WO2016072679A1 - 강도와 충격 인성이 우수한 선재 및 그 제조방법 - Google Patents
강도와 충격 인성이 우수한 선재 및 그 제조방법 Download PDFInfo
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- WO2016072679A1 WO2016072679A1 PCT/KR2015/011650 KR2015011650W WO2016072679A1 WO 2016072679 A1 WO2016072679 A1 WO 2016072679A1 KR 2015011650 W KR2015011650 W KR 2015011650W WO 2016072679 A1 WO2016072679 A1 WO 2016072679A1
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- impact toughness
- strength
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- wire rod
- manganese
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Classifications
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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
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
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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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- 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
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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
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
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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
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
Definitions
- the present invention relates to a wire rod having excellent strength and impact toughness that can be used for parts of industrial machines, automobiles, etc. exposed to various external load environments, and a method of manufacturing the same.
- the wire of ferrite or pearlite structure has a limit in securing excellent strength and impact toughness.
- Materials with these structures generally have high impact toughness, but relatively low strength, and when cold drawn to increase strength, high strength can be obtained, but impact toughness decreases sharply in proportion to strength increase. There is this.
- bainite or tempered martensite is used to realize excellent strength and impact toughness simultaneously.
- the bainite structure can be obtained by constant temperature heat treatment using hot rolled steel
- the temper martensite structure can be obtained by quenching and tempering heat treatment.
- these tissues cannot be stably obtained by the usual hot rolling and continuous cooling processes alone, and thus must be subjected to such additional heat treatment using hot rolled steel.
- wire rods that can stably obtain bainite or martensite structure using hot rolling and continuous cooling processes without additional heat treatment have not yet been developed, and thus there is a demand for wire rod development.
- the present invention is to provide a wire rod and a method for manufacturing the same that can have a high strength and excellent impact toughness only by hot rolling and continuous cooling process without an additional heat treatment process.
- One aspect of the present invention is by weight, carbon (C): 0.05 to 0.15%, silicon (Si): 0.2% or less, manganese (Mn): 3.0 to 4.0%, phosphorus (P): 0.020% or less, sulfur ( S): 0.020% or less, Boron (B): 0.0010% to 0.0030%, Titanium (Ti): 0.010% to 0.030%, Nitrogen (N): 0.0050% or less, Aluminum (Al): 0.010% to 0.050%, the rest is Fe and Contains inevitable impurities,
- the microstructure provides a wire rod with excellent strength and impact toughness, including area fractions, 90% or more bainitic ferrite and the remainder martensite (M / A).
- carbon (C) 0.05 ⁇ 0.15%
- silicon (Si) 0.2% or less
- manganese (Mn) 3.0 ⁇ 4.0%
- phosphorus (P) 0.020% or less
- Sulfur (S) 0.020% or less
- Boron (B) 0.0010-0.0030%
- Titanium (Ti) 0.010-0.030%
- Nitrogen (N) 0.0050% or less
- Aluminum (Al) 0.010-0.050% Reheating the steel comprising Fe and unavoidable impurities;
- It provides a method of producing a wire rod excellent in strength and impact toughness comprising the step of air cooling the cooled steel.
- the present invention by using only the hot rolling and continuous cooling process can provide a wire rod excellent in strength and impact toughness required in the material or parts for industrial machinery and automobiles.
- the conventional additional heat treatment process can be omitted, which is very advantageous to reduce the overall manufacturing cost.
- the wire rod of the present invention is by weight, carbon (C): 0.05 to 0.15%, silicon (Si): 0.2% or less, manganese (Mn): 3.0 to 4.0%, phosphorus (P): 0.020% or less, sulfur (S) ): 0.020% or less, boron (B): 0.0010 to 0.0030%, titanium (Ti): 0.010 to 0.030%, nitrogen (N): 0.0050% or less, aluminum (Al): 0.010 to 0.050%, the rest is Fe and inevitable Contains impurities.
- Carbon is an essential element for securing strength and is dissolved in steel or exists in carbide or cementite form.
- the easiest way to increase the strength is to increase the carbon content to form carbides or cementite, but on the contrary, ductility and impact toughness decrease, so it is necessary to control the amount of carbon added within a certain range.
