CN103160734B - A kind of pressurized vessel P460NL1 (L2) super-thick steel plate and production method thereof - Google Patents

Abstract

The invention discloses a kind of pressurized vessel P460NL1(L2) super-thick steel plate, it is characterized in that: the chemical composition (unit comprising following mass percent, wt%): C:0.09 ~ 0.17, Si:0.55 ~ 0.85, Mn:1.30 ~ 1.70, P :≤0.010, S :≤0.003, micro alloying element (V+Nb+Ti+Cr+Ni) :≤2.0, Als:0.020 ~ 0.050, other is Fe and relict element, wherein, described pressurized vessel P460NL1(L2) super-thick steel plate contains ferritic bainite-martensite structure up to 5%.The present invention is by rational chemical composition design, LF+VD refinery practice ensures steel cleanliness factor, cross the techniques such as heating, rolling and normalizing treatment effectively to implement simultaneously, successfully have developed thickness to be 250mm guaranteed cost, to protect flaw detection pressurized vessel P460NL1(L2) super-thick steel plate, its yield strength controls at 420 ~ 500MPa, and tensile strength controls at 560 ~ 700 MPa; Elongation controls at 17%-25%; V-type-50 DEG C of transverse impact power controls are built in 100 ~ 200J.

Description

A kind of pressurized vessel P460NL1 (L2) super-thick steel plate and production method thereof

Technical field

The present invention relates to field of steel material production, particularly relate to a kind of pressurized vessel P460NL1(L2) super-thick steel plate and production method thereof.

Background technology

P460NL1(L2) belong to normalizing in Europe superscript EN10028 and can weld fine grained steel, it has that intensity is high, good toughness, excellent in low temperature toughness, the feature such as wear-resisting, corrosion-resistant, mainly be widely used industries such as being applied to oil, chemical industry, power station, boiler, specifically for making equipment and the components such as reactor, interchanger, separator, spherical tank, oil gas tank, liquefied petroleum gas tank, nuclear power reactor pressure vessel, boiler-steam dome.But in recent years, P460NL1(L2) range of application expansion, demand constantly increases, due to P460NL1(L2) not only require higher intensity, and require good low-temperature impact toughness, therefore, production process is complicated, and cost is relatively high.

Publication number disclosed in 17 days October in 2012 of Chinese patent to be 102732782A application number be 201210182417.5 patent of invention name be called a kind of steel plate for heavy-gauge pressure vessel, it is characterized in that: the component contained containing following weight percent: C:0.15%-0.18%, Si:0.25%-0.50%, Mn:1.50%-1.60%, P≤0.020%, S≤0.012%, Nb:0.030%-0.050%, Al:0.020%-0.050%, its technique comprises the following steps: 1) smelt: will containing following weight percent C: 0.15%-0.18%, Si: 0.25%-0.50%, Mn: 1.50%-1.60%, P≤0.020%, S≤0.012%, Nb: 0.030%-0.050%, the molten steel of Al: 0.020%-0.050% component is first through electrosmelting, send into the refining of LF refining furnace, liquid steel temperature meets or exceeds 1550-1570 DEG C and proceeds to VD stove Fruit storage, 2) continuous casting: adopt 300mm blank, 3) heat: billet heating temperature is the highest 1240 DEG C, soaking temperature 1220 DEG C, total heat-up time >=6h, 4) rolling: adopt recrystallization zone+Unhydrated cement two-phase control rolling technique to be rolled, first stage rolling temperature is 1050 DEG C ~ 1100 DEG C, subordinate phase rolling temperature 810 DEG C-860 DEG C, and finishing temperature is 750 DEG C-800 DEG C, ACC water-cooled is entered, red temperature 650 DEG C-700 DEG C after rolling, 5) thermal reactor buttress: the steel plate stacking temperature that rolls off the production line is not less than 350 DEG C, and stacking is torn open after 24 hours and stamped flaw detection, 6) thermal treatment: qualified steel plate of detecting a flaw carries out normalizing thermal treatment at normalizing furnace, and normalizing process is: Heating temperature 900-920 DEG C, soaking time 1.8min/mm, water-cooled accelerating cooling after coming out of the stove, steel plate red temperature 550 DEG C-650 DEG C.But this technique is relatively complicated, and yield strength is at more than 410MPa, and tensile strength can only at about 560MPa, and performance is relatively low.

