CN111250664A - Method for preventing cracks of valve body casting of low-pound-grade large-caliber check valve - Google Patents
Method for preventing cracks of valve body casting of low-pound-grade large-caliber check valve Download PDFInfo
- Publication number
- CN111250664A CN111250664A CN202010188339.4A CN202010188339A CN111250664A CN 111250664 A CN111250664 A CN 111250664A CN 202010188339 A CN202010188339 A CN 202010188339A CN 111250664 A CN111250664 A CN 111250664A
- Authority
- CN
- China
- Prior art keywords
- casting
- riser
- valve body
- sand
- open
- 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.)
- Pending
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/22—Moulds for peculiarly-shaped castings
- B22C9/24—Moulds for peculiarly-shaped castings for hollow articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
- B22C9/088—Feeder heads
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
Abstract
The invention relates to the technical field of valve body casting, in particular to a method for preventing cracks of a valve body casting of a low-pound-grade large-caliber check valve, which comprises the following steps of uniformly placing foam plates at a neck part, a seat part, a first parting surface rear part, a second parting surface rear part and a third parting surface rear part of a valve body core box flange; arranging anti-cracking ribs between the four open risers and the five open risers of the outer mold seat part, and placing chillers at positions corresponding to the anti-cracking ribs of the sand cores; two thermal pitch circles are arranged at the four positions of the open riser and the five positions of the open riser, and a supplement channel is arranged between the two thermal pitch circles; the pouring speed, temperature and molten steel melting property are strictly controlled. According to the invention, the chill is placed at the position corresponding to the sand core anti-cracking rib, the chill improves the temperature field of the casting to enable the casting to tend to be sequentially solidified, the supplement channels are arranged between the two thermal pitch circles, and when the casting liquid in the film is short, the supplement channels supplement the casting, so that the casting is prevented from generating cracks, and the casting cannot generate cracks during casting.
Description
Technical Field
The invention relates to the technical field of valve body casting, in particular to a method for preventing cracks of a valve body casting of a low-pound-grade large-caliber check valve.
Background
The valve is an important component of an industrial pipeline, a basic structural component of a mechanical product with a movable mechanism has the advantages that with the continuous progress of science and technology, the requirement on the quality of the valve is higher and higher, the quality of the valve is closely related to the quality of a valve casting, and no good valve exists when no good casting exists; the influence of cracks on the casting is most prominent, and the existing large-caliber check valve body casting is easy to generate cracks during pouring.
Disclosure of Invention
The invention aims to solve the defect that cracks are easy to generate during pouring in the prior art, and provides a method for preventing the cracks of a low-pound-grade large-caliber check valve body casting.
In order to achieve the purpose, the invention adopts the following technical scheme:
designing a method for preventing cracks of a low-pound-grade large-caliber check valve body casting, which comprises the following steps of;
s1: a first blind riser, a second blind riser, a third blind riser, a fourth blind riser, a fifth blind riser and a sixth blind riser on the valve body are designed symmetrically;
s2: the open riser I, the open riser II and the open riser III are designed at the core heads of the three flanges;
s3: uniformly placing foam plates on the neck part, the seat part, the first parting surface rear part, the second parting surface rear part and the third parting surface rear part of the valve body core box flange, wherein the sand core adopts two half moulds to form a whole core, and a semicircular gap is artificially drawn on the parting surface of the sand core;
s4: arranging anti-cracking ribs between the four exposed risers and the five exposed risers of the seat part of the outer die, placing chills at positions corresponding to the anti-cracking ribs of the sand core, and placing chromite sand at the neck parts of the outer die and the sand core flange, the anti-cracking ribs and the seat part of the sand core;
s5: two thermal pitch circles are arranged at the four positions of the open riser and the five positions of the open riser, and a supplement channel is arranged between the two thermal pitch circles;
s6: the pouring speed, temperature and molten steel melting property are strictly controlled.
