CN107043894B - Ductility and the excellent pearlite steel and its manufacturing method of impact flexibility - Google Patents
Ductility and the excellent pearlite steel and its manufacturing method of impact flexibility Download PDFInfo
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- CN107043894B CN107043894B CN201611193421.6A CN201611193421A CN107043894B CN 107043894 B CN107043894 B CN 107043894B CN 201611193421 A CN201611193421 A CN 201611193421A CN 107043894 B CN107043894 B CN 107043894B
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
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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
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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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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Abstract
The present invention discloses a kind of ductility and the excellent pearlite steel and its manufacturing method of impact flexibility, the steel, in terms of weight %, including：C：0.85% or more, Si：0.45% or more, Cr：0.55% or more, Mn：0.15~1.1%, surplus Fe and other inevitable impurity, and meet 10C+2Si+Cr≤17.8, pearlite is 80% or more in terms of area fraction in microstructure, the area of group comprising the cementite with hierarchic structure in the pearlite is 20% or more of total group, wherein, C in the relational expression, Si and Cr the expression value of the content of the weight % each elements indicated.
Description
Technical field
The present invention relates to the excellent steel of a kind of ductility and impact flexibility and its manufacturing methods.
Background technology
Ensure that the most basic method of hardness of steel is to increase carbon (C) content.It generally can be by adding 0.8 weight % or more
C obtains the tensile strength of 1000MPa or more.
On the other hand, when there is the steel of C ranges as described above by the manufacture of pair rolling method, microstructure
80% or more is formed by pearlite (Pearlite), and pearlite is by the excellent ferrite of the low-down ductility of C solid solubility
(Ferrite) and the cementite (cementite) of intensity and the very high cementite of hardness (Iron carbide) system is with lamella
A kind of complex tissue of structure (Lamellar structure) composition passes through the mutually auxiliary pass of two different tissues of physical property
System determines whole physical properties of pearlite.
On the other hand, using the steel of pearlitic structrure be processed and as pressure vessel, railroad track, bridge steel cable etc.
The material of the product in all industry of steel is needed to use.Wherein, in most cases final products medium pearlite point
Number is 50% or more, therefore pearlite plays very important influence to the physical property of material.
As described above, when matrix is pearlite, as the method for the physical property for improving entire material, addition is utilized
The other elements such as Mn, Si, Cr or rolling condition, the heat treatment method for changing material carry out 1) control and are formed in original austenite
The pro-eutectoid ferrite (Proeutectoid ferrite) of (Prior austenite) crystal boundary or point of proeutectoid cementite
Number；Or 2) the method for adjusting the piece interlamellar spacing (Lamellar spacing) of pearlite or carburizing body thickness of pearlite etc..
On the other hand, since pearlitic structrure is the complex tissue of ferrite and cementite, stress when material is broken
The boundary for concentrating on two tissues, to expand along the boundary face of ferrite and cementite with the fracture path inside pearlite
The problem of exhibition, and there is also this problems for method 1), 2) above-mentioned.
Invention content
(1) technical problems to be solved
An aspect of of the present present invention is designed to provide a kind of ductility and the excellent steel and its manufacturer of impact flexibility
Method.
On the other hand, technical problem of the invention is not limited to the above.The technical problem of the present invention can be from this
The full content of specification understands, for those skilled in the art to which the present invention belongs, understands that the present invention's is additional
Technical problem does not have hell and high water.
(2) technical solution
An aspect of of the present present invention is related to a kind of ductility and the excellent pearlite steel of impact flexibility, the steel, with weight
% meters are measured, including：C：0.85% or more, Si：0.45% or more, Cr：0.55% or more, Mn：0.15~1.1%, surplus Fe with
And other inevitable impurity, and meet 10C+2Si+Cr≤17.8,
Pearlite is 80% or more in terms of area fraction in microstructure,
The area of group comprising the cementite with hierarchic structure in the pearlite is the 20% of total group (colony)
More than.
Also, another aspect of the present invention relates to a kind of manufacturers of the excellent pearlite steel of ductility and impact flexibility
Method includes the following steps：Steel billet is heated, the steel billet, in terms of weight %, including：C：0.85% or more, Si：
0.45% or more, Cr：0.55% or more, Mn：0.15~1.1%, surplus Fe and other inevitable impurity, and meet
10C+2Si+Cr≤17.8；
It rolls the steel billet of heating and obtains stocking；
The stocking is quickly cooled to 650~750 DEG C be quickly cooled down with the cooling velocity of 8 DEG C/s or more and terminates temperature
Degree, is then cooled down with 5 DEG C/s cooling velocities below；And
The cooling stocking is kept for 3 minutes or more within the temperature range of 600~400 DEG C.
