CN107365891A - Constructional Steel - Google Patents
Constructional Steel Download PDFInfo
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- CN107365891A CN107365891A CN201710193348.0A CN201710193348A CN107365891A CN 107365891 A CN107365891 A CN 107365891A CN 201710193348 A CN201710193348 A CN 201710193348A CN 107365891 A CN107365891 A CN 107365891A
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- hardness
- steel
- top layer
- central part
- constructional steel
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/08—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires for concrete reinforcement
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Architecture (AREA)
- Crystallography & Structural Chemistry (AREA)
- Thermal Sciences (AREA)
- Physics & Mathematics (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
It is an object of the invention to provide one kind except high-tensile, outside underrelaxation characteristic and delayed fracture resistance, has the Constructional Steel of high solderability concurrently.To reach the purpose, Constructional Steel that the present invention uses for：Constructional Steel with the hardness top layer lower than central part, tensile strength are more than 1500MPa；Relaxation value under the conditions of 180 DEG C of steam press maintenance is less than 10%；In the state of in the 20% ammonium thiocyanate aqueous solution for be immersed in 50 DEG C, when having loaded 70% test load of the tensile strength until the delayed fracture time of fracture is more than 10 hours；And the hardness Vs on the top layer is 0.50 times~0.96 times of the hardness Vi of the central part.
Description
Technical field
Invention involved by the application of this part more particularly to as prestressed-concrete pile, prestressed concrete column etc. are pre- should
The Constructional Steel of the enhancing steel of power concrete construction.
Background technology
In the past, Constructional Steel was that high-strength PC is widely used as the PC such as concrete-pile, concrete column, bridge with steel
The enhancing steel of (prestressed concrete) structure.PC steel have by the JIS G 3137 of heat treatment manufacture:2008 it is " thin
Footpath abnormity PC rod irons ", the JIS G 3109 manufactured by cold working:2008 " PC rod irons " etc., these yield strength, tension is strong
Degree, elongation, relaxation value are standardized.High-strength PC is standardized as the D kinds that tensile strength is more than 1420MPa with steel.
PC rod irons have tensile stress to be acted on all the time in order to give prestressing force to concrete product.Prestressed concrete
PC rod irons in native structure because use all the year round and rainwater from concrete caused by fragmented parts etc. immerse when, the table of PC rod irons
Face can partly corrode.In the state of tensile stress is acted on, when hydrogen invades the inside of PC rod irons from the erodable section,
So-called delayed fracture can be caused in the case of having.In tensile stress long term in the case where being placed on such corrosive environment
In the case of PC steel, the PC steel can produce delayed fracture, after the several years to many decades, meeting in the case that the PC steel have
Fracture suddenly.Therefore, with high intensity, anti-delayed fracture characteristic is also required for the PC rod irons.
Thus, for example patent document 1 discloses the technology for improving anti-delayed fracture characteristic.Specifically, the institute of patent document 1
The manufacture method of disclosed steel to the steel of quenching by implementing tempering, so that the hardness of a part for the steel is less than
The hardness of the other parts of the steel, the tempering include：Heated using sensing heating or direct-electrifying by the steel
The heating process of 10% instant heating from epidermis to radius；Described add will be being have passed through after the heating process starts within 1 second
The refrigerating work procedure of the steel quenching of thermal technology's sequence, the heating-up temperature of the heating process is the more than Ac1 transformation temperatures tempering
Treatment conditions be set to：More than 1.5 times centered on skin section tempering carries out value N.
Thus, using patent document 1 disclosed in technology, in general having the higher anti-delayed fracture of tensile strength
The PC rod irons for the tendency that property more declines, by having soft portion on surface, excellent delayed fracture resistance is had concurrently so as to realize
With the PC rod irons of predetermined tensile strength.
Prior art literature
Patent document
Patent document 1：Japanese Patent No. 5337792
However, technology disclosed in patent document 1 due within after heating process starts 1 second by via heating process
Steel are quenched, it is thus impossible to carry out the processing needed for discovery underrelaxation.Accordingly, it is difficult to realize market demands to have tension concurrently strong
The PC rod irons of degree, underrelaxation characteristic and delayed fracture resistance.
In addition, above-mentioned PC rod irons are such as fixed into caged and made in casting concrete precedent in the case of having using spot welding
With；Iron wire is fixed into curl using spot welding around the PC rod irons of the cage bar of load elongation power in the case of having and made
With.But exist：The tensile strength of PC rod irons itself is higher, the tendency that solderability more declines, except above-mentioned high tensile is strong
Outside degree, underrelaxation characteristic and delayed fracture resistance, in the market also requires to have high solderability concurrently.
The content of the invention
Therefore, present inventor has performed attentively studying as a result, it is possible to provide a kind of involved in the present invention for building
Steel.
That is, Constructional Steel involved in the present invention has the hardness top layer lower than central part, it is characterised in that tension is strong
Spend for more than 1500MPa, the relaxation value under the conditions of 180 DEG C of steam press maintenance is less than 10%, be immersed in 50 DEG C 20%
In the state of in the ammonium thiocyanate aqueous solution, when having loaded 70% test load of the tensile strength until the delay of fracture is broken
The time is split for more than 10 hours, and the hardness Vs on the top layer and the central part hardness Vi meet 0.50Vi≤Vs≤0.96Vi.
In addition, in Constructional Steel involved in the present invention, the hardness Vi of preferably described central part for 450HV with
Upper below 550HV.
In addition, in Constructional Steel involved in the present invention, the hardness Vs on preferably described top layer is more than 225HV
Below 528HV.
In addition, in Constructional Steel involved in the present invention, preferably described top layer is with from surface to center
Size is as the depth from surface 1%~30% when 100%.
Also, the elongation at break that Constructional Steel involved in the present invention is preferably point postwelding is more than 5%.
In addition, it is more than 1420MPa that Constructional Steel involved in the present invention, which is preferably 0.2% yield strength,.
