CN1037417C - Protective agent for inner surface of centrifugal cast pipe - Google Patents
Protective agent for inner surface of centrifugal cast pipe Download PDFInfo
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- CN1037417C CN1037417C CN94117554A CN94117554A CN1037417C CN 1037417 C CN1037417 C CN 1037417C CN 94117554 A CN94117554 A CN 94117554A CN 94117554 A CN94117554 A CN 94117554A CN 1037417 C CN1037417 C CN 1037417C
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- protective agent
- cast
- centrifugal
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- centrifugal cast
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Abstract
The present invention relates to a protective agent for the inner surface of a centrifugal cast pipe, which belongs to the field of metallurgy centrifugal casting, and the present invention is especially suitable for various metallic materials. The protective agent comprises the chemical components of 10 to 35 wt% of Na2CO3, 20 to 35 wt% of CaF2, 4 to 10 wt% of Al2O3, 0.1 to 5 wt% of K2O and SiO2 as rest. The components of the protective agent are reasonably matched, so the protective agent can overcome various defects of the inner wall of cast pipes in the past, and the defects are caused by centrifugal casting; the protective agent meets the requirements of special steel centrifugal cast pipes, carbon steel centrifugal cast pipes and cast-iron centrifugal cast pipes for product quality. The protective agent of the present invention has the characteristics of low melting temperature, favorable flowability, light specific weight, convenient use, etc.
Description
The invention belongs to metallurgical centrifugal casting field.Be specially adapted to the protective agent for inner surface of centrifugal cast pipe of multiple material.
In the prior art, centrifugally cast pipe is to adopt the high-temperature metal liquation of predetermined weight to be injected in the casting mold of rotation at a high speed, under action of centrifugal force, molten metal is dispensed on the casting mold inwall equably, obtains cast tube after cooled and solidified.Adopting centre spinning method to produce the easy mass defect that occurs of cast tube inwall has (1) cast tube inner surface because secondary oxidation forms oxide-film easily, and cooled oxide-film shortens wrinkle into, causes the inner wall coarse out-of-flatness.(2) the cast tube inwall forms shrinkage cavity and loose easily.Liquid metals begins crystallization in the foundry goods outer wall, develop to the hole inner face gradually, solidification shrinkage is constantly replenished by ring-shaped liquid metal in the hole, but because bore area also has cooling to a certain degree, before does not solidify as yet fully the gross section, bore area has reached setting temperature, and then last remaining liq just forms annular shrinkage cavity band, rarefied zone between main solidification layer and endoporus solidification layer, sometimes even can reach 1/4～1/3 of tube thickness.(3) the cast tube inwall is easy to generate crackle.Because have liquid the contraction in the process of setting of metallic solution, solidification shrinkage and Solid State Contraction cause the cast tube inwall to crack.Have above-mentioned defective according to spun cast pipe, so people begin to adopt the protectant way of interpolation to solve the quality problems of cast tube inwall.For example Japanese clear 51-10818, the centrifugal casting solvent of being introduced; Clear 60-124460, the cast covering slag; Clear 60-223650, the bimetal centrifugal casting covering slag; Clear 62-158558, the manufacture method of centrifugal casting sleeve etc.These covering slags that are used for centrifugal casting are broadly divided into two classes from composition.One class covering slag is the compound that contains B or B.Because contain B in the slag, then the B element is easy to spread in molten metal, make that B content increases in the molten metal, metalwork is easy to embrittlement and causes defective such as crackle, and the cost of covering slag is also higher, and limitation is arranged in use.And another kind of covering slag is to belong to the compound that does not contain B or B, and composition is more single, but the result of use of covering slag is not remarkable.In sum, no matter be any covering slag, be applicable to only that all the low-alloy steel centrifugal casting of general cast iron or spheroidal graphite cast-iron, normal steel casting or alloying element content＜2% is used.
