CN102876970A - Steel with yield strength larger than or equal to 390 MPa for high-rise buildings and production method of steel - Google Patents

Abstract

Steel with yield strength larger than or equal to 390 MPa for high-rise buildings comprises the following components by weight: 0.14 to 0.18 percent of C, 1.45 to 1.60 percent of Mn, 0.30 to 0.50 percent of Si, 0.035 to 0.050 percent of Nb, 0.045 to 0.065 percent of V, 0.007 to 0.017 percent of Ti, less than or equal to 0.025 percent of P, less than or equal to 0.005 percent of S, 0.015 to 0.050 percent of Als, and 0.001 to 0.005 percent of Ca. The production method comprises the following steps: combined blow after desulfurization, LF furnace refining, RH furnace treatment, denaturating treatment by adding a Ca-Si wire, pouring under the argon shield, casting blank heating, rolling, laminar cooling, normalizing, atomizing or spraying a small amount of water to cool, and stand-by application. The steel has the advantages that the yield strength is 370 to 490 MPa, the tensile strength is larger than or equal to 490 MPa, the yield ratio is less than or equal to 0.77, the impacting energy is larger than or equal to 100 J under the temperature of minus 20 DEG C, the section shrinkage rate in the through thickness direction is larger than or equal to 35%, the process flow is relatively short, and the thickness is 100 to 120 mm, which fully meets the requirement on the steel for the high-rise buildings.

Description

Yield strength 〉=390MPa Steels for High Rise Buildings and production method

Technical field

The present invention relates to a kind of construction(al)steel, refer to particularly yield strength 〉=390MPa, the thickness specification is low yield strength ratio Steels for High Rise Buildings and the production method thereof of 100～120mm.

Background technology

Along with the soil growing tension, so that Highrise buildings is able to fast development, increasing to the super-thick steel plate demand.Because the stressed complexity of high building structure, the steel plate that requires to adopt has high strength, outside the high tenacity, also requires to have the characteristics such as low yield strength ratio, anti-lamellar tearing.Steel plate for tall building was generally selected the 345MPa grade steel plate in the past, can not satisfy the large-scale construction engineering project demand, at present progressively to 390MPa and the development of above level steel plate.Therefore, the invention provides a kind of 390MPa level low yield strength ratio Highrise buildings with manufacturing technology and the production method of special heavy plate, to satisfy the requirement of the Larger Engineering Projects such as Highrise buildings.

Before the present invention, the report of domestic relevant low yield strength ratio super-thick steel plate is more, and has applied for patent of invention.Chinese patent application number is 200910089346.2 patent documentation, a kind of " super-thick steel plate for low yield ratio buildings with 460 MPa grade yield strength and manufacture method " disclosed, its steel plate composition weight percent is: C0.14～0.18%, Si0.35～0.45%, Mn1.40～1.50%, Nb0.025～0.035%, V0.040～0.050%, Ti0.010～0.020%, P＜0.020%, S＜0.008%, all the other are Fe; Rolling technology: 1220～1250 ℃ of Heating temperatures, adopt austenite recrystallization district and austenite non-recrystallization district two-stage control rolling.Thermal treatment process: steel plate is heated to 800～850 ℃ of two-phase regions, and 10～20 ℃ of soaking times adopt cold quenching after the insulation, control final cooling temperature≤100 ℃; Steel plate after the quenching carries out 450～600 ℃ of temper, finally obtains low yield strength ratio high-strength building steel plate.Its deficiency is in to process in: steel plate hot and adopts quenching+tempering, and technique is comparatively complicated, and the production cycle is longer.

Chinese patent application number is 200910012823.5 patent documentation, discloses " a kind of super thick anti-lamellar tearing steel plate manufacture method ", and it comprises smelting, ingot casting, forging, rolling, thermal treatment, and producing thickness is the anti-lamellar tearing steel plate of 130～400mm.It is characterized in that, between the ingot casting operation, be provided with forging process, steel ingot is forged into the steel plate blank and forges postheat treatment.Described forging process initial forging temperature is 1225～1250 ℃, and final forging temperature is 850～900 ℃, and compression ratio is not less than 3.Its deficiency is: die casting is adopted in cast, and forges, and is higher than the sheet billet continuous casting mode cost of current maturation.