Summary of the invention

The object of the invention is to overcome prior art deficiency, provide that a kind of part convenient for production, chemical is reasonable in design, guaranteed cost, guarantor's flaw detection pressurized vessel P460NL1(L2) super-thick steel plate and production method thereof.

A kind of pressurized vessel P460NL1(L2) super-thick steel plate, comprise the chemical composition (unit of following mass percent, wt%): C:0.09 ~ 0.17, Si:0.55 ~ 0.85, Mn:1.30 ~ 1.70, P :≤0.010, S :≤0.003, micro alloying element (V+Nb+Ti+Cr+Ni) :≤2.0, Als:0.020 ~ 0.050, other is Fe and relict element, wherein, described pressurized vessel P460NL1(L2) super-thick steel plate contains ferritic bainite-martensite structure up to 5%.

Described pressurized vessel P460NL1(L2) carbon equivalent≤0.53 of super-thick steel plate.

The function analysis of above-mentioned chemical element is as follows:

C: be most basic strengthening element in steel, improves intensity, but C affect the welding property of steel and affect toughness, considers, and the content of carbon is tried one's best the lower of control.

Si: be solution strengthening element, favourable to the intensity improving steel plate.

Mn: be solution strengthening element, all favourable to the intensity and toughness improving steel plate.

P: unfavorable to welding, and there is certain cold shortness, in this steel grade, belong to harmful element, what should control is as far as possible low.

S: easily form MnS type impurity, have certain red brittleness, belong to harmful element in this steel grade, what should control is as far as possible low.

V, Nb, Ti: can be combined with C, N in steel, form fine carbide or carbonitride, can play crystal grain thinning and dispersion-strengthened action, thus reach the net effect of the obdurability effectively improving steel.

Ni: the intensity both strongly having improved steel on the one hand, the level that another aspect makes again the toughness of iron keep high all the time, its temperature that becomes fragile is then extremely low, the lattice parameter of Ni is close with γ-iron, so can become continuous solid solution, this is just conducive to the hardenability improving steel, and Ni can reduce stagnation point and increase austenitic stability, so its quenching temperature can reduce, hardening capacity is good.

Al: grain refining intensificatiom effect can be played.

A kind of pressurized vessel P460NL1(L2) production method of super-thick steel plate, comprise following production stage:

A.KR hot metal pretreatment technology: ensure liquid level thickness of slag layer≤20mm, molten iron ensures molten iron (by mass percentage) S≤0.005% after KR stirring desulphurization, ensure desulfurization cycle≤21min, desulfurization temperature drop≤20 DEG C;

B. converter smelting process: enter stove molten iron (by mass percentage) S≤0.005%, P≤0.050%, molten iron temperature >=1270 DEG C, slag making basicity R presses 2.5-4.0 and controls, tapping carbon >=0.05%, tapping P≤0.010%, S≤0.010%; Point blows number of times and must not be greater than 2 times, avoids tapping process slag;

C.LF refinery practice: take the large quantity of slag to carry out slag making, guarantee white slag hold-time >=15min;

D.VD refinery practice: VD vacuum tightness must reach below 67Pa, the dwell time is necessary >=15min, soft blow 2-5min or do not blow after vacuum breaker, and in soft blow process, molten steel must not be exposed, upper steel temperature 1570 ± 15 DEG C;

E. die casting process: ingot mould temperature≤120 DEG C before using of reaching the standard grade, during cast, the feed trumpet distance controlling with collector nozzle of ladle suitable for reading is at≤140mm, before cast, the mode that ingot casting powder half takes straw rope to hang hangs in ingot mould, hanging height is higher than 300 ~ 400mm bottom ingot mould, second half open water after add in 1 ~ 4min, the body casting time presses 14-18min and controls, cap mouth pouring time is pressed 5-7min and is controlled, when being cast to cap mouth 1/3 position, add heat preserving agent insulation, after steel ingot casting, about 8h carries out the demoulding;

