KR20120132839A - Structural damper steel with low yield ratio and method of manufacturing the same - Google Patents

Structural damper steel with low yield ratio and method of manufacturing the same Download PDF

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KR20120132839A
KR20120132839A KR1020110051200A KR20110051200A KR20120132839A KR 20120132839 A KR20120132839 A KR 20120132839A KR 1020110051200 A KR1020110051200 A KR 1020110051200A KR 20110051200 A KR20110051200 A KR 20110051200A KR 20120132839 A KR20120132839 A KR 20120132839A
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South Korea
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steel
less
weight
damper steel
hot rolling
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KR1020110051200A
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Korean (ko)
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김종호
황성두
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현대제철 주식회사
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Priority to KR1020110051200A priority Critical patent/KR20120132839A/en
Publication of KR20120132839A publication Critical patent/KR20120132839A/en

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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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

PURPOSE: Earthquake-proof damper steel for with a low yield ratio and a manufacturing method thereof are provided to improve the earthquake-proof performance of a building by providing a low yield ratio, a high elongation ratio, and excellent low-temperature impact characteristic. CONSTITUTION: Earthquake-proof damper steel comprises 0.01-0.05 weight% of C, 0.05-0.1 weight% of Si, 0.1-0.5 weight% of Mn, 0.015 weight% or less of P, 0.01 weight% or less of S, 0.03 weight% or less of Ti, 40ppm or less of N, and the remaining amount of Fe and inevitable impurities. The earthquake-proof damper steel has a tensile strength of 250-280MPa, a yield strength of 160-190MPa, an elongation ratio of 50-52 weight%, and a 0°C impact toughness of 200-250J. [Reference numerals] (AA) Start; (BB) End; (S110) Slab reheating(SRT: 1150-1250°C); (S120) Hot rolling(FDT: 950-1050°C); (S130) Cooling(Air-cooling)

Description

STRUCTURED DAMPER STEEL WITH LOW YIELD RATIO AND METHOD OF MANUFACTURING THE SAME

The present invention relates to a damper steel used to secure the seismic performance of a building, and more particularly, to a damper steel having a low yield ratio and a high elongation rate by adjusting an alloy component.

Recently, large-scale earthquakes have occurred. When an earthquake occurs, buildings collapse, causing a number of casualties and property damages.

In order to reduce the earthquake damage caused by the collapse of buildings, earthquake-resistant steels should be used. In particular, damper steels have a buffering effect between steels.

The damper steel is required to have a low yield ratio and a high elongation.

An object of the present invention is to provide a damper steel that satisfies the yield strength of 160 ~ 190MPa, tensile strength of 250 ~ 280MPa.

Another object of the present invention is to provide a damper steel having excellent elongation of 50 to 52% and showing low temperature impact toughness of 200 to 250J.

The present invention is a weight%, carbon (C): 0.01 ~ 0.05%, silicon (Si): 0.05 ~ 0.1%, manganese (Mn): 0.1 ~ 0.5%, phosphorus (P): 0.015% or less, sulfur (S) A seismic damper steel comprising: 0.01% or less, titanium (Ti): 0.03% or less, nitrogen (N): 40 ppm or less, and remaining iron (Fe) and unavoidable impurities.

At this time, the damper steel for earthquake resistance preferably has mechanical properties of tensile strength of 250 to 280 MPa, yield strength of 160 to 190 MPa, elongation of 50 to 52%, and 0 ° C impact toughness of 200 to 250J.

In addition, the present invention is a weight%, carbon (C): 0.01 ~ 0.05%, silicon (Si): 0.05 ~ 0.1%, manganese (Mn): 0.1 ~ 0.5%, phosphorus (P): 0.015% or less, sulfur ( S): 0.01% or less, titanium (Ti): 0.03% or less, nitrogen (N): 40 ppm or less, and a slab reheating step of reheating a steel material consisting of remaining iron (Fe) and unavoidable impurities; A hot rolling step of hot rolling the steel; And a cooling step of cooling the steel material.

At this time, in the slab reheating step, the slab reheating temperature (SRT) is 1150 ~ 1250 ℃, in the hot rolling step, the finish hot rolling temperature (FDT) is preferably 950 ~ 1050 ℃.

The present invention provides an earthquake-proof damper steel exhibiting a resistance ratio, high elongation, and excellent low-temperature impact toughness, thereby bringing an effect of improving the seismic performance of a building using the same.

1 is a flowchart schematically illustrating a method for manufacturing a damper steel for earthquake resistance according to an embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving the same will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, with reference to the accompanying drawings, a detailed description will be given of a damper steel having a resistance ratio and excellent elongation according to a preferred embodiment of the present invention.

Seismic Damper Steel

The seismic damper steel having resistance yield ratio and high elongation according to the present invention can be used to connect the interlayer structural materials of buildings, and aims to have low yield ratio, high tensile strength and low temperature impact toughness to improve seismic performance. Shall be.