The effect of invention
Constructional Steel involved in the present invention due to being with the hardness top layer lower than central part, tensile strength
More than 1500MPa, the relaxation value under the conditions of 180 DEG C of steam press maintenance is less than 10%, is being immersed in 50 DEG C of 20% sulphur cyanogen
In the state of in sour aqueous ammonium, when loading 70% test load of the tensile strength until the delayed fracture time of fracture
For more than 10 hours, and the hardness Vs on the top layer and the central part hardness Vi met predetermined inequality, therefore, it is possible to provide
One kind both maintains high-tensile, and underrelaxation, the PC steel for balancing good high intensity of high anti-delayed fracture characteristic good
Rod W.
Brief description of the drawings
Fig. 1 is the schematic diagram for showing the concept of process A~process C of present invention heat treatment.
Fig. 2 be for being shown with Q-tempering steel in the case of process A~process C heat treatment concept
Schematic diagram.
Fig. 3 is the chart for the relation for showing elapsed time that the Analysis of Heat Transfer of PC rod irons drawn and Temperature Distribution.
Fig. 4 is the chart for the relation for showing cool time that the Analysis of Heat Transfer of PC rod irons drawn and Temperature Distribution.
Fig. 5 is the schematic diagram for showing the concept of process A~process C of present invention heat treatment.
Fig. 6 is to show distance from surface of the tensile strength for the embodiment 1 of 1600MPa levels, embodiment 2 and comparative example 1
With the figure of the relation of Vickers hardness.
Fig. 7 be show embodiment 3 that tensile strength is 1650MPa levels from the distance on surface and the relation of Vickers hardness
Figure.
Fig. 8 is to show that the distance from surface and Vickers of embodiment 4 that tensile strength is 1700MPa levels and comparative example 2 are hard
The figure of the relation of degree.
Fig. 9 is the microphotograph (100 times and 400 times) of the raw material before the Quenching Treatment of embodiment 1.
Figure 10 is the microphotograph (100 times and 400 times) of the steel after the Quenching Treatment of embodiment 1.
Figure 11 is the micro- of the steel after surface soft temper processing and warm correction process quenching by embodiment 1
Mirror photo (100 times and 400 times).
The explanation of reference
W：PC rod irons
1：Manufacture device
2：Quench heating coil (quenching unit)
3：Quench side coolant jacket (quenching side cooling unit)
4：Top layer soft temper heating coil (top layer soft temper unit)
5：Deformation assigns device (deformation given unit)
6：It is tempered side coolant jacket (tempering side cooling unit)
Embodiment
Below, the embodiment party of Constructional Steel involved in the present invention and the manufacture method of the Constructional Steel is described in detail
Formula.
1. Constructional Steel
Constructional Steel involved in the present invention is characterised by thering is the hardness top layer lower than central part, tensile strength
For more than 1500MPa, the relaxation value under the conditions of 180 DEG C of steam press maintenance is less than 10%, is being immersed in 50 DEG C of 20% sulphur
In the state of in cyanic acid aqueous ammonium, when having loaded 70% test load of the tensile strength until the delayed fracture of fracture
Time is more than 10 hours, and the hardness Vs on the top layer and the central part hardness Vi meet 0.50Vi≤Vs≤0.96Vi.
The Constructional Steel of the present invention is, for example, the enhancing steel for being used as the prestressed concrete structures such as PC stakes, PC posts
High intensity PC rod irons, solid pole shape is presented.The Constructional Steel has more than 1500MPa high-tensile,
There is the hardness top layer lower than the central part (softening layer) on surface.Specifically, the hardness Vs on the top layer, specifically top layer
Average hardness Vs, be the hardness Vi of the central part of the Constructional Steel shown in above-mentioned number 2, specifically central part is flat
0.50 times~0.96 times of equal hardness Vi.Because：In 0.50 of the hardness Vs on the top layer less than the hardness Vi of the central part
In the case of times, it is difficult to realize underrelaxation；In the case of higher than 0.96 times of the hardness Vi of central part, it is difficult to softened
The effect of anti-delayed fracture characteristic obtained by top layer.
Preferably, the hardness Vi of the central part of Constructional Steel of the invention is more than 450HV below 550HV.This is
Because when the hardness Vi of central part is less than 450HV, it is impossible to ensure the intensity as PC rod irons.In the present invention, by central part
Hardness Vi specifically for below 550HV, but not the hardness Vi of the central part itself has a critical meaning, but because conduct
It is used as the hardness of the central part (mother metal) of PC rod irons, there's almost no the situation higher than 550HV.
If as described above, the hardness Vs on top layer relative to the central part of the Constructional Steel hardness Vi for 0.50Vi~
0.96Vi, then the effect of anti-delayed fracture characteristic involved in the present invention, but the more preferably hardness on top layer can be obtained
Vs specifically more than 225HV below 528HV.Because when the hardness Vs on top layer is less than 225HV, it is difficult to realize low pine
Relax, during higher than 528HV, it is difficult to obtain the effect of anti-delayed fracture characteristic.
The depth on the preferably top layer with above-mentioned hardness is using the size from surface to center as when 100%
Depth from surface 1%~30%.Because when the depth on the top layer is less than 1%, it is difficult to obtain because existing in hardness ratio
Desired anti-delayed fracture characteristic caused by the low top layer of center portion, when deeper than 30%, the ratio of mother metal relative to top layer ratio
Example is too low, it is difficult to obtains desired intensity.
Relaxation value of the Constructional Steel of the present invention under the conditions of 180 DEG C of steam press maintenance is less than 10%.In general,
During the maintenance of concrete during in order to shorten manufacture prestressed-concrete pile or post, with 180 DEG C~200 DEG C in the case of having
Steam press maintenance is carried out under the atmosphere of 10 air pressure or so.In the steam press maintenance, the relaxation of the PC rod irons in concrete has increase
Tendency, but in the present invention, under the conditions of 180 DEG C of steam press maintenance, because relaxation value is less than 10%, accordingly, it is capable to
Enough realize high relaxation property.