F. heating process: stewing steel temperature 550-600 DEG C, time 2h, heat-up rate 80 DEG C/S, insulation 7h, heat-up rate 100 DEG C/S when temperature rises to 750 DEG C, when temperature rises to 1000 DEG C, heat-up rate is not limit, temperature is incubated 17h when rising to 1280 DEG C, and temperature is tapped 1260 DEG C time;

G. rolling technology: one-phase start rolling temperature 1100 DEG C ~ 1150 DEG C, two-stage start rolling temperature≤920 DEG C, reduction in pass >=20mm, finishing temperature 820 ~ 860 DEG C;

H. cooling control technology: red temperature between 600 ~ 650 DEG C, speed of cooling 10 ~ 20 DEG C/S;

I. cooling in heap technique: roll off the production line after steel plates straightening cooling in heap in time, cooling in heap temperature >=300 DEG C, heap cool time >=36h;

J. thermal treatment process: machine stove carries out normalizing treatment outside, temperature is 910 ± 20 DEG C, soaking time 2.0-2.5min/mm, steel plate come out of the stove after water-cooled 100s.

The present invention is by rational chemical composition design, LF+VD refinery practice ensures steel cleanliness factor, cross the techniques such as heating, rolling and normalizing treatment effectively to implement simultaneously, successfully have developed thickness to be 250mm guaranteed cost, to protect flaw detection pressurized vessel P460NL1(L2) super-thick steel plate, its yield strength controls at 420 ~ 500MPa, and tensile strength controls at 560 ~ 700 MPa; Elongation controls at 17%-25%; V-type-50 DEG C of transverse impact power controls are built in 100 ~ 200J.

Embodiment

Pressurized vessel P460NL1(L2 of the present invention) super-thick steel plate, the mass percent of its chemical composition and each composition: C:0.09 ~ 0.17, Si:0.55 ~ 0.85, Mn:1.30 ~ 1.70, P :≤0.010, S :≤0.003, micro alloying element (V+Nb+Ti+Cr+Ni) :≤2.0, Als:0.020 ~ 0.050, other is Fe and relict element, wherein, described pressurized vessel P460NL1(L2) super-thick steel plate contains ferritic bainite-martensite structure up to 5%.

Pressurized vessel P460NL1(L2 of the present invention) preparation technology of super-thick steel plate comprises the following steps:

A.KR hot metal pretreatment technology: the molten iron that arrives at a station must be taken off front slag and take off rear slag, ensure liquid level thickness of slag layer≤20mm, molten iron ensures molten iron (by mass percentage) S≤0.005% after KR stirring desulphurization, ensure desulfurization cycle≤21min, desulfurization temperature drop≤20 DEG C.

B. converter smelting process: enter stove molten iron (by mass percentage) S≤0.005%, P≤0.050%, molten iron temperature >=1270 DEG C, molten iron Intake Quantity error controls by ± 1t, steel scrap strictly adopts high-quality scrap stock, slag making basicity R presses 2.5-4.0 and controls, tapping carbon >=0.05%, tapping P≤0.010%, S≤0.010%; Point blows number of times and must not be greater than 2 times, avoids tapping process slag;

C.LF refinery practice: omnidistance Argon in refining process, Argon intensity needs to regulate according to different link.Add refining slag, take the large quantity of slag to carry out slag making, guarantee white slag hold-time >=15min, add silicon-calcium wire before leaving from station;

D.VD refinery practice: VD vacuum tightness must reach below 67Pa, the dwell time is necessary >=15min, and soft blow 2-5min or do not blow after vacuum breaker, in soft blow process, molten steel must not be exposed.Normally wrap the pumpdown time online: (vacuumizing front liquid steel temperature-target temperature leaving from station)/1.7min.Insulating covering agent, ensures to be paved with molten steel face, must close argon gas, upper steel temperature 1570 ± 15 DEG C before adding insulating covering agent;

E. die casting process: ingot mould temperature≤120 DEG C before using of reaching the standard grade; during cast, the feed trumpet distance controlling with collector nozzle of ladle suitable for reading is at≤140mm; before cast; the mode that ingot casting powder half takes straw rope to hang hangs in ingot mould; hanging height is higher than 300 ~ 400mm bottom ingot mould; second half open water after add in 1 ~ 4min; the body casting time presses 14-18min and controls; cap mouth pouring time is pressed 5-7min and is controlled; when being cast to cap mouth 1/3 position, add heat preserving agent insulation (heat preserving agent uniform fold is paved).After steel ingot casting, about 8h carries out the demoulding;

