CN102212752A - Low-temperature angle steel and manufacturing method thereof - Google Patents
Low-temperature angle steel and manufacturing method thereof Download PDFInfo
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Abstract
The invention relates to a low-temperature angle steel and a manufacturing method thereof, and belongs to the field of low-temperature steels. The angle steel has excellent low-temperature toughness at the temperature of above 40 DEG C below zero, the yield strength of the angle steel reaches 350MPa, and the angle steel is suitable to be used as a power transmission iron tower material under the low-temperature conditions of high cold regions. The angle steel comprises the following chemical components in percentage by weight: 0.05 to 0.18 percent of C, 0.5 to 1.7 percent of Mn, 0.01 to 0.55 percent of Si, 0.005 to 0.01 percent of Ga, 0.01 to 0.08 percent of V, 0.02 to 0.08 percent of Nb, 0.001 to 0.005 percent of Ca, 0.005 to 0.05 percent of Ti, 0.01 to 0.06 percent of Als, 0.15 to 0.25 percent of Cu, 0.0005 to 0.002 percent of B, 0 to 0.01 percent of P, 0 to 0.005 percent of S, and the balance of Fe and inevitable impurities. The angle steel has the advantages of simplicity in process, purity, tissue stability, yield strength of more than 350MPa and excellent low-temperature toughness at the temperature of above 40 DEG C below zero; and by adopting the alloying principles of multiple elements and low quantity, the angle steel has high and low-temperature performance and low cost.
Description
Technical field
The invention belongs to the low-temperature steel field, specifically relate to a kind of low temperature hot-rolled angle steel and manufacture method thereof.
Background technology
The low temperature breakage problem of material is to use and gives birth to along with large-scale steel structure in 30 or 40 years in last century generation, and the thirties in last century, the Hasselt, Belgium bridge after only building up 14 months the fracture crash took place, and temperature was-20 ℃ at that time.Local failure takes place on January 2nd, 1938 in the bridge of crossing highway near Berlin when temperature sharply drops to-10 ℃, occurs reaching the crack of 3m on the body of a bridge.The fifties, fracture takes place and crashes in a bridge block of Quebec, CAN after being open to traffic 27 months, and temperature was-35 ℃ at that time.December 27 nineteen sixty-five, the sinking of collapsing of gas field, the North Sea " Hypon " number marine rig derrick, the time temperature be 3 ℃.On January 4th, 1984, a crane arm brittle failure accident takes place in Xinjiang of China, causes 1 people's death, and operating ambient temperature at that time is-15 ℃.Studies show that the stress of material is lower than yield strength, also be lower than design and need use stress that steel brittle failure was still lost efficacy, accident takes place suddenly, and process is of short duration rapidly, and people determine that by self-examination research accident cause low temperature is the immediate cause that causes material damage.
China is vast in territory, a lot of regional winter temperatures are below-20 ℃ in the north, limit temperature reaches below-40 ℃, especially the Northeast, belong to cool temperature zone and climate of frigid zone area, have features such as temperature is low, the temperature difference is big, snowfall is big, density of air is big, and continue to such an extent that the time is longer, the low temperature time of occurrence is general more than 3～6 months, and regional average temperature of the whole year is all below 0 ℃ in large and small Xing'an Mountains.The coldest month temperature in the Northeast is roughly between-10 ℃～-30 ℃, wherein the long-time average annual value of various places, area, Xing'an Mountains extreme minimum temperature is mostly about-40 ℃, and extreme value can reach about-45 ℃, along with in recent years, the acute variation of atmosphere and physical environment, the extreme astronomical phenomena frequency of occurrences increases, and table 1 has been added up the calculating low temperature T of China some areas
j(taking from the heating standard, is continuous 5 days cryogenic mean value in 50 years) and the lowest temperature T that occurs in history
z
The calculating low temperature T of table 1 China some areas
jThe lowest temperature T that occurred in history
z(℃)
Low-temperature steel mainly should have following performance: 1. toughness-brittle transition temperature is lower than use temperature; 2. the intensity that meets design requirement; 3. in use temperature undertissue Stability Analysis of Structures; 4. good weldability and processing forming; Patented technology about Cryogenic Steel is as follows:
The publication number of having authorized is that CN101545077A, denomination of invention are the patent of invention of " a kind of Cryogenic Steel and manufacture method thereof ", a kind of low temperature steel plate and manufacture method are disclosed, be mainly exploitation at the low temperature steel plate, its low-temperature steel has excellent low-temperature flexibility under-80 ℃, be mainly used in the low temperature steel plate of petroleum natural gas pipeline, low temperature gas storage tank body LPG, LNG.The content of noble metal Ni element is 0.05-0.35% in this technical scheme.