Wherein, C in the relational expression, Si the and Cr expressions value of the content of the weight % each elements indicated.
In addition, the solution of the technical problem does not enumerate whole features of the present invention.The various spies of the present invention
Seek peace based on its advantages of and effect, can refer to following specific implementation mode and be more fully understood.
(3) advantageous effect
Steel according to the present invention, in fracture due to the crackle that is formed inside the pearlite as matrix along
With the Path extension of the merogenesis of cementite lamella, therefore have the effect of that ductility and toughness is excellent.
Description of the drawings
Fig. 1 is the schematic diagram for indicating the hierarchic structure of cementite in pearlite.
Fig. 2 is the photo for the intrapearlitic cementite with hierarchic structure for shooting example 1.
Fig. 3 is the photo for the intrapearlitic cementite and proeutectoid cementite with hierarchic structure for shooting example 2.
Fig. 4 is the photo of the crackle occurred in the intrapearlitic cementite for shoot example 3.
Fig. 5 is the photo for the intrapearlitic cementite without hierarchic structure for shooting comparative example 1.
Specific implementation mode
In the following, being illustrated to the preferred embodiment of the present invention.But embodiments of the present invention can be deformed into it
His diversified forms, the scope of the present invention are not limited to embodiment described below.Also, embodiments of the present invention be for
More completely illustrate to those skilled in the art the present invention and provides.
Present inventors have recognized that having the steel that pearlite is used as matrix in pearlite underbead crack
(crack) the problem of being formed along the boundary face of ferrite and cementite.This illustrates the advantages of complex tissue in fault activities side
Face is not worked completely, therefore the present inventor conducts in-depth research in order to solve the above problem.
As a result, it has been found that the structure by controlling microstructure, can make in fracture in the pearlite as matrix
Portion is formed by Path extension of the crackle along the merogenesis with cementite lamella, so as to improve ductility and toughness, and by
This completes the present invention.
In the following, the excellent steel of ductility and impact flexibility to one embodiment of the present of invention are described in detail.
The excellent pearlite steel of the ductility and impact flexibility of an aspect of of the present present invention, which is characterized in that with weight %
Meter, including：C：0.85% or more, Si：0.45% or more, Cr：0.55% or more, Mn：0.15~1.1%, surplus Fe and its
His inevitable impurity, and meet 10C+2Si+Cr≤17.8, microstructure's medium pearlite is 80 area % or more, described
The area of group (colony) comprising the cementite with hierarchic structure in pearlite is 20% or more of total group.
First, the composition of alloy of the pearlite steel excellent to the ductility of an aspect of of the present present invention and impact flexibility carries out
It is described in detail.In the following, the unit of each element content is weight %.
C：0.85% or more, Si：0.45% or more, Cr：0.55% or more and 10C+2Si+Cr≤17.8
C is the essential element to form pearlite, is miniaturization to pearlitic structrure and to increase work hardening rate effective
Element.
It is well known that Si increases intensity by pearlite solution strengthening and pearlitic structrure miniaturization, in cementite
Solid solubility is very low, and reduces the liveness of C, to hinder the growth of cementite.
Cr has the effect of pearlitic structrure miniaturization, is pearlite stabilizing element, therefore with increase eutectoid phase
Pearlite forms the effect that phase transition temperature improves when becoming initial temperature and adding Cr.Although also, Cr is the solid solubility of cementite
Relatively high element, but at a temperature of cementite is formed, it is slow compared to other displaced type elements diffusion speed, therefore with obstruction
The effect of pearlite growth.
Be conducive to the hierarchic structure of merogenesis when having in crack propagation to be formed in the pearlite of the steel of the present invention
Cementite, need consider influence pearlite in cementite growth each element between interaction, C should be met：0.85%
Above, Si：0.45% or more and Cr：0.55% or more.It is highly preferred that can be C：0.9% or more, Si：0.5% or more and
Cr：0.6% or more.
But C, Si, Cr all have the effect for improving intensity, as the increase of intensity is based on the ductility of cementite merogenesis
It is reduced with the improvement of toughness, it is therefore preferred that the upper limit of the element is limited to meet the model of 10C+2Si+Cr≤17.8
It encloses.