Preferably, the foam board size in S3 is 100 x 30 x 20mm, the foam is no more than 30mm from the surface of the sand core, and the foam spacing is 30-40 mm.
Preferably, the thickness of the ferrochrome sand in the S4 is 15-20 mm.
Preferably, after the casting in S6 is started, the molten steel is rapidly and smoothly poured into the mold cavity, and at the end of the casting, the speed is slowed down.
Preferably, the casting temperature of the molten steel in the S6 is controlled at 1550-.
The invention provides a method for preventing cracks of a low-pound-grade large-caliber check valve body casting, which has the beneficial effects that:
the chill is placed at the position corresponding to the sand core anti-cracking rib, the chill improves the temperature field of the casting to enable the casting to tend to be sequentially solidified, a certain solidification sequence is provided, sufficient supplement capacity is provided, the great stress generated during integral shrinkage is eliminated, two thermal section circles are arranged to avoid too fast heat loss, a supplement channel is arranged between the two thermal section circles, when casting liquid in the film is not available, the casting is prevented from generating cracks through supplement channel supplement, and cracks can not occur during casting.
Drawings
Fig. 1 is a schematic structural diagram of a method for preventing cracks of a low-pound-grade large-caliber check valve body casting provided by the invention.
In the figure: the anti-cracking riser comprises a first blind riser 1, a first open riser 2, a second blind riser 3, a third blind riser 4, a fourth blind riser 5, a second open riser 6, a third open riser 7, a fifth blind riser 8, a sixth blind riser 9, a fourth open riser 10, a fifth open riser 11, a cross runner 12, a straight runner 13, an anti-cracking rib 14, a thermal joint circle 15, a supplementing channel 16, a neck 17, a seat 18, a first parting surface rear part 19, a second parting surface rear part 20 and a third parting surface rear part 21.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Example 1
Referring to fig. 1, a method for preventing cracks of a low-pound-grade large-caliber check valve body casting comprises the following steps:
s1: the first blind riser 1, the second blind riser 3, the third blind riser 4, the fourth blind riser 5, the fifth blind riser 8 and the sixth blind riser 9 on the valve body adopt a symmetrical design, a sprue 13 is communicated with a cross gate 12, and the cross gate 12 feeds molten steel to the runner flange through the fifth blind riser 8 and the sixth blind riser 9, so that the risk of cracking of a neck part of the runner flange due to the molten steel fed from the middle flange is reduced, and the casting stress of a casting is reduced;
s2: the open riser I2, the open riser II 6 and the open riser III 7 are designed at the core heads of the three flanges, exhaust holes communicated with the outside are reserved at the three end core heads for strengthening exhaust, and the sand mold and the sand core are fully dried before core setting, so that the gas forming amount is reduced;
s3: foam boards are uniformly placed at the neck 17, the seat 18, the first parting surface rear part 19, the second parting surface rear part 20 and the third parting surface rear part 21 of the flange of the valve body core box, the size of the foam board is 100 x 30 x 20mm, the distance between foam and the surface of a sand core is 20mm, the foam interval is 30mm, the foam boards enhance the deformability of the sand core, the sand core adopts two half dies to form a whole core, a semicircular gap is artificially drawn out from the parting surface of the sand core, a certain gap is reserved between the two half-core contact surfaces during combination, a sand core yielding space is artificially manufactured, and the deformability of the sand core is increased to the maximum extent;
s4: an anti-cracking rib 14 is arranged between the four 10 of the open riser and the five 11 of the open riser of the seat part of the outer die, a chiller is arranged at the position corresponding to the anti-cracking rib of the sand core, chromite sand is arranged at the neck part of the outer die and the flange of the sand core, the anti-cracking rib and the seat part of the sand core, the thickness of the chromite sand is 15mm, the solidification time of the chromite sand at the position is reduced, the chill improves the temperature field of the casting to enable the casting to tend to be solidified in sequence, a certain solidification sequence is provided, and the cooling system has enough supplementary capacity and eliminates the maximum stress generated during the integral;
s5: two heat-joint circles 15 are arranged at the four 10 and five 11 positions of the open riser, the heat-joint circles 15 prevent the heat from being lost too fast, a supplement channel 16 is arranged between the two heat-joint circles 15, and when casting liquid in the film is short, the casting liquid is supplemented through the supplement channel 16 to prevent the casting from generating cracks;
s6: strictly controlling the pouring speed, temperature and molten steel melting property, reasonably controlling the pouring speed and pouring temperature, keeping the tapping temperature at 1620 ℃ for 3 minutes, pouring at 1550 ℃, quickly and stably injecting into a mold cavity, slowing down the speed at the final pouring stage to avoid false filling, controlling the sand falling time, and removing the box and cleaning the sand after cooling for 8 hours.
