CN102994898A - Casting method of C12A material casting piece for supercritical unit - Google Patents
Casting method of C12A material casting piece for supercritical unit Download PDFInfo
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- CN102994898A CN102994898A CN2012103665027A CN201210366502A CN102994898A CN 102994898 A CN102994898 A CN 102994898A CN 2012103665027 A CN2012103665027 A CN 2012103665027A CN 201210366502 A CN201210366502 A CN 201210366502A CN 102994898 A CN102994898 A CN 102994898A
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Abstract
The invention discloses a casting method for casting high-temperature high-pressure valve body product made of a supercritical C12A material. The casting method comprises the following steps of: (1) primary smelting; (2) degassing and deoxygenation; (3) secondary refining and deep desulfuration; (4) flatly casting and vertical pouring; and (5) subsequent heat treatment. According to the method, through the chemical component control of molten steel, molten steel smelting process control, casting process control and heat treatment process control, the high-temperature high-pressure valve body product made of the supercritical CA12 material can be casted and manufactured, and the casting piece can meet the technical requirement of a product. The final product manufactured by the invention has the advantages that the mechanical strength has the following yield strength range: sigma s is more than or equal to 415 (MPa), sigma b is equal to 585-720 (MPa), the sigma 5 is more than or equal to 20% and psi is more than or equal to 45%, the metallographic structure of a casting piece is lath-shaped martensite, the ferrite content is less than 3%, the HB is in the range of 190-220, and the using requirement of the product is met.
Description
Technical field
The present invention relates to casting technology field, be specifically related to the method for casting production that a kind of High Temperature High Pressure ultra supercritical is used the valve body product.
Background technology
The C12A material is high pressure resistant, the high-temperature material of most significant end in U.S. ASTM and the ASME standard of materials, the overcritical and super-huge boiler power station valve of ultra supercritical of the 600MW to 1000MW of China recent years exploitation must use material.Because it will replace the high temperature high-pressure resistant materials such as traditional ZG20CrMoV, ZG15Cr1MolV, WC9 550 ℃ and 55MPa (work normality) time stable and reliable working performance, fill up the material vacancy in China steam-pipe 590-650 ℃ temperature range, make overcritical and bottleneck has been removed in the development large-scale unit of ultra supercritical power station.
The production of the large C12A material valve body that China uses now is subjected to the blockade of foreign Technology at present, about 300,000 yuan of the valve body of this material of import needs per ton, the costliness that price is suitable, and just 100,000 yuan/tons of the highest domestic finished product prices.If the direct Foundry Production of domestic energy goes out the C12A material, use the power station valve product of this material that it is squeezed into the international market, will have a huge impact for the thermal power generating equipment development of China, have wide market outlook and good economic benefit.
American Standard C12A chemical ingredients is: C 0.08～0.12%, and Si 0.2～0.5%, Mn0.3～0.6%, and P 0.02%S 0.01%, Cr 8.0～9.5%, and Ni 0.04%, and Mo 0.85～1.05%.
Technical difficult points is embodied in a following aspect of seeing during ultra supercritical C12A valve body product Foundry Production:
1. this product only has 0.08-0.12% because of the narrow range of chemical ingredients C, and the requirement of S is≤0.010% simultaneously, Cr content is higher at 8.0-9.5, contain simultaneously Nb:0.060-0.10%, N is 0.030-0.070, and V is 0.18-0.25%, Al is≤0.040 chemical ingredients narrow range, control element is many, and alloy addition is large, and smelting time is long, the easy oxidation of molten steel, the melting difficulty is large.
2. its casting manufacturability of this products C 12A material is poor, smelts that difficulty is large, teeming temperature controlled range 30 degree only, and crack defect is serious after the careless slightly formed product.The fluidity molten steel of material is poor, and Cr very easily oxidation form the slag inclusion thing and affect the internal quality of casting.
3. the wall thickness of this valve body is generally all thinner, and processability of product structure is poor, and traditional flat pouring technique of flat casting is to existing very large difficulty, the inner quality of product to be difficult to guarantee in the feeding of this valve body.
