CN101328522B - Smelting production method of low activation martensitic steel for fusion reactor - Google Patents

Smelting production method of low activation martensitic steel for fusion reactor Download PDF

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CN101328522B
CN101328522B CN2008100213286A CN200810021328A CN101328522B CN 101328522 B CN101328522 B CN 101328522B CN 2008100213286 A CN2008100213286 A CN 2008100213286A CN 200810021328 A CN200810021328 A CN 200810021328A CN 101328522 B CN101328522 B CN 101328522B
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furnace
vacuum
melting
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added
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CN2008100213286A
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CN101328522A (en
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刘少军
黄群英
李春京
吴宜灿
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中国科学院等离子体物理研究所
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
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Abstract

The invention relates to a method for producing a low-activation martensitic steel for a fusion reactor by melting. The method comprises: step one, a charging material is smelted in a vacuum induction furnace: (1) when a vacuum degree is between 0.1 and 10 Pa, argon gas is passed through the vacuum induction furnace till the vacuum degree is between 0.005 and 0.08MPa, and a smelting temperature is between 1450 and 1650 DEG C; (2) alloys are added in sequence: firstly, pure Fe is melted; Cr and W are added into the furnace; then Ta and V are added into the furnace, and finally C and Mn are added into the furnace; simultaneously, the level of an oxygen content in the pure Fe is observed; before Cr is added, a little of C is added into the furnace for carrying out deoxidation treatment; (3) on-line detection is carried out to the compositions of alloy elements; the alloy elements are added according to a detection result; and (4) after the compositions are qualified, a mixture is cast under the vacuum at a casting temperature of between 1450 and 1550 DEG C. Step two, according to the compositions and the inner quality level of a cast ingot which is obtained by vacuum induction and melting, whether the cast ingot is remelted and refined in a vacuum electroslag remelting furnace or a common electroslag remelting furnace with argon protection. Step three, a needed CLAM steel bar material is prepared by the production of forging, cogging and hot rolling. The method has the characteristics of simple smelting operation, stable process and low production cost; the compositions and impurities of the produced CLAM steel meet the design requirement; and the method has no aliquation of the compositions and tissues and high degree of purity and is suitable for the application of the fusion reactor.