- Silicon together with aluminum, is known as a deoxidation element and is an element that improves strength. Silicon is known to be an element that is very effective in increasing the strength through solid solution strengthening of steel as it is dissolved in ferrite when added. However, since the strength is greatly increased by the addition of silicon, but the ductility and impact toughness decrease rapidly, the addition of silicon is very limited in the case of cold forged parts that require sufficient ductility. In the present invention to minimize the drop in strength, in order to ensure excellent impact toughness, the content of the silicon is included in less than 0.2%. If the silicon content exceeds 0.2%, it may be difficult to secure the target impact toughness. More preferably, it contains 0.1% or less.
- Manganese increases the strength of the steel and improves the hardenability to facilitate the formation of low temperature structures such as bainite or martensite at a wide range of cooling rates.
- the manganese content is less than 3.0%, the hardenability is not sufficient, so it is difficult to stably secure the low temperature structure by the continuous cooling process after hot rolling.
- it exceeds 4.0% the hardenability is so high that martensite structure is obtained even at air cooling, which is not suitable.
- Phosphorus (P) 0.020% or less
- phosphorus is segregated at grain boundaries to lower toughness and reduce delayed fracture resistance, it is preferable not to be included as much as possible, and for this reason, the upper limit thereof is limited to 0.020%.
- the sulfur segregates at grain boundaries, lowers toughness, forms low melting emulsions, and inhibits hot rolling, so it is preferably not included. For this reason, the upper limit of the present invention is limited to 0.020%.
- the boron is an element that improves the hardenability, is an element that diffuses into the austenite grain boundary and suppresses the formation of ferrite during cooling and facilitates the formation of bainite or martensite.
- the added amount is less than 0.0010%, the effect according to the addition cannot be expected, and if it exceeds 0.0030%, the effect can not be expected to increase any more, and the grain boundary strength is lowered due to the precipitation of boron nitride at the grain boundary, resulting in hot workability. Can be reduced. Therefore, in consideration of this point, in the present invention, the addition range of boron is made 0.0010 to 0.0030%.
- the titanium has the highest reactivity with nitrogen to form nitride first.
- titanium When titanium is added to form TiN and exhausts most of the nitrogen in the steel, it prevents the precipitation of BN so that boron is present in a soluble state, thereby improving hardenability.
- the added amount is less than 0.010%, the effect of the addition is insufficient, and if it exceeds 0.030%, coarse nitride may be formed to deteriorate mechanical properties.
- the content of titanium is 0.010 to 0.030%.
- the nitrogen should be kept as soluble with boron and should not be included as much as possible in order to fully exhibit the effect of improving hardenability. Therefore, in the present invention, the content is preferably 0.0050% or less.
- Aluminum is a powerful deoxidation element that removes oxygen in steel to improve cleanliness, and also combines with nitrogen dissolved in steel to form AlN, thereby improving impact toughness.
- the content is less than 0.010%, the effect of addition is difficult to be expected. If the content exceeds 0.050%, a large amount of alumina inclusions are generated, and mechanical properties can be greatly reduced. In consideration of this point, in the present invention, it is preferable to make the aluminum content in the range of 0.010% to 0.050%.
- the composition may additionally contain less than 0.3% chromium (Cr).
- Cr chromium
- the chromium increases the strength and hardenability of steels similar to manganese. If the chromium content is 0.3% or more, the strength may increase due to the improvement of hardenability and the solid solution strengthening effect, but the impact toughness may be lowered.
- the content of chromium is preferably included in the range of less than 0.3%.
- the rest includes Fe and unavoidable impurities.
- the present invention does not exclude the addition of alloys other than the alloy compositions mentioned above.
- the content of the manganese (Mn), titanium (Ti), boron (B) and nitrogen (N) is preferably contained so as to satisfy the following relational formula (1).
- manganese (Mn), titanium (Ti), boron (B) and nitrogen (N) means the content by weight of the corresponding element, respectively.
- Manganese in the present invention increases the hardenability to help the bainitic ferrite is easily produced even when the cooling rate is relatively small. Titanium combines with nitrogen to form nitrides, allowing boron to be sufficiently dissolved in steel, thereby suppressing ferrite production and facilitating bainitic ferrite production.
- the inventors of the present invention focused on the above point, and as a result of repeated studies and experiments, the relationship between the manganese, titanium, boron and nitrogen was satisfied Mn + 5 (Ti-3.5N) / B ⁇ 5.0 by weight%
- the relationship 1 is derived.