Application number is that 201010157592.X, denomination of invention are the application for a patent for invention of " high-strength and low-temperature tough steel ", it discloses a kind of fish tail slab technical scheme, be applicable to engineering machinery, the railway casting steel that uses down as the extremely frigid zones cold condition, as railway track with joint bar etc., charcoal low-silicon steel in belonging to, it is 28.6-36J at-40 ℃ of ballistic works, yield strength is 680-780MPa, comprise noble metal Ni element and Mo element in the chemical ingredients of low-temperature steel, improved the production cost of low-temperature steel.
Application number is 200910019494.7, denomination of invention is the application for a patent for invention of " a kind of-40 ℃ to-60 ℃ low-temperature impact toughness are hot rolled H-shaped and preparation method thereof ", it discloses hot rolled H-shaped that a kind of being applicable to-40 ℃ to-60 ℃ of low temperature use down, its V-type sample at-40 ℃ to-60 ℃ following ballistic works above 27J.The content of noble metal Ni element is 0.30-0.90% in the chemical ingredients of H shaped steel.
Above-mentioned steel grade all contains the noble metal Ni element.
In recent years, the brittle failure at low temperatures of China's electric power pylon has caused domestic expert's extensive concern.According to China's Electric Power Network Planning, will be northeastward, North China, the Northwest builds many transmitting line, these regional winter temperatures are lower, minimum temperature will reach below-40 ℃, electric power pylon is big with the material specification, load is big, execution conditions are abominable, at present the performance difference of existing angle steel under different low temperature condition lacked experimental study, with the performance that steel should have, do not have the correlation test data to support the extremely frigid zones electrical network.Existing steel grade is under-40 ℃ of cold condition, and toughness and plasticity all significantly reduce, and it is not clear that can the prior art standard satisfy under the abominable cold condition power grid operation requirement.
Iron tower of power transmission line, is disposed according to State Grid Corporation of China mainly based on Q235 and Q345 hot-rolled angle steel section bar with material, and the Q420B angle steel has obtained widespread use in electric power pylon in recent years, and the Q460C angle steel has also obtained application in the part pilot project.A lot of regional winter temperatures are below-20 ℃ in the north, limit temperature reaches below-40 ℃, under such temperature, requirement according to GB/50017-2003 " Code for design of steel structures ", steel construction is selected with steel, generally select its quality grade :-20 ℃≤T＜0 ℃, select C, D level steel by work temperature; During T＜-20 ℃, select D, E level steel.According to above regulation, need select D level even E level steel for use, could satisfy the electric power pylon operating requirement.
Because the restriction of China's steel production equipment and state of the art, the practical production experience that existing section bar manufacturer does not all produce D level or E level angle steel, can't large quantities ofly supply cheap low temperature angle steel on the market, therefore, once used a large amount of A levels and B level steel at extremely frigid zones, but along with in recent years, the acute variation of atmosphere and physical environment, the extreme meteorological frequency of occurrences increases, and the low stress brittle fracture accident of tower material repeatedly occurred.Representative accident is that the fracture of the first and second line iron tower main materials is opened in Changchun Power Supply Company on the 12nd 66kV farming March in 2010.
Daily life, the Economic development of country all be unable to do without even depends critically upon the use of steel, the brittle failure of steel was lost efficacy and serious consequence such as will be caused cutting off the water and electricity supply, traffic jam, house and electric tower collapse, manpower and materials are suffered heavy losses, the collapsing of electric power pylon that wherein is called as lifeline engineering, to directly cause the power supply system paralysis, initiation fire, the production and construction of influence country and people's life security.Therefore, exploitation is specifically designed to the extremely frigid zones electric power pylon and has unusual meaning with steel.As everyone knows, mainly contain the low-temperature flexibility that two kinds of approach improve steel at present, a kind of is to realize that by changing hot rolling technology and thermal treatment process refined crystalline strengthening improves low-temperature flexibility; Another kind is to add alloying constituents such as a certain amount of Ni, Mo to reach the high purpose of low-temperature flexibility.General actual production often adopts these two kinds of methods to improve the low-temperature flexibility of steel simultaneously, but because Ni, Mo cost are too high, economic production is difficult to realize.Therefore seek a kind of electric power pylon that can satisfy and low production cost stable and have great economic and social benefit, China's electric power pylon has been played very positive perfect effect with the hot-rolled angle steel steel grade with hot-rolled angle steel at-40 ℃ of low-temperature impact toughness.