Example 2
Referring to fig. 1, a method for preventing cracks of a low-pound-grade large-caliber check valve body casting comprises the following steps:
s1: the first blind riser 1, the second blind riser 3, the third blind riser 4, the fourth blind riser 5, the fifth blind riser 8 and the sixth blind riser 9 on the valve body adopt a symmetrical design, a sprue 13 is communicated with a cross gate 12, and the cross gate 12 feeds molten steel to the runner flange through the fifth blind riser 8 and the sixth blind riser 9, so that the risk of cracking of a neck part of the runner flange due to the molten steel fed from the middle flange is reduced, and the casting stress of a casting is reduced;
s2: the open riser I2, the open riser II 6 and the open riser III 7 are designed at the core heads of the three flanges, exhaust holes communicated with the outside are reserved at the three end core heads for strengthening exhaust, and the sand mold and the sand core are fully dried before core setting, so that the gas forming amount is reduced;
s3: foam boards are uniformly placed at the neck 17, the seat 18, the first parting surface rear part 19, the second parting surface rear part 20 and the third parting surface rear part 21 of the flange of the valve body core box, the size of the foam board is 100 x 30 x 20mm, the distance between foam and the surface of a sand core is 25mm, the foam interval is 35mm, the foam boards enhance the yielding performance of the sand core, the sand core adopts two half dies to form a whole core, a semicircular gap is artificially drawn out from the parting surface of the sand core, a certain gap is reserved on the contact surface of the two half dies during combination, a sand core yielding space is artificially manufactured, and the yielding performance of the sand core is increased to the maximum extent;
s4: an anti-cracking rib 14 is arranged between the four 10 of the open riser and the five 11 of the open riser of the seat part of the outer die, a chiller is arranged at the position corresponding to the anti-cracking rib of the sand core, chromite sand is arranged at the neck part of the outer die and the flange of the sand core, the anti-cracking rib and the seat part of the sand core, the thickness of the chromite sand is 17mm, the solidification time of the chromite sand at the position is reduced, the chill improves the temperature field of the casting to enable the casting to tend to be solidified in sequence, a certain solidification sequence is provided, and the cooling system has enough supplementary capacity and eliminates the maximum stress generated during the integral;
s5: two heat-joint circles 15 are arranged at the four 10 and five 11 positions of the open riser, the heat-joint circles 15 prevent the heat from being lost too fast, a supplement channel 16 is arranged between the two heat-joint circles 15, and when casting liquid in the film is short, the casting liquid is supplemented through the supplement channel 16 to prevent the casting from generating cracks;
s6: strictly controlling the pouring speed, temperature and molten steel melting property, reasonably controlling the pouring speed and pouring temperature, keeping the tapping temperature at about 1620 ℃ for 4 minutes, pouring at 1565 ℃, quickly and stably injecting into a die cavity, slowing down the speed at the final pouring stage to avoid false filling, controlling the sand falling time, and removing the sand after cooling for 8 hours.
