CN105838986A - Casting method of scum gate valve body for mining - Google Patents

Abstract

The invention discloses a casting method of a scum gate valve body for mining. The casting method comprises steps as follows: (1), a pouring liquid is prepared and comprises chemical components in percentage by weight as follows: 0.22%-0.26% of C, 0.25%-0.45% of Si, 0.60%-0.80% of Mn, 0.30%-0.50% of Ti, 0.01%-0.02% of Ho, 0.05%-0.10% of W, 0.10%-0.15% of B, smaller than or equal to 0.03% of P, smaller than or equal to 0.02% of S and the balance of Fe; step (2), a casting-infiltration coating is prepared; (3), valve body pouring is performed; (4), heat treatment and finishing are performed. According to the scum gate valve body obtained with the casting method, the uniform and stable casting-infiltration composite layer is formed on the surface; furthermore, the scum gate valve body has the advantages of excellent corrosion resistance, wear resistance and scraping resistance, high finished product ratio, stable quality, good appearance quality and usability and long service life, and is suitable for deslagging of mines.

Description

A kind of casting method of mining scum gate valves valve body

Technical field

The present invention relates to valve casting technology field, particularly relate to the casting method of a kind of mining scum gate valves valve body.

Background technology

Valve is flowable materials conveying and the vitals controlled, and in use, in addition to the requirement of the technical specifications such as temperature to be met, pressure, is also adapted to the different needs of heterogeneity material, such as corrosion, wear, adhesion etc..Meanwhile, sealing property and the service life of valve is also highly important technical specification.

Casting infiltration is at mo(U)ld face by raw material furnishing coating application such as alloyed powders, parent metal immersion antireflective coating material capillary porosity during cast, rely on molten metal heat to make alloy powder melt, melt, combine together with parent metal, thus form the surface composite layer with superperformance at cast(ing) surface.Infiltration technology is promoting while cast properties, has and need not the advantage that special equipment, technique are simple, with short production cycle, with low cost.But, it is susceptible to the problems such as pore, slag inclusion and surface composite layer uneven thickness due to Infiltration technology, causes casting flaw when being applied to valve body production, affect presentation quality and the service life of valve body.Document " research of casting infiltration raising cast steel valve wearability " uses technology of infiltration casting to prepare the valve that flushing resistance is good, improves the service life of valve, but it also indicates that simultaneously, and the problem of casting quality layer poor stability yet suffers from, and need to improve further.Therefore, selecting suitable processing temperature, suitable base material and casting to ooze coating, optimize casting method, improving technology of infiltration casting, to be combined the quality stability of valve body moulding most important.

Summary of the invention

The object of the invention is contemplated to make up the defect of prior art, it is provided that a kind of steady quality, presentation quality and serviceability are good, the casting method of the mining scum gate valves valve body of length in service life.

The present invention is achieved by the following technical solutions:

The casting method of a kind of mining scum gate valves valve body, comprises the following steps:

(1) preparation potting syrup, the chemical component weight percentage ratio of described potting syrup is as follows: C:0.22%-0.26%, Si:0.25%-0.45%, Mn:0.60%-0.80%, Ti:0.30%-0.50%, Ho:0.01%-0.02%, W:0.05%-0.10%, B:0.10%-0.15%, P≤0.03%, S≤0.02%, surplus is Fe, each raw material is i.e. obtained potting syrup in medium-frequency induction furnace after 1580-1620 DEG C of melting, adjustment chemical composition；