Specifically, the tensile strength of 250 ~ 280MPa, yield strength 160 ~ 190MPa, elongation 50 ~ 52%, 0 ℃ impact toughness 200 ~ 250J aims.

To this end, the damper steel for earthquake resistance according to the present invention is carbon (C): 0.01 ~ 0.05%, silicon (Si): 0.05 ~ 0.1%, manganese (Mn): 0.1 ~ 0.5%, phosphorus (P): 0.015% or less , Sulfur (S): 0.01% or less, titanium (Ti): 0.03% or less, nitrogen (N): 40 ppm or less, and the remaining iron (Fe) and unavoidable impurities.

Hereinafter, the role and content of each component included in the damping steel for earthquake resistance according to the present invention will be described.

Carbon (C)

Carbon (C) is added to secure the strength, based on low carbon in order to lower the tensile strength and yield strength.

The carbon is preferably added in 0.01 to 0.05% by weight of the total weight of the damper steel according to the present invention, more preferably 0.03% by weight can be presented. If the carbon content is less than 0.01% by weight, it is not possible to secure the required tensile strength and yield strength, and if the carbon content is more than 0.05% by weight, there is a problem that a low yield ratio cannot be obtained.

Silicon (Si)

Silicon contributes to strength and, in particular, serves as a deoxidizer to remove oxygen in the steel.

The silicon is preferably added at 0.05 to 0.1% by weight of the total weight of the hot-rolled steel sheet according to the present invention in consideration of inherent deoxidation effect and surface quality, and more preferably 0.08% by weight. If the content of silicon is less than 0.05% by weight, the deoxidation effect due to the addition of silicon is insufficient. On the contrary, when the content of silicon exceeds 0.1% by weight, the strength rises, making it difficult to achieve a resistance ratio.

Manganese (Mn)

Manganese (Mn) is very effective as a solid solution strengthening element, and is an effective element for securing strength by improving the hardenability of steel. In addition, manganese is an austenite stabilizing element, which contributes to the refinement of ferrite grains by retarding ferrite and pearlite transformation.

The manganese is preferably added in a content ratio of 0.1 to 0.5% by weight of the total weight of the API hot-rolled steel sheet according to the present invention in consideration of the strength improving effect and the center segregation, and more preferably 0.3% by weight. .

If the amount of manganese added in the damper steel according to the present invention is less than 0.1% by weight, the solid solution strengthening effect is insignificant. On the contrary, when the amount of manganese exceeds 0.5% by weight, the yield ratio increases and weldability is greatly reduced.

Phosphorus (P)

Phosphorous (P) is added to inhibit cementite formation and increase strength.

However, since phosphorus inhibits weldability and impact toughness, and causes final material variation by slab center segregation, the phosphorus (P) is 0.01% by weight of the total weight of the damper steel according to the present invention. It is preferable to restrictively add within the following ranges.

Sulfur (S)

Sulfur (S) inhibits the toughness and weldability of steel, and forms an MnS non-metallic inclusion by binding with manganese, thereby generating cracks during steel processing.

Therefore, high sulfur (S) content is impaired impact toughness, it is preferable to limit to less than 0.01% by weight of the total weight of the damper steel according to the present invention.

Titanium (Ti)

In the present invention, titanium (Ti) is a precipitate forming element, and forms TiN during slab reheating, thereby suppressing austenite grain growth and increasing strength. In particular, TiN precipitates are not easily dissolved at high temperatures due to the high dissolution temperature, and thus serve to refine the grains in the weld heat affected zone (HAZ).

In the damper steel according to the present invention, titanium is preferably added at 0.03% by weight or less of the total weight to secure weldability.

Seismic damper steel manufacturing method

1 is a flowchart schematically illustrating a method for manufacturing a damper steel for earthquake resistance according to an embodiment of the present invention.

Referring to FIG. 1, the illustrated method for manufacturing a damper-resistant damper steel includes a slab reheating step S110, a hot rolling step S120, and a cooling step S130.

Reheat slab

In the slab reheating step (S110), the weight%, carbon (C): 0.01 ~ 0.05%, silicon (Si): 0.05 ~ 0.1%, manganese (Mn): 0.1 ~ 0.5%, phosphorus (P): 0.015% or less, The slab steel in semi-finished state having a composition of sulfur (S): 0.01% or less, titanium (Ti): 0.03% or less, nitrogen (N): 40 ppm or less, and remaining iron (Fe) and unavoidable impurities is reheated.

Through reheating of slab steels, the segregated components are cast again.

At this time, the slab reheating temperature (SRT) in this step is preferably carried out in a temperature range of 1150 ~ 1250 ℃ in the heating furnace, it is also preferably carried out for 90 to 150 minutes.

If the slab reheating temperature (SRT) is less than 1150 ℃ or the reheating time is less than 90 minutes, the segregated components during casting is not reusable, there is a problem that the rolling load is increased during hot rolling.

On the contrary, when the slab reheating temperature (SRT) exceeds 1250 ° C. or the reheating time exceeds 150 minutes, the austenite grains increase and the strength decreases, and the excessive heating process causes the damper steel manufacturing cost to increase.