- the content of the manganese (Mn) and silicon (Si) in the present invention is preferably contained so as to satisfy the following relation 2.
- manganese (Mn) and silicon (Si) refer to the content by weight of the corresponding element, respectively.
- Manganese in the present invention increases the hardenability to help the bainite is easily produced even when the cooling rate is relatively small.
- silicon is dissolved in steel, which increases strength but decreases impact toughness.
- the inventors have studied and experimented with the above-mentioned points. As a result, when the relationship between manganese and silicon satisfies Mn / Si ⁇ 18 based on the weight percent, the bainitic ferrite structure having better strength and impact toughness is obtained. It is to confirm that the wire rod can be provided and to present the compositional relational expression.
- the ratio of the maximum concentration [Mn max ] and the minimum concentration [Mn min ] of manganese in an arbitrary cross-sectional area satisfies the following expression (3).
- manganese helps to easily produce bainitic ferrite even when the cooling rate is relatively small by increasing the hardenability, but martensite may be easily generated when the manganese is locally segregated, and in the region where manganese is depleted Can be formed, the microstructure becomes non-uniform, impact toughness may be inferior.
- the present inventors have focused on the above point, and as a result of repeated studies and experiments, a wire rod of bainitic ferrite structure having excellent strength and impact toughness when the ratio between the maximum concentration and the minimum concentration of manganese in an arbitrary cross-sectional area of the wire is 3 or less. It is to confirm that it can provide and to present this relationship.
- the microstructure of the wire rod of the present invention preferably contains more than 90 area% of bainitic ferrite and residual martensite Austenite constituent (M / A).
- bainite may be referred to in various terms depending on the carbon content or morphology. It is commonly referred to as upper / lower bainite above medium carbon (about 0.2-0.45 wt%).
- upper / lower bainite above medium carbon about 0.2-0.45 wt%).
- it is called bainitic ferrite, acicular ferrite, granular ferrite, or the like depending on the temperature range.
- it is a low carbon region, and includes bainitic ferrite tissue.
- the microstructure of the wire rod of the present invention contains more than 90 area% of bainitic ferrite, excellent strength and impact toughness can be secured.
- ferrites other than bainitic ferrite may be advantageous in terms of impact toughness, but are not preferable because the reduction in strength cannot be prevented.
- the phase martensite is formed along the main phase bainitic ferrite grain boundary, and if the fraction is high, the strength of the steel may be increased, but the impact toughness may be deteriorated, so it is desirable to manage the fraction as low as possible. .
- the fraction of the island martensite is 10% or less (that is, 90% or more of the bainitic ferrite structure, the main phase).
- the grain size of said phase martensite (M / A) is 5 micrometers or less.
- the impact toughness may be inferior because the area of the interface in contact with the bainitic ferrite matrix is increased.
- Method for producing a wire rod of the present invention after providing a steel having the above-described composition, the step of reheating it; Hot rolling the reheated steel; After the hot rolling, the step of cooling to a temperature range of Bf ⁇ Bf-50 °C at a rate of 0.1 ⁇ 2 °C / s; And air-cooling the cooled steel material.
- the reheating temperature range employable in the present invention may be in the range of 1000 to 1100 ° C.
- the form of the said steel is not specifically limited, Usually, it is preferable that it is a bloom or billet form.
- the reheated steel is hot rolled to produce a wire rod.
- the finishing hot rolling temperature of the said hot rolling is not specifically limited, It is preferable to manage in the range of 850-950 degreeC.
- the hot rolled steel is cooled, the cooling is preferably cooled to a cooling rate of 0.1 ⁇ 2 °C / s to the temperature range of Bf ⁇ Bf-50 °C. If the cooling end temperature exceeds Bf, it is difficult to secure a sufficient amount of bainitic ferrite structure. If the cooling end temperature is lower than Bf-50 ° C, the steel is sufficiently cooled and easy to handle, but the cooling end temperature is lower than Bf to Bf-50 ° C. It is preferable to set it as the temperature range of.
- the Bf means the temperature at which the phase transformation from austenite to bainite or bainitic ferrite is terminated.
- the cooling rate in the present invention is 0.1 It is preferable to manage at -2 degrees C / s.
- the wire rod thus prepared was shown in Table 2 by analyzing the microstructure, and the tensile strength and impact toughness were measured and shown in Table 2.