Description

A kind of smelting production method of low activation martensitic steel for fusion reactor
Technical field
The invention belongs to the metal material processing technical field, relate to a kind of smelting preparation method who is applicable to the low activation martensitic steel of fusion reactor.
Background technology
China low activation martensitic steel CLAM is a kind of fusion reactor structured material with independent intellectual property right that the applicant researches and develops, and belongs to high pure martensitic steel, requires impurity is carried out strictness control.
The T91/P91 steel is the commercial martensite high temperature steel of a kind of modified version, have good high-temperature heat resistance and antioxidant property, be widely used in superheater and reheater piping in the station boiler, this steel purity requirement height (S≤0.010wt%, P≤0.020wt%), domestic main dependence import at present.
But adopt electric arc furnace smelting technology can't prepare qualified CLAM steel, major cause is: (1) owing to melting under non-vacuum environment, main alloying element can produce certain scaling loss, as the easy oxidation of C, Mn volatilizees easily, and Cr absorbs airborne N easily, is difficult to accomplish the accurate control of composition; (2) because the CLAM steel requires very strictly to impurity element, therefore be difficult to adopt traditional desulfurization, deoxidation and dephosphorization technology to realize the control requirement of impurity element such as O≤0.01%, P≤0.005%, S≤0.005%, Al≤0.01% (mass percent).
Summary of the invention
Problem at the existence of electric arc furnace smelting technology, the present invention has developed a kind of low activation martensitic steel for fusion reactor smelting production method, suitably controlling on the basis of starting material purity, adopt the mode of " vacuum induction melting (main melting technology)+esr (assisted melting technology belongs to optional technology) ".During vacuum induction melting, adopt suitable melting technology, realization is to the control of alloying element and O, Al, S and P then depend primarily on starting material and vacuum melting pre-treating technology, during esr, select suitable slag system and remelting processing, further reduce the content of elemental gas and S, P, solve simultaneously component segregation significantly, remove inclusion, melt out the qualified CLAM steel of composition and interior tissue.Last hammer cogging, hot rolling is prepared into required CLAM shaped steel.
Technical scheme of the present invention is as follows:
A kind of smelting production method of fusion reactor low activation martensitic steel is characterized in that: comprise following process:
The first step, in vacuum induction furnace, furnace charge is carried out melting:
1) with the FeCa alloy pure iron being taken off S handles;
2) alloying element such as Cr, W, V, Ta, Mn are carried out high-temperature vacuum dehydration degassing processing before the melting; Perhaps adopt antivacuum dehydration degassing processing technology: at first to Al 2O 3Powder or CaF 2Powder carries out high temperature dehydration, uses Al then 2O 3Powder or CaF 2Powder embedding alloy is with secluding air, thermal dehydration degasification under non-vacuum environment at last, 300~800 ℃ of Heating temperatures;
3) prepare burden according to target martensitic steel design mix, the pure iron vacuum induction furnace of packing into, alloying element is by Cr, W, V, Ta, C, the Mn vacuum alloy hopper of packing in proper order;
4) after vacuum induction melting furnace is evacuated to 0.1~10Pa, fill high-purity argon gas to 0.005~0.08MPa, the fusing pure iron, and add C and take off O to 5~100ppm;
5) alloying: add pure metal Cr and W by hopper, be warming up to 1450~1650 ℃, add pure metal V, Ta successively after fusing is finished, after waiting to melt, be evacuated to the following maintenance of 0.1~10Pa 3~10 minutes; Add pure C and pure metal Mn then behind applying argon gas to 0.005~0.08MPa;
6) online detection alloy element component and augment alloying element according to test result treats that the qualified back of composition gets ingot casting 1450~1550 ℃ of vacuum pourings of tapping and carry out;
Check ingot casting composition and interior tissue,, can finish melting work, otherwise need carry out the second step assisted melting if meet the demands;
In second step, ingot casting is forged with preparation remelting consumable electrode, 800~1200 ℃ of forging temperatures, austenitizing soaking time 45~75min, forging ratio>4: 1; Remelting refining in the common electrical slag hearth of vacuum electroslag furnace or argon shield then, smelt the qualified CLAM steel ingot casting of composition and interior tissue:
1) selects high-purity Al for use 2O 3+ CaF 2Perhaps CaO+Al 2O 3+ CaF 2As electroslag;
2) electroslag is carried out drying treatment, be injected into after the fusing in the crystallizer of vacuum electroslag furnace or common electrical slag hearth;
The against vacuum electroslag remelting furnace fills high-purity argon gas to 0.005~0.05MPa after being evacuated to 0.1~5Pa;
For common electroslag remelting furnace, in crystallizer, fill the high-purity argon gas protection;
3) adopt size of current to control the burn-off rate of remelting consumable electrode, range of current is 200~500A;
4) after remelting finishes, take out the remelting ingot casting.
Described fusion reactor structured material low activation martensitic steel smelting production method, it is characterized in that: hammer cogging, hot rolling prepare required section bar:
1) processing parameter during hammer cogging is: 1100~1200 ℃ of initial forging temperatures, soaking time 45~75min, 800~900 ℃ of final forging temperatures, forging ratio>4: 1;
2) rolling technological parameter of resultant martensitic steel section bar is: annealing temperature and soaking time: 1000~1100 ℃/45~75min, and 750~850 ℃ of finishing temperatures, every time maximum rolling reduction is no more than 50%.
