Background technology
Pressure vessel steel purposes is extremely wide, is widely used in the industries such as oil, chemical industry, power station, boiler, is generally used for and makes reactor, heat exchanger, separator, airway, boiler-steam dome etc.12Cr2Mo1R faces hydrogen tank steel and is mainly used in hydrogenator, and it is the great key equipment of modern petroleum refining industry, its normally in High Temperature High Pressure, face hydrogen, have under the severe working conditions of the corrosive mediums such as hydrogen sulfide and move.Therefore need anti-temper embrittlement ability, the strong starting material of anti-hydrogen etch ability to make hydrogenator.
Because pressurized vessel is worked under high temperature, high pressure and hydroconversion condition, a series of the key technical indexes such as material purity, anti-embrittlement ability, internal soundness are required very harsh.Manufacture hydrogenation reaction apparatus and use the demand of large substance super thick (being greater than 100mm) steel plate also increasing, for reducing the manufacturing cost of various devices, these devices all trend towards maximizing; For improving the safe reliability of large-scale plant, require more and more stricter to the plate quality using.The mode of producing from current special heavy plate, except adopting original forging method, also has popular continuous metal cast process.But continuous casting is produced and is subject to the restriction of technical qualification cannot produce the excessive special heavy plate of thickness, the revolving furnace continuous casting slab thickness of maximum is 390mm in the world at present, due to the restriction of the inner segregation of continuous-casting converter billet and compression ratio, can only produce the special heavy plate that thickness is less than 100mm.
China Patent No. is 201010598263.9 patent documentation, disclose a kind of at high-quality molten iron, KR hot metal pretreatment, 100 tons of top and bottom combined blown converters, Argon processing, the refining of LF stove, die casting cast, walking beam furnace, 3800mm milling train, ACC laminar flow is cooling, 11 roller thermal straightening machines, cooling in heap, modified, finishing, outer inspection, flaw detection, under the process sequence of warehouse-in, produce large thickness Cr-Mo system 12 Cr 2 Mo 1 R container steel and production method thereof, its chemical composition and mass percent (%) C:0.10~0.14, Si:0.20~0.50, Mn:0.30~0.60, P :≤0.018, S :≤0.010, Cr:2.0~2.50, Ni :≤0.20, Mo:0.90~1.10, Als :≤0.040.But in this patent, utilized the mode of converter smelting+die casting cast to make steel, although guaranteed that large substance steel plate has enough draught and the raw material of becoming a useful person, cannot guarantee high purity, and die casting cast lumber recovery has been lower, operating environment is poor.The chemical composition of the steel simultaneously providing in this patent example cannot meet faces hydrogen steel temper embrittlement sensitivity coefficient (J coefficient) index, therefore cannot use as facing hydrogen steel.
Summary of the invention
The problem to be solved in the present invention is to face hydrogen steel temper embrittlement sensitivity coefficient (J coefficient) height, the cleaning of steel is poor, the lower problem of die casting cast lumber recovery, a kind of temper embrittlement sensitivity coefficient J=(Si+ Mn) (P+ Sn) × 10000≤100J is provided, the cleanliness factor of molten steel is higher, metal structure and chemical composition are even, steel plate thickness be greater than 100 millimeters face hydrogen tank steel and production method thereof.
Realize the measure of above-mentioned purpose:
A kind of thickness >=100 millimeter face hydrogen tank steel, its component and weight percent content are: C:0.08~0.12%, Si:0.05~0.12%, Mn:0.30~0.45%, P :≤0.012%, S :≤0.010%, Cr:2.10~2.25%, Ni :≤0.18%, Mo:0.95~1.10%, Cu :≤0.12%, Sn :≤0.005%, As :≤0.004%, Sb :≤0.003%, N :≤0.008%, O≤0.003%, all the other are Fe and inevitable impurity; And should meet temper embrittlement sensitivity coefficient J=(Si+ Mn) (P+ Sn) × 10000≤80.