- the area fraction and grain size of phase martensite (M / A) in the microstructure of the wire rod were measured using an image analyzer, and the concentration of manganese was measured using an Electron Probe Micro-Analysis (EPMA).
- the room temperature tensile test was measured by performing a crosshead speed of 0.9mm / min to the yield point, 6mm / min after that.
- the impact test was measured at room temperature using an impact tester having a curvature of the edge portion of the striker impacting the specimen of 2mm and a test capacity of 500J.
- relation 1 is Mn + 5 (Ti-3.5N) / B, relation 2 is Mn / Si, and the rest is Fe and inevitable impurities.
- Inventive Example 8 the content of silicon is 0.1% by weight or less, it can be seen that the impact toughness is further improved.
- Inventive examples satisfying both manganese, titanium, boron, and nitrogen relation 1 (Mn + 5 (Ti-3.5N) /B ⁇ 5.0) and manganese and silicon relation 2 (Mn / Si ⁇ 18) It can be seen that 2, 3, 5, 7, 6, 9 and 11 have better impact toughness as compared with the case where it is not.
- Comparative Example 12 Although the carbon content is high, the tensile strength is excellent, but the impact toughness is inferior, because carbon is solid-solution phase M / A phase increases the stable M / A phase.
- Comparative Example 13 is a case where the silicon content is out of the scope of the present invention, the silicon also increases the amount of solid solution at the base as the addition amount increases similarly to carbon, and eventually exhibits the effect of solid solution strengthening. In other words, even when the silicon addition amount is 0.25%, the tensile strength is very large, but the impact toughness is drastically reduced.
- Comparative Example 14 since the addition amount of manganese and boron decreases the hardenability of the steel, even if the cooling conditions are satisfied, the ferrite and the bainitic ferrite structures are mixed to reduce the tensile strength.
- Comparative Example 15 shows that the emphasis component satisfies the scope of the present invention, but martensite is formed as the cooling rate increases in the manufacturing process, but the strength increases, but the impact toughness deteriorates.
- Comparative Example 16 shows that the accentuating component satisfies the scope of the present invention, but the cooling rate is slow in the manufacturing process, the ferrite is formed, the strength is reduced.
- Comparative Example 17 shows that when the amount of titanium added is small, since the amount of solute boron decreases, the hardenability decreases, and when the cooling rate is small, the amount of precipitated cornerstones increases and the tensile strength decreases.
- Comparative Example 18 shows that when a large amount of manganese is added, since the curing ability is too large, martensite is generated even when cooled at the cooling rate suggested in the present invention, the strength is increased, but impact toughness is inferior. In addition, since manganese is segregated in the steel, the impact toughness is inferior due to the formation of locally uneven tissue.