Example 3
Referring to fig. 1, a method for preventing cracks of a low-pound-grade large-caliber check valve body casting comprises the following steps:
s1: the first blind riser 1, the second blind riser 3, the third blind riser 4, the fourth blind riser 5, the fifth blind riser 8 and the sixth blind riser 9 on the valve body adopt a symmetrical design, a sprue 13 is communicated with a cross gate 12, and the cross gate 12 feeds molten steel to the runner flange through the fifth blind riser 8 and the sixth blind riser 9, so that the risk of cracking of a neck part of the runner flange due to the molten steel fed from the middle flange is reduced, and the casting stress of a casting is reduced;
s2: the open riser I2, the open riser II 6 and the open riser III 7 are designed at the core heads of the three flanges, exhaust holes communicated with the outside are reserved at the three end core heads for strengthening exhaust, and the sand mold and the sand core are fully dried before core setting, so that the gas forming amount is reduced;
s3: foam boards are uniformly placed at the neck 17, the seat 18, the first parting surface rear part 19, the second parting surface rear part 20 and the third parting surface rear part 21 of the flange of the valve body core box, the size of the foam board is 100 x 30 x 20mm, the distance between foam and the surface of a sand core is 30mm, the foam interval is 40mm, the foam boards enhance the deformability of the sand core, the sand core adopts two half dies to form a whole core, a semicircular gap is artificially drawn out from the parting surface of the sand core, a certain gap is reserved between the two half-core contact surfaces during combination, a sand core yielding space is artificially manufactured, and the deformability of the sand core is increased to the maximum extent;
s4: an anti-cracking rib 14 is arranged between the four 10 of the open riser and the five 11 of the open riser of the seat part of the outer die, a chiller is arranged at the position corresponding to the anti-cracking rib of the sand core, chromite sand is arranged at the neck part of the outer die and the flange of the sand core, the anti-cracking rib and the seat part of the sand core, the thickness of the chromite sand is 20mm, the solidification time of the chromite sand at the position is reduced, the chill improves the temperature field of the casting to enable the casting to tend to be solidified in sequence, a certain solidification sequence is provided, and the cooling system has enough supplementary capacity and eliminates the maximum stress generated during the integral;
s5: two heat-joint circles 15 are arranged at the four 10 and five 11 positions of the open riser, the heat-joint circles 15 prevent the heat from being lost too fast, a supplement channel 16 is arranged between the two heat-joint circles 15, and when casting liquid in the film is short, the casting liquid is supplemented through the supplement channel 16 to prevent the casting from generating cracks;
s6: strictly controlling the pouring speed, temperature and molten steel melting property, reasonably controlling the pouring speed and pouring temperature, keeping the tapping temperature at about 1620 ℃ for 5 minutes, pouring at 1580 ℃, quickly and stably injecting into a mold cavity, slowing down the speed at the final pouring stage to avoid filling in a false state, controlling the sand falling time, and cooling for 8 hours before unpacking and cleaning sand.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.
Claims (5)
1. The method for preventing the cracks of the valve body casting of the low-pound-grade large-caliber check valve is characterized by comprising the following steps of:
s1: a first blind riser (1), a second blind riser (3), a third blind riser (4), a fourth blind riser (5), a fifth blind riser (8) and a sixth blind riser (9) on the valve body are designed in a symmetrical mode;
s2: open risers I (2), open risers II (6) and open risers III (7) are designed at the core heads of the three flanges;
s3: uniformly placing foam plates at a neck (17), a seat (18), a first parting surface rear part (19), a second parting surface rear part (20) and a third parting surface rear part (21) of a valve body core box flange, wherein a sand core adopts two half dies to form a whole core, and a semicircular gap is artificially drawn at the parting surface of the sand core;
s4: an anti-cracking rib (14) is arranged between the four (10) of the open riser and the five (11) of the open riser of the seat of the outer die, a chill is placed at the position corresponding to the anti-cracking rib of the sand core, and chromite sand is placed at the neck of the flange of the outer die and the sand core, the anti-cracking rib and the seat of the sand core;
s5: two thermal pitch circles (15) are arranged at the four (10) and five (11) positions of the open riser, and a supplement channel (16) is arranged between the two thermal pitch circles (15);
s6: the pouring speed, temperature and molten steel melting property are strictly controlled.