4. therefore the materials'use performance requriements is higher, higher to the heat treatment requirements of product, present domestic without ready-made thermal treatment process, must through a large amount of tests, could grasp.The mechanical property of product is had relatively high expectations, and ferritic content is less than 3% in the metallographic structure.
5. the metallographic structure of this material is for being lath martensite, material volume in changing martensitic process is to expand rapidly, therefore must strictly control the defectives such as the guarantee product does not crack such as processes such as outlet cleaning, cutting dead head and repair welding, thermal treatments in castingprocesses in whole production process.
In order to solve above-mentioned deficiency of the prior art, the present invention proposes a kind of new solution.
Summary of the invention
The purpose of this invention is to provide a kind of Foundry Production ultra supercritical C12A material method for casting production of High Temperature High Pressure valve body product, the method is passed through molten steel chemical Composition Control, smelting molten steel process, casting technique and heat treated process control, realize the Foundry Production of ultra supercritical C12A material at high temperature high pressure valve body product, and make foundry goods satisfy the technical requirements of product fully.
For reaching the foregoing invention purpose, the technical solution adopted in the present invention is: the method for casting production of a kind of overcritical, ultra supercritical unit with C12A material foundry goods is provided, it is characterized in that: may further comprise the steps, (1) is refining just; (2) deoxidation of degassing; (3) secondary refining, dark desulfurization is processed; (4) flat casting upright casting; (5) in postorder thermal treatment.
For realizing that alloy in the step (1) is added fashionable control to C, S content, adopt the alloy of low-carbon (LC), low-sulfur phosphorus or adopt metal directly to add; Add suitable ferro-niobium and chromium nitride and adjust chemical composition content by calculating during to the control of Nb, N element, when the fusing decarburization, C, S content are controlled in the lower scope simultaneously, qualified with the chemical ingredients that guarantees molten steel.
Adopt in the step (2) composite deoxidant to the molten steel deoxidation of degassing.
Step (3) adopts the ladle refining furnace of LF that molten steel is carried out secondary refining, dark desulfurization is processed, and simultaneously for preventing the generation of the casting flaws such as casting slag inclusion that Cr content height causes, being blown into argon gas when tapping in ladle purifies molten steel, allow slag inclusion thing and the gases such as oxygen, hydrogen in the molten steel discharge, make molten steel as far as possible pure.
Step (4) may further comprise the steps, and A, is blown into a certain amount of argon gas in casting mold before cast, makes the molten steel that pours into not produce air-breathing oxidation, reduces the generation of casting defect; B, put down the casting upright casting, with the middle end surfaces of foundry goods upwards, place rising head and set up the rising head subsidy in its underpart on the middle pipe, blind riser is set up in the bottom of feeding difficulty in the arm loam core, strengthens feeding.。
At the high-efficiency insulated plate that adopts the rich soil family of Britain that arranges of described rising head, strengthen the feeding effect to foundry goods.
The stress-removal of annealing first in step (5) is processed disappear scarce, the soldering, stress-removal of detecting a flaw again and is carried out the mode of property heat treatment after qualified again, has greatly improved the quality of product, prevents the appearance in production process control such as crackle.
Described property heat treatment may further comprise the steps, a, normalizing treatment: advance stove to be heated to 300 ℃ under less than 200 ℃ of conditions in furnace temperature, be incubated after 2 hours, be warming up to 520 ± 10 ℃ with≤70 ℃/h speed, be incubated 1.5 hours, then, the heat-up rate of≤80 ℃/h of warp is warming up to 680 ± 10 ℃, be incubated 2 hours, be warming up to 1040 ± 10 ℃ with the speed of 90 ℃/h again after the laggard line space of insulation 4h be chilled to 200-300 ℃; B, temper :≤60 ℃/h heat-up rate to 350 ± 10 ℃, be incubated 2 hours, then, stove is chilled to≤comes out of the stove after 200 ℃ behind the insulation 6h after the heat-up rate of≤80 ℃/h is warming up to 77 ± 10 ℃.