, should in load in the state of the Constructional Steel of the present invention is in the 20% ammonium thiocyanate aqueous solution for be immersed in 50 DEG C
Until the delayed fracture time of fracture is more than 10 hours during 70% test load of tensile strength, more preferably 100 hours
More than.Therefore, Constructional Steel of the invention more declines the delayed fracture characteristic of tendency to generally there is tensile strength higher,
The tensile strength in more than 1500MPa is able to maintain that, is greatly improved.
In addition, the elongation at break of the point postwelding of the Constructional Steel of the present invention is preferably more than 5%.Have
The Constructional Steel of more than 1500MPa tensile strength has the elongation at break of more than 5% point postwelding concurrently, thereby using this
The concrete construction of Constructional Steel can obtain desired characteristic.
In addition, 0.2% yield strength of the Constructional Steel of the present invention is preferably 1420MPa.Thus, building of the invention
With steel in the case of using 0.2% yield strength as index, although having sufficient engineering properties, PC steel also is suitable as
The use of material.
Also, for the composition composition of the Constructional Steel of the present invention, have what is generally comprised as PC with steel
Alloying component forms.It is, for example, possible to use carbon is below 0.45 mass %, silicon is the mass % of 0.2 mass %~2.50, manganese
For the mass % of 0.60 mass %~0.90, phosphorus is below 0.030 mass %, and sulphur is below 0.035 mass %, and copper is 0.30 matter
Measure below %, titanium is the mass % of 0.01 mass %~0.10, and boron be below 0.01 mass %, remainder have by iron with can not
The steel for the chemical composition that the impurity avoided is formed.
Herein, the element needed for the intensity of the steel after the carbon as alloying component is in order to ensure quenching.But due to
The weldabilities such as spot welding can be lost in a large amount of addition carbon, it is therefore preferable that being below 0.45 mass %.Silicon as alloying component is to improve
Yield point, significantly contribute to relaxation value, solderability, the improved element of delayed fracture characteristic.In the present invention, the silicon is with 0.2
More than quality % is present, so as to be particular enable to improve solderability, delayed fracture characteristic.But during addition more than 2.00 mass %,
Problem can be produced in the case of due to having in steel rolling process processed, therefore preferably below 2.50 mass %.As alloy into
Titanium, the boron divided is to improve hardenability, and have improves the important of the effect of fatigue properties and intensity by realizing intercrystalline strengthening
Element.But due to turning into brittle when largely addition titanium, boron, it is therefore preferred to titanium is below 0.10 mass %,
Boron is below 0.01 mass %.
As described above, Constructional Steel involved in the present invention is because tensile strength is more than 1500MPa, at 180 DEG C
Under the conditions of steam press maintenance relaxation value be less than 10%, in the 20% ammonium thiocyanate aqueous solution for be immersed in 50 DEG C in the state of,
When loading 70% test load of the tensile strength until the delayed fracture time of fracture is more than 10 hours, and the top layer
Hardness Vs be less than more than 0.50 times 0.96 times of hardness Vi of the central part, both maintain height therefore, it is possible to provide one kind
Intensity, and the good high-strength PC rod iron W of balance of low, the high anti-delayed fracture characteristic good of relaxation.Further, since institute of the present invention
The elongation at break of the point postwelding for the Constructional Steel being related to is more than 5%, and therefore, solderability is high, has used the construction(al)steel
The concrete construction of material can obtain desired characteristic.
2. the manufacture method of Constructional Steel
Next, illustrate the manufacture method of Constructional Steel involved in the present invention.Construction(al)steel involved in the present invention
Material is handled the steel (workpiece) of quenching, is preferably included：Lead at least by the steel sensing heating of quenching or directly
Electrical heating, it is anxious to being carried out using the size from the surface of the steel to center as the depth from surface 1%~30% when 100%
The top layer soft temper process (process A) of speed heating；The deformation that in warm region the steel are assigned with deformation assigns process (process
B)；The temper cooling sequence (process C) that the steel via process A and process B are rapidly cooled down.Below, the process of reference picture 1
Summary description figure come illustrate comprising equivalent to pretreatment it is quenching process, realize include process A~process C conduct it is for building
The manufacture device (production line) 1 of one embodiment of the manufacture method of steel.
In the present embodiment, manufacture device 1 includes：Quench heating line as the quenching unit for implementing pretreatment process
Circle 2；Quenching side coolant jacket 3 as quenching side cooling unit；Top layer as the top layer soft temper unit for implementing process A is soft
Change tempering heating coil 4；Deformation as the deformation given unit for implementing process B assigns device 5；As time for implementing process C
The tempering side coolant jacket 6 of fiery side cooling unit.These Quench heating coils 2, quenching side coolant jacket 3, the heating of top layer soft temper
Coil 4, deformation assign device 5, tempering side coolant jacket 6 such as disposed in linear transport path, as heat treatment object
Steel PC rod irons W by axial direction of the pinch roll as delivery unit along rod iron W, be continuously transported to each heat treatment successively
Equipment.Below, each process is illustrated.
Pretreatment process：In pretreatment process, the steel of the material of Constructional Steel will be used as by the use of Quench heating coil 2
Material (non-PC rod iron W herein) sensing heating or direct-electrifying heating, after instant heating to hardening heat, using quenching coolant jacket
3 flash quenching coolants, are quenched and are continuously quenched.Hardening heat now is not particularly limited in the present invention, but
Such as preferably carried out under the arbitrary temp of 850 DEG C~1200 DEG C of scope.
, can also be as shown in Fig. 2 utilizing tempering heating after PC rod irons W quenching has been carried out in the pretreatment process
Coil 11 comes sensing heating or direct-electrifying heating, after PC rod irons W whole cross section instant heating to temperature, profit
With the tempering injection of coolant jacket 12 tempering coolant and it is quenched, turns into Q-tempering steel.Cooling velocity now is preferably 500
Below DEG C/sec.