Summary of the invention
The object of the present invention is to provide a kind of electric power pylon Q350MPa hot-rolled angle steel and manufacture method thereof with excellent low-temperature flexibility.The present invention mainly adopts polynary a spot of alloying principle, in conjunction with multi-pass hot rolling and thermal treatment process, develop the Q350MPa hot-rolled angle steel, described angle steel has excellent low-temperature flexibility more than-40 ℃, is adapted to the electric power pylon that uses under China's extremely frigid zones cold condition.
For achieving the above object, the technical solution used in the present invention is as follows:
A kind of low temperature angle steel, its improvements are that the weight percent proportioning of described angle steel chemical ingredients is: C:0.05～0.18%, Mn:0.5～1.70%, Si:0.01～0.55%, Ga:0.005～0.01%, V:0.01～0.08%, Nb:0.02～0.08%, Ca:0.001～0.005%; Ti:0.005～0.05%, Als:0.01～0.06%, Cu:0.15%～0.25%, B:0.0005～0.002%, P:0～0.01%, S:0～0.005%, all the other are Fe and unavoidable impurities.
Another optimal technical scheme of the present invention is: the weight percent proportioning of described angle steel chemical ingredients is: C:0.05～0.18%, Mn:0.65～1.70%, Si:0.01～0.55%, Ga:0.005～0.01%, V:0.01～0.08%, Nb:0.02～0.08%, Ca:0.001～0.005%; Ti:0.005～0.05%, Als:0.01～0.06%, Cu:0.15%～0.25%, B:0.0005～0.002%, P:0～0.01%, S:0～0.005%, all the other are Fe and unavoidable impurities.
Another optimal technical scheme of the present invention is: add a kind of among V and the Nb in the described angle steel at least, V and Nb total content are no more than 0.12%.
Another optimal technical scheme of the present invention is: described manufacture method may further comprise the steps:
1) according to the weight percent proportioning of chemical ingredients, C:0.05～0.18%, Mn:0.5～1.70%, Si:0.01～0.55%, Ga:0.005～0.01%, V:0.01～0.08%, Nb:0.02～0.08%, Ca:0.001～0.005%; Ti:0.005～0.05%, Als:0.01～0.06%, Cu:0.15%～0.25%, B:0.0005～0.002%, P:0～0.01%, S:0～0.005%, all the other are Fe and unavoidable impurities, wherein V and Nb total content are no more than 0.12%;
2) refining just: control its tapping temperature at 1630～1660 ℃;
3) carry out converter refining, the control refining time is at 15～30min;
4) carry out casting after the vacuum deaeration, obtain steel billet;
5) the described steel billet of step 4 is heated to 1190～1290 ℃ and carries out the multi-pass hot rolling and obtain angle steel, finishing temperature between 860～940 ℃, air cooling;
Another optimal technical scheme of the present invention is: in rolling beginning, along with the reduction of steel billet temperature, in the austenitic area and the ferrite recrystallization temperature district continuous rolling of steel billet, hot rolling pass is 10 times.
Another optimal technical scheme of the present invention is: described angle steel is equilateral or the scalene hot-rolled angle steel.
Another optimal technical scheme of the present invention is: the ferrite grain size of described angle steel is not less than 8 grades after the normalizing.
The effect and the mechanism of each alloying element are as follows:
C: exist with interstitial atom in steel, also can combine with the strong carbon compound element of steel grade combines as Ti, Nb, V, W etc., forms the carbide of small and dispersed, plays the effect that suppresses grain growth and precipitation strength, is one of the most effective strengthening element.But along with the increase of C content, though the hardness of steel increases, unit elongation and impelling strength descend very big, and wherein the low-temperature flexibility decline scope is bigger.Take into account the intensity and the low-temperature flexibility of steel, the C content range that adopts among the present invention will be 0.05～0.18%.