Produce the method for facing hydrogen tank steel of a kind of thickness >=100 millimeter, its step:
1) carry out electrosmelting, control tapping temperature at 1620~1640 ℃;
2) by molten steel preheating 3~5 minutes;
3) carry out the processing of LF stove: add quickened lime according to 45~70Kg/ ton steel, add silico-calcium or ferrosilicon powder according to 0.03~0.05Kg/ ton steel, add AD15 reductor according to 0.015~0.025Kg/ ton steel;
4) skim, the weight percent content of controlling Si in molten steel exists: 0.05~0.15%;
5) in VD vacuum oven, carry out vacuum-treat and Argon, according within 80~100ml/ minute, being blown into argon gas; Control vacuum tightness and be no more than 67Pa, and carry out the pressurize of at least 25 minutes, vacuum processing time is no less than 25 minutes and stops blowing argon gas simultaneously;
6) according to 2.7~3.0 meters of/ton of disposable feeding Si-Ca of steel lines;
7) carry out Argon again, be blown into according to 80~100ml/ minute, argon blowing time is not less than 8 minutes;
8) carry out continuous casting, control casting speed at 1.6~1.7 ms/min, and control slab thickness and be no less than 150 millimeters;
9) heap is chilled to room temperature;
10) adopt low frequency bipolar series plate blank electroslag furnace to carry out electric slag refusion and smelting stripping:
A) will splice and pack electroslag furnace into by the strand of electrosmelting, and form consumable utmost point loop; And pre-melted slag is packed in the crystallizer of electroslag furnace according to 20~30Kg/ ton steel;
B) carry out stripping simultaneously adopt protective guard to carry out slow cooling: in the time that the liquid steel level height in electroslag furnace reaches 70 millimeters of 60~<, stripping speed control is in 3.5~<, 4.5 mm/min; In the time that the liquid steel level height in electroslag furnace reaches 80 millimeters of 70~<, stripping speed control is in 4.5~<, 6.5 mm/min; When the liquid steel level height in electroslag furnace reach 80 millimeters and above after, stripping speed control is in 6.5~8.5 mm/min;
C) when stripping speed control is during in 7.5~8.5 mm/min, carry out remelting, and added aluminum shot until remelting finishes according to 32~36g/ minute;
D) carry out feeding, in the time that consumable electrode is melted to 300~350 millimeters of length residues, carry out feeding, and the now stripping speed of controlling in 6.5~7.5 mm/min until remelting finishes to become strand, and continue slow cooling;
In remelting, control A, B, C and D total inclusion content≤1.5 grade in molten steel, O≤0.003%, N≤0.007%;
11) carry out mould cold, mould cool time is 2~2.5 hours;
12) strand is inserted to burial pit and carry out coolingly, the time is no less than 48 hours;
13) to strand heating, control soaking temperature at 1200~1260 ℃, control heating rate at 11~13 minutes/centimetre, final heating and temperature control is at 1180~1230 ℃;
14) carry out segmentation rolling: control the start rolling temperature of roughing section at 1070~1130 ℃, the start rolling temperature of finish rolling section is at 890~910 ℃, finishing temperature is at 860~880 ℃, and finish rolling open rolling thickness is at 220~240 millimeters, and finish rolling end three passage total reductions are not less than 30%;
15) carry out air cooling, air cooling to 680~720 ℃;
16) adopt normalizing+tempering heat treatment, control normalizing temperature at 910~930 ℃, the normalizing time was at 150~200 minutes; Tempering temperature is at 690~710 ℃, and tempering time was at 160~240 minutes;
17) stand-by.
The effect of each component and main technique and the reason of control in the present invention:
C:C is one of element of the indispensable raising steel strength of steel grade, and every increase by 0.10% tensile strength of carbon content approximately improves 60MPa, and yield strength approximately improves 20~30MPa.Along with the increase of carbon content, steel grade Fe3C increases, and hardenability also increases, and the tensile strength of steel and yield strength can improve, and plasticity and toughness index can decline, welding property variation.And this steel grade is applicable to the equipment such as hydrogenator, not only requires certain intensity, and mainly need excellent toughness index and welding property.So regulation C content is on the low side, under be limited to 0.05%, be above limited to 0.12%.Within the scope of this, not only guarantee the intensity of steel and be applicable to production operation, with the use properties that has guaranteed this steel grade.