Process A：Process A is top layer soft temper process, will be in pretreatment work using top layer soft temper heating coil 4
Be quenched in sequence handle (include Q-tempering) PC rod iron W sensing heatings or direct-electrifying heat, by PC rod irons W from
Surface to center size as the depth instant heating from surface 1%~30% when 100% to 300 DEG C~750 DEG C return
Fiery temperature.For the viewpoint that can realize more appropriate tempering, the temperature is more preferably 420 DEG C~600 DEG C.
Herein, with reference to the simulation result obtained by Analysis of Heat Transfer, illustrate rod iron relative to heating and cool down the elapsed time
Heat transfer conditions, wherein, the Analysis of Heat Transfer is heat transfer solution when used the high-frequency induction heating of FEM model (FEM)
Analysis.Fig. 3 is the chart for the relation for showing elapsed time that the Analysis of Heat Transfer of PC rod irons drawn and Temperature Distribution, and Fig. 4 is to show
The cool time and the chart of the relation of Temperature Distribution that the Analysis of Heat Transfer of PC rod irons is drawn.The analysis condition is：For S40C
Radius 3.65mm solid pole, heating layer depth is 0.154mm, and the heat time is 0.17 second, cool time 0.63
Second, initial temperature are 20 DEG C.Fig. 3 shows what is terminated since the heating in a certain section of the steel in continuous heat to cooling
(+0.63 second 0.17 second) elapsed time was 100%, 6 from surface to the center position of the steel passed through relative to the time
Each temperature change.Fig. 4 shows the respective of every 0.3 second terminated relative to r (from the distance of center)/R (radius) from heating
Temperature.
It was found from these Fig. 3 and Fig. 4 simulation result, the skin section for heating initial stage is high temperature, and central part is the temperature of low temperature
Degree distribution, but understand that the temperature by skin section and central part over time becomes uniform, pass through further with the time, by
In heat radiation, the temperature of skin section is begun to decline.
Thus, the condition for the instant heating that the top layer soft temper heating coil 4 is carried out suitably is set, in PC rod irons W
Top layer soft temper process in untill PC rod irons W total cross-section evenly heating during, the temperature difference from surface to central part
It is optimised, so as to form the hardness top layer lower than the central part, the hardness Vi centered on specifically hardness Vs
0.50 times~0.96 times of top layer.Specifically, by suitably adjusting the input work of the top layer soft temper heating coil 4
Rate, penetration of current, surface power density, surface heating-up temperature, heat time, PC rod irons W surface and the temperature at center
Consistent soaking temperature, top layer bating effect rate, so as to control the depth from surface of instant heating.Herein, electric current is worn
Saturating depth δ is the value obtained using numerical expression as shown below.
Wherein, ρ：Specific insulation (Ω m), μr：Relative dielectric constant, f：Frequency (Hz)
Surface power density P is the value obtained using numerical expression as shown below.
Wherein, Pw：It is input to the power (kW) of workpiece, S：Surface area (the m of the workpiece of heated per unit time2)
Surface bating effect rate z is the value obtained using numerical expression as shown below.
Wherein, δ：Penetration of current (mm), Ts：Surface heating-up temperature (DEG C), Tc：Central part temperature (degree Celsius 5)
In the present embodiment, be 10kW~50kW preferably in input power, penetration of current be 0.1mm~
0.5mm, surface power density are 1000W/m2~5000W/m2, and surface heating-up temperature is 300 DEG C~750 DEG C, and the heat time is
0.15 second~10 seconds, soaking time was 0.5 second~20 seconds, and top layer bating effect rate combines between being 10%~50%.By
Predetermined amount of heat is applied to PC rod irons W in short time and heated, be in order to avoid：Heat transfer is to until PC rod irons W's is interior
Portion, until immediate vicinity is softened, decline so as to PC rod irons W itself intensity.In addition, by controlling temperature, so as to
Enough any tensile strength for adjusting obtained PC rod irons W.
In the top layer soft temper process, preferably top layer soft temper heating coil 4 is high-frequency induction heating line
Circle, more preferably frequency is more than 1kHz.Because by carrying out high-frequency sensing heating, so as to effectively enter
Row due to Kelvin effect only docks the heating of the part of near surface, the short time only to using the size to center as
The skin section heating of the depth from surface 1%~30% when 100%, can easily form the top layer than central part softening.
Process B：The process B is that deformation assigns process, and the processing that is quenched at least having obtained pretreatment process (is included and quenched
Fire tempering) PC rod irons W warm region assign deformation while carrying out soaking.The process B is by PC rod irons W in warm region
Device is assigned using deformation and assigns deformation to PC rod irons W, improves PC rod irons W relaxation value.Herein, warming region should
PC rod irons W surface temperature is 300 DEG C~750 DEG C, more preferably 420 DEG C~600 DEG C.In addition, assign shape as to PC rod irons W
The unit of change, such as method, the hot-stretch side of the line straightening machine for using the rotating cylinder mode for being built-in with multiple corrective pieces can be used
Method etc., but it is not limited to these.Assigning deformation to PC rod irons W can be with not only 1 time, and is divided into repeatedly to implement.
In the present embodiment, after such as being heated in above-mentioned process A, for example, implementing process B simultaneously within 10 seconds
PC rod irons W is imported into deformation to assign in device 5, so as to assign shape in warm region without especially heating PC rod irons W
Become.
The processing time of the process B, 1 is more preferably to process C cool time after specifically terminating from process A
Second~20 seconds.Because when the processing time of process B was less than 1 second, it is impossible to fully assign deformation to PC rod irons W, it is difficult to realize
Desired relaxation value.In addition, when the processing time of process B was more than 20 seconds, common tempering can be turned into, it is difficult to realize desired strong
Degree.