Mn: be very important useful alloying element, main solid solution is played the effect of solution strengthening in ferrite, can improve the intensity and the hardness of steel.It is again good reductor and sweetening agent, contains a certain amount of manganese and can eliminate or weaken the fragility that steel causes because of sulphur, thereby improve steel toughness at low temperatures.Mn belongs to the FCC stabilizing element, can enlarge austenite region, makes A
1And A
3Temperature reduces, A
4Point raises.Because A
3The point temperature descends, proeutectoid ferrite is separated out under lower temperature, thereby has suppressed growing up of crystal grain, refinement tissue.And also suppressed carbide simultaneously and separated out at the crystal boundary place of supercooled austenite, played the effect that reduces DBTT, therefore, Mn is the main alloy element in the low-temperature steel; But the superheated susceptivity of invar increases when its content is high, and under superheated situation a little, alligatoring just takes place crystal grain, and produces temper brittleness, so the Mn content that adopts among the present invention is in 0.50～1.70% scope.
Wherein:
Ac
1: perlite is to the temperature of austenitic transformation during heating;
Ar
1: austenite is to the temperature of perlitic transformation during cooling;
Ac
3: proeutectoid ferrite all changes austenitic finishing temperature into during heating;
Ar
3: austenite is to the beginning temperature of ferritic transformation during cooling;
Ac
4: secondary cementite all dissolves in austenitic finishing temperature during heating;
Ar
4: the temperature that from austenite, begins to separate out secondary cementite during cooling.
Si: often be added on and be used for deoxidation in the steel, do not form carbide but solid solution in ferrite, the solid solution effect is strong, it is very strong BCC stable element, DBTT is raise, and can reduce the toughness of steel, thus the present invention with Si constituent content scope strict regulation in 0.01～0.55%.
Ga: generally add gallium element with the thick gallium of cheapness or the form of iron-gallium compound, studies show that, the gallium element of trace can increase substantially the hardening capacity of steel; But content Gao Shiyi slightly causes cold short phenomenon, so the Ga elemental range that adopts among the present invention is 0.005～0.01%.
V, Nb: be strong carbon compound forming element, the VC that forms in steel, NbC grade in an imperial examination two-phase particle can hinder the austenite crystal of steel when heating and grow up, and can suppress recrystallize after rolling and the grain growth behind the recrystallize, play the effect of crystal grain thinning, and then improve the intensity and the low-temperature flexibility of steel; But easily produce intergranular crack as Nb, when V is excessive, and reduce the weldability of steel, so both content sums should not surpass 1.2%.
Ca: as the scavenging agent of deoxidation desulfuration, can cleaning molten steel, improve the purity of steel, can improve the form of non-metallic inclusion, make the MnS nodularization in the steel, the potential of performance material during its too high levels, easily forms thick non-metallic inclusion.Gu Ca content is controlled in 0.001～0.005% scope.
Ti: be a kind of intensive carbide and nitride forming element, easily form particles such as tiny TiC and TiN, TiC and TiN are highly stable, effective pinning crystal boundary, and crystal grain thinning, and have the stable effect of the tissue of heating once more.A spot of Ti element is improved the intensity of steel and low-temperature flexibility; But because Ti is very strong BCC (body centred cubic crystal) stable element, therefore adds Ti DBTT is improved, and excessive Ti easily forms thick TiN or TiC, pinning effect is weakened, can cause damage the toughness of steel.So regulation Ti content of the present invention is 0.005～0.05%.
Al: the main deoxidant element of this element, the Al of certain content can form the AlN particle of tiny indissoluble with the N in the steel, and disperse distributes and plays the effect of crystal grain thinning, improves the intensity and the toughness of steel, but the too high inclusion that easily causes of aluminium amount is too much, and is unfavorable to the low-temperature flexibility of steel.Therefore the content range of Al of the present invention is 0.01～0.06%.
Cu: be a kind of FCC (face-centered cubic crystal) stable element, by separating out second effect of playing precipitation strength mutually during the tempering, a small amount of Cu element can make DBTT descend, and improves low-temperature flexibility, the antifatigue crack propagation ability of steel; When Cu content is higher, can be because second phasor separated out be big and the uncontrollable toughness that directly causes steel descends and the rising of DBTT, and excessive Cu also can cause becoming fragile during steel billet casting and the hot rolling, so the content span of control of Cu of the present invention is 0.15%～0.25%.
