CN1008149B - Technique of continuous casting of high strength cast-iron pipe by adding low amount of rare-earth alloy - Google Patents
Technique of continuous casting of high strength cast-iron pipe by adding low amount of rare-earth alloyInfo
- Publication number
- CN1008149B CN1008149B CN 86106799 CN86106799A CN1008149B CN 1008149 B CN1008149 B CN 1008149B CN 86106799 CN86106799 CN 86106799 CN 86106799 A CN86106799 A CN 86106799A CN 1008149 B CN1008149 B CN 1008149B
- Authority
- CN
- China
- Prior art keywords
- rare earth
- iron
- choked flow
- cast iron
- notch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
The present invention relates to the technology for continuously casting iron pipes with little rare earth and high strength in casting metallurgy, and aims to solve the problems of low tensile strength, poor water pressure resistant performance, easy leakage, etc. existing in the technology for continuously casting common gray iron pipes. The present invention increases the amount of M-[n] in castings, adopts the iron notch internal-resistance flow method, and is added with rare earth alloy in order to improve the graphite form of castings, remove slag and gas, and enhance the compactness of casting tissue and the amount of pearlite. Simultaneously, the present invention adopts the stokehole incubation technology so as to eliminate the free cementite and the tissue sensitive property of the outer pellicles of cast pipes, obtains cast iron pipes with dense tissue, high strength and good water pressure resistant performance, and improves economic benefit by 80 yuan/ton.
Description
The present invention belongs to metallurgical casting technology.
In existing technology, cast iron pipe is made with the common grey iron continuous casting process mostly continuously.This technology mainly comprises: the molten iron of 1 carbon equivalent high, and the percentage by weight of its composition (following all same) scope is:
C Si Mn P S
3.4～4.6 2.0～2.9 0.4～0.6 ≤0.1 ≤0.1
2. molten iron tapping temperature≤1400 ℃, pouring temperature 〉=1350 ℃.
3. adopt inside and outside device water flowing cooling, 5～28 ℃ of inflow temperatures.
The advantage of this technology is: I) small investment, technology is simple.II) low to raw material and production lot requirement, adaptability is strong.III) low price.But there is following shortcoming in this casting method: 1. graphite flake is thick, and skewness, organizes big to the sensitiveness of cooling velocity.2. there is 10～15% the free cementite of having an appointment in the metallographic structure.Above-mentioned shortcoming causes pipe tensile strength low; The water pressure resistance poor performance, easy to leak; Problem such as percentage of damage height in the work progress.
For the advantage of the method for smelting that keeps the casting pig continuous pipe-casting and overcome its shortcoming, the present invention is special to propose that a kind of technical conditions are simple, product quality is high and method that cost is low-method of smelting of the low rare earth high strength cast iron used of cast iron pipe continuously.
Main design of the present invention is: 1. cast iron is contained the Mn amount and bring up to 1.0～1.4%.2. adopt " choked flow method in the iron notch " to add a spot of rare earth alloy.3. adopt the inoculated technology of stokehold.It is to realize by the way with furnace charge adding ferromanganese behind the furnace cupola stove that raising contains the Mn amount.Reach at molten iron temperature under 1380～1400 ℃ the condition, add 0.2～0.6% rare earth alloy (lucium composition: R with " choked flow method in the iron notch "
ExO
y: 33%, Si:38%).Use 0.2～0.4% ferrosilicon (75%Si) to carry out the inoculation of stokehold then.Hot metal composition after the processing is:
Educate C Si Mn P S R
ExO
y
3.6～4.2 2.4～3.0 1.0～1.4 ≤0.1 ≤0.05 0.020～0.045
The molten iron of this composition can carry out continuous trombone slide by existing tube-pulling craft.By this treatment technology, improved the Mn amount that contains, the S amount is reduced to below 0.05%, make dense structure, content of pearlite in alloy 〉=85% of graphite refinement cast iron pipe, free cementite content≤3%, thereby make tensile strength improve 25%, the water pressure resistance performance improves 50%, has reduced fragility and construction percentage of damage.
Accompanying drawing is that furnace cupola " choked flow method in the iron notch " adds the rare earth alloy schematic diagram.It mainly comprises: furnace cupola (1), iron notch (3), rare earth alloy (4), choked flow brick (5) and tapping hole (6).Wherein choked flow brick (5) is about 2/3 place of whole iron notch (3) length by being placed on apart from tapping hole (6).Rare earth alloy (4) places between tapping hole (6) and the choked flow brick (5) and near choked flow brick (5).
The cast iron pipe that with the diameter is 400mm below is an example, and specific embodiments of the invention are described:
By the prior art distribution, and with furnace charge adding ferromanganese (65%Mn), the hot metal composition after the fusing reaches:
C Si Mn P S
3.6～4.2 2.1～2.6 1.0～1.4 ≤0.1 ≤0.1
Lucium 1.6kg with the 5-10mm diameter is equivalent to 0.2～0.6% to 4.8kg(again), place between tapping hole (6) and the choked flow brick (5) and in the iron notch (3) near choked flow brick (5).When treating that molten iron temperature in the furnace cupola (1) reaches 1380-1400 ℃, emit molten iron (2), make its at first with choked flow brick (5) near rare earth alloy (4) contact, under the effect of molten iron (2), rare earth alloy is in fusion or semi-molten state, and be subjected to the obstruction of choked flow brick (5) in its direction of advance, reflux so that rare earth alloy (4) fully mixes with molten iron (2), then in the space inflow casting ladle by choked flow brick (5) bottom.Waiting to tap a blast furnace reaches at 2/3 o'clock of total iron water amount, adds 1.6kg-3.2kg(and be equivalent to 0.2～0.4% in iron notch (3)) Antaciron (containing 75%Si) carry out inoculation.Molten iron chemical composition after the processing is as follows:
C Si Mn P S R
exO
y
3.6～4.2 2.4～3.0 1.0～1.4 ≤0.1 ≤0.05 0.020～0.045
The molten iron of this chemical composition, poring rate and the tube-pulling craft with the prior art regulation carries out continuous pipe-casting again.The material of choked flow brick (5) can be used common SiO
2Brick or Al
2O
3Brick, its big or small Ying Yineng is placed in the iron notch (3) and is advisable, and its height does not flow through from choked flow brick (5) top with molten iron (2) is advisable.Choked flow brick (5) is the 1/3(about 50～80mm) of iron notch (3) height with the bottom spacing of iron notch (3).