It is low to the objective of the invention is to propose a kind of fusion temperature, good combination property, the wide and effective protective agent of centrifugal casting easily of the scope of application.
Centrifugally cast pipe for special steel, because alloying element content height, particularly chromium content height, the molten metal surface contacts with air in casting cycle, very easily generate chromium oxide film, and the flowability of molten steel is reduced with the more complicated compound of formation such as FeO, MgO.Have high-alloy steel to have solidification shrinkage rate than characteristics such as the big and heat conductivility differences of carbon steel again, therefore when spun casting, the easier generation oxide-film of inner surface wrinkle, inwall form defectives such as shrinkage cavity, loose and crackle easily.According to the needs of different centrifugal casting material, the effective protectant concrete chemical component content of the centrifugal casting that the scope of application that we propose is wider % by weight is: Na
2CO
310～35%; CaF
220～35%; Al
2O
34～10%; K
2O 0.1～5%, and all the other are SiO
2
Industrial, protectant basicity is normally according to CaO in the slag and SiO
2The ratio calculation of weight percentage, work as CaO/SiO
2＞1 o'clock is basic slag, works as CaO/SiO
2＜1 o'clock is acid slag.Therefore be acid slag at the effective protective agent of centrifugal casting of the present invention, SiO
2Can adopt cheap raw material form to provide, cost is lower, and can guarantee the glass of slag.Na in addition
2CO
3Not only can obviously reduce protectant melt temperature and viscosity, and it runs into thermal decomposition and can put into a certain amount of CO
2Gas forms protective atmosphere, has increased protective agent and has prevented metal secondary oxidation and heat preservation effect, because of than Na
2CO
3Content should be controlled at 10～35%.In protective agent of the present invention, add cheap fluorite, i.e. CaF
2Its main purpose is to impel the silica condensate to disintegrate, thereby reduces protectant viscosity and fusing point, and the protective agent after the fusing can be evenly distributed on the foundry goods inwall, so CaF in the protective agent of the present invention
2Addition should be in 20～35% scopes.Al in protective agent of the present invention
2O
3Can play and regulate protectant fusing point effect, but content is unsuitable too high, then protectant viscosity raises when too high levels, and the flowability of liquation is variation then, because of a little Al
2O
3Should be 4～10%.In protective agent of the present invention, add an amount of K
2O can play fluxing action, its K
2O content should be 0.1～5%.In protective agent of the present invention, also have some in addition and be difficult for removed unnecessary material, for example MgO, Fe
2O
3, MnO etc., these materials are that the cheap raw material that adopt owing to protective agent of the present invention are brought into, therefore unnecessary like this material content in protective agent of the present invention is low more, protective agent then of the present invention effect in use can be good more.So protective agent of the present invention is under the situation that does not increase cost of material, these unnecessary materials are few more good more.
Protective agent of the present invention can overcome the various defectives that the cast tube inwall that causes owing to centrifugal casting is in the past occurred, and can satisfy the requirement that special steel, carbon steel, cast iron spun cast pipe improve the quality of products.It is low that protective agent of the present invention has melt temperature, good fluidity, and light specific gravity adds characteristics such as convenient.This protective agent can cover metal pipe internal surface rapidly equably under action of centrifugal force after adding, make itself and air isolated, has prevented the oxidation of inwall metal surface, makes the pipe fitting inner surface smooth, bright and clean and surface quality is good.This protective agent is covered in metallic interior surface; because the thermal conductivity ratio metal of melt cinder is much lower, reduced scattering and disappearing of metal inner surface heat, the inwall metal can the long period keep molten condition; be beneficial to from outer wall to the inwall folk prescription to consecutive solidification, inwall does not then form shrinkage cavity, defective such as loose.And because the covering of melt cinder, improved the heat transfer condition of metal freezing, avoided the appearance of implosion.This protective agent in use can be emitted a certain amount of CO
2Gas was in the gas atmosphere inside pipe wall before solidifying fully, therefore also strengthened preventing that inwall secondary oxidation and folk prescription are to the effect of solidifying.This slag is the glassy state slag, and it is good to have the property of stripping off, can be voluntarily after the cooling and metal separation.