Si:Si mainly improves steel strength with solution strengthening form, is also the deoxidant element of steel grade.If but Si content is higher in steel, can cause that reduction of area declines, particularly impact toughness decreased is obvious, simultaneously also unfavorable to the weldability of steel, and this steel grade is mainly used to make the equipment such as hydrogenator, Si height is also unfavorable for anti-hydrogen-type corrosion, therefore Si content is chosen in to 0.05%~0.15%.
Mn: guaranteeing that aspect the intensity and toughness of steel, Mn is indispensable element.And low manganese is favourable for the toughness of steel grade weld metal, therefore the content of Mn is chosen in to 0.30~0.60%.
P, S: control P≤0.012%, S≤.010%, this is owing to only having smelting Clean Steel, the over-all properties of guarantee steel of the present invention.
Cr: the content of Cr is chosen in to 2.10~2.50%, is because Cr can improve steel plate hardening capacity, and ferritic phase apparition is moved to right, and widens the cooling rate interval of bainitic transformation, promotes the formation of middle temperature transformation tissue, improves steel plate yield strength.
Ni:Ni has strengthening effect, adds 1% Ni can improve steel strength 20MPa.Ni can also improve the toughness, particularly low-temperature flexibility of steel significantly.Steel grade adds Ni, is that base material or simulation welded heat affecting zone have all been improved low-temperature flexibility significantly. but when too high levels, except increasing production cost, also cause steel-plate iron oxide scale to be difficult to come off, therefore the upper limit be controlled at≤0.20%.
The content of Mo:Mo is chosen in 0.95~1.10%, is because Mo can improve steel plate hardening capacity, and ferritic phase apparition is moved to right, and widens the cooling rate interval of bainitic transformation, promotes the formation of middle temperature transformation tissue, improves steel plate yield strength.
Cu:Cu content is controlled at≤and 0.18%, be because Cu is austenite former, in expanding austenite phase region, also in drawing process, promote austenitic formation and stabilization.The low-temperature flexibility that Ni improves steel simultaneously also improves the intensity of steel, but in the time of Ni too high levels, can make the hardening capacity of steel plate and hardenability increase, and makes steel plate HAZ toughness drop, worsens the welding property of steel plate.The existence of a small amount of Cu can obviously improve the corrosion potential of steel, thereby improves the corrosion resistance nature of steel.Simultaneously in the time that the content of Cu acquires a certain degree, but the precipitate of ε-Cu can improve the intensity of steel plate. and the content of Cu higher than 0.18% time, can cause the hot-short phenomenon of steel, worsens plate surface quality.
Sn:Sn, As and Sb element are harmful element for this invention, and these three kinds of elements are very large for the temper brittleness impact of steel grade of the present invention, therefore carried out ceiling restriction for these three kinds of elements.
N :≤0.008%, steel grade N element is larger for the Toughness of steel plate, has therefore done the restriction of the upper limit.
The present invention is compared with existing converter technology, the steel of producing has that purity is high, sulphur content is low, non-metallic inclusion is few, surface of steel ingot is smooth, crystallization even compact, metal structure and chemical composition evenly, the steel plate thickness produced can be at 100~150 millimeters, can also meet market completely to facing the mechanical property requirements of hydrogen tank steel.
Embodiment
Below the present invention is described in detail:
Table 1 is the value list of various embodiments of the present invention and comparative example;
Table 2 is the main technologic parameters list of various embodiments of the present invention and comparative example;
Table 3 is various embodiments of the present invention and the list of comparative example Performance Detection situation;
Table 4 is various embodiments of the present invention and comparative example drawing by high temperature mechanical properties test result.