B: the boron that adds minute quantity can improve the performance of steel significantly, the boron of trace can suppress the segregation of phosphorus, sulphur harmful element and rupture along brilliant, boron along brilliant segregation can reduce phosphorus, sulphur in the segregation of crystal boundary and rupturing along brilliant of causing, thereby significantly improves the low-temperature flexibility of steel.Boron can improve inclusion and get form and distribution, after adding the boron processing, because the surfactivity height of boron, can be adsorbed on sulfide and oxide surface, stop inclusion further to be grown up, make inclusion become tiny, rounding, be uniformly distributed in crystal boundary, strengthen crystal boundary, reduce stress raisers, suppress crack initiation and reduce crack growth rate, the toughness of material is improved.In boron adding niobium steel, boron and niobium can form the effect that mixture plays crystal grain thinning; And the boron of trace can increase substantially the hardening capacity of steel, improves the toughness of steel by the tissue (lower bainite or tempered sorbite) that obtains to have uniformly good comprehensive mechanical properties; But boron must maintain micro-scope, along with the content of boron increases, will form thick inclusion, and the performance of steel is had disadvantageous effect.
P: be the harmful element in the steel,, form banded structure, make the mechanical property of steel inhomogeneous, it is generally acknowledged that phosphorus is to cause that the major cause of brittle failure takes place ferrous materials at low temperatures because its segregation tendency is serious.So its content is few more good more, the present invention controls to phosphorus content below 0.01%.
S: be the harmful element in most of steel grades, the segregation tendency is serious, easily causes steel low temperature along crystalline substance fracture and high-temperature embrittlement, and can cause steel to have shortcomings such as anisotropy toughness is low.So should strictly control its content, the present invention is controlled at sulphur content below 0.005%.
Owing to adopted technique scheme, compared with prior art, the obtained beneficial effect of the present invention comprises:
1) has excellent low-temperature flexibility at-40 ℃
By the requirement of China to the low-temperature impact toughness of steel, ballistic work Akv promptly satisfies the low temperature impact properties index greater than 27J under corresponding temperature, the ballistic work of hot-rolled angle steel of the present invention under-40 ℃ is 60-88J, and hot-rolled angle steel of the present invention as can be known satisfies the impelling strength index at-40 ℃;
2) yield strength is greater than 350MPa
Adopt GB/T13239-2006 cryogenic tensile test method to carry out the cryogenic stretching performance test, the result shows that the yield strength of hot-rolled angle steel greater than 350MPa, has the coupling of excellent low-temperature flexibility and excellent mechanical performances;
3) cost is low
Described low temperature with angle steel with manganese and gallium for nickel, adopt polynary a spot of alloying principle; Simultaneously, change the content of B element in the steel in the process of smelting by the ferro-boron that adds cheapness; When improving the angle steel low-temperature performance, greatly reduce cost, be suitable as the electric power pylon tower material under the extremely frigid zones cold condition;
4) technology is simple, and steel is pure, and tissue is stable
The process characteristic of its invention is: carry out refining just earlier, the control steel billet is at higher temperature converter refining then, reduce S, P content, gas content and carry out the vacuum denitrification deoxidation in the control steel, after the vacuum deaeration, steel billet is carried out 10 passage hot rollings, in the austenitic area and recrystallization temperature district continuously hot rolling.Steel billet is softer in the austenitic area, has excellent plasticity-, by making steel billet have the shape of angle steel after the 4 passage hot rollings, and make the austenite crystal fragmentation, become a plurality of tiny subgrains behind the forming core, along with the reduction of steel billet temperature, Continuous Heat rolls into equilateral or unequal-angle bar in ferrite recrystallization temperature district, a large amount of distortion makes the crystal grain distortion produce working hardening, and makes crystal grain have little time to grow up by air cooling, obtains ferrite grain size at last and is higher than 8 hot-rolled angle steel.The manufacturing approach craft of hot-rolled angle steel of the present invention is simple, and gained angle steel tissue is stable, and stable mechanical property is applicable to large-scale industrial production.
Description of drawings
The present invention is further described below in conjunction with accompanying drawing.
Fig. 1 is that the standard summer is than v-notch impact specimen;
Fig. 2 is the cryogenic tensile sample;
Mark unit among the figure: mm.
Embodiment
The present invention will be described in detail below in conjunction with example.
All embodiments all are to adopt conventional the smelting and rolling equipment, carry out according to the step that the front is narrated:
Embodiment 1:
Have excellent low-temperature flexibility electric power pylon Q350MPa hot-rolled angle steel, the weight percent proportioning of its chemical ingredients is: C:0.145%, Mn:0.65%, Si:0.21%, Ga:0.005%, V:0.025%, Ca:0.001%; Ti:0.005%, Als:0.02%, Cu:0.16%, B:0.0005, P:0～0.01%, S:0～0.005%, all the other are Fe and inevitable trace impurity.