The manufacture method of covering slag of the present invention is identical with preparation method of powder in the past; raw material are ground by putting into ball mill after the necessary requirement preparation; ball milling granularity＜80 orders; to install in the small plastic bag or in the little paper bag less than 80 purpose protective agent powder branches again; after casting latter stage or casting end of a period; drop into the casting mold from cold junction end cap aperture immediately; high-temperature liquid metal is then immediately with its fusing; centrifugal force is uniformly distributed in inwall everywhere with it; the protective gas of emitting can keep not loosing in several minutes in pipe, and protectant addition is 1.2～3.6Kg/m
2
Embodiment.
According to the protective agent component content that inner surface of centrifugal cast pipe proposed by the invention is used, we have done 4 batches of protective agents altogether in its scope, and its concrete component content sees Table 1.In order to contrast convenient and in table 1, also to have listed 2 protectant compositions of Japan.Identical process system is all adopted in the protectant manufacturing of the invention described above.Protective agent powder behind the ball milling＜80 orders, and use in the packing polybag.Table 2 is the result of use table of comparisons of each protective agent on the different materials cast tube among the embodiment; as seen from Table 2; each cast tube that uses protective agent spun casting of the present invention to go out; no matter be hot junction (accompanying drawing 1) or the cold junction (accompanying drawing 2) that is prone to defective; defectives such as the equal non-oxidation of its inwall, wrinkle, loose, shrinkage cavity and crackle, cast tube cooling back protective agent all comes off voluntarily, cast tube inner wall smooth, smooth, fine and close and have gloss.
Description of drawings.
Accompanying drawing 1 is to use the macrograph figure of protective agent of the present invention hot junction cast tube.
Accompanying drawing 2 is to use the macrograph figure of protective agent cold junction cast tube of the present invention.
Table 1 embodiment protective agent composition contrast table
| Project | Protective agent composition (Wt%) | ||||||||
| SiO 2 | Al 2O 3 | K 2O | Na 2CO 3 | CaF 2 | B 2O 3 | NaO | F | MgO+Fe 2O 2+MnO | |
| 1 (the present invention) | 43.24 | 4.11 | 0.18 | 19.44 | 28.58 | / | / | / | 4.45 |
| 2 (the present invention) | 38.00 | 9.56 | 2.91 | 19.44 | 28.58 | / | / | / | 3.51 |
| 3 (the present invention) | 43.54 | 9.37 | 3.88 | 11.72 | 27.69 | / | / | / | 3.80 |
| 4 (the present invention) | 35.52 | 4.52 | 0.12 | 29.16 | 26.67 | / | / | / | 4.01 |
| 5 (day the present invention) | All the other | / | / | / | / | 6.1 | 6.2 | 0 | / |
| 6 (day the present invention) | All the other | / | / | / | / | 14.3 | 19.6 | 14.8 | / |
Table 2 protective agent result of use contrast information slip
| Project | The metal cast tube material | Preparation method | Using method | The protective agent cost | The metal cast tube situation | Remarks |
| 1 | 4Cr28Ni16 | Ball milling is made simple | Throw-in play adds convenient | Cheaply | That inner wall smooth, low power do not have is loose, shrinkage cavity, defects i.e.cracks, and the protective agent exfoliative is good | See accompanying drawing 1 |
| 2 | 4Cr28Ni16 | That inner wall smooth, low power do not have is loose, shrinkage cavity, defects i.e.cracks, and the protective agent exfoliative is good | See accompanying drawing 2 | |||
| 3 | 3Cr24Ni7SiN(Re) | That inner wall smooth, low power do not have is loose, shrinkage cavity, defects i.e.cracks, and the protective agent exfoliative is good | ||||