The smelting production method of described low activation martensitic steel for fusion reactor is characterized in that: in second step, to the common electrical slag hearth, can add suitable Al powder to take off the free oxygen in the slag system to electroslag in the reflow process, prevent that the oxygen in the slag system from spreading in molten steel.
The smelting production method of described low activation martensitic steel for fusion reactor is characterized in that: the ingot mold system is cleaned and the heated baking degasification with pure iron water earlier before cast during vacuum pouring, 300~800 ℃ of storing temperatures.
The smelting production method of described low activation martensitic steel for fusion reactor is characterized in that: Al 2O 3+ CaF 2Consisting of of slag system: Al 2O 320~40%+CaF 2Surplus; CaO+Al 2O 3+ CaF 2Consisting of of slag system: CaO5~15%+Al 2O 320~40%+CaF 2Surplus.
The present invention adopts the mode of " vacuum induction melting (main melting technology)+esr (assisted melting technology; belong to optional technology) ", at first in vacuum induction furnace furnace charge is carried out melting, then ingot casting composition and internal soundness is detected, if meet the demands, promptly finish melting; Otherwise need to carry out remelting refining in the common electrical slag hearth of vacuum electroslag furnace or argon shield, to smelt the qualified CLAM steel ingot casting of composition and interior tissue, carry out hammer cogging at last, hot rolling prepares required CLAM shaped steel.
The present invention has the following advantages:
1, can use general high pure raw materials to smelt preparation Clean Steel CLAM, reduce production cost;
2, Zhi Bei CLAM composition of steel is qualified, has reached design requirements;
3, Zhi Bei CLAM steel ingot does not have composition and microstructure segregation, and the inclusion rank is low, high purity;
4, smelting operation is simple, and the process repeatability height can be realized large-scale industrial production;
5, can prepare required CLAM shaped steel as required.
Description of drawings
Fig. 1 (a) and (b) are that the CLAM steel inclusion that the present invention prepares is observed photo (980 ℃/30min cold quenching).
Embodiment
Adopt technology of the present invention, prepared qualified CLAM steel, the shared massfraction of each component is respectively: Cr:8.5~9.5%, W 1.3~1.7%, V 0.15~0.25%, and Ta 0.12~0.18%, and Mn 0.40~0.50%, C0.08~0.12%, it is as follows specifically to smelt preparation technology's flow process:
The first step: in vacuum induction furnace, furnace charge is carried out melting:
1, pure iron shove charge is put into vacuum alloy hopper with alloy raw material;
2, at first add pure metal Cr, W raw material in vacuum induction furnace, heat up and vacuumize, about 1500~1600 ℃, vacuum tightness reaches 5~10Pa to smelting temperature greatly;
3, treat to stop to vacuumize after the interior raw material partial melting of stove, feed Ar gas and protect molten clear back adding pure metal V, Ta to 0.05MPa.Alloy melting backsight molten bath situation is evacuated to the following 3-10min of maintenance of 0.1~10Pa gradually;
4, add pure C, pure metal Mn raw material, online detection alloy element component is also augmented alloying element according to test result, treat that composition leaves standstill for some time after qualified after, temperature in the time of 1450~1550 ℃, in stove, directly pour into a mould ingot casting;
Inclusion is observed and is found, has large-sized inclusions in the CLAM steel ingot casting that adopts vacuum induction melting to prepare, and interior tissue is defective, need carry out remelting refining
Second step: forge the preparation consumable electrode, 850~1150 ℃ of forging temperatures, austenitizing soaking time 45~75min, forging ratio 5~6.In the common electroslag remelting furnace of argon shield, carry out remelting refining then, prepare and smelt composition and the qualified CLAM steel of purity:
1, selects purified 70%CaF for use 2+ 30%Al 2O 3Electroslag.At first electroslag is carried out drying treatment, with the electroslag fusing, inject the iron crystallizer then;
2, feed argon shield, power-on, beginning remelting.Control burn-off rate by size of current during remelting, range of current is 300~400A;
3, in the reflow process, add an amount of aluminium powder in the electroslag.Purpose is the free oxygen of taking off in the electroslag, prevents that the oxygen in the slag bath from spreading in the molten bath, makes the ingot casting oxygen level increase;
The 3rd step, forging and rolling, prepare required CLAM shaped steel:
Forging process: forge soaking time~1h, 1100~1150 ℃ of initial forging temperatures/, final forging temperature 〉=850~900 ℃, forging ratio 6~7;
Rolling technology: 1000~1050 ℃ of annealing temperatures, soaking time~1h, 750~800 ℃ of finishing temperatures, the type of cooling are air cooling, total deformation 75~95%.
In the 4th step, final heat treating regime is: 960-1040 ℃/25-35min quenches; 740-780 ℃/80-100min tempering.
Table 1 is the CLAM steel actual measurement component list for preparing, and table 2 is inclusion rating results.
Table 1CLAM composition test result (sample state is rolling attitude)
Element ??Fe ??C ??W ??V ??Ta ??Mn
Design load ??Bal. ??0.10±0.02 ??1.5±0.2 ??0.20±0.05 ??0.15±0.02 ??0.45±0.10
Test value ??0.093 ??1.499 ??0.196 ??0.15 ??0.44
Impurity ??O ??P ??S ??Al ??Si
Design load ??<0.01 ??<0.005 ??<0.005 ??<0.01 ??<0.01
Test value ??0.0017 ??0.00299 ??0.00274 ??0.0035 ??0.002
Table 2 inclusion analysis result (rolling attitude, quench treatment)
It is simple that the present invention has smelting operation, be easy to that suitability for industrialized production, production cost are low, equipment and the strong characteristics of technique applicability, implement the CLAM steel that the present invention produces, its chemical composition satisfies the control requirement fully, and without component segregation, the field trash rank is low in the steel, high purity, the master alloying control accuracy is high, and the section bar product of making after hammer cogging and hot rolling can satisfy fusion reactor to the requirement of structural material.