A kind of production low-temperature flexibility electric power pylon method of Q350MPa hot-rolled angle steel, its step:
(1) refining just: control its tapping temperature at 1630～1640 ℃;
(2) carry out converter refining, control refining time at 15min;
(3) carry out vacuum deaeration and casting;
(4) steel billet is heated to 1195～1130 ℃ and carries out 10 passage hot rollings, finishing temperature between 860～940 ℃, air cooling.
Embodiment 2:
Have excellent low-temperature flexibility electric power pylon Q350MPa hot-rolled angle steel, the weight percent proportioning of its chemical ingredients is: C:0.16%, Mn:1.06%, Si:0.37%, Ga:0.006%, Nb:0.045%, Ca:0.002%; Ti:0.01%, Als:0.032%, Cu:0.18%, B:0.0007%, P:0～0.01%, S:0～0.005%, all the other are Fe and inevitable trace impurity.
A kind of production low-temperature flexibility electric power pylon method of Q350MPa hot-rolled angle steel, its step:
(1) refining just: control its tapping temperature at 1635～1645 ℃;
(2) carry out converter refining, control refining time at 18min;
(3) carry out vacuum deaeration and casting;
(4) steel billet is heated to 1220～1245 ℃ and carries out 10 passage hot rollings, finishing temperature between 860～940 ℃, air cooling.
Embodiment 3:
Have excellent low-temperature flexibility electric power pylon Q350MPa hot-rolled angle steel, the weight percent proportioning that its chemical ingredients gets is: C:0.16%, Mn:1.32%, Si:0.44%, Ga:0.008%, V:0.065%, Ca:0.003%; Ti:0.025%, Als:0.045%, Cu:0.19%, B:0.001%, P:0～0.01%, S:0～0.005%, all the other are Fe and inevitable trace impurity.
A kind of production low-temperature flexibility electric power pylon method of Q350MPa hot-rolled angle steel, its step:
(1) refining just: control its tapping temperature at 1640～1645 ℃;
(2) carry out converter refining, the control refining time is at 20min;
(3) carry out vacuum deaeration and casting;
(4) steel billet is heated to 1230～1250 ℃ and carries out 10 passage hot rollings, finishing temperature between 860～940 ℃, air cooling.
Embodiment 4:
Have excellent low-temperature flexibility electric power pylon Q350MPa hot-rolled angle steel, the weight percent proportioning of its chemical ingredients is: C:0.17%, Mn:1.58%, Si:0.55%, Ga:0.01%, Nb:0.08%, Ca:0.004%; Ti:0.033%, Als:0.43%, Cu:0.18%, B:0.0012%, P:0～0.01%, S:0～0.005%, all the other are Fe and inevitable trace impurity.
A kind of production low-temperature flexibility electric power pylon method of Q350MPa hot-rolled angle steel, its step:
(1) refining just: control its tapping temperature at 1640～1650 ℃;
(2) carry out converter refining, control refining time at 15min;
(3) carry out vacuum deaeration and casting;
(4) steel billet is heated to 1245～1265 ℃ and carries out 10 passage hot rollings, finishing temperature between 860～940 ℃, air cooling.
Embodiment 5:
Have excellent low-temperature flexibility electric power pylon Q350MPa hot-rolled angle steel, the weight percent proportioning of its chemical ingredients is: C:0.175%, Mn:1.70%, Si:0.55%, Ga:0.01%, V:0.045%, Nb:0.043%, Ca:0.005%; Ti:0.042%, Als:0.51%, Cu:0.2%, B:0.0015%, P:0～0.01%, S:0～0.005%, all the other are Fe and inevitable trace impurity.
A kind of production low-temperature flexibility electric power pylon method of Q350MPa hot-rolled angle steel, its step:
(1) refining just: control its tapping temperature at 1640～1655 ℃;
(2) carry out converter refining, control refining time at 28min;
(3) carry out vacuum deaeration and casting;
(4) steel billet is heated to 1255～1285 ℃ and carries out 10 passage hot rollings, finishing temperature between 860～940 ℃, air cooling.
Vertically get stretching and impact specimen along hot-rolled angle steel, the strict GB/T3808 of execution adopts Charpy impact machine tester, adopts the GB/T229-1994 metal summer to carry out shock test than the v-notch in the test with notched test piece method.And adopting GB/T13239-2006 cryogenic tensile test method to carry out the cryogenic stretching performance test, specimen size such as Fig. 1 and Fig. 2, table 1 have listed the mechanical property of each example under-40 ℃ of temperature.