Chinese patent application number is 200810200100.3 patent documentation, it discloses " a kind of steel plate with high strength and low yield ratio ", its chemical ingredients comprises: C0.15～0.20%, Si1.0～2.0%, Mn1.8～2.0%, Al≤0.036%, V0.05～0.1%, P≤0.01%, S≤0.005%, Cr0.8～1.0%, surplus are Fe and other inevitable impurity.It obtains a kind of hot-rolled steel sheet with high strength and low yield strength ratio by traditional TMCP rolling technology, and intensity reaches 1200～1500MPa, has simultaneously preferably low-temperature impact toughness.Its deficiency is: the steel plate design component content is higher, and carbon equivalent reaches more than 0.65, and the welding property of steel plate is had adverse influence.

Chinese patent application number is 200710054569.6 patent documentation, its disclose " a kind of big thickness tall building structure is with high-strength steel and production method thereof, and this steel chemical composition is: C:0.15～0.18%; Si:0.20～0.40%, Mn:1.50～1.62%, P≤0.015%; S≤0.005%; Ni:0.25～0.45%, V:0.075～0.085%, Nb:0.040～0.050%; Al:0.020～0.045%; Cr≤0.30%, Ti≤0.20%, all the other are Fe and inevitable impurity.This invention steel has added Ni, Cr alloy, and production technique has adopted electrosmelting and slab ingot mould to pour into a mould, and has increased production cost.

Chinese patent application number is 201010582378.9 patent documentation, and it discloses a kind of " anti-seismic steel for building of anti-lamellar tearing excellent property and production method thereof ".Its chemical ingredients forms C, Si, Mn, P≤0.015%, S≤0.005%, Nb, Ti, Als, and remaining is Fe.Traditional control technique is adopted in this invention, and Banded Structure of Steel Plate is more serious, has destroyed the thickness direction homogeneity of structure, be unfavorable for the anti-lamellar tearing shape of steel plate performance, and product thickness is below the 100mm.

Summary of the invention

The objective of the invention is the deficiency for the prior art existence, a kind of yield strength 〉=390MPa is provided, tensile strength 〉=490MPa, yield tensile ratio≤0.77,-20 ℃ of ballistic work 〉=100J, full thickness direction relative reduction in area φ % 〉=35%, and the thickness specification is in Steels for High Rise Buildings and the production method thereof of 100～120mm.

Realize the measure of above-mentioned purpose:

A kind of yield strength 〉=390MPa level Steels for High Rise Buildings, its component and weight percent content are: C:0.14～0.18%, Mn:1.45～1.60%, Si:0.30～0.50%, Nb:0.035～0.050%, V:0.045～0.065%, Ti:0.007～0.017%, P≤0.025%, S≤0.005%, Als:0.015～0.050%, Ca:0.001～0.005%, all the other are Fe and inevitable impurity.

The method of production yield strength 〉=390MPa level Steels for High Rise Buildings, its step:

1) after the KR desulfurization, adopts top bottom blowing in converter;

2) carry out the refining of LF stove, and the S in the control molten steel≤0.003%;

3) carry out the RH stove and process, be no more than the lower treatment time of 67Pa in vacuum tightness and be not less than 15 minutes, and O≤15ppm in the control molten steel, N≤1.5ppm;

4) carry out denaturing treatment, add silicon-calcium wire according to 2～3 meters/ton steel;

5) adopt argon for protecting pouring, and the control molten steel overheat is controlled the strand draught 5～8%, below the center segregation C1.0 level at 15～20 ℃;

6) to the strand heating, the control soaking zone was 1150～1250 ℃ of lower soaking 45～60 minutes;

7) be rolled, control roughing start rolling temperature is no more than 1100 ℃, and controls every time draft of this section and be not less than 10%, and steel plate thickness is 1.3～1.6 times of finished product thickness during the roughing end; Control finish rolling finishing temperature is at 820～850 ℃, and controlling every time draft of this section is 8～10%;

8) carrying out laminar flow, is under 4～8 ℃/second in speed of cooling, is cooled to 600～700 ℃;

9) carry out normalizing, the control normalizing temperature is at 870～890 ℃;

10) spray or spray water on a small quantity and cool off, temperature is controlled at 600～700 ℃ after the cooling;

11) stand-by.