In addition, the implementation order of the process B is not limited to after process A, as long as deformation can be assigned in warm region, such as
Shown in Fig. 5, process B can also be implemented before process A.In this case, before process B is implemented, using being tempered heating coil
13 couples of PC rod irons W whole cross section sensing heating or direct-electrifying heating, PC rod irons W whole cross section is heated to back
Fiery temperature, implement the process B, so as to assign the PC rod irons W to deformation in warm region.The PC implemented before process B
The temperature of rod iron W whole cross section is not particularly limited, but usually 300 DEG C~700 DEG C, more preferably 300 DEG C~500
℃。
Process C：Process C is temper cooling sequence, will be via process A using the injection tempering coolant of coolant jacket 6 is tempered
It is quenched with the PC rod irons W of process B and is continuously tempered.Process C is pre- to be rapidly cooled to more than 100 DEG C/sec of cooling velocity
Fixed chilling temperature, so as to can also form the layer of soft on top layer using 1 tempering, and have from predetermined depth
There is uniform hardness to be distributed, the PC rod irons W of more than 1500MPa tensile strength can be manufactured.
Process C processing time is more preferably 1 second~60 seconds.Because when process C processing time was less than 1 second,
Can not sufficiently cool PC rod irons W, more than 60 seconds carry out when, it is difficult to realize desired tensile strength.
In addition, as long as the manufacture method of Constructional Steel involved in the present invention includes above-mentioned each operation, in addition
Hot-working, cold working and rolling, bracing wire, casting etc. can be applicable, can also suitably select the temperature of each operation.In addition, with adding
Work is suitably quenched simultaneously, temper, so as to adjust the intensity of Constructional Steel.
Next, illustrate the embodiment and comparative example of Constructional Steel involved in the present invention.
[embodiment 1]
For the Constructional Steel of embodiment 1, as steel (experiment material) be utilize comprising the chemistry shown in table 1 below into
The diameter (nickname) divided is 10.7mm, and the thin footpath abnormity PC rod irons that external diameter is 11.10mm make.
[table 1]
| Chemical composition | C | Si | Mn | P | S | Cu | Ti | B |
| Quality % | 0.32 | 1.89 | 0.72 | 0.011 | 0.004 | 0.01 | 0.03 | 0.0020 |
In embodiment 1, first, steel are quenched.Specifically, utilized by using Quench heating coil 2
50kHz high-frequency induction heating, after making the steel with temperature i.e. 1010 DEG C more than 3.75 seconds A3 points for being warming up to the steel, enter
The row soaking of 9.58 seconds, afterwards, immediately using quenching coolant jacket 3, using water cooling with about 168 DEG C/sec of cooling velocity from 900 DEG C
I.e. 30 DEG C of the Mf points temperature below of the steel is rapidly cooled to be quenched.Next, use top layer soft temper heater wire
Circle 4, is heated using induction heating method.Specific heat treatment condition is the defeated of top layer soft temper heating coil 4
It is 21kW to enter power, and heating-up temperature is 530 DEG C, and the heat time is 0.75 second, and soaking temperature is 455 DEG C, and penetration of current is
0.398mm, surface power density is 2532kW/m2, top layer bating effect rate is 14.2%.Moreover, will be from top layer soft temper
The steel that heating coil 4 comes out imported into deformation and assign device 5, and deformation is assigned to the steel in warm region.Assigned by deformation
Device 5 assigns start temperature as 450 DEG C come the deformation carried out, and the deformation process time is 7.92 seconds.Afterwards, in tempering coolant jacket 6
In, using water cooling with about 100 DEG C/sec of cooling velocity, room temperature is rapidly cooled to by the steel of device 5 out are assigned from deformation.
The steel of embodiment 1 are obtained by the process.In addition, the manufacturing process of the embodiment 1 is equivalent to above-mentioned Fig. 1.In addition, the reality
Apply the top layer soft temper process (process A) of example 1 and deformation assign process (process B) heat treatment condition and other embodiment and
Comparative example is as shown in table 2 in the lump.
[table 2]
[embodiment 2]
Embodiment 2 equally makes steel using the experiment material same with the above embodiments 1.Embodiment 2 is with implementing
Example 1 is only that top layer soft temper condition is different, in addition obtains steel under identical condition.Specifically, embodiment 2
Heat treatment condition be that the input power of top layer soft temper heating coil 4 is 40kW, heating-up temperature is 535 DEG C, the heat time
For 1.38 seconds, soaking temperature was 472 DEG C, penetration of current 0.159mm, and surface power density is 4823kW/m2, and top layer is soft
It is 29.6% to change effect rate.Moreover, it is 470 DEG C that the deformation for assigning device 5 by deformation to carry out, which assigns start temperature, deformation process
Time is 7.92 seconds.
[embodiment 3]
Embodiment 3 equally makes steel using the experiment material same with the above embodiments 1.Embodiment 3 is with implementing
Example 1 is only that quenching condition is different with top layer soft temper condition, in addition obtains steel under identical condition.It is specific and
Speech, high-frequency induction heating of the embodiment 3 using Quench heating coil 2 using frequency 50kHz, makes the steel be warming up to 3.75 seconds
Temperature more than the A3 points of the steel is after 970 DEG C, cold with about 500 DEG C/sec using water cooling immediately using quenching coolant jacket 3
But speed is rapidly cooled to the Mf points temperature below i.e. room temperatures of the steel to be quenched.Moreover, at the heat of top layer soft temper
Manage bar part is that the input power of top layer soft temper heating coil 4 is 38kW, and heating-up temperature is 525 DEG C, the heat time 0.75
Second, soaking temperature is 440 DEG C, penetration of current 0.225mm, and surface power density is 4582kW/m2, top layer bating effect
Rate is 28.8%.Moreover, it is 440 DEG C to assign device 5 to assign start temperature the deformation that carries out by deformation, the deformation process time is
7.92 the second.
[embodiment 4]
Embodiment 4 equally makes steel using the experiment material same with the above embodiments 1.Embodiment 4 is with implementing
Example 1 is only that top layer soft temper condition is different, in addition obtains steel under identical condition.Specifically, embodiment 4
Heat treatment condition be that the input power of top layer soft temper heating coil 4 is 28kW, heating-up temperature is 495 DEG C, the heat time
For 1.38 seconds, soaking temperature was 435 DEG C, penetration of current 0.159mm, and surface power density is 3376kW/m2, and top layer is soft
It is 30.5% to change effect rate.Moreover, the deformation for assigning device 5 by deformation to carry out, which assigns, starts (temperature) as 435 DEG C, at deformation
It is 7.92 seconds to manage the time.