Through the low rare earth high strength cast iron pipe that this embodiment handles, the tensile strength of its material is σ
b=20～24kg/mm
2, improve 25% than the gray cast iron pipe tensile strength of prior art; Water pressure resistance P=30kg/cm
2, improve 50% than the gray cast iron pipe water pressure resistance of prior art; The pipe ring bending strength on average reaches 40kg/mm
2
Implementing process of the present invention is applicable to the cast iron pipe of φ 100～φ 600mm.The tube-pulling craft that is adopted is identical with the existing tube-pulling craft of gray cast iron pipe.
The ferromanganese chemical composition that technology of the present invention adopted is the ferromanganese that contains Mn65%, the also available ferromanganese that contains Mn45%.The rare earth alloy that is adopted is No. 1 rare earth alloy, also available other rare earth alloy (comprising rare earth ferrosilicon, rare earth silicon-calcium, rare earth alsimay etc.) that contains rare earth 18～80%.The inovulant that is adopted is the ferrosilicon that contains 75%Si, the also available ferrosilicon that contains 95%Si or 45%Si.
Claims (5)
1, the method for smelting of the low rare earth high strength cast iron used of cast iron pipe continuously in a kind of metallurgical casting field, the compositing range of the chemical composition of its melting gained is (percentage by weight):
C Si Mn P S RexOy
3.6～4.2 2.4～3.0 1.0～1.4 ≤0.1 ≤0.05 0.020～0.045
This method of smelting mainly comprises furnace cupola [1] fusing casting water; Adding ferromanganese with furnace charge makes in the molten iron manganese content bring up to 1.0～1.4%; Wait to tap a blast furnace when reaching total iron water amount 2/3, in iron notch [3], add ferrosilicon and carry out the stokehold inoculation; 1380～1400 ℃ molten iron tapping temperature; Pouring temperature more than or equal to 1350 ℃; The process for cooling of inside and outside device recirculated water is characterized in that it also comprises: lay choked flow brick [5] in iron notch [3], also locate to put into " the iron notch choked flow method " of rare earth alloy [4] near choked flow brick [5] between tapping hole [6] and choked flow brick [5].
2, the method for smelting of the low rare earth high-temperature cast iron used of continuous cast iron pipe according to claim 1, the height that it is characterized in that the choked flow brick (5) that " choked flow method in the iron notch " laid in iron notch (3), do not flow through with molten iron (2) and to be advisable from choked flow brick (5) top, length is advisable can be placed in the iron notch (3), and choked flow brick (5) is that 1/3 of iron notch (3) height is advisable with the spacing of iron notch (3) bottom.
3, the method for smelting of the low rare earth high strength cast iron used of continuous cast iron pipe according to claim 1 and 2 is characterized in that the addition that " choked flow method in the iron notch " adds rare earth alloy (4) is 0.2～0.6%.
4, the method for smelting of the low rare earth high strength cast iron of using according to claim 1 or 3 described continuous cast iron pipes, it is characterized in that to add rare earth alloy (4) can be No. 1 rare earth alloy, it also can be rare earth ferrosilicon, rare earth silicon-calcium, the U.S. alloy of rare earth aluminium silicon etc., the lucium composition is RexOy:33%, Si:38%.
5, the method for smelting of low rare high-strength cast iron of using of continuous cast iron pipe according to claim 1, it is characterized in that carrying out the stokehold inoculation, to add the ferrosilicon amount be 0.2～0.4%, it is Si:75% that institute adds the ferrosilicon chemical analysis, also available Si:45%, the ferrosilicon of Si:95%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86106799 CN1008149B (en) | 1986-10-07 | 1986-10-07 | Technique of continuous casting of high strength cast-iron pipe by adding low amount of rare-earth alloy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86106799 CN1008149B (en) | 1986-10-07 | 1986-10-07 | Technique of continuous casting of high strength cast-iron pipe by adding low amount of rare-earth alloy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN86106799A CN86106799A (en) | 1988-07-06 |
| CN1008149B true CN1008149B (en) | 1990-05-30 |
Family
ID=4803375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 86106799 Expired CN1008149B (en) | 1986-10-07 | 1986-10-07 | Technique of continuous casting of high strength cast-iron pipe by adding low amount of rare-earth alloy |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1008149B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8005309B2 (en) | 2004-02-09 | 2011-08-23 | Sanyo Electric Co., Ltd. | Image coding apparatus, image decoding apparatus, image display apparatus and image processing apparatus |
-
1986
- 1986-10-07 CN CN 86106799 patent/CN1008149B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8005309B2 (en) | 2004-02-09 | 2011-08-23 | Sanyo Electric Co., Ltd. | Image coding apparatus, image decoding apparatus, image display apparatus and image processing apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| CN86106799A (en) | 1988-07-06 |
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| CF01 | Termination of patent right due to non-payment of annual fee |