Various embodiments of the present invention are produced according to following steps:
Its step:
1) carry out electrosmelting, control tapping temperature at 1620~1640 ℃;
2) by molten steel preheating 3~5 minutes;
3) carry out the processing of LF stove: add quickened lime according to 45~70Kg/ ton steel, add silico-calcium or ferrosilicon powder according to 0.03~0.05Kg/ ton steel, add AD15 reductor according to 0.015~0.025Kg/ ton steel;
4) skim, the weight percent content of controlling Si in molten steel exists: 0.05~0.15%;
5) in VD vacuum oven, carry out vacuum-treat and Argon, according within 80~100ml/ minute, being blown into argon gas; Control vacuum tightness and be no more than 67Pa, and carry out the pressurize of at least 25 minutes, vacuum processing time is no less than 25 minutes and stops blowing argon gas simultaneously;
6) according to 2.7~3.0 meters of/ton of disposable feeding Si-Ca of steel lines;
7) carry out Argon again, be blown into according to 80~100ml/ minute, argon blowing time is not less than 8 minutes;
8) carry out continuous casting, control casting speed at 1.6~1.7 ms/min, and control slab thickness and be no less than 150 millimeters;
9) heap is chilled to room temperature;
10) adopt low frequency bipolar series plate blank electroslag furnace to carry out electric slag refusion and smelting stripping:
A) will splice and pack electroslag furnace into by the strand of electrosmelting, and form consumable utmost point loop; And pre-melted slag is packed in the crystallizer of electroslag furnace according to 20~30Kg/ ton steel;
B) carry out stripping simultaneously adopt protective guard to carry out slow cooling: in the time that the liquid steel level height in electroslag furnace reaches 70 millimeters of 60~<, stripping speed control is in 3.5~<, 4.5 mm/min; In the time that the liquid steel level height in electroslag furnace reaches 80 millimeters of 70~<, stripping speed control is in 4.5~<, 6.5 mm/min; When the liquid steel level height in electroslag furnace reach 80 millimeters and above after, stripping speed control is in 6.5~8.5 mm/min;
C) when stripping speed control is during in 7.5~8.5 mm/min, carry out remelting, and added aluminum shot until remelting finishes according to 32~36g/ minute;
D) carry out feeding, in the time that consumable electrode is melted to 300~350 millimeters of length residues, carry out feeding, and the now stripping speed of controlling in 6.5~7.5 mm/min until remelting finishes to become strand, and continue slow cooling;
In remelting, control A, B, C and D total inclusion content≤1.5 grade in molten steel, O≤0.003%, N≤0.007%;
11) carry out mould cold, mould cool time is 2~2.5 hours;
12) strand is inserted to burial pit and carry out coolingly, the time is no less than 48 hours;
13) to strand heating, control soaking temperature at 1200~1260 ℃, control heating rate at 11~13 minutes/centimetre, final heating and temperature control is at 1180~1230 ℃;
14) carry out segmentation rolling: control the start rolling temperature of roughing section at 1070~1130 ℃, the start rolling temperature of finish rolling section is at 890~910 ℃, finishing temperature is at 860~880 ℃, and finish rolling open rolling thickness is at 220~240 millimeters, and finish rolling end three passage total reductions are not less than 30%;
15) carry out air cooling, air cooling to 680~720 ℃;
16) adopt normalizing+tempering heat treatment, control normalizing temperature at 910~930 ℃, the normalizing time was at 150~200 minutes; Tempering temperature is at 690~710 ℃, and tempering time was at 160~240 minutes;
17) stand-by.
The component value list (one) of table 1 various embodiments of the present invention and comparative example
The component value list (two) of table 1 various embodiments of the present invention and comparative example
The main technologic parameters list (one) of table 2 various embodiments of the present invention and comparative example
The main technologic parameters list (two) of table 2 various embodiments of the present invention and comparative example
The main technologic parameters list (three) of table 2 various embodiments of the present invention and comparative example
The main technologic parameters list (four) of table 2 various embodiments of the present invention and comparative example
The main technologic parameters list (five) of table 2 various embodiments of the present invention and comparative example
Table 3 is various embodiments of the present invention and comparative example mechanical properties test the results list
table 4drawing by high temperature mechanical properties test the results list of various embodiments of the present invention and comparative example
Note: comparative example 1 and 2 is for adopting the situation of converter smelting.
As everyone knows, steel plate thickness is larger, and mechanical property is more difficult to guarantee.But can find out from table 3 and table 4, comparative example 1 and 2 is compared with the present invention, although mechanical property is more or less the same, thickness differs widely, the thicklyest reach 150 millimeters.This is explanation just, and the present invention is guaranteeing that mechanical property meets under the prerequisite of the new market requirement, has met again user's needs steel plate thickness and has been greater than 100 millimeters of above new demands.