Only it need to meet 10C+2Si+Cr≤17.8, there is no need to be particularly limited to each upper limit of C, Si, Cr, still
It can be the upper limit of 2.0%, Cr can be 2.0% that the upper limit of C, which can be the upper limit of 1.6%, Si,.
Mn：0.15~1.1%
Mn has the effect of pearlitic structrure miniaturization and improves and be used to form the quenching degree of stable pearlitic structrure.
When Mn contents are less than 0.15%, intrapearlitic cementite is difficult to be formed as stable hierarchic structure.But when
When Mn contents are more than 1.1%, the segregation of steel can be encouraged and cause cryo tissue.Therefore, the content of Mn be preferably 0.15~
1.1%, more preferably 0.2~1.0%.
Remaining ingredient of the present invention is iron (Fe).Only, impurity is possible in general manufacturing process inevitable
Ground is unintentionally mixed into from raw material or ambient enviroment, therefore cannot exclude.For the technology people in general manufacturing process
It is that understand that the impurity, therefore do not refer to entire contents particularly in the present specification for member.
In the following, the microstructure of the excellent pearlite steel of ductility and impact flexibility to an aspect of of the present present invention carries out
It is described in detail.
Microstructure's medium pearlite of the excellent pearlite steel of ductility and impact flexibility of an aspect of of the present present invention
Area fraction is 80% or more, and the area of the group (colony) comprising the cementite with hierarchic structure in the pearlite
It is 20% or more of total group.
When the area fraction of pearlite is less than 80% or group (colony) comprising the cementite with hierarchic structure
When area is less than the 20% of total group, ductility or impact flexibility can deteriorate.
Cementite with hierarchic structure
Indicate that the schematic diagram of the hierarchic structure of cementite in pearlite illustrates referring to Fig.1, the carburizing of hierarchic structure
Length direction in body along cementite is formed with stairstepping.The cementite of hierarchic structure has the height of stepped width W, ladder
Spend the h and corner I to be defined perpendicular to the direction of width direction and short transverse.Also, from corner I to the length side of cementite
When drawing vertical line to the face of k, the length of the vertical line can be defined as to the thickness t of cementite.The hierarchic structure can also
By indicating that Fig. 2 of the photo of the microstructure of example 1 is confirmed.
Initiation stress concentration is easy in hierarchic structure centered on the corner parts of ladder, therefore compares general plate knot
The characteristic that structure has the merogenesis of the thickness direction of cementite relatively easy.It is generated with pearl that is, the hierarchic structure of cementite has
The effect of the crack path of the merogenesis of body of light.
Crackle with cementite merogenesis extend the case where compared with the case where being extended along the crystal boundary of ferrite/cementite,
The required crack propagation energy of unit length becomes larger, and therefore, has the effect of inhibiting crack propagation, to improve the tough of material
Property and ductility.
The area fraction of microstructure's medium pearlite of steel of the present invention is 80% or more, and cementite is in pearlite
The area of the group (colony) of the pearlite of hierarchic structure is 20% or more of total group, therefore, the carburizing of the hierarchic structure
Body generates the crack path of the merogenesis with pearlite, so as to improve ductility and impact flexibility.
The average value of (ladder width) of cementite with hierarchic structure/(step-thickness) is 3.5 or less
Cementite with hierarchic structure (ladder width w)/(average value of step-thickness t) is to forming with cementite
The crackle of merogenesis have an impact.When described value is more than 3.5, the crack propagation carryover effects of the merogenesis based on cementite are not
Greatly, therefore the promotion effect unobvious of ductility and toughness.Wherein, the width and thickness of ladder is surveyed using same unit
Fixed value.
Crack path
For the steel of the present invention, when observing the section including tensile axis of tensile test specimen, by being formed inside pearlite
The total length L of crackle, in crack path the cementite lamella of merogenesis quantity n and piece interlamellar spacing λPDefinitionValue can
To be 1 or more 1.5 or less.Wherein, L and λPIt is the value being measured using uniform units.
Crackle while forming the cementite with the hierarchic structure inside pearlite and cause the merogenesis of cementite
When extension, by the quantity n and lamella of the cementite lamella of merogenesis in the total length L of the crackle formed inside pearlite, crack path
Spacing λPDefinitionValue be less than 1.5 when, have the effect of raising ductility and toughness
On the other hand, crackle is got over to the direction (cementite thickness direction) parallel with pearlite piece interlamellar spacing and is extended, described
The lower limit of value is closer to 1, and therefore, lower limit is preferably 1.