2. The method of claim 1, wherein the foam sheet size in S3 is 100 x 30 x 20mm, the foam is no more than 30mm from the sand core surface, and the foam spacing is 30-40 mm.
3. The method for preventing the valve body casting cracks of the low-pound-grade large-caliber check valve according to claim 1, wherein the thickness of the ferrochrome sand in the S4 is 15-20 mm.
4. The method of claim 1, wherein the casting is performed in a manner such that the casting is performed smoothly and quickly after the start of the casting in S6, and the casting is slowed down at the end of the casting.
5. The method for preventing the valve body casting cracks of the low-pound-grade large-caliber check valve as claimed in claim 1, wherein the casting temperature of the molten steel in the S6 is controlled at 1550-.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010188339.4A CN111250664A (en) | 2020-03-17 | 2020-03-17 | Method for preventing cracks of valve body casting of low-pound-grade large-caliber check valve |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010188339.4A CN111250664A (en) | 2020-03-17 | 2020-03-17 | Method for preventing cracks of valve body casting of low-pound-grade large-caliber check valve |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111250664A true CN111250664A (en) | 2020-06-09 |
Family
ID=70954819
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010188339.4A Pending CN111250664A (en) | 2020-03-17 | 2020-03-17 | Method for preventing cracks of valve body casting of low-pound-grade large-caliber check valve |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111250664A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112548043A (en) * | 2020-11-24 | 2021-03-26 | 安徽应流集团霍山铸造有限公司 | Crack prevention method for complex-structure steel casting based on embedded type crack prevention ribs |
| CN113263140A (en) * | 2020-09-04 | 2021-08-17 | 浙江泰能机械制造有限公司 | Bottom and middle cross gate and valve pouring, middle way and middle way flange feeding system |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103433434A (en) * | 2013-09-02 | 2013-12-11 | 山东墨龙石油机械股份有限公司 | Method for casting valve body of flat gate valve |
| CN104646635A (en) * | 2015-01-29 | 2015-05-27 | 夏平桂 | Casting method for valve body of expansion valve |
| CN206550287U (en) * | 2017-03-24 | 2017-10-13 | 辉县市腾飞机械制造有限公司 | Foundry Works's moulding impression-taking apparatus |
| CN208341652U (en) * | 2018-06-24 | 2019-01-08 | 福建大通互惠精密铸造有限公司 | A kind of ball valve body cast steel part mould with novel dead head |
| CN110216245A (en) * | 2019-04-20 | 2019-09-10 | 福建大通互惠精密铸造有限公司 | 150 pounds of brake valve body portions of one kind are without hot top mould and design method |
| CN110216244A (en) * | 2019-04-20 | 2019-09-10 | 福建大通互惠精密铸造有限公司 | A kind of the casting tool and its manufacturing process of check valve body steel-casting |
| CN110242781A (en) * | 2019-04-24 | 2019-09-17 | 福建大通互惠精密铸造有限公司 | A kind of super-duplex stainless steel 5A material butterfly valve body and manufacturing method |
-
2020
- 2020-03-17 CN CN202010188339.4A patent/CN111250664A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103433434A (en) * | 2013-09-02 | 2013-12-11 | 山东墨龙石油机械股份有限公司 | Method for casting valve body of flat gate valve |
| CN104646635A (en) * | 2015-01-29 | 2015-05-27 | 夏平桂 | Casting method for valve body of expansion valve |
| CN206550287U (en) * | 2017-03-24 | 2017-10-13 | 辉县市腾飞机械制造有限公司 | Foundry Works's moulding impression-taking apparatus |
| CN208341652U (en) * | 2018-06-24 | 2019-01-08 | 福建大通互惠精密铸造有限公司 | A kind of ball valve body cast steel part mould with novel dead head |