The effect of each element among the present invention

C: the most effectively element of hardness of steel is provided, enlarges austenite phase block elements.When every increase by 0.10% tensile strength of carbon content approximately improves 70MPa, yield strength approximately improves 30MPa, to reducing yield tensile ratio comparatively significant effect is arranged simultaneously; But will greatly damage toughness and the welding property of steel plate when carbon content is too high, therefore with carbon content control in 0.14～0.18% scope;

Mn: in steel, as substitutional atom, enlarge the austenite phase region, reduce the A3 temperature, can increase the hardening capacity of steel simultaneously.Because its refine pearlite, significantly improve the intensity of low-carbon (LC) and middle carbon perlitic steel, when gaining in strength on the ductility of steel plate without impact, utilize manganese to come reinforced ferrite and perlite in the ordinary low-alloy steel, improve the intensity of steel, general control is 1%～2%, and the present invention considers normalizing heat treatment technique, therefore is controlled at 1.45～1.60%;

Si: improving the intensity of steel in the mode of solution strengthening, also is reductor good in the smelting process.But when silicone content is too high in the steel, can cause yield tensile ratio to rise, reduce plasticity and the toughness of steel, easily make steel form banded structure simultaneously, make lateral performance be lower than vertical performance, so the present invention be controlled at 0.3～0.5%;

Nb: the effect in steel, main is crystal grain thinning.Add 0.005～0.05% niobium in the steel and can significantly improve yield strength and impelling strength, reduce its ductile-brittle transition temperature, therefore add 0.035～0.050% niobium;

V: produce precipitation strength in steel, one side has produced carbonitride in control and has produced precipitation strength prevention Austenite Grain Growth in heating time the, while again separating out after normalizing, armor plate strength after the assurance normalizing.Be controlled at 0.045～0.065% among the present invention;

Ti: strong carbonitride element, easily be combined with O, C, N, form highly stable Ti(C, N), it when strand heats, can hinder Austenite Grain Growth only just fusing into slowly more than 1000 ℃ in the sosoloid effectively.But add when more, can cause the nitride alligatoring of titanium, reduce low-temperature flexibility, the titanium of trace is very effective to the toughness of improving welded heat affecting zone.The present invention adopts little titanium to process, and is controlled at 0.007～0.017%;

Als: the deoxidation nitrogen fixation as when steel-making, can improve the crystalline grain of steel Coarsening Temperature as effective aluminium, stop austenite crystal, if but when excessive, therefore the austenite crystal alligatoring of growing up easily on the contrary is controlled at 0.015～0.050%;

Ca: process the form that reaches the change sulfide inclusion by calcium, reach the purpose of improving inclusion plasticity, thereby reduce sulfide to the harm of steel plasticity and cutting ability.Therefore after processing, silico-calcium guarantees that calcium contents is 0.001～0.005%.

The present invention compared with prior art, the yield strength of the Steels for High Rise Buildings steel plate of producing is at 370～490MPa, tensile strength 〉=490MPa, yield tensile ratio≤0.77,-20 ℃ of ballistic work 〉=100J, full thickness direction relative reduction in area 〉=35%, technical process is relatively short, and thickness is in the requirement of satisfying Steels for High Rise Buildings fully of 100 ~ 120mm.