F. heating process: Heating temperature and heat-up time: stewing steel temperature 550-600 DEG C, time 2h, heat-up rate 80 DEG C/S, 7h is incubated when temperature rises to 750 DEG C, heat-up rate 100 DEG C/S, when temperature rises to 1000 DEG C, heat-up rate is not limit, insulation 17h when temperature rises to 1280 DEG C, and temperature is tapped 1260 DEG C time;

G. rolling technology: combine steel-making chemical composition, for preventing mixed crystal and coarse grains, one-phase is taked " high temperature, low speed, depress greatly ", start rolling temperature 1100 DEG C ~ 1150 DEG C, the steel thickness that dries in the air is greater than 180mm, for the finish rolling stage add up deflection and crystal grain thinning, dislocations strengthening lays the foundation.Two-stage start rolling temperature≤920 DEG C, reduction in pass >=20mm, finishing temperature 820 ~ 860 DEG C;

H. cooling control technology: in order to ensure steel plate internal grain degree, by adjustment cooling manifold group number after rolling, red temperature is between 600 ~ 650 DEG C, and speed of cooling 10 ~ 20 DEG C/S, is then sent to straightener aligning;

I. cooling in heap technique: roll off the production line after steel plates straightening cooling in heap in time, cooling in heap temperature >=300 DEG C, heap cool time >=36h.By slow cooling, have little time release to avoid internal stress and produce implosion, impel the inner obnoxious flavour of steel plate to overflow simultaneously further.

J. thermal treatment process: machine stove carries out normalizing treatment outside, temperature is 910 ± 20 DEG C, soaking time 2.0-2.5min/mm, steel plate come out of the stove after water-cooled 100s.

Embodiment one

The present embodiment pressurized vessel P460NL1(L2) super-thick steel plate, the mass percent of its chemical composition and each composition is: C:0.09, Si:0.55, Mn:1.30, P:0.010, S:0.003, micro alloying element (V+Nb+Ti+Cr+Ni) :≤2.0, Als:0.020 ~ 0.050, other is Fe and relict element, wherein, described pressurized vessel P460NL1(L2) super-thick steel plate contains ferritic bainite-martensite structure up to 5%.

This super-thick steel plate is preparation technology comprise the following steps:

A.KR hot metal pretreatment technology: the molten iron that arrives at a station must be taken off front slag and take off rear slag, ensure that liquid level thickness of slag layer is 20mm, molten iron ensures that after KR stirring desulphurization molten iron (by mass percentage) is 0.005% containing S, ensure the desulfurization cycle be 21min, desulfurization temperature drop is 20 DEG C.

B. converter smelting process: it is 0.005% that the percent mass entering stove molten iron S is made a gesture of measuring, the percent mass of P is made a gesture of measuring is 0.050%, molten iron temperature is 1270 DEG C, molten iron Intake Quantity error controls by ± 1t, steel scrap strictly adopts high-quality scrap stock, slag making basicity R controls by 2.5, to make a gesture of measuring be 0.05% to the percent mass of tapping carbon, and it be that the percent mass of 0.010%, S makes a gesture of measuring is 0.010% that the percent mass of tapping P is made a gesture of measuring; Point blows number of times and must not be greater than 2 times, avoids tapping process slag;

C.LF refinery practice: omnidistance Argon in refining process, Argon intensity needs to regulate according to different link.Add refining slag, take the large quantity of slag to carry out slag making, guarantee that the white slag hold-time is 15min, before leaving from station, add silicon-calcium wire;

D.VD refinery practice: VD vacuum tightness must reach below 67Pa, the dwell time is necessary >=15min, and soft blow 2-5min or do not blow after vacuum breaker, in soft blow process, molten steel must not be exposed.Normally wrap the pumpdown time online: (vacuumizing front liquid steel temperature-target temperature leaving from station)/1.7min.Insulating covering agent, ensures to be paved with molten steel face, must close argon gas, upper steel temperature 1570 ± 15 DEG C before adding insulating covering agent.