Claims (4)

1. the smelting production method of a fusion reactor low activation martensitic steel is characterized in that:
The per-cent that each composition accounts for total mass is: matrix is the Fe element, Cr 8.5-9.5%, W 1.3-1.7%, V0.15-0.25%, Ta 0.12-0.18%, Mn 0.40-0.50%, C 0.08-0.12%.
The melting technology process is as follows:
The first step, in vacuum induction furnace, furnace charge is carried out melting:
1) with the FeCa alloy pure iron being taken off S handles;
2) before the melting alloying elements cr, W, V, Ta, Mn are carried out high-temperature vacuum dehydration degassing processing; Perhaps adopt antivacuum dehydration degassing processing technology: at first to Al 2O 3Powder or CaF 2Powder carries out high temperature dehydration, uses Al then 2O 3Powder or CaF 2Powder embedding alloy is with secluding air, thermal dehydration degasification under non-vacuum environment at last, Heating temperature 300-800 ℃;
3) prepare burden according to target martensitic steel design mix, the pure iron vacuum induction furnace of packing into, alloying element is by Cr, W, V, Ta, C, the Mn vacuum alloy hopper of packing in proper order;
4) after vacuum induction melting furnace is evacuated to 0.1-10Pa, fill high-purity argon gas to 0.005-0.08MPa, the fusing pure iron, and add C and take off O to 5-100ppm;
5) alloying: add pure metal Cr and W by hopper, be warming up to 1450-1650 ℃, add pure metal V, Ta successively after fusing is finished, after waiting to melt, be evacuated to the following maintenance of 0.1-10Pa 3-10 minute; Applying argon gas adds pure C and pure metal Mn to 0.005-0.08MPa then;
6) online detection alloy element component and augment alloying element according to test result treats that the qualified back of composition gets ingot casting the 1450-1550 ℃ of vacuum pouring of tapping and carry out;
Check ingot casting composition and interior tissue,, can finish melting work, otherwise need carry out the second step assisted melting if meet the demands;
In second step, ingot casting is forged with preparation remelting consumable electrode, forging temperature 800-1200 ℃, austenitizing soaking time 45-75min, forging ratio>4: 1; Remelting refining in the common electrical slag hearth of vacuum electroslag furnace or argon shield then, smelt the qualified CLAM steel ingot casting of composition and interior tissue:
1) selects high-purity Al for use 2O 3+ CaF 2Perhaps CaO+Al 2O 3+ CaF 2As electroslag;
2) electroslag is carried out drying treatment, be injected into after the fusing in the crystallizer of vacuum electroslag furnace or common electrical slag hearth; The against vacuum electroslag remelting furnace fills high-purity argon gas to 0.005-0.05MPa after being evacuated to 0.1-5Pa; For common electroslag remelting furnace, in crystallizer, fill the high-purity argon gas protection;
3) adopt size of current to control the burn-off rate of remelting consumable electrode, range of current is 200-500A;
4) after remelting finishes, take out the remelting ingot casting;
Al 2O 3+ CaF 2Consisting of of slag system: Al 2O 320-40%+CaF 2Surplus; CaO+Al 2O 3+ CaF 2Consisting of of slag system: CaO5-15%+Al 2O 320-40%+CaF 2Surplus.
2. fusion reactor structured material low activation martensitic steel smelting production method according to claim 1, it is characterized in that: hammer cogging, hot rolling prepare required section bar:
1) processing parameter during hammer cogging is: initial forging temperature 1100-1200 ℃, and soaking time 45-75min, final forging temperature 800-900 ℃, forging ratio>4: 1;
2) rolling technological parameter of resultant martensitic steel section bar is: annealing temperature and soaking time: 1000-1100 ℃/45-75min, finishing temperature 750-850 ℃, every time maximum rolling reduction is no more than 50%.
3. the smelting production method of low activation martensitic steel for fusion reactor according to claim 1, it is characterized in that: in second step, to the common electrical slag hearth, can add suitable Al powder to take off the free oxygen in the slag system to electroslag in the reflow process, prevent that the oxygen in the slag system from spreading in molten steel.
4. the smelting production method of low activation martensitic steel for fusion reactor according to claim 1 is characterized in that: elder generation before cast of ingot mold system cleaning of pure iron water and heated baking degasification during vacuum pouring, storing temperature 300-800 ℃.
CN2008100213286A 2008-07-17 2008-07-17 Smelting production method of low activation martensitic steel for fusion reactor CN101328522B (en)

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CN103128239B (en) * 2013-02-28 2014-12-24 北京科技大学 Method for preparing nanocrystalline low activation martensitic steels
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