Embodiment

The below is described in detail the present invention:

Table 1 is various embodiments of the present invention and the tabulation of Comparative Examples Performance Detection situation;

Various embodiments of the present invention are according to following steps production:

Its step:

1) after the KR desulfurization, adopts top bottom blowing in converter;

2) carry out the refining of LF stove, and the S in the control molten steel≤0.003%;

3) carry out the RH stove and process, be no more than the lower treatment time of 67Pa in vacuum tightness and be not less than 15 minutes, and O≤15ppm in the control molten steel, N≤1.5ppm;

4) carry out denaturing treatment, add silicon-calcium wire according to 2～3 meters/ton steel;

5) adopt argon for protecting pouring, and the control molten steel overheat is controlled the strand draught 5～8%, below the center segregation C1.0 level at 15～20 ℃;

6) to the strand heating, the control soaking zone was 1150～1250 ℃ of lower soaking 45～60 minutes;

7) be rolled, control roughing start rolling temperature is no more than 1100 ℃, and controls every time draft of this section and be not less than 10%, and steel plate thickness is 1.3～1.6 times of finished product thickness during the roughing end; Control finish rolling finishing temperature is at 820～850 ℃, and controlling every time draft of this section is 8～10%;

8) carrying out laminar flow, is under 4～8 ℃/second in speed of cooling, is cooled to 600～700 ℃;

9) carry out normalizing, the control normalizing temperature is at 870～890 ℃;

10) spray or spray water on a small quantity and cool off, temperature is controlled at 600～700 ℃ after the cooling;

11) stand-by.

Embodiment 1

Finished product thickness requires to be 120mm.

Present embodiment adopts steel billet composition and content (wt%)

The main technologic parameters value:

Slab thickness is 300mm, and strand is 1233 ℃ in the soaking zone temperature, soaking time 48 minutes;

1060 ℃ of rough rolling step start rolling temperatures (? should be no more than 1100 ℃), rolling pass 6 roads, every time draft are 10～11%, and it is 160mm that roughing finishes thickness, and it is 1.33 times of finished product thickness;

Every time draft of finish rolling stage is 8～10%, and finishing temperature is 848 ℃;

The laminar flow rate of cooling is 5 ℃/s, and final cooling temperature is 647 ℃;

877 ℃ of normalizing temperatures;

The water spray cooling temperature is 650 ℃.

Embodiment 2

Finished product thickness requires to be 110mm.

Present embodiment adopts steel billet composition and content (wt%)

The main technologic parameters value:

Slab thickness is 300mm, and strand is 1193 ℃ in the soaking zone temperature, soaking time 50 minutes;

1058 ℃ of rough rolling step start rolling temperatures, rolling pass 7 roads, every time draft be 10～12%, and it is 160mm that roughing finishes thickness, and it is 1.45 times of finished product thickness;

Every time draft of finish rolling stage is 9～10%, and finishing temperature is 840 ℃;

The laminar flow rate of cooling is 4.5 ℃/s, and final cooling temperature is 656 ℃;

890 ℃ of normalizing temperatures;

The spray cooling temperature is 675 ℃.

Embodiment 3

Finished product thickness requires to be 100mm.

Present embodiment adopts steel billet composition and content (wt%)

The main technologic parameters value:

Slab thickness is 300mm, and strand is 1185 ℃ in the soaking zone temperature, soaking time 55 minutes;

1093 ℃ of rough rolling step start rolling temperatures, rolling pass 5 roads, every time draft be 10～11.5%, and it is 150mm that roughing finishes thickness, and it is 1.5 times of finished product thickness;

Every time draft of finish rolling stage is 9～10%, and finishing temperature is 825 ℃;

The laminar flow rate of cooling is 4 ℃/s, and final cooling temperature is 605 ℃;

872 ℃ of normalizing temperatures;

The spray cooling temperature is 652 ℃.

Embodiment 4

Finished product thickness requires to be 105mm.

Present embodiment adopts steel billet composition and content (wt%)

The main technologic parameters value:

Slab thickness is 300mm, and strand is 1206 ℃ in the soaking zone temperature, soaking time 60 minutes;

1093 ℃ of rough rolling step start rolling temperatures, rolling pass 5 roads, every time draft be 10～12%, and it is 150mm that roughing finishes thickness, and it is 1.43 times of finished product thickness;

Every time draft of finish rolling stage is 9～10%, and finishing temperature is 849 ℃;

The laminar flow rate of cooling is 8 ℃/s, and final cooling temperature is 621 ℃;

885 ℃ of normalizing temperatures;

The spray cooling temperature is 625 ℃.

Embodiment 5

Finished product thickness requires to be 115mm.