The corner direction of cementite with hierarchic structure and the corner direction of the proeutectoid cementite with hierarchic structure
Differential seat angle be 10 ° or more
The microstructure of the steel of the present invention further comprises the proeutectoid cementite with hierarchic structure, has the rank
The corner direction of terraced structure with the hierarchic structure proeutectoid cementite corner direction differential seat angle can be 10 ° with
On.
When crackle is in the pearlite internal extended being made of the cementite of hierarchic structure, still with the crystalline substance with hierarchic structure
Boundary's proeutectoid cementite meets, at this point, when the differential seat angle in the direction of the ladder corner of two cementites is more than 10 °, due to resistance
Hinder the extension of crackle, therefore improves ductility and toughness.It when its value is less than 10 °, hinders the effect of crack propagation weak, therefore extends
Property and toughness improve effect unobvious.
The breaking elongation for meeting the steel of above-mentioned composition of alloy and the present invention of microstructure is 6% or more, room temperature (25
DEG C) impact characteristics be 20J/cm2More than, so as to ensure excellent ductility and impact flexibility.
In the following, the manufacturing method of the excellent pearlite steel of ductility and impact flexibility to another aspect of the present invention into
Row explanation.
The manufacturing method of the excellent pearlite steel of ductility and impact flexibility of another aspect of the present invention, including it is following
Step：Steel billet is heated, the steel billet, in terms of weight %, including：C：0.85% or more, Si：0.45% or more, Cr：
0.55% or more, Mn：0.15~1.1%, surplus Fe and other inevitable impurity, and meet 10C+2Si+Cr≤
17.8；
It rolls the steel billet of heating and obtains stocking；
The stocking is quickly cooled to 650~750 DEG C be quickly cooled down with the cooling velocity of 8 DEG C/s or more and terminates temperature
Degree, is then cooled down with 5 DEG C/s cooling velocities below；And
The cooling stocking is kept for 3 minutes or more within the temperature range of 600~400 DEG C.
Heating steel billet and milling step
Heating meets the steel billet of above-mentioned composition of alloy, and rolls the steel billet of heating to obtain stocking.
At this point, the heating and rolling of the steel billet can be manufactured by the manufacturing method of common hot rolled steel plate or wire rod,
Therefore it is not specially limited.But as preferred an example, the heating temperature of the steel billet is 1000~1250 DEG C, described to roll
The temperature of system can be 900~1000 DEG C.
Also, the steel billet can be that either the square billet stocking can be hot rolled steel plate or wire rod to slab.
Cooling step
The stocking is quickly cooled to 650~750 DEG C be quickly cooled down with the cooling velocity of 8 DEG C/s or more and terminates temperature
Degree, is then cooled down with 5 DEG C/s cooling velocities below.By the cooling stocking within the temperature range of 600~400 DEG C
Kept for 3 minutes or more.
Described be quickly cooled down is on the whole to be maintained at pearlite score to inhibit the formation of proeutectoid cementite
80% or more, it prevents in the element sets such as Cr, Si inside proeutectoid cementite or its boundary face, so that it is guaranteed that in pearlite
Portion forms the content of the elements such as C, Cr, Si, Mn needed for the cementite of hierarchic structure.
It is in order to inhibit the formation of cryo tissue, in pearl to carry out cooling after being quickly cooled down with 5 DEG C/s cooling velocities below
The cementite at initial stage is set to be formed as stable hierarchic structure inside body of light.
At this point, the stocking can be stocking after rolling or be reheated to 900 DEG C or more after being cooled to room temperature
Stocking.Because when being reheated after cooling, also by cooling step and step can be kept to obtain identical effect.
Keep step
The cooling stocking is kept for 3 minutes or more within the temperature range of 600~400 DEG C.It, can after being kept for 3 minutes
It is air-cooled to room temperature.
When keeping temperature to be less than 400 DEG C, cryo tissue may be generated, when keeping temperature to be higher than 600 DEG C, intensity meeting
Become very poor.Also, when being less than 3 minutes the retention time, it is difficult to ensure pearlite score.
In the following, by embodiment, the present invention will be described in more detail.But it need to be noted that, the following examples
It is of the invention and illustration just for the sake of being described in more detail, do not limit the interest field of the present invention.Because the present invention's
Content that interest field is recorded by claims and the content thus rationally derived determine.