(2) coating is oozed in preparation casting, described casting is oozed coating and is prepared by the raw materials in: chromium nitride iron powder 30-40, vanadium carbide 5-10, Rutile type titanium dioxide 1-2, polyvinyl alcohol 0.5-1, acrylic acid 0.1-0.2, Ammonium persulfate. 0.01-0.015, Lithium metasilicate 2-4, sodium fluoride 1-2, CNT 1-2, silane resin acceptor kh-550 0.5-1, maltodextrin 0.1-0.15；It is first by uniform for dispersed with stirring in CNT, Rutile type titanium dioxide and silane resin acceptor kh-550 addition ethanol in proper amount that the preparation method of coating is oozed in described casting, it is subsequently adding chromium nitride iron powder, vanadium carbide stirring 1-2h, it is dried and removes 100-120 DEG C of process 0.5-1h after ethanol, obtain component A；First polyvinyl alcohol, maltodextrin are added 85-95 DEG C of dissolving in suitable quantity of water and completely, be subsequently adding acrylic acid and Ammonium persulfate. 60-70 DEG C stirring 2-4h, obtain B component after cooling；Component A, B component is uniform with remaining raw material mixed grinding, obtain casting and ooze coating；

(3) cast valve body, first by core in 220-240 DEG C of drying and processing 4-6h, then casting is oozed coating and is coated uniformly on core surface, coating thickness is 1.5-2.5mm, process 1-2h, then mould assembling then at 160-180 DEG C, then potting syrup is poured into a mould under the conditions of 1520-1560 DEG C, it is cooled to room temperature with 20-30 DEG C/h, then carries out finishing；

(4) heat treatment, valve body after step (3) being processed is in 200-300 DEG C of isothermal holding 2-4h, then it is to slowly warm up to 800-850 DEG C of isothermal holding 6-8h with 60-80 DEG C/h, again with 30-50 DEG C/h of slow cooling to 600-650 DEG C of isothermal holding 4-6h, finally it is slowly dropped to room temperature with 50-60 DEG C/h, again obtains finished product after finishing.

The invention have the advantage that

The present invention utilizes CNT, Rutile type titanium dioxide and silane resin acceptor kh-550 that chromium nitride iron powder, vanadium carbide are carried out surface coating modification as casting infiltration layer material; alloy powder is had good surface protection effect; improve the wettability with molten metal, strengthen metallurgical interface bond strength；Using acrylic acid modified polyvinyl alcohol as binding agent, bond strength is high, and can form stable capillary gap, improves molten metal and wettability that casting is oozed between coating, advantageously forms uniform, stable casting infiltration layer；Being processed by the mixed grinding of remaining raw material, the casting obtained is oozed coating and is fused with metallic matrix through cast, and the compound valve body matrix obtained, through the subsequent processing steps such as Overheating Treatment, finishing, finally gives finished product again.The gate valve body obtained by casting method of the present invention, surface forms uniform, stable casting and oozes composite bed, and has excellent corrosion-resistant, wear-resistant, scraping and wiping resistance performance, and yield rate is high, steady quality, presentation quality and serviceability are good, service life is long, it is adaptable to mine deslagging.

Detailed description of the invention

The casting method of a kind of mining scum gate valves valve body, comprises the following steps:

(1) preparation potting syrup, wherein the chemical component weight percentage ratio of potting syrup is as follows: C:0.22%, Si:0.25%, Mn:0.60%, Ti:0.30%, Ho:0.01%, W:0.05%, B:0.10%, P:0.03%, S:0.02%, surplus is Fe, each raw material is i.e. obtained potting syrup in medium-frequency induction furnace after 1580 DEG C of meltings, adjustment chemical composition；

(2) coating is oozed in preparation casting, wherein casting is oozed coating and is made up of the raw material of following weight (kg): chromium nitride iron powder 30, vanadium carbide 5, Rutile type titanium dioxide 1, polyvinyl alcohol 0.5, acrylic acid 0.1, Ammonium persulfate. 0.01, Lithium metasilicate 2, sodium fluoride 1, CNT 1, silane resin acceptor kh-550 0.5, maltodextrin 0.1；It is first by uniform for dispersed with stirring in CNT, Rutile type titanium dioxide and silane resin acceptor kh-550 addition ethanol in proper amount that the preparation method of coating is oozed in described casting, it is subsequently adding chromium nitride iron powder, vanadium carbide stirring 1h, it is dried and removes 100 DEG C of process 0.5h after ethanol, obtain component A；First polyvinyl alcohol, maltodextrin are added 85 DEG C of dissolvings in suitable quantity of water and completely, be subsequently adding acrylic acid and Ammonium persulfate. 60 DEG C stirring 2h, obtain B component after cooling；Component A, B component is uniform with remaining raw material mixed grinding, obtain casting and ooze coating；