E. die casting process: ingot mould temperature≤120 DEG C before using of reaching the standard grade; during cast, the feed trumpet distance controlling with collector nozzle of ladle suitable for reading is at≤140mm; before cast; the mode that ingot casting powder half takes straw rope to hang hangs in ingot mould; hanging height is higher than 300 ~ 400mm bottom ingot mould; second half open water after add in 1 ~ 4min; the body casting time presses 14-18min and controls; cap mouth pouring time is pressed 5-7min and is controlled; when being cast to cap mouth 1/3 position, add heat preserving agent insulation (heat preserving agent uniform fold is paved).After steel ingot casting, about 8h carries out the demoulding;

F. heating process: Heating temperature and heat-up time: stewing steel temperature 550-600 DEG C, time 2h, heat-up rate 80 DEG C/S, 7h is incubated when temperature rises to 750 DEG C, heat-up rate 100 DEG C/S, when temperature rises to 1000 DEG C, heat-up rate is not limit, insulation 17h when temperature rises to 1280 DEG C, and temperature is tapped 1260 DEG C time;

G. rolling technology: combine steel-making chemical composition, for preventing mixed crystal and coarse grains, one-phase is taked " high temperature, low speed, depress greatly ", start rolling temperature 1100 DEG C, the steel thickness that dries in the air is greater than 180mm, for the finish rolling stage add up deflection and crystal grain thinning, dislocations strengthening lays the foundation.Two-stage start rolling temperature is 920 DEG C, reduction in pass >=20mm, finishing temperature 820 DEG C;

H. cooling control technology: in order to ensure steel plate internal grain degree, by adjustment cooling manifold group number after rolling, red temperature is between 600 ~ 650 DEG C, and speed of cooling 10 DEG C/S, is then sent to straightener aligning;

I. cooling in heap technique: roll off the production line after steel plates straightening cooling in heap in time, and cooling in heap temperature is 300 DEG C, and heap cool time is 36h.By slow cooling, have little time release to avoid internal stress and produce implosion, impel the inner obnoxious flavour of steel plate to overflow simultaneously further.

J. thermal treatment process: machine stove carries out normalizing treatment outside, temperature is 910 ± 20 DEG C, and soaking time is 2.0min/mm, steel plate come out of the stove after water-cooled 100s.

Embodiment two

The present embodiment pressurized vessel P460NL1(L2) super-thick steel plate, the mass percent of its chemical composition and each composition is: C:0.11, Si:0.70, Mn:1.4, P:0.009, S:0.0025, micro alloying element (V+Nb+Ti+Cr+Ni) :≤2.0, Als:0.020 ~ 0.050, other is Fe and relict element, wherein, described pressurized vessel P460NL1(L2) super-thick steel plate contains ferritic bainite-martensite structure up to 5%.

This super-thick steel plate preparation technology is substantially identical with embodiment one, its difference is only: in KR hot metal pretreatment technology step: ensure that liquid level thickness of slag layer is 18mm, it is 0.004% that the percent mass of molten iron molten iron S after KR stirring desulphurization is made a gesture of measuring, and the desulfurization cycle is 19min, desulfurization temperature drop is 18 DEG C.

In converter smelting process step: it is 0.004% that the percent mass entering stove molten iron S is made a gesture of measuring, the percent mass of P is made a gesture of measuring is 0.040%, molten iron temperature is 1320 DEG C, slag making basicity R is 2.8, it is 0.06% that the percent mass of tapping carbon is made a gesture of measuring, it be that the percent mass of 0.009%, S makes a gesture of measuring is 0.009% that the percent mass of tapping P is made a gesture of measuring;

In LF refinery practice step: the white slag hold-time is 16min;

In rolling technology step: start rolling temperature is 1110 DEG C, two-stage start rolling temperature is 890 DEG C, and finishing temperature is 830 DEG C;

In cooling control technology step: speed of cooling is 13 DEG C/S;

In cooling in heap processing step: cooling in heap temperature is 325 DEG C, heap cool time is 38h.

In thermal treatment process step: soaking time is 2.2min/mm.