(embodiment)
It carries out the steel billet for meeting ingredient system described in following table 1 to be heated to 1050 DEG C, then in 1000~900 DEG C of temperature
It is rolled in degree range and obtains stocking.It after the stocking is rolled or is cooled to room temperature and is reheated to 900 DEG C, so
The cooling condition described in following table 1 is utilized to manufacture steel afterwards.Wherein, it is quickly cooled down final temperature and is unified for 700 DEG C.
Structure observation is carried out to the steel manufactured by the above method, pearlite area fraction is measured, is wrapped in pearlite
(ladder width)/(ladder thickness of the area of the group (colony) of cementite containing hierarchic structure, the cementite with hierarchic structure
Degree) average value,Value, the corner direction of cementite with hierarchic structure and being first total to the hierarchic structure
The differential seat angle in corner direction, the breaking elongation of tension test and room temperature (25 DEG C) impact flexibility of cementite are analysed, and is tied
Fruit indicates in table 2 below.
Wherein,Middle L, n and λPIt is when observing the section including tensile axis of tensile test specimen, to be formed inside pearlite
The total length L of crackle, in crack path the cementite lamella of merogenesis quantity n and piece interlamellar spacing λP。
The ladder knot of cementite is observed under 40,000 times or more of multiplying power using high magnification electron microscope (FE-SEM)
Structure, and illustrate the area fraction of the group with hierarchic structure.
Also, using room temperature determination of tensile test method breaking elongation, room temperature is determined under the conditions of V-notch test pieces
Impact flexibility.
【Table 1】
【Table 2】
In comparative example 1, Mn contents are not up to 0.15% in terms of weight %, and the ladder knot of cementite is not formed in pearlite
Structure, therefore elongation percentage and impact characteristics difference are without improving physical property.
In comparative example 2, Cr contents are not up to 0.55% in terms of weight %, and the ladder knot of cementite is not formed in pearlite
Structure, therefore elongation percentage and impact characteristics difference are without improving physical property.
In comparative example 3, Si contents are not up to 0.45% in terms of weight %, and the ladder knot of cementite is not formed in pearlite
Structure, therefore elongation percentage and impact characteristics difference are without improving physical property.
In comparative example 4, C content is not up to 0.85% in terms of weight %, and the ladder knot of cementite is not formed in pearlite
Structure, therefore elongation percentage and impact characteristics difference are without improving physical property.
Because example 1~7 meets the composition of alloy and manufacturing condition of the present invention, so as to confirm breaking elongation and room temperature
Impact characteristics are excellent.
Further, it is possible to confirm, after rolling in-process stock or it is cooled to room temperature and carries out cooling step after being reheated to 900 DEG C
Rapid and holding step also has same effect.
In comparative example 5~7, the value of 10C+2Si+Cr is more than 17.8, because the intensity of steel is excessively high, although intrapearlitic carburizing
The bodily form becomes hierarchic structure, but to the no effect of the improvement of elongation percentage and room temperature impact characteristics.
In comparative example 8, the cooling velocity that section is quickly cooled down in the manufacturing process of steel is less than 8 DEG C/s, therefore does not give birth to
The width of cementite ladder and the average value of carburizing body thickness are more than in the hierarchic structure generated at stable hierarchic structure, part
3.5, L/ (n × λP) value be more than 1.5, to the no effect of the improvement of elongation percentage and room temperature impact characteristics.
In comparative example 9, it is more than 5 DEG C/s to be quickly cooled down postcooling speed, therefore without generating stable hierarchic structure, part
The average value of the width of cementite ladder and carburizing body thickness is more than 3.5, L/ (n × λ in the hierarchic structure of generationP) value be more than
1.5, to the no effect of the improvement of elongation percentage and room temperature impact characteristics.
In comparative example 10, the retention time in 600 DEG C of -400 DEG C of sections was less than 3 minutes in the manufacturing process of steel, therefore did not had
Have and generates stable hierarchic structure, the average value of the width and carburizing body thickness of cementite ladder in the hierarchic structure that part generates
More than 3.5, L/ (n × λP) value be more than 1.5, to the no effect of the improvement of elongation percentage and room temperature impact characteristics.
More than, with reference to embodiment, the present invention is described, but it will be understood to those skilled in the art that not surpassing
Go out in the range of technological thought and the technical field of the present invention described in claim, a variety of modifications can be carried out to the present invention
And change.