The mechanical property of the finished product that make by the present invention reaches in yield strength σ s 〉=415 (MPa), σ b:585-720 (MPa), δ 5 〉=20%, ψ 〉=45%, the scope and the foundry goods metallographic structure is lath martensite, ferrite content is less than 3%, HB reaches in the scope of 190-220, reaches the service requirements of product.
Embodiment
The below is described in detail the specific embodiment of the present invention.
The purpose of this invention is to provide a kind of Foundry Production ultra supercritical C12A material method for casting production of High Temperature High Pressure valve body product, the method is passed through molten steel chemical Composition Control, smelting molten steel process, casting technique and heat treated process control, realize the Foundry Production of ultra supercritical C12A material at high temperature high pressure valve body product, and make foundry goods satisfy the technical requirements of product fully.
Because its chemical ingredients claimed range of C12A material is narrower, wherein C content only is 0.08-0.12%, S content is≤0.010%, Cr, the Mo constituent content is higher again, also contain simultaneously Nb, the N rare elements, there is very large difficulty in the melting, add fashionable to C for solving alloy, the control of S content, adopt low-carbon (LC) in batching through meticulous calculating, the alloy of low-sulfur phosphorus or employing metal etc. directly add, to Nb, add suitable ferro-niobium and chromium nitride and adjust chemical composition content by calculating during the control of N element, simultaneously when the fusing decarburization with C, S content is controlled in the lower scope, and is qualified with the chemical ingredients that guarantees molten steel.
The processing of degassing at molten steel has span of control because of the content aluminium element, and to carry out the mode of deoxidation no longer feasible to add aluminium for tradition, and my company adopts a kind of novel composite deoxidant to the molten steel deoxidation of degassing.Adopt simultaneously the ladle refining furnace of LF that molten steel is carried out secondary refining, dark desulfurization is processed, and simultaneously for preventing the generation of the casting flaws such as casting slag inclusion that Cr content height causes, being blown into argon gas when tapping in ladle purifies molten steel, allow slag inclusion thing and the gases such as oxygen, hydrogen in the molten steel discharge, make molten steel as far as possible pure.And in casting mold, before cast, be blown into a certain amount of argon gas, and make the molten steel that pours into not produce air-breathing oxidation, reduce the generation of casting defect.
On casting technique: in recent years, along with the strict demand of power station to the inner quality of valve products, foundry goods does not require UT (Ultrasonic Testing) whole body UT (Ultrasonic Testing) inspection till now by original, and castability has been proposed larger requirement.Special valve body product for the C12A material, because the casting of this kind valve body of characteristic of material is by traditional flat pouring technique of flat casting more difficult assurance just, my company changes the flat pouring technique of flat casting of valve body into flat casting upright casting technique with this understanding, with the middle end surfaces of foundry goods upwards, place rising head on the middle pipe and set up the rising head subsidy in its underpart, blind riser is set up in the bottom of feeding difficulty in the arm loam core, strengthens feeding.At the high-efficiency insulated plate that adopts the rich soil family of Britain that arranges of rising head, strengthen the feeding effect to foundry goods.
It is the mechanical property that guarantees product in postorder thermal treatment, metallographic structure, the performances such as hardness reach requirement, in the meticulous measuring and calculating of thermal treatment process, first with sample testing repeatedly, test repeatedly is until test out qualified performance requriements, just try out in product, obtained secondary defective such as crackle etc. no longer occurring for product in controlling in the once production of the good effect postorder of success at product, by the optimized production process flow process, defective again disappears after traditional property heat treatment, the technical process of soldering stress-removal be adjusted into the stress-removal of annealing first process detect a flaw again disappear scarce, soldering, carry out again the mode of property heat treatment after stress-removal is qualified, greatly improve the quality of product, prevented the appearance in production process control such as crackle.
