etc. The bottom member is removed from the upper diversion side body by cutting at a height of 700 to 1400 a + m, and then the bottom member having an inner diameter 10 to 100 mm larger than the inner diameter at the cutting line of the upper diversion side body is cut from the upper diversion side body. The purpose is to weld the parts.

The slag pot repair method according to the present invention will be explained in detail below.

This type of slag pot is a container made of GII steel in which high-temperature molten slag with a small amount of molten metal mixed in is injected, cooled, and transported, so it is subjected to severe thermal stress due to rapid heating and cooling, and the steel shell itself becomes slag-resistant. It must have sufficient heat capacity to absorb heat and cool and solidify it, and it must also have good adaptability to thermal expansion and contraction deformation. There is a need for it to be safe and unbreakable, with the least possible damage occurring.

However, despite the above-mentioned requirements, slag pots inevitably suffer from cracking, melting, and deterioration due to metal fatigue due to long-term use, especially at the inner bottom of the slag pot. Since these concentrate, the bottom member is cut and removed from the upper diversion side body of the slag pot at a height of 700 to 1400 sIII from the bottom of the slag pot and 6 to 10 times the thickness of the slag pot plate. The work is made easier by making sure that sufficient elongation deformation is maintained in this range, and by cutting at a normal part to alleviate stress concentration by avoiding the lowest part with a complicated shape and structure. be.

If the cutting height is less than 700 degrees, cutting or welding cannot be performed without defects, so in slag pots that are subject to rapid heating and cooling, safety cannot be ensured even by repair. If it exceeds 1400mm, it will be close to the complicated part of the main body on the upper diverted side, so the workability will be poor.
The quality after repair also deteriorates. Therefore, if the cutting height is not lower than 1400a+- from the bottom of the slag pot, the degree of restraint around the weld will increase when welding with a new bottom member after cutting, resulting in cracks or the slag pot after repair. Because the residual stress is excessive, it cannot withstand long-term use, and can only be used for a very short period of time, and safety cannot be ensured, so it is not suitable for practical use. Therefore, the cutting position is set at 700 to 1400 m+e from the bottom of the slag pot.

In addition, as explained above, after cutting and removing the bottom member with cracks, melting loss, deformation deterioration, damage, etc., cut the bottom member with an inner diameter 10 to 100 mm larger than the inner diameter at the cutting line of the upper flow-side main body. However, this involves cutting and removing the bottom member that has significant cracks, melting, deformation, deterioration, damage, etc., and then joining the newly manufactured bottom member by welding. Since the diameter near the cutting line is smaller, the diameter of the new bottom member should be at least 10 mm thicker (otherwise, it will be difficult to use, and the smaller this diameter difference is, the easier welding will be during repairs). However, since the finish upon completion of the repair will be poor, the inner diameter of the bottom member must be at least 10 mm larger than the inner diameter of the cut line of the upper diverted body, and the diameter of the bottom member must be greater than 100 mm. If the diameter of the bottom member is increased, the problem arises that metal clogging of the slag pot after repair occurs frequently.Therefore, the bottom member is designed to have an inner diameter 10 to 100 mm larger than the inner diameter at the cutting line of the upper flow-side main body.

A method for repairing a slag pot according to the present invention will be explained with reference to FIG.

In Figure 1, with the top surface of Slugbok S as a reference,
Slugbok) 700-1400m of height H4 from the bottom of S
Insert a marking line on the inner surface 2 of the iron skin at o+ and cut 3
Then, the LT member (not shown) that is subject to cracks, melting damage, deformation and deterioration is removed and replaced with a newly manufactured bottom member 5.

In this case, the inner diameter at the cutting line of the upper diversion side main body 1,
After welding the upper end of the new bottom member 5 of 7 and the cut part of the upper flow side main body 1, the inner diameter local part 8 of the upper flow side main body 1 is treated with a solvent and the bottom member The finishing is done by overlay welding on the local part 9 of the outer surface of 5.

[Example 1] Next, an example of a slag pot correction method according to the present invention will be described.

Example 1 A slag pot with severe deformation and deterioration was cut at a position of 800 mm from the bottom of the slag pot, and a diameter of 2230 mm was cut at the same height.
When we butt-welded a bottom member made of 5C-46 cast steel with a weight of 8 mm, a weight of 5.5 tons, a side iron skin thickness of 70 mm, and a bottom iron skin thickness of 120 mm to a diameter of 2210 a + m at the cut part of the upper diverted side main body, the result was approximately 1011111 mm. There was a difference in texture and the bottom member was large. Therefore, after welding, the area near the joint on the inner surface of the main body on the upper flow side was applied with a solvent of about 10+a+, and the area around the joint on the outer surface of the main body on the upper flow side was applied with a grinder. It was completed by overlay welding with a height of 30 mL11.

The results were very good, and the product was able to be restored to a new appearance, and when it was inspected 8 months after it was used, there were no cracks, melting damage, deformation, or metal adhesion.

Example 2 A slag pot with cracks and bottom holes was cut at a large height of 130011IIQ from the bottom of the slag pot, and a pre-fabricated slag pot with an inner diameter of 274 mm and a height of 1300 mm was cut.
3.2mm 5 @ side iron skin thickness 70mm, bottom plate thickness 120+*
When a bottom member made of 5C-4619 steel with a weight of 8 tons was welded to an upper diversion side main body with an inner diameter of 2840 mm at the cut line, a difference of approximately 50 mm occurred.

This was repaired by performing CO2 semi-automatic overlay welding near the joint on the inner surface of the main body on the upper diverted side and by cutting the outside of the bottom member to match the skin.

As a result, 1300III11 from the bottom of the slag pot.
It looked like it was slightly bent at the weld line, but it was able to be repaired to make it look like new.Furthermore, after using it for 3 consecutive months, there were no FJJ problems such as metal adhesion or metal clogging. I was not able to admit.

Incidentally, the repair time is approximately 1/10 of the time required to manufacture a new product.
Moreover, the repair cost is about 1/3 of the cost of manufacturing a new product.

[Effects of the Invention] As explained above, since the slag pot repair method according to the present invention has the above configuration, the joint between the upper diversion side main body and the new bottom member is repaired while the bottom member is larger. Thermal expansion during use is significantly suppressed, and
I made several extra bottom parts in a planned manner and attached the bare metal.
If the slag pot becomes unusable due to holes, large cracks, etc., the bottom member can be replaced relatively quickly with a construction period of 7 to 10 days. It has excellent industrial effects such as being relatively lightweight and relatively easy to manufacture.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a slag pot repair method according to the present invention. S... Slag pot, 1... Upper diverted side body, 2 Iron skin,
3. Cutting line, 4. Height, 5. Bottom member, 6. Upper flow side main body inner diameter (Dl), 7. Bottom member inner diameter (D2),
8. Internal local area, 9. External local area.

Claims (1)

[Claims] When repairing a slag pot that has become unusable due to cracks, melting damage, deformation, etc., a height of 70 mm from the bottom of the slag pot is
The bottom member is removed from the upper flow side main body by cutting at a position of 0 to 1400 mm, and then the bottom member has an inner diameter 10 to 100 mm larger than the inner diameter at the cutting line of the upper flow side main body.
A slag pot repair method characterized by welding the cut portion of the upper diverted body.