Embodiment three

The present embodiment pressurized vessel P460NL1(L2) super-thick steel plate, the mass percent of its chemical composition and each composition is: C:0.13, Si:0.80, Mn:1.45, P:0.008, S:0.002, micro alloying element (V+Nb+Ti+Cr+Ni) :≤2.0, Als:0.020 ~ 0.050, other is Fe and relict element, wherein, described pressurized vessel P460NL1(L2) super-thick steel plate contains ferritic bainite-martensite structure up to 5%.

This super-thick steel plate preparation technology is substantially identical with embodiment one, its difference is only: in KR hot metal pretreatment technology step: ensure that liquid level thickness of slag layer is 17mm, it is 0.003% that the percent mass of molten iron molten iron S after KR stirring desulphurization is made a gesture of measuring, and the desulfurization cycle is 18min, desulfurization temperature drop is 17 DEG C.

In converter smelting process step: it is 0.003% that the percent mass entering stove molten iron S is made a gesture of measuring, the percent mass of P is made a gesture of measuring is 0.030%, molten iron temperature is 1370 DEG C, slag making basicity R is 3.2, it is 0.07% that the percent mass of tapping carbon is made a gesture of measuring, it be that the percent mass of 0.008%, S makes a gesture of measuring is 0.008% that the percent mass of tapping P is made a gesture of measuring;

In LF refinery practice step: the white slag hold-time is 18min;

In rolling technology step: start rolling temperature is 1125 DEG C, two-stage start rolling temperature is 870 DEG C, and finishing temperature is 840 DEG C;

In cooling control technology step: speed of cooling is 15 DEG C/S;

In cooling in heap processing step: cooling in heap temperature is 350 DEG C, heap cool time is 40h.

In thermal treatment process step: soaking time is 2.3min/mm.

Embodiment four

The present embodiment pressurized vessel P460NL1(L2) super-thick steel plate, the mass percent of its chemical composition and each composition is: C:0.15, Si:0.60, Mn:1.6, P:0.007, S:0.0015, micro alloying element (V+Nb+Ti+Cr+Ni) :≤2.0, Als:0.020 ~ 0.050, other is Fe and relict element, wherein, described pressurized vessel P460NL1(L2) super-thick steel plate contains ferritic bainite-martensite structure up to 5%.

This super-thick steel plate preparation technology is substantially identical with embodiment one, its difference is only: in KR hot metal pretreatment technology step: ensure that liquid level thickness of slag layer is 16mm, it is 0.002% that the percent mass of molten iron molten iron S after KR stirring desulphurization is made a gesture of measuring, and the desulfurization cycle is 17min, desulfurization temperature drop is 16 DEG C.

In converter smelting process step: it is 0.002% that the percent mass entering stove molten iron S is made a gesture of measuring, the percent mass of P is made a gesture of measuring is 0.020%, molten iron temperature is 1420 DEG C, slag making basicity R is 3.3, it is 0.08% that the percent mass of tapping carbon is made a gesture of measuring, it be that the percent mass of 0.007%, S makes a gesture of measuring is 0.007% that the percent mass of tapping P is made a gesture of measuring;

In LF refinery practice step: the white slag hold-time is 19min;

In rolling technology step: start rolling temperature is 1140 DEG C, two-stage start rolling temperature is 840 DEG C, and finishing temperature is 850 DEG C;

In cooling control technology step: speed of cooling is 18 DEG C/S;

In cooling in heap processing step: cooling in heap temperature is 375 DEG C, heap cool time is 42h.

In thermal treatment process step: soaking time is 2.4min/mm.

Embodiment five

The present embodiment pressurized vessel P460NL1(L2) super-thick steel plate, the mass percent of its chemical composition and each composition is: C:0.17, Si:0.85, Mn:1.70, P:0.006, S:0.001, micro alloying element (V+Nb+Ti+Cr+Ni) :≤2.0, Als:0.020 ~ 0.050, other is Fe and relict element, wherein, described pressurized vessel P460NL1(L2) super-thick steel plate contains ferritic bainite-martensite structure up to 5%.

This super-thick steel plate preparation technology is substantially identical with embodiment one, its difference is only: in KR hot metal pretreatment technology step: ensure that liquid level thickness of slag layer is 15mm, it is 0.001% that the percent mass of molten iron molten iron S after KR stirring desulphurization is made a gesture of measuring, and the desulfurization cycle is 15min, desulfurization temperature drop is 15 DEG C.