Present embodiment adopts steel billet composition and content (wt%)

The main technologic parameters value:

Slab thickness is 300mm, and strand is 1176 ℃ in the soaking zone temperature, soaking time 60 minutes;

1085 ℃ of rough rolling step start rolling temperatures, rolling pass 5 roads, every time draft be 10～11.5%, and it is 160mm that roughing finishes thickness, and it is 1.39 times of finished product thickness;

Every time draft of finish rolling stage is 8～10%, and finishing temperature is 825 ℃;

The laminar flow rate of cooling is 7 ℃/s, and final cooling temperature is 621 ℃;

873 ℃ of normalizing temperatures;

The spray cooling temperature is 615 ℃.

The mechanical property detection case tabulation of each embodiment of table 5

As can be seen from Table 1, carry out normal temperature stretching, Z-direction stretching ,-20 ℃ of impact of collision toughness tests through steel plate of the present invention, its result: at normal temperatures, tensile property meets the service requirements of this rank Highrise buildings steel plate fully, and has larger surplus capacity, ballistic work＞100J in-20 ℃ of impact of collision toughness, Z-direction tensile property rank is more than 36%, satisfy Z35 steel plate rank fully, and most of surplus capacity is also all larger, illustrates that Plate Steel of the present invention has good anti-lamellar tearing ability; Steel plate yield tensile ratio≤0.77 shows that steel plate has more excellent shock resistance, and steel plate inspection II level is qualified, and in a word, Plate Steel of the present invention has excellent comprehensive mechanical performance.

Plate Steel pouring type of the present invention adopts sheet billet continuous casting, does not need to adopt die casting production, and operation is comparatively simple, and production cost is lower, and rhythm of production is very fast; As-normalized condition delivery, steel plate interior tissue more all and stablize, the mode that adopts simultaneously the mist control cold or that water on a small quantity after the normalizing to cool off guarantees the raising of the tiny all even plate properties of interior tissue.Plate Steel of the present invention is of many uses, can be applicable to high level, Super High, factories and miness, pylon, large span and large scale structure engineering construction.

Above-described embodiment only exemplifies for the best, and is not to be restriction to embodiments of the present invention.

Claims (2)

1. yield strength 〉=390MPa level Steels for High Rise Buildings, its component and weight percent content are: C:0.14～0.18%, Mn:1.45～1.60%, Si:0.30～0. 50%, Nb:0.035～0.050%, V:0.045～0.065%, Ti:0.007～0.017%, P≤0.025%, S≤0.005%, Als:0.015～0.050%, Ca:0.001～0.005%, all the other are Fe and inevitable impurity.

2. produce the method for a kind of yield strength claimed in claim 1 〉=390MPa level Steels for High Rise Buildings, its step:

1) after the KR desulfurization, adopts top bottom blowing in converter;

2) carry out the refining of LF stove, and the S in the control molten steel≤0.003%;

3) carry out the RH stove and process, be no more than the lower treatment time of 67Pa in vacuum tightness and be not less than 15 minutes, and O≤15ppm in the control molten steel, N≤1.5ppm;

4) carry out denaturing treatment, add silicon-calcium wire according to 2～3 meters/ton steel;

5) adopt argon for protecting pouring, and the control molten steel overheat is controlled the strand draught 5～8%, below the center segregation C1.0 level at 15～20 ℃;

6) to the strand heating, the control soaking zone was 1150～1250 ℃ of lower soaking 45～60 minutes;

7) be rolled, control roughing start rolling temperature is no more than 1100 ℃, and controls every time draft of this section and be not less than 10%, and steel plate thickness is 1.3～1.6 times of finished product thickness during the roughing end; Control finish rolling finishing temperature is at 820～850 ℃, and controlling every time draft of this section is 8～10%;

8) carrying out laminar flow, is under 4～8 ℃/second in speed of cooling, is cooled to 600～700 ℃;

9) carry out normalizing, the control normalizing temperature is at 870～890 ℃;

10) spray or spray water on a small quantity and cool off, temperature is controlled at 600～700 ℃ after the cooling;

11) stand-by.