[comparative example]
[comparative example 1]
Comparative example 1 equally makes steel using the experiment material same with the above embodiments 1.Comparative example 1 is with implementing
Example 1 is only that quenching condition, top layer soft temper condition, deformation giving condition are different, in addition under identical condition
To steel.Specifically, high-frequency induction heating of the comparative example 1 using Quench heating coil 2 using frequency 50kHz, makes the steel
Behind temperature i.e. 1000 DEG C more than 3.75 seconds A3 points for being warming up to the steel, immediately using quenching coolant jacket 3, using water cooling with
About 500 DEG C/sec of cooling velocity is rapidly cooled to the Mf points temperature below i.e. room temperatures of the steel to be quenched.Moreover, top layer
The heat treatment condition that soft temper heating coil 4 is carried out is that the input power of top layer soft temper heating coil 4 is 9kW, is added
Hot temperature is 510 DEG C, and the heat time is 1.18 seconds, and soaking temperature is 461 DEG C, penetration of current 0.398mm, surface electric power
Density is 930kW/m2, top layer bating effect rate is 9.7%.In addition, the deformation for assigning device 5 by deformation to carry out is assigned and started
Temperature is 457 DEG C, and the deformation process time is 6.79 seconds.
[comparative example 2]
Comparative example 2 is only that top layer soft temper condition and deformation giving condition are different from above-mentioned comparative example 1, except this it
Steel are obtained under identical condition outside.Specifically, at the heat that the top layer soft temper heating coil 4 of comparative example 2 is carried out
Manage bar part is that the input power of top layer soft temper heating coil 4 is 8kW, and heating-up temperature is 478 DEG C, the heat time 1.18
Second, soaking temperature is 436 DEG C, penetration of current 0.398mm, and surface power density is 827kW/m2, top layer bating effect
Rate is 8.8%.In addition, it is 430 DEG C to assign device 5 to assign start temperature the deformation that carries out by deformation, the deformation process time is
6.79 the second.
Below, the result of the test of the steel of above-mentioned each embodiment and comparative example is shown.Herein, each embodiment and ratio are illustrated
Tension test compared with example, hardness distribution, metal structure observation, solderability it is related test, the experiment that relaxation is related, delayed fracture
The result of experiment.
Tension test：The tension test carried out for each embodiment and comparative example is with JIS Z 2241 using No. 2 samples
On the basis of and carry out.Tensile strength, 0.2% yield strength, elongation at break, even elongation are obtained using the tension test
Rate, yield ratio.Each embodiment and the tensile strength of comparative example, 0.2% yield strength, elongation at break, uniform elongation, surrender
Than as shown in table 3.
[table 3]
From the result of the tension test, the embodiment of whichever tensile strength grade, all obtaining 0.2% yield strength is
More than 1535MPa, elongation at break are more than 8.5%, and uniform elongation is more than 2.1% characteristic.
Hardness is distributed：Fig. 6~Fig. 8 show each embodiment and comparative example from the distance of steel surface and the pass of Vickers hardness
System.Fig. 6 shows embodiment 1, embodiment 2 and the comparative example 1 that tensile strength is 1600MPa levels, and Fig. 7 shows that tensile strength is
The embodiment 3 of 1650MPa levels, Fig. 8 show the embodiment 4 and comparative example 2 that tensile strength is 1700MPa levels.
As shown in fig. 6, for each steel of tensile strength 1600MPa levels, in embodiment 1, the depth on top layer is
0.5mm, hardness (average hardness from surface to the 0.5mm) Vs on top layer are 469HV, the hardness of central part (from surface to 1.5~
6.0mm average hardness) Vi is 500HV.0.94 times of hardness Vi centered on the case hardness Vs of embodiment 1.Embodiment 2
In, the depth on top layer is 1.0mm, and hardness (average hardness from surface to the 1.0mm) Vs on top layer is 447HV, central part it is hard
(from surface to 1.5~6.0mm average hardness), Vi is 485HV to degree.Hardness Vi centered on the case hardness Vs of embodiment 1
0.92 times.In contrast, in comparative example 1, the depth on top layer is 0.1mm, hardness (being averaged from surface to 0.1mm on top layer
Hardness) Vs is 487HV, hardness (from surface to 1.5~6.0mm average hardness) Vi of central part is 509HV.Embodiment 4
0.98 times of hardness Vi centered on case hardness Vs.0.98 of hardness Vi centered on the case hardness Vs of comparative example 1
Times.Therefore, when with identical tensile strength grade to compare, embodiment 1 and embodiment 2 are able to confirm that with from surface to center
Size as the depth from surface 4.5% or 9% when 100%, including centered on hardness 0.92 times of hardness or
0.94 times of top layer.Comparative example 1 is able to confirm that hardness of the hardness on surface substantially with central part does not change, and is almost formed without
Top layer.
As shown in fig. 7, for the steel of tensile strength 1650MPa levels, in embodiment 3, the depth on top layer is
0.9mm, hardness (average hardness from surface to the 0.9mm) Vs on top layer are 462HV, the hardness of central part (from surface to 1.5~
6.0mm average hardness) Vi is 551HV.0.84 times of hardness Vi centered on the case hardness Vs of embodiment 3.It is in addition, real
Apply example 3 and be able to confirm that the depth from surface 8.1% when using the size from surface to center as 100%, including hardness are
0.84 times of top layer of central part hardness.