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Abstract
Description
No. | 조성성분(중량%) | 관계식 1 | 관계식 2 | |||||||||
C | Si | Mn | Cr | P | S | Ti | B | N | Al | |||
1 | 0.12 | 0.19 | 3.1 | 0.15 | 0.018 | 0.019 | 0.015 | 0.0025 | 0.0044 | 0.023 | 2.3 | 16.3 |
2 | 0.08 | 0.18 | 3.7 | - | 0.017 | 0.020 | 0.020 | 0.0016 | 0.0049 | 0.015 | 12.6 | 20.6 |
3 | 0.10 | 0.13 | 3.6 | 0.18 | 0.014 | 0.017 | 0.017 | 0.0028 | 0.0042 | 0.040 | 7.7 | 27.7 |
4 | 0.07 | 0.20 | 3.4 | 0.07 | 0.011 | 0.015 | 0.025 | 0.0030 | 0.0036 | 0.033 | 24.1 | 17.0 |
5 | 0.11 | 0.18 | 3.5 | 0.24 | 0.016 | 0.013 | 0.030 | 0.0023 | 0.0039 | 0.038 | 39.0 | 19.4 |
6 | 0.05 | 0.16 | 3.8 | 0.22 | 0.015 | 0.015 | 0.011 | 0.0024 | 0.0044 | 0.043 | -5.4 | 23.8 |
7 | 0.07 | 0.16 | 3.2 | 0.11 | 0.014 | 0.016 | 0.023 | 0.0017 | 0.0050 | 0.026 | 19.4 | 20.0 |
8 | 0.06 | 0.09 | 3 | - | 0.013 | 0.011 | 0.027 | 0.0018 | 0.0048 | 0.020 | 31.3 | 33.3 |
9 | 0.10 | 0.15 | 3.9 | 0.10 | 0.020 | 0.014 | 0.017 | 0.0027 | 0.0037 | 0.030 | 11.4 | 26.0 |
10 | 0.13 | 0.19 | 3.3 | 0.16 | 0.016 | 0.018 | 0.013 | 0.0018 | 0.0045 | 0.035 | -4.3 | 17.4 |
11 | 0.11 | 0.18 | 4 | 0.05 | 0.009 | 0.020 | 0.019 | 0.0022 | 0.0040 | 0.044 | 15.4 | 22.2 |
12 | 0.25 | 0.16 | 3.4 | - | 0.014 | 0.013 | 0.030 | 0.0025 | 0.0037 | 0.019 | 37.5 | 21.3 |
13 | 0.15 | 0.25 | 3.3 | 0.13 | 0.011 | 0.015 | 0.021 | 0.0020 | 0.0050 | 0.022 | 12.1 | 13.2 |
14 | 0.11 | 0.15 | 2 | 0.07 | 0.018 | 0.014 | 0.018 | 0.0005 | 0.0043 | 0.031 | 31.5 | 13.3 |
15 | 0.09 | 0.17 | 3.6 | - | 0.016 | 0.017 | 0.021 | 0.0025 | 0.0041 | 0.028 | 16.9 | 21.2 |
16 | 0.08 | 0.16 | 3.2 | 0.21 | 0.011 | 0.016 | 0.02 | 0.0021 | 0.0047 | 0.017 | 11.7 | 20.0 |
17 | 0.06 | 0.15 | 3.5 | 0.17 | 0.012 | 0.011 | 0.005 | 0.0027 | 0.0035 | 0.034 | -9.9 | 23.3 |
18 | 0.07 | 0.18 | 4.3 | 0.12 | 0.010 | 0.012 | 0.016 | 0.0018 | 0.0048 | 0.026 | 2.1 | 23.9 |
구분 | No. | 냉각속도(℃/s) | M/A 분율(%) | M/A 결정립도(㎛) | 인장강도(MPa) | 충격 인성(J) | 관계식 3 |
발명예 | 1 | 0.5 | 7 | 3.9 | 659 | 158 | 2.1 |
2 | 1 | 8 | 3.3 | 660 | 163 | 2.6 | |
3 | 0.2 | 5 | 4.7 | 652 | 180 | 2.3 | |
4 | 2 | 10 | 2.0 | 680 | 159 | 2.4 | |
5 | 1.3 | 9 | 2.4 | 664 | 160 | 2.2 | |
6 | 1.9 | 9 | 2.1 | 670 | 152 | 2.8 | |
7 | 1.5 | 8 | 2.3 | 665 | 168 | 2.3 | |
8 | 0.3 | 5 | 4.6 | 635 | 199 | 2.0 | |
9 | 0.8 | 7 | 3.5 | 657 | 172 | 2.7 | |
10 | 0.7 | 7 | 3.8 | 650 | 155 | 2.2 | |
11 | 1.1 | 8 | 3.3 | 663 | 165 | 2.9 | |
비교예 | 12 | 2 | 15 | 2.5 | 730 | 100 | 2.4 |
13 | 1 | 11 | 3.5 | 754 | 87 | 2.4 | |
14 | 0.7 | 9 | 2.4 | 543 | 172 | 1.6 | |
15 | 3 | 12 | 1.7 | 700 | 94 | 2.6 | |
16 | 0.05 | 4 | 6.1 | 557 | 157 | 2.3 | |
17 | 1 | 2 | 8.6 | 560 | 151 | 2.5 | |
18 | 1.8 | 8 | 3.2 | 825 | 80 | 3.3 |
Claims (12)
- 중량%로, 탄소(C): 0.05~0.15%, 실리콘(Si): 0.2% 이하, 망간(Mn): 3.0~4.0%, 인(P): 0.020% 이하, 황(S):0.020% 이하, 보론(B): 0.0010~0.0030%, 타이타늄(Ti): 0.010~0.030%, 질소(N): 0.0050% 이하, 알루미늄(Al): 0.010~0.050%, 나머지는 Fe 및 불가피한 불순물을 포함하고,미세조직은 면적분율로, 90% 이상의 베이니틱 페라이트와 나머지는 도상 마르텐사이트(M/A)를 포함하는 강도와 충격 인성이 우수한 선재.