Table 1 test steel performance assay
| Example | R el(MPa) | ?R m(MPa) | A(％) | Akv (40 ℃) is (J) vertical | Grain fineness number (level) |
| Embodiment 1 | 355 | ?515 | 32 | ?60 | 8 |
| |
367 | ?522 | 29 | ?75 | 8 |
| Embodiment 3 | 382 | ?557 | 31 | ?85 | 9 |
| Embodiment 4 | 386 | ?566 | 27 | ?88 | 9.5 |
| Embodiment 5 | 353 | ?517 | 30 | ?80 | 8 |
By the requirement of China to the low-temperature impact toughness of steel, ballistic work AKV promptly satisfies the low temperature impact properties index greater than 27J under corresponding temperature, and hot-rolled angle steel of the present invention as shown in Table 1 satisfies the impelling strength index at-40 ℃.
It is simple that the present invention has technology, steel is pure, tissue is stable, yield strength is greater than 350MPa, in the advantage that has excellent low-temperature flexibility more than-40 ℃, and with manganese and gallium for nickel, adopt polynary a spot of alloying principle, when improving the angle steel low-temperature performance, greatly reduce cost, be suitable as the electric power pylon tower material under the extremely frigid zones cold condition.
Invention has been described according to specific exemplary embodiment herein.It will be conspicuous carrying out suitable replacement to one skilled in the art or revise under not departing from the scope of the present invention.Exemplary embodiment only is illustrative, rather than to the restriction of scope of the present invention, scope of the present invention is by appended claim definition.
Claims (7)
1. low temperature angle steel, the weight percent proportioning that it is characterized in that described angle steel chemical ingredients is: C:0.05～0.18%, Mn:0.5～1.70%, Si:0.01～0.55%, Ga:0.005～0.01%, V:0.01～0.08%, Nb:0.02～0.08%, Ca:0.001～0.005%; Ti:0.005～0.05%, Als:0.01～0.06%, Cu:0.15%～0.25%, B:0.0005～0.002%, P:0～0.01%, S:0～0.005%, all the other are Fe and unavoidable impurities.
2. Cryogenic Steel as claimed in claim 1, the weight percent proportioning that it is characterized in that described angle steel chemical ingredients is: C:0.05～0.18%, Mn:0.65～1.70%, Si:0.01～0.55%, Ga:0.005～0.01%, V:0.01～0.08%, Nb:0.02～0.08%, Ca:0.001～0.005%; Ti:0.005～0.05%, Als:0.01～0.06%, Cu:0.15%～0.25%, B:0.0005～0.002%, P:0～0.01%, S:0～0.005%, all the other are Fe and unavoidable impurities.
3. Cryogenic Steel as claimed in claim 1 is characterized in that adding at least in the described angle steel a kind of among V and the Nb, and V and Nb total content are no more than 0.12%.
4. a low temperature as claimed in claim 1 is characterized in that described manufacture method may further comprise the steps with the manufacture method of angle steel:
1) according to the weight percent proportioning of chemical ingredients, C:0.05～0.18%, Mn:0.5～1.70%, Si:0.01～0.55%, Ga:0.005～0.01%, V:0.01～0.08%, Nb:0.02～0.08%, Ca:0.001～0.005%; Ti:0.005～0.05%, Als:0.01～0.06%, Cu:0.15%～0.25%, B:0.0005～0.002%, P:0～0.01%, S:0～0.005%, all the other are Fe and unavoidable impurities, wherein V and Nb total content are no more than 0.12%;
2) refining just: the control tapping temperature is at 1630～1660 ℃;
3) carry out converter refining, the control refining time is at 15～30min;
4) carry out casting after the vacuum deaeration, obtain steel billet;
5) the described steel billet of step 4 is heated to 1190～1290 ℃ and carries out the multi-pass hot rolling and obtain angle steel, finishing temperature between 860～940 ℃, air cooling.
5. a kind of low temperature as claimed in claim 4 is characterized in that rolling beginning with the manufacture method of angle steel, and along with the reduction of steel billet temperature, in the austenitic area and the ferrite recrystallization temperature district continuous rolling of steel billet, hot rolling pass is 10 times.
6. a kind of low temperature as claimed in claim 4 is characterized in that with the manufacture method of angle steel described angle steel is equilateral or the scalene hot-rolled angle steel.
7. a kind of low temperature as claimed in claim 4 is with the manufacture method of angle steel, it is characterized in that the ferrite grain size of described angle steel is not less than 8 grades after the normalizing.