The product heat treatment process is: heat treatment mode: 1) normalizing treatment: advance stove to be heated to 300 ℃ in furnace temperature under less than 200 ℃ of conditions, be incubated after 2 hours, be warming up to 520 ± 10 ℃ with≤70 ℃/h speed, be incubated 1.5 hours, then, be warming up to 680 ± 10 ℃ through the heat-up rate of≤80 ℃/h, be incubated 2 hours, be incubated the laggard line space of 4h after being warming up to 1040 ± 10 ℃ with the speed of 90 ℃/h again to be chilled to 200-300 ℃.2) temper :≤60 ℃/h heat-up rate to 350 ± 10 ℃, be incubated 2 hours, then, stove is chilled to≤comes out of the stove after 200 ℃ behind the insulation 6h after the heat-up rate of≤80 ℃/h is warming up to 77 ± 10 ℃.
The mechanical property of the finished product reaches in yield strength σ s 〉=415 (MPa), σ b:585-720 (MPa), δ 5 〉=20%, ψ 〉=45%, the scope and the foundry goods metallographic structure is lath martensite, ferrite content is less than 3%, HB reaches in the scope of 190-220, reaches the service requirements of product.
Although the specific embodiment of the present invention is described in detail, should not be construed as the restriction to the protection domain of this patent.In the described scope of claims, the various modifications that those skilled in the art can make without creative work and distortion still belong to the protection domain of this patent.
Claims (8)
1. overcritical, the ultra supercritical unit method for casting production of C12A material foundry goods is characterized in that: may further comprise the steps (1) first refining; (2) deoxidation of degassing; (3) secondary refining, dark desulfurization is processed; (4) flat casting upright casting; (5) in postorder thermal treatment.
2. method for casting production as claimed in claim 1 is characterized in that: for realizing that alloy in the step (1) is added fashionable control to C, S content, adopt the alloy of low-carbon (LC), low-sulfur phosphorus or adopt metal directly to add; Add suitable ferro-niobium and chromium nitride and adjust chemical composition content by calculating during to the control of Nb, N element, when the fusing decarburization, C, S content are controlled in the lower scope simultaneously, qualified with the chemical ingredients that guarantees molten steel.
3. method for casting production as claimed in claim 1 is characterized in that: adopt composite deoxidant to the molten steel deoxidation of degassing in the step (2).
4. method for casting production as claimed in claim 1, it is characterized in that: step (3) adopts the ladle refining furnace of LF that molten steel is carried out secondary refining, dark desulfurization is processed, and simultaneously for preventing the generation of the casting flaws such as casting slag inclusion that Cr content height causes, being blown into argon gas when tapping in ladle purifies molten steel, allow slag inclusion thing and the gases such as oxygen, hydrogen in the molten steel discharge, make molten steel as far as possible pure.
5. method for casting production as claimed in claim 1, it is characterized in that: step (4) may further comprise the steps, and A, is blown into a certain amount of argon gas in casting mold before cast, makes the molten steel that pours into not produce air-breathing oxidation, reduces the generation of casting defect; B, put down the casting upright casting, with the middle end surfaces of foundry goods upwards, place rising head and set up the rising head subsidy in its underpart on the middle pipe, blind riser is set up in the bottom of feeding difficulty in the arm loam core, strengthens feeding.。
6. method for casting production as claimed in claim 4 is characterized in that: at the high-efficiency insulated plate that adopts the rich soil family of Britain that arranges of described rising head, strengthen the feeding effect to foundry goods.
7. method for casting production as claimed in claim 1, it is characterized in that: the stress-removal of annealing first in step (5) is processed disappear scarce, the soldering, stress-removal of detecting a flaw again and is carried out the mode of property heat treatment after qualified again, greatly improve the quality of product, prevented the appearance in production process control such as crackle.