As shown in figure 8, for each steel of tensile strength 1700MPa levels, in embodiment 4, the depth on top layer is
0.5mm, hardness (average hardness from surface to the 0.5mm) Vs on top layer are 469HV, the hardness of central part (from surface to 1.5~
6.0mm average hardness) Vi is 500HV.0.96 times of hardness Vi centered on the case hardness Vs of embodiment 1.Phase therewith
Right, in comparative example 2, the depth on top layer is 0.1mm, and hardness (average hardness from surface to the 0.1mm) Vs on top layer is 510HV,
Hardness (from surface to 1.5~6.0mm average hardness) Vi of central part is 514HV.Therefore, with identical tensile strength grade
During comparing, embodiment 4 is able to confirm that the depth from surface 4.5% when using the size from surface to center as 100%,
Include 0.96 times of top layer of hardness centered on hardness.Comparative example 2 is able to confirm that the hardness on surface is substantially hard with central part
Degree does not change, and is almost formed without top layer.
Metal structure：Next, Fig. 9~Figure 11 shows the top layer of the steel of embodiment 1 and the metal structure of central part
Microphotograph.Before Fig. 9 shows the pretreatment of embodiment 1, the specifically microphotograph of the raw material before Quenching Treatment
(100 times and 400 times).It is able to confirm that from the photo, the raw material before Quenching Treatment have ferrite lamellae on surface, internally deposit
In the line and staff control of ferrite and pearlite.After Figure 10 shows the pretreatment of embodiment 1, the specifically steel after Quenching Treatment
The microphotograph (100 times and 400 times) of material.It is able to confirm that from the photo, the steel after Quenching Treatment are using in Quenching Treatment
Portion turns into martensitic structure, ferrite lamellae be present on surface.Figure 11 shows surface soft temper processing and the shape by embodiment 1
Become and assign process by the microphotograph (100 times and 400 times) of the steel after quenching.It is able to confirm that from the photo, with quenching
It is same after processing, ferrite lamellae be present on surface.But the different top layer of hardness and the border of mother metal can not be differentiated from Figure 11.
Solderability：The evaluation of the solderability carried out to each embodiment and comparative example is to the weldering shown in each steel table 4 below
Connect current value, power cycles number 2, plus-pressure 0.07Mpa, spiral bar 3.2mm line footpath JIS SWM-B welding condition carry out
Point postwelding, has carried out tension test.Table 4 below shows the welding current value of each embodiment and comparative example, is obtained by tension test
Fracture rate, elongation at break (average elongation, minimum elongation rate).
[table 4]
*>Show that experiment is ended without being broken in 100h
It is able to confirm that from the result of the tension test of the postwelding, the extension at break of the point postwelding of each embodiment and comparative example
Rate (average elongation) is all more than 8.1%, the characteristic with more than 5% elongation at break.
Relaxation test：The relaxation test carried out to each embodiment and comparative example is in each sample load criteria in steam pressure
70% load of tensile strength, 180 DEG C are warming up to from normal temperature with 4 hours, after being kept for 3 hours at 180 DEG C, progress stove is cold,
Slip of the load variations amount after 23 hours relative to initial load load is shown.In addition, the tensile strength of standard is being implemented
It is 1600MPa in example 1, embodiment 2 and comparative example 1, is 1650MPa in embodiment 3, is in embodiment 4 and comparative example 2
1700MPa.Upper table 4 shows the result of the relaxation test of each embodiment and comparative example.
Whichever it is able to confirm that from the result of the relaxation test, the steam pressure of steel of embodiment and comparative example at 180 DEG C
Relaxation value under curing condition all reaches less than 10%.
Delayed fracture is tested：The delayed fracture experiment carried out for each embodiment and comparative example is corroded with (civic organization)
The experiment carried out on the basis of the JSCE S 1201 of anticorrosion association distribution.Specifically, the tension of standard has been loaded in each sample
70% load of intensity is simultaneously immersed in NH4SCN (ammonium thiocyanate, concentration 20%, 50 DEG C of liquid temperature) solution, and evaluation is untill fracture
Time.In addition, the tensile strength of above-mentioned standard is same with the situation of relaxation test.Above-mentioned table 4 show each embodiment and
The result of the delayed fracture experiment of comparative example.
It is able to confirm that from the result of delayed fracture experiment, it is involved in the present invention hard centered on surface is including hardness
Each embodiment on 0.50 times~0.96 times of top layer of degree, the time untill the fracture obtained by delayed fracture experiment all reach
More than 10 hours.Particularly, in 1~embodiment of embodiment 3, it is able to confirm that and was not also broken even more than 100 hours.Therewith
Relatively, by adjusting heat treatment condition, comparative example 1 and the comparative example 2 for not forming the hardness top layer lower than central part are disconnected to delay
Time untill splitting the resulting fracture of experiment is 3.9 hours, 5.6 hours, shorter.Therefore, it is involved in the present invention in table
Face has each embodiment on 0.50 times~0.96 times of top layer of hardness centered on hardness, lower than central part with without hardness
Comparative example 1, the comparative example 2 on top layer compare, it is known that greatly improve delayed fracture characteristic.In addition, in general, delayed fracture
The tendency that characteristic has tensile strength higher and more declined, but as described in Example 4, it is known that even the steel of 1700MPa levels,
It is in a ratio of 13.3 hours, is greatly improved with conventional a few hours.
Constructional Steel involved in the present invention is understood because tensile strength is more than 1500MPa from above-mentioned result of the test,
But it is less than 10% in the relaxation value of 180 DEG C of steam press maintenance conditions, is immersed in 50 DEG C of the 20% ammonium thiocyanate aqueous solution
In the state of, load the tensile strength 70% test load when until fracture the delayed fracture time for 60 hours with
On, it is both to maintain high-tensile therefore, and underrelaxation, the good high intensity of balance of high anti-delayed fracture characteristic good
Constructional Steel.Further, since the elongation at break of the point postwelding of Constructional Steel involved in the present invention is more than 5%,
It may thus be appreciated that also have high solderability concurrently.