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| CN102851584A (en) * | 2012-04-20 | 2013-01-02 | 宿迁南钢金鑫轧钢有限公司 | Niobium-containing large-sized high-strength angle iron and production technology thereof |
| CN103042028A (en) * | 2012-12-21 | 2013-04-17 | 山西新泰钢铁有限公司 | Method for rolling H-shaped steel with stable impact energy |
| CN103526120A (en) * | 2013-09-25 | 2014-01-22 | 安徽宏源线路器材有限公司 | Low-temperature impact resistant angle steel for power transmission iron tower |
| CN103938075A (en) * | 2014-04-04 | 2014-07-23 | 北京国网富达科技发展有限责任公司 | Preparation method of high-toughness Q420 grade hot-rolled equal angle steel for iron tower |
| CN103938063A (en) * | 2014-04-04 | 2014-07-23 | 北京国网富达科技发展有限责任公司 | Preparation method of high-toughness Q345 grade hot-rolled equal angle steel for iron tower |
| CN104018081A (en) * | 2014-06-25 | 2014-09-03 | 武汉钢铁(集团)公司 | Low-temperature resistant special steel bar and production method thereof |
| CN104087827A (en) * | 2014-07-15 | 2014-10-08 | 武汉钢铁(集团)公司 | Atmosphere-corrosion-resistant and low-temperature-impact-resistant high-specification angle steel and production method thereof |
| CN107502835A (en) * | 2017-08-17 | 2017-12-22 | 北京国网富达科技发展有限责任公司 | A kind of weather-proof angle steel of steel tower high-strength and high ductility and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85102174A (en) * | 1985-04-01 | 1986-09-17 | 重庆大学 | Low temperature structural carbon steel |
| CN101868560A (en) * | 2007-11-22 | 2010-10-20 | Posco公司 | High strength and low yield ratio steel for structure having excellent low temperature toughness |
-
2011
- 2011-06-09 CN CN2011101544127A patent/CN102212752A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85102174A (en) * | 1985-04-01 | 1986-09-17 | 重庆大学 | Low temperature structural carbon steel |
| CN101868560A (en) * | 2007-11-22 | 2010-10-20 | Posco公司 | High strength and low yield ratio steel for structure having excellent low temperature toughness |
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| CN102851584A (en) * | 2012-04-20 | 2013-01-02 | 宿迁南钢金鑫轧钢有限公司 | Niobium-containing large-sized high-strength angle iron and production technology thereof |
| CN103042028A (en) * | 2012-12-21 | 2013-04-17 | 山西新泰钢铁有限公司 | Method for rolling H-shaped steel with stable impact energy |
| CN103526120A (en) * | 2013-09-25 | 2014-01-22 | 安徽宏源线路器材有限公司 | Low-temperature impact resistant angle steel for power transmission iron tower |
| CN103526120B (en) * | 2013-09-25 | 2016-09-07 | 安徽宏源线路器材有限公司 | Low-temperature impact resistant angle steel for power transmission iron tower |
| CN103938075A (en) * | 2014-04-04 | 2014-07-23 | 北京国网富达科技发展有限责任公司 | Preparation method of high-toughness Q420 grade hot-rolled equal angle steel for iron tower |
| CN103938063A (en) * | 2014-04-04 | 2014-07-23 | 北京国网富达科技发展有限责任公司 | Preparation method of high-toughness Q345 grade hot-rolled equal angle steel for iron tower |
| CN103938063B (en) * | 2014-04-04 | 2016-03-30 | 北京国网富达科技发展有限责任公司 | A kind of preparation method of steel tower high tenacity Q345 level hot rolling equal angle steel |
| CN104018081A (en) * | 2014-06-25 | 2014-09-03 | 武汉钢铁(集团)公司 | Low-temperature resistant special steel bar and production method thereof |
| CN104018081B (en) * | 2014-06-25 | 2016-07-13 | 武汉钢铁(集团)公司 | A kind of low temperature resistant special reinforced and production method |
| CN104087827A (en) * | 2014-07-15 | 2014-10-08 | 武汉钢铁(集团)公司 | Atmosphere-corrosion-resistant and low-temperature-impact-resistant high-specification angle steel and production method thereof |
| CN107502835A (en) * | 2017-08-17 | 2017-12-22 | 北京国网富达科技发展有限责任公司 | A kind of weather-proof angle steel of steel tower high-strength and high ductility and preparation method thereof |
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