In converter smelting process step: it is 0.001% that the percent mass entering stove molten iron S is made a gesture of measuring, the percent mass of P is made a gesture of measuring is 0.010%, molten iron temperature is 1470 DEG C, slag making basicity R is 4.0, it is 0.09% that the percent mass of tapping carbon is made a gesture of measuring, it be that the percent mass of 0.006%, S makes a gesture of measuring is 0.006% that the percent mass of tapping P is made a gesture of measuring;

In LF refinery practice step: the white slag hold-time is 21min;

In rolling technology step: start rolling temperature is 1150 DEG C, two-stage start rolling temperature is 820 DEG C, and finishing temperature is 860 DEG C;

In cooling control technology step: speed of cooling is 20 DEG C/S;

In cooling in heap processing step: cooling in heap temperature is 400 DEG C, heap cool time is 44h.

In thermal treatment process step: soaking time is 2.5min/mm.

, rolling technology, cooling control technology, cooling in heap technique, thermal treatment process cold by KR hot metal pretreatment technology, converter smelting process, LF refinery practice, VD refinery practice, die casting process, heating process, control control, obtain the pressurized vessel P460NL1(L2 of described chemical composition) super-thick steel plate, following table is the pressurized vessel P460NL1(L2 according to above-described embodiment gained) super-thick steel plate mechanical property table.

The P460NL1(L2 of this trial production 250mm) property indices all reaches standard-required and surplus capacity is comparatively large, and wherein yield strength controls at 420-500MPa, and tensile strength controls at 560-700 MPa; Elongation controls at 17%-25%; V-type-50 DEG C of transverse impact power controls, built in 100 ~ 200J, reach P460NL1(L2 completely) standard-required.

Outer inspection and flaw detection: the steel plate developed examine outward in strict accordance with, the percentage of A-class goods 100%, detects a flaw by EN 10160, and the ratio wherein reaching S3/E3 standard is 85%, and the ratio reaching S1/E1 standard is 100%, reaches desired result.

Claims (3)

1. a pressurized vessel P460NL1 super-thick steel plate, comprise the chemical composition (unit of following mass percent, wt%): C:0.09 ~ 0.17, Si:0.55 ~ 0.85, Mn:1.30 ~ 1.70, P :≤0.010, S :≤0.003, micro alloying element (V+Nb+Ti+Cr+Ni) :≤2.0, Als:0.020 ~ 0.050, other is Fe and relict element, described pressurized vessel P460NL1 super-thick steel plate contains the ferritic bainite-martensite structure up to 5%, comprises following production stage:

A.KR hot metal pretreatment technology: ensure liquid level thickness of slag layer≤20mm, molten iron ensures molten iron (by mass percentage) S≤0.005% after KR stirring desulphurization, ensure desulfurization cycle≤21min, desulfurization temperature drop≤20 DEG C;

B. converter smelting process: enter stove molten iron (by mass percentage) S≤0.005%, P≤0.050%, molten iron temperature >=1270 DEG C, slag making basicity R presses 2.5-4.0 and controls, tapping carbon >=0.05%, tapping P≤0.010%, S≤0.010%; Point blows number of times and must not be greater than 2 times, avoids tapping process slag;

C.LF refinery practice: take the large quantity of slag to carry out slag making, guarantee white slag hold-time >=15min;

D.VD refinery practice: VD vacuum tightness must reach below 67Pa, the dwell time is necessary >=15min, soft blow 2-5min or do not blow after vacuum breaker, and in soft blow process, molten steel must not be exposed, upper steel temperature 1570 ± 15 DEG C;

E. die casting process: ingot mould temperature≤120 DEG C before using of reaching the standard grade, during cast, the feed trumpet distance controlling with collector nozzle of ladle suitable for reading is at≤140mm, before cast, the mode that ingot casting powder half takes straw rope to hang hangs in ingot mould, hanging height is higher than 300 ~ 400mm bottom ingot mould, second half open water after add in 1 ~ 4min, the body casting time presses 14-18min and controls, cap mouth pouring time is pressed 5-7min and is controlled, when being cast to cap mouth 1/3 position, add heat preserving agent insulation, after steel ingot casting, 8h carries out the demoulding;