Claims (9)
1. a kind of ductility and the excellent pearlite steel of impact flexibility, the steel, in terms of weight %, including：C：0.85%
Above, Si：0.45% or more, Cr：0.55% or more, Mn：0.15~1.1%, surplus Fe and other inevitable impurity,
And meet 10C+2Si+Cr≤17.8,
Pearlite is 80% or more in terms of area fraction in microstructure,
The area of group comprising the cementite with hierarchic structure in the pearlite is 20% or more of total group,
Wherein, C in the relational expression, Si the and Cr expressions value of the content of the weight % each elements indicated.
2. ductility according to claim 1 and the excellent pearlite steel of impact flexibility, which is characterized in that have described
The average value of ladder width/step-thickness of the cementite of hierarchic structure is 3.5 or less.
3. ductility according to claim 1 and the excellent pearlite steel of impact flexibility, which is characterized in that when observation institute
When stating the section including tensile axis of the room temperature tensile test specimen of steel, by the total length L of the crackle formed inside pearlite, crackle
The quantity n of the cementite lamella of merogenesis and piece interlamellar spacing λ in pathPDefinitionValue be 1 or more, 1.5 or less.
4. ductility according to claim 1 and the excellent pearlite steel of impact flexibility, which is characterized in that the pearly-lustre
Body includes the proeutectoid cementite with hierarchic structure,
The corner in the corner direction and the proeutectoid cementite with the hierarchic structure of the cementite with the hierarchic structure
The differential seat angle in direction is 10 ° or more.
5. ductility according to claim 1 and the excellent pearlite steel of impact flexibility, which is characterized in that the steel
Breaking elongation be 6% or more, room temperature impact characteristics be 20J/cm2More than.
6. the manufacturing method of a kind of ductility and the excellent pearlite steel of impact flexibility, includes the following steps：
Steel billet is heated, the steel billet, in terms of weight %, including：C：0.85% or more, Si：0.45% or more, Cr：
0.55% or more, Mn：0.15~1.1%, surplus Fe and other inevitable impurity, and meet 10C+2Si+Cr≤
17.8；
It rolls the steel billet of heating and obtains stocking；
The stocking is quickly cooled to the cooling velocity of 8 DEG C/s or more to 650~750 DEG C of the final temperature that is quickly cooled down, so
It is cooled down afterwards with 5 DEG C/s cooling velocities below；And
The cooling stocking is kept for 3 minutes or more within the temperature range of 600~400 DEG C,
Wherein, C in the relational expression, Si the and Cr expressions value of the content of the weight % each elements indicated.
7. the manufacturing method of ductility according to claim 6 and the excellent pearlite steel of impact flexibility, feature exist
In being rolled in the step of heating temperature of steel billet is 1000~1250 DEG C, obtains the stocking in the step of heating the steel billet
Temperature range is 900~1000 DEG C.
8. the manufacturing method of ductility according to claim 6 and the excellent pearlite steel of impact flexibility, feature exist
In after the step of obtaining the stocking, further comprising being cooled to room temperature stocking and being heated to 900 DEG C or more of heating
Step.
9. the manufacturing method of ductility according to claim 6 and the excellent pearlite steel of impact flexibility, feature exist
In after the holding step, further comprising the cooling step for being cooled to room temperature stocking.
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| KR10-2015-0183579 | 2015-12-22 | ||
| KR1020150183579A KR101767763B1 (en) | 2015-12-22 | 2015-12-22 | Pearlite steel material having excellent ductility and impact toughness, and method for manufacturing the same |
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| JP2939770B2 (en) * | 1991-02-25 | 1999-08-25 | 新日本製鐵株式会社 | Method of manufacturing high strength bead wire |
| JP2002226914A (en) * | 2001-02-01 | 2002-08-14 | Nippon Steel Corp | Manufacturing method of rail with high wear resistance and high toughness |
| US20040187981A1 (en) * | 2002-04-05 | 2004-09-30 | Masaharu Ueda | Pealite base rail excellent in wear resistance and ductility and method for production thereof |
| JP4008320B2 (en) | 2002-09-12 | 2007-11-14 | 株式会社神戸製鋼所 | Rolled and drawn wire rods for bearings |
| JP5459342B2 (en) | 2012-03-26 | 2014-04-02 | 新日鐵住金株式会社 | Manufacturing method of high-strength galvanized bolts with excellent hydrogen embrittlement resistance |
-
2015
- 2015-12-22 KR KR1020150183579A patent/KR101767763B1/en active IP Right Grant
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- 2016-12-21 CN CN201611193421.6A patent/CN107043894B/en active Active
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| KR20170075058A (en) | 2017-07-03 |
| CN107043894A (en) | 2017-08-15 |
| KR101767763B1 (en) | 2017-08-14 |
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