(3) cast valve body, first by core in 220 DEG C of drying and processing 4h, then oozes casting coating and is coated uniformly on core surface, coating thickness is 1.5mm, processes 1h, then mould assembling then at 160 DEG C, again potting syrup is poured into a mould under the conditions of 1520 DEG C, be cooled to room temperature with 20 DEG C/h, then carry out finishing；

(4) heat treatment, valve body after step (3) being processed, in 200 DEG C of isothermal holding 2h, is then to slowly warm up to 800 DEG C of isothermal holding 6h with 60 DEG C/h, then with 30 DEG C/h of slow coolings to 600 DEG C of isothermal holding 4h, finally it is slowly dropped to room temperature with 50 DEG C/h, again obtains finished product after finishing.

Wherein the model of chromium nitride iron powder selects FeNCr10-A.

The performance test results of the said goods is as follows:

Casting infiltration layer intensity is 59.6HRC, and service life is 6 times of common WCB valve body, and during actual condition uses, composite bed will not peel off, ftracture, and operation conditions is good.

Claims (1)

1. the casting method of a mining scum gate valves valve body, it is characterised in that comprise the following steps:

(1) preparation potting syrup, the chemical component weight percentage ratio of described potting syrup is as follows: C:0.22%-0.26%, Si:0.25%-0.45%, Mn:0.60%-0.80%, Ti:0.30%-0.50%, Ho:0.01%-0.02%, W:0.05%-0.10%, B:0.10%-0.15%, P≤0.03%, S≤0.02%, surplus is Fe, each raw material is i.e. obtained potting syrup in medium-frequency induction furnace after 1580-1620 DEG C of melting, adjustment chemical composition；

(2) coating is oozed in preparation casting, described casting is oozed coating and is prepared by the raw materials in: chromium nitride iron powder 30-40, vanadium carbide 5-10, Rutile type titanium dioxide 1-2, polyvinyl alcohol 0.5-1, acrylic acid 0.1-0.2, Ammonium persulfate. 0.01-0.015, Lithium metasilicate 2-4, sodium fluoride 1-2, CNT 1-2, silane resin acceptor kh-550 0.5-1, maltodextrin 0.1-0.15；It is first by uniform for dispersed with stirring in CNT, Rutile type titanium dioxide and silane resin acceptor kh-550 addition ethanol in proper amount that the preparation method of coating is oozed in described casting, it is subsequently adding chromium nitride iron powder, vanadium carbide stirring 1-2h, it is dried and removes 100-120 DEG C of process 0.5-1h after ethanol, obtain component A；First polyvinyl alcohol, maltodextrin are added 85-95 DEG C of dissolving in suitable quantity of water and completely, be subsequently adding acrylic acid and Ammonium persulfate. 60-70 DEG C stirring 2-4h, obtain B component after cooling；Component A, B component is uniform with remaining raw material mixed grinding, obtain casting and ooze coating；

(3) cast valve body, first by core in 220-240 DEG C of drying and processing 4-6h, then casting is oozed coating and is coated uniformly on core surface, coating thickness is 1.5-2.5mm, process 1-2h, then mould assembling then at 160-180 DEG C, then potting syrup is poured into a mould under the conditions of 1520-1560 DEG C, it is cooled to room temperature with 20-30 DEG C/h, then carries out finishing；

(4) heat treatment, valve body after step (3) being processed is in 200-300 DEG C of isothermal holding 2-4h, then it is to slowly warm up to 800-850 DEG C of isothermal holding 6-8h with 60-80 DEG C/h, again with 30-50 DEG C/h of slow cooling to 600-650 DEG C of isothermal holding 4-6h, finally it is slowly dropped to room temperature with 50-60 DEG C/h, again obtains finished product after finishing.