8. method for casting production as claimed in claim 7, it is characterized in that: described property heat treatment may further comprise the steps, a, normalizing treatment: advance stove to be heated to 300 ℃ under less than 200 ℃ of conditions in furnace temperature, be incubated after 2 hours, be warming up to 520 ± 10 ℃ with≤70 ℃/h speed, be incubated 1.5 hours, then, be warming up to 680 ± 10 ℃ through the heat-up rate of≤80 ℃/h, be incubated 2 hours, be incubated the laggard line space of 4h after being warming up to 1040+10 ℃ with the speed of 90 ℃/h again to be chilled to 200300 ℃; B, temper :≤60 ℃/h heat-up rate to 350 ± 10 ℃, be incubated 2 hours, then, stove is chilled to≤comes out of the stove after 200 ℃ behind the insulation 6h after the heat-up rate of≤80 ℃/h is warming up to 77 ± 10 ℃.
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| CN2012103665027A CN102994898A (en) | 2012-09-28 | 2012-09-28 | Casting method of C12A material casting piece for supercritical unit |
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Cited By (6)
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| CN103223471A (en) * | 2013-05-15 | 2013-07-31 | 日月重工股份有限公司 | Method for manufacturing medium-pressure outer cylinder spheroidal graphite iron casting of ultra-supercritical turbine |
| CN103627848A (en) * | 2013-10-30 | 2014-03-12 | 温州锐特铸造有限公司 | Smelting method of steel high-pressure valve body |
| CN103789631A (en) * | 2014-01-16 | 2014-05-14 | 安徽省杨氏恒泰钢管扣件加工有限公司 | Steel tube material for long-distance conveying pipeline and preparation method thereof |
| CN105908058A (en) * | 2016-06-14 | 2016-08-31 | 四川六合锻造股份有限公司 | Smelting method based on nickel-based heat-resistance alloy |
| CN108411186A (en) * | 2018-02-09 | 2018-08-17 | 浙江英洛华装备制造有限公司 | A kind of supercritical generating sets C12A steel smelting and pouring techniques |
| CN114836697A (en) * | 2022-05-07 | 2022-08-02 | 延津县通达铸钢工业制造有限公司 | Supercritical material C12A high-pressure valve and casting process thereof |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103223471A (en) * | 2013-05-15 | 2013-07-31 | 日月重工股份有限公司 | Method for manufacturing medium-pressure outer cylinder spheroidal graphite iron casting of ultra-supercritical turbine |
| CN103627848A (en) * | 2013-10-30 | 2014-03-12 | 温州锐特铸造有限公司 | Smelting method of steel high-pressure valve body |
| CN103627848B (en) * | 2013-10-30 | 2014-11-26 | 温州锐特铸造有限公司 | Smelting method of steel high-pressure valve body |
| CN103789631A (en) * | 2014-01-16 | 2014-05-14 | 安徽省杨氏恒泰钢管扣件加工有限公司 | Steel tube material for long-distance conveying pipeline and preparation method thereof |
| CN105908058A (en) * | 2016-06-14 | 2016-08-31 | 四川六合锻造股份有限公司 | Smelting method based on nickel-based heat-resistance alloy |
| CN108411186A (en) * | 2018-02-09 | 2018-08-17 | 浙江英洛华装备制造有限公司 | A kind of supercritical generating sets C12A steel smelting and pouring techniques |
| CN108411186B (en) * | 2018-02-09 | 2020-07-10 | 浙江英洛华装备制造有限公司 | C12A steel smelting and pouring process for supercritical generator set |
| CN114836697A (en) * | 2022-05-07 | 2022-08-02 | 延津县通达铸钢工业制造有限公司 | Supercritical material C12A high-pressure valve and casting process thereof |
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Address after: Jianong Town Village 614000 Sichuan Shawan District emerging city of Leshan Province Applicant after: LESHAN TIANHUA MACHINERY MANUFACTURING CO., LTD. Address before: Jianong Town Village 614000 Sichuan Shawan District emerging city of Leshan Province Applicant before: Leshan Tianhua Machinery Manufacturing Co., Ltd. |
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Application publication date: 20130327 |