Industrial applicability
Constructional Steel involved in the present invention is because tensile strength is more than 1500MPa, in 180 DEG C of steam press maintenance bar
Relaxation value under part is less than 10%, and the time untill the fracture of delayed fracture experiment is more than 10 hours, anti-delayed fracture
Characteristic good, it is therefore, particularly useful in the case of as PC rod irons used in prestressing force are brought to concrete product.Separately
Outside, Constructional Steel involved in the present invention is due to having high solderability concurrently, therefore, uses the concrete construction of the Constructional Steel
Thing is particularly useful in terms of it can obtain desired characteristic.
Claims (11)
1. a kind of Constructional Steel, it has the hardness top layer lower than central part, it is characterised in that
Tensile strength is more than 1500MPa,
Relaxation value under the conditions of 180 DEG C of steam press maintenance is less than 10%,
In the state of in the 20% ammonium thiocyanate aqueous solution for be immersed in 50 DEG C, born in 70% experiment for loading the tensile strength
Until the delayed fracture time of fracture is more than 10 hours during lotus, and
The hardness Vs on the top layer and hardness Vi of the central part meets 0.50Vi≤Vs≤0.96Vi.
2. Constructional Steel as claimed in claim 1,
The hardness Vi of the central part is more than 450HV below 550HV.
3. Constructional Steel as claimed in claim 1,
The hardness Vs on the top layer is more than 225HV below 528HV.
4. Constructional Steel as claimed in claim 1,
The hardness Vi of the central part is more than 450HV below 550HV,
The hardness Vs on the top layer is more than 225HV below 528HV.
5. the Constructional Steel as described in any one of Claims 1 to 4,
The top layer is to be used as the depth from surface 1%~30% when 100% using the size from surface to center.
6. the high strength steel as described in any one of Claims 1 to 4,
The elongation at break of point postwelding is more than 5%.
7. high strength steel as claimed in claim 5,
The elongation at break of point postwelding is more than 5%.
8. the Constructional Steel as described in any one of Claims 1 to 4,
0.2% yield strength is more than 1420MPa.
9. Constructional Steel as claimed in claim 5,
0.2% yield strength is more than 1420MPa.
10. Constructional Steel as claimed in claim 6,
0.2% yield strength is more than 1420MPa.
11. Constructional Steel as claimed in claim 7,
0.2% yield strength is more than 1420MPa.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016063853A JP2017179399A (en) | 2016-03-28 | 2016-03-28 | Steel material for building |
| JP2016-063853 | 2016-03-28 |
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| CN107365891A true CN107365891A (en) | 2017-11-21 |
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| JP (1) | JP2017179399A (en) |
| KR (1) | KR20170113134A (en) |
| CN (1) | CN107365891A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1099427A (en) * | 1993-08-27 | 1995-03-01 | 日本钢管株式会社 | Steel bar for prestressed concrete excellent in delayed fracture resistance at weld zone |
| CN1121535A (en) * | 1994-06-27 | 1996-05-01 | 高周波热炼株式会社 | High strength, high weldability steel bars and wires for prestressed concrete |
| CN1177648A (en) * | 1996-07-15 | 1998-04-01 | 日本钢管株式会社 | PC concrete iron and method for producing same |
| JP2004360005A (en) * | 2003-06-04 | 2004-12-24 | Nippon Steel Corp | High strength pc steel wire having excellent delayed fracture property, and its production method |
| CN101983247A (en) * | 2008-03-31 | 2011-03-02 | 高周波热练株式会社 | Steel material, process for producing steel material, and apparatus for producing steel material |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5395819A (en) * | 1977-02-03 | 1978-08-22 | Nippon Steel Corp | High tensile pc steel wire with uniformly hardened structure and manufacture thereof |
| JPS58338A (en) * | 1981-06-26 | 1983-01-05 | High Frequency Heattreat Co Ltd | Manufacturing device for steel rod or steel wire for prestressed concrete with superior delay breaking and superior mechanical characteristics |
| JPS581022A (en) * | 1981-06-26 | 1983-01-06 | High Frequency Heattreat Co Ltd | Manufacturing device of steel rod or steel wire for prestressed concrete excellent in its delayed breakdown characteristic and mechanical quality |
| JPH06262247A (en) * | 1993-03-10 | 1994-09-20 | Nippon Steel Corp | Manufacture of pc steel wire having excellent delayed fracture characteristics for autoclave aging concrete |
| JPH10298713A (en) * | 1997-04-23 | 1998-11-10 | Nippon Steel Corp | Quenched and tempered steel wire rod excellent in delayed fracture resistance in spot-weld zone |
| JP4146205B2 (en) * | 2002-10-10 | 2008-09-10 | 新日本製鐵株式会社 | PC steel wire having good delayed fracture resistance, its manufacturing method, and PC stranded wire |
| JP5315790B2 (en) * | 2008-05-19 | 2013-10-16 | 新日鐵住金株式会社 | High strength PC steel wire with excellent delayed fracture resistance |
-
2016
- 2016-03-28 JP JP2016063853A patent/JP2017179399A/en active Pending
-
2017
- 2017-03-17 KR KR1020170033605A patent/KR20170113134A/en unknown
- 2017-03-28 CN CN201710193348.0A patent/CN107365891A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1099427A (en) * | 1993-08-27 | 1995-03-01 | 日本钢管株式会社 | Steel bar for prestressed concrete excellent in delayed fracture resistance at weld zone |
| CN1121535A (en) * | 1994-06-27 | 1996-05-01 | 高周波热炼株式会社 | High strength, high weldability steel bars and wires for prestressed concrete |
| CN1177648A (en) * | 1996-07-15 | 1998-04-01 | 日本钢管株式会社 | PC concrete iron and method for producing same |
| JP2004360005A (en) * | 2003-06-04 | 2004-12-24 | Nippon Steel Corp | High strength pc steel wire having excellent delayed fracture property, and its production method |
| CN101983247A (en) * | 2008-03-31 | 2011-03-02 | 高周波热练株式会社 | Steel material, process for producing steel material, and apparatus for producing steel material |
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| KR20170113134A (en) | 2017-10-12 |
| JP2017179399A (en) | 2017-10-05 |
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