| CN110216245A (en) * | 2019-04-20 | 2019-09-10 | 福建大通互惠精密铸造有限公司 | 150 pounds of brake valve body portions of one kind are without hot top mould and design method |
| CN110216244A (en) * | 2019-04-20 | 2019-09-10 | 福建大通互惠精密铸造有限公司 | A kind of the casting tool and its manufacturing process of check valve body steel-casting |
| CN110242781A (en) * | 2019-04-24 | 2019-09-17 | 福建大通互惠精密铸造有限公司 | A kind of super-duplex stainless steel 5A material butterfly valve body and manufacturing method |
Non-Patent Citations (1)
| Title |
|---|
| 杜西灵等: "《袖珍铸造工手册》", 28 February 2001, 北京：机械工业出版社 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113263140A (en) * | 2020-09-04 | 2021-08-17 | 浙江泰能机械制造有限公司 | Bottom and middle cross gate and valve pouring, middle way and middle way flange feeding system |
| CN112548043A (en) * | 2020-11-24 | 2021-03-26 | 安徽应流集团霍山铸造有限公司 | Crack prevention method for complex-structure steel casting based on embedded type crack prevention ribs |
| CN112548043B (en) * | 2020-11-24 | 2023-04-28 | 安徽应流集团霍山铸造有限公司 | Anti-cracking method for complex-structure steel castings based on embedded anti-cracking ribs |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102554130B (en) | Casting method for high-nickel austenite nodular cast iron exhaust manifold | |
| CN113399641B (en) | High-density die-casting forming method of aluminum alloy die casting | |
| CN202984579U (en) | Cylinder cover casting die | |
| CN111250664A (en) | Method for preventing cracks of valve body casting of low-pound-grade large-caliber check valve | |
| CN112872297B (en) | Stepped feeding casting process for large-sized profile section casting | |
| CN113547098B (en) | Multi-riser tube for battery case of aluminum alloy new energy automobile and low-pressure casting method of multi-riser tube | |
| CN102688990A (en) | Aluminium alloy hydraulic motor shell gravity casting mould and manufacturing method thereof | |
| JP2012176424A (en) | Low temperature mold and low pressure casting method | |
| CN107042284A (en) | A kind of device for sand coated iron mould method for producing steel-casting | |
| CN102161080A (en) | Manufacturing tool of high-compact wide and thick plate blank for wide and thick plate rolling mill and method | |
| CN113172216A (en) | Method and device for enhancing cooling of casting in casting process | |
| CN110918923B (en) | Casting process of sequential directional solidification double-layer conical shell structure casting | |
| CN202951845U (en) | Hub feeding gating system | |
| CN112705675A (en) | Technological method for space curved surface plate type investment casting | |
| CN106623810A (en) | Casting method for motorcycle aluminum alloy wheel with hollow hub | |
| CN102784889A (en) | Casting method of complex-structure ductile iron thin-wall casting of ship turbocharger | |
| CN102350485A (en) | Device and process for repairing shrinkage holes during steel billet casting through intermediate-frequency electric heating | |
| US11897028B2 (en) | Controlled nozzle cooling (CNC) casting | |
| CN113477886A (en) | Casting system and casting process for steam turbine cylinder body casting | |
| CN114643336A (en) | V-method casting process of nodular cast iron casting | |
| CN103934438B (en) | Internal densener is used for the casting method of heavy section steel castings | |
| CN108115100B (en) | Method for preventing female rotor from shrinkage cavity and shrinkage porosity | |
| CN104607599A (en) | Ultrasonic test block casting production process | |
| CN105081260A (en) | Die-casting process for roller support of washing machine | |
| CN105499493A (en) | Casting technology for preventing shrinkage and porosity |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200609 |