| 4 | 4Cr25Ni2O, ductile iron pipe | That inner wall smooth, low power do not have is loose, shrinkage cavity, defects i.e.cracks, and the nodular cast iron pipe does not have stacked defective, no air chill tendency, and the protective agent exfoliative is good | ||||
| 5 | Ductile iron pipe | Ball milling | Compressed air is blown into | More expensive | Do not have stacked defective, microscopic structure does not have the air chill tendency | |
| 6 | Ductile iron pipe | Do not have stacked defective, microscopic structure does not have the air chill tendency |
Claims (1)
1, a kind of protective agent for inner surface of centrifugal cast pipe, it is characterized in that this protectant concrete chemical composition by weight % be: Na
2CO
310～35%; CaF
220～35%; Al
2O
34～10%; K
2O 0.1～5%, and all the other are SiO
2
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94117554A CN1037417C (en) | 1994-11-02 | 1994-11-02 | Protective agent for inner surface of centrifugal cast pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94117554A CN1037417C (en) | 1994-11-02 | 1994-11-02 | Protective agent for inner surface of centrifugal cast pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1126122A CN1126122A (en) | 1996-07-10 |
| CN1037417C true CN1037417C (en) | 1998-02-18 |
Family
ID=5038434
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN94117554A Expired - Fee Related CN1037417C (en) | 1994-11-02 | 1994-11-02 | Protective agent for inner surface of centrifugal cast pipe |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1037417C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101462148B (en) * | 2007-12-19 | 2012-05-30 | 鸿富锦精密工业（深圳）有限公司 | Alloy-processing tool and coating agent thereof |
| CN104439194B (en) * | 2014-11-19 | 2017-02-01 | 北京天力创玻璃科技开发有限公司 | Anti-oxidation protective agent for composite roll |
| CN110614353A (en) * | 2018-06-20 | 2019-12-27 | 无锡市东明冠特种金属制造有限公司 | Method for reducing machining allowance of inner cavity of centrifugal cast tube |
| CN114045374B (en) * | 2021-11-19 | 2022-11-25 | 西峡龙成冶金材料有限公司 | Special covering slag for nodular cast iron and preparation method and application thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5110818A (en) * | 1974-04-19 | 1976-01-28 | Saint Gobain | |
| US4319925A (en) * | 1981-03-06 | 1982-03-16 | Weston Research Corporation | Coating compositions for metal casting molds |
| JPS60124460A (en) * | 1983-12-09 | 1985-07-03 | Kubota Ltd | Flux for pouring |
| JPS62158558A (en) * | 1986-01-07 | 1987-07-14 | Nippon Steel Corp | Production of centrifugally cast sleeve |
| CN1067839A (en) * | 1991-06-24 | 1993-01-13 | 华中理工大学 | Internal treating balls of centrifugal casting mould |
| CN1068764A (en) * | 1992-07-14 | 1993-02-10 | 冶金工业部钢铁研究总院 | Centrifugal casting molten-slag |
-
1994
- 1994-11-02 CN CN94117554A patent/CN1037417C/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5110818A (en) * | 1974-04-19 | 1976-01-28 | Saint Gobain | |
| US4319925A (en) * | 1981-03-06 | 1982-03-16 | Weston Research Corporation | Coating compositions for metal casting molds |
| JPS60124460A (en) * | 1983-12-09 | 1985-07-03 | Kubota Ltd | Flux for pouring |
| JPS62158558A (en) * | 1986-01-07 | 1987-07-14 | Nippon Steel Corp | Production of centrifugally cast sleeve |
| CN1067839A (en) * | 1991-06-24 | 1993-01-13 | 华中理工大学 | Internal treating balls of centrifugal casting mould |
| CN1068764A (en) * | 1992-07-14 | 1993-02-10 | 冶金工业部钢铁研究总院 | Centrifugal casting molten-slag |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1126122A (en) | 1996-07-10 |
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