- 청구항 1에 있어서,상기 선재는 크롬(Cr): 0.3% 미만을 추가적으로 포함하는 강도와 충격 인성이 우수한 선재.
- 청구항 1에 있어서,상기 망간(Mn), 타이타늄(Ti), 보론(B) 및 질소(N)의 함량은 하기 관계식 1을 만족하는 강도와 충격 인성이 우수한 선재.[관계식 1]Mn+5(Ti-3.5N)/B ≥ 5.0
- 청구항 1에 있어서,상기 망간(Mn) 및 실리콘(Si)의 함량은 하기 관계식 2를 만족하는 강도와 충격 인성이 우수한 선재.[관계식 2]Mn/Si ≥ 18
- 청구항 1에 있어서,상기 선재는 임의의 단면에서 망간의 최대 농도[Mnmax]와 최소 농도[Mnmin]의 비가 하기 관계식 3을 만족하는 강도와 충격 인성이 우수한 선재.[관계식 3][Mnmax]/[Mnmin] ≤ 3
- 청구항 1에 있어서,상기 도상 마르텐사이트(M/A)의 결정립도는 5㎛ 이하인 강도와 충격 인성이 우수한 선재.
- 중량%로, 탄소(C): 0.05~0.15%, 실리콘(Si): 0.2% 이하, 망간(Mn): 3.0~4.0%, 인(P): 0.020% 이하, 황(S):0.020% 이하, 보론(B): 0.0010~0.0030%, 타이타늄(Ti): 0.010~0.030%, 질소(N): 0.0050% 이하, 알루미늄(Al): 0.010~0.050%, 나머지는 Fe 및 불가피한 불순물을 포함하는 강재를 재가열하는 단계;상기 재가열된 강재를 열간 압연하는 단계;상기 열간 압연 후, Bf~Bf-50℃의 온도범위까지 0.1~2℃/s의 속도로 냉각하는 단계; 및상기 냉각된 강재를 공냉하는 단계를 포함하는 강도와 충격 인성이 우수한 선재의 제조방법.
- 청구항 7에 있어서,상기 강재는 크롬(Cr): 0.3% 미만을 추가적으로 포함하는 강도와 충격 인성이 우수한 선재의 제조방법.
- 청구항 7에 있어서,상기 망간(Mn), 타이타늄(Ti), 보론(B) 및 질소(N)의 함량은 하기 관계식 1을 만족하는 강도와 충격 인성이 우수한 선재의 제조방법.[관계식 1]Mn+5(Ti-3.5N)/B ≥ 5.0
- 청구항 7에 있어서,상기 망간(Mn) 및 실리콘(Si)의 함량은 하기 관계식 2를 만족하는 강도와 충격 인성이 우수한 선재의 제조방법.[관계식 2]Mn/Si ≥ 18
- 청구항 7에 있어서,상기 재가열 온도는 1000~1100℃로 행하는 강도와 충격 인성이 우수한 선재의 제조방법.
- 청구항 7에 있어서,상기 열간 압연의 마무리 열간 압연은 850~950℃의 온도범위에서 행하는 강도와 충격 인성이 우수한 선재의 제조방법.
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MX2017005038A MX2017005038A (es) | 2014-11-03 | 2015-11-02 | Varilla de alambre que tiene resistencia mejorada y tenacidad al impacto y metodo de preparacion para la misma. |
US15/516,783 US20170298471A1 (en) | 2014-11-03 | 2015-11-02 | Wire rod having enhanced strength and impact toughness and preparation method for same |
CN201580059619.2A CN107075648B (zh) | 2014-11-03 | 2015-11-02 | 强度和冲击韧性优异的线材及其制造方法 |
JP2017523479A JP6488008B2 (ja) | 2014-11-03 | 2015-11-02 | 強度及び衝撃靭性に優れた線材及びその製造方法 |
DE112015004992.4T DE112015004992T5 (de) | 2014-11-03 | 2015-11-02 | Walzdraht mit verbesserter festigkeit und schlagzähigkeit und herstellungsverfahren für diesen |
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