F. heating process: stewing steel temperature 550-600 DEG C, time 2h, heat-up rate 80 DEG C/S, insulation 7h, heat-up rate 100 DEG C/S when temperature rises to 750 DEG C, when temperature rises to 1000 DEG C, heat-up rate is not limit, temperature is incubated 17h when rising to 1280 DEG C, and temperature is tapped 1260 DEG C time;

G. rolling technology: one-phase start rolling temperature 1100 DEG C ~ 1150 DEG C, two-stage start rolling temperature≤920 DEG C, reduction in pass >=20mm, finishing temperature 820 ~ 860 DEG C;

H. cooling control technology: red temperature between 600 ~ 650 DEG C, speed of cooling 10 ~ 20 DEG C/S;

I. cooling in heap technique: roll off the production line after steel plates straightening cooling in heap in time, cooling in heap temperature >=300 DEG C, heap cool time >=36h;

J. thermal treatment process: machine stove carries out normalizing treatment outside, temperature is 910 ± 20 DEG C, soaking time 2.0-2.5min/mm, steel plate come out of the stove after water-cooled 100s.

2. pressurized vessel P460NL1 super-thick steel plate as claimed in claim 1, is characterized in that: carbon equivalent≤0.53 of described pressurized vessel P460NL1 super-thick steel plate.

3. the pressurized vessel production method of P460NL1 super-thick steel plate as claimed in claim 1, is characterized in that: comprise following production stage:

A.KR hot metal pretreatment technology: ensure liquid level thickness of slag layer≤20mm, molten iron ensures molten iron (by mass percentage) S≤0.005% after KR stirring desulphurization, ensure desulfurization cycle≤21min, desulfurization temperature drop≤20 DEG C;

B. converter smelting process: enter stove molten iron (by mass percentage) S≤0.005%, P≤0.050%, molten iron temperature >=1270 DEG C, slag making basicity R presses 2.5-4.0 and controls, tapping carbon >=0.05%, tapping P≤0.010%, S≤0.010%; Point blows number of times and must not be greater than 2 times, avoids tapping process slag;

C.LF refinery practice: take the large quantity of slag to carry out slag making, guarantee white slag hold-time >=15min;

D.VD refinery practice: VD vacuum tightness must reach below 67Pa, the dwell time is necessary >=15min, soft blow 2-5min or do not blow after vacuum breaker, and in soft blow process, molten steel must not be exposed, upper steel temperature 1570 ± 15 DEG C;

E. die casting process: ingot mould temperature≤120 DEG C before using of reaching the standard grade, during cast, the feed trumpet distance controlling with collector nozzle of ladle suitable for reading is at≤140mm, before cast, the mode that ingot casting powder half takes straw rope to hang hangs in ingot mould, hanging height is higher than 300 ~ 400mm bottom ingot mould, second half open water after add in 1 ~ 4min, the body casting time presses 14-18min and controls, cap mouth pouring time is pressed 5-7min and is controlled, when being cast to cap mouth 1/3 position, add heat preserving agent insulation, after steel ingot casting, 8h carries out the demoulding;

F. heating process: stewing steel temperature 550-600 DEG C, time 2h, heat-up rate 80 DEG C/S, insulation 7h, heat-up rate 100 DEG C/S when temperature rises to 750 DEG C, when temperature rises to 1000 DEG C, heat-up rate is not limit, temperature is incubated 17h when rising to 1280 DEG C, and temperature is tapped 1260 DEG C time;

G. rolling technology: one-phase start rolling temperature 1100 DEG C ~ 1150 DEG C, two-stage start rolling temperature≤920 DEG C, reduction in pass >=20mm, finishing temperature 820 ~ 860 DEG C;

H. cooling control technology: red temperature between 600 ~ 650 DEG C, speed of cooling 10 ~ 20 DEG C/S;

I. cooling in heap technique: roll off the production line after steel plates straightening cooling in heap in time, cooling in heap temperature >=300 DEG C, heap cool time >=36h;

J. thermal treatment process: machine stove carries out normalizing treatment outside, temperature is 910 ± 20 DEG C, soaking time 2.0-2.5min/mm, steel plate come out of the stove after water-cooled 100s.