Hot rolling

In the hot rolling step (S120), the reheated steel is hot rolled through the slab reheating step (S110).

At this time, the finish hot rolling temperature (FDT) is preferably 950 ~ 1050 ℃ corresponding to the austenite recrystallization stop temperature (RST) or more so that the steel structure before the cooling after hot rolling has a structure of the austenite phase.

If the finish hot rolling temperature (FDT) is less than 950 ℃ abnormal reverse rolling occurs, the elongated ferrite and perlite are present, the pearlite band is formed can reduce the ductility. On the contrary, when the finish hot rolling temperature FDT exceeds 1050 ° C., there is a problem in that the strength of the damper steel for earthquake resistance produced is not sufficiently secured.

In the hot rolling step (S120), the reduction ratio may be determined according to the thickness of the damper-resistant damper steel.

Cooling

In the cooling step (S130) to cool the hot rolled steel.

At this time, in the present invention, the cooling is preferably carried out by air cooling.

In the case of the cooling of the quenching method after the end of hot rolling, it is easy to secure the strength of the steel, but a large cost is required for the control of the cooling rate, etc., and the moldability and impact characteristics may be impaired.

However, in the case of the air-cooling method as in the present invention, it is advantageous to form the supercooled structure according to the delay of the phase transformation and thereby achieve a resistance ratio, and to secure the low-temperature shock characteristics that are important separately from the strength in the damper steel for earthquake resistance.

In addition, in the case of the damper steel for earthquake resistance prepared by the method according to the present invention, tensile strength (TS): 250 ~ 280 MPa, yield strength (YS): 160 ~ 190 MPa or more, elongation (EL): 50 ~ 52%, 0 It can exhibit the mechanical properties of the impact toughness 200 ~ 250J.

Example

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

1. Preparation of Damper Steel Specimen

Alloy compositions applied to the steel specimens according to Example 1 and Comparative Examples 1 and 2 are shown in Table 1 below.

  (Unit: weight%) division C Si Mn P S Ti N Example 1 0.03 0.08 0.4 0.015 0.01 0.02 0.003 Comparative Example 1 0.03 0.08 0.6 0.015 0.01 0.02 0.003 Comparative Example 2 0.03 0.08 0.4 0.03 0.01 0.02 0.003

The slab steel having a composition according to Example 1 and Comparative Examples 1 to 2 as described in Table 1 was heated at 1200 ° C. for 2 hours, and hot-rolled immediately after the slab extraction in a heating furnace to obtain hot-rolled steel specimens. Was manufactured, and the finish hot rolling temperature was 950 ° C. Thereafter, without performing cooling separately, the hot-rolled steel specimens were air cooled.

2. Property evaluation

Table 2 shows the mechanical properties of the steel specimens according to Example 1 and Comparative Examples 1 and 2.

division YS [MPa] TS [MPa] EL [%] Impact toughness
(J, @ 0 ℃) Target  160-190 250-280 50-52 200 ~ 250J Example 1 177 263 50.2 231 Comparative Example 1 198 293 45 245 Comparative Example 2 181 261 49.3 187

Referring to Table 2, in the case of Example 1, it can be seen that all of the target tensile strength 250 ~ 280MPa, yield strength 160 ~ 190 MPa or more, elongation 50 ~ 52% or more, low temperature impact toughness 200 ~ 250J .

On the other hand, referring to Table 2, in the case of Comparative Example 1 in which excess of manganese was added in 0.6% by weight, the strength was higher than the target value, the elongation was low, and in the case of Comparative Example 2 in which phosphorus was added in excess of 0.03% The impact toughness was lower than the target.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Such changes and modifications are intended to fall within the scope of the present invention unless they depart from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

S110: Slab reheating step
S120: Hot Rolling Step
S130: cooling stage

Claims (6)

By weight%, carbon (C): 0.01 to 0.05%, silicon (Si): 0.05 to 0.1%, manganese (Mn): 0.1 to 0.5%, phosphorus (P): 0.015% or less, sulfur (S): 0.01% Or less, titanium (Ti): 0.03% or less, nitrogen (N): 40 ppm or less, and an earthquake-resistant damper steel composed of remaining iron (Fe) and unavoidable impurities.
The method of claim 1,
The seismic damper steel
Seismic damper steel, characterized in that the tensile strength of 250 ~ 280MPa, yield strength 160 ~ 190MPa range
The method of claim 1,
The seismic damper steel
The damper steel for earthquake resistance, characterized in that the elongation ranges from 50% to 52%.
The method of claim 1,
The seismic damper steel
A damper steel for earthquake resistance, characterized in that it is in the range of 200 to 250J impact toughness.
By weight%, carbon (C): 0.01 to 0.05%, silicon (Si): 0.05 to 0.1%, manganese (Mn): 0.1 to 0.5%, phosphorus (P): 0.015% or less, sulfur (S): 0.01% Below, the slab reheating step of reheating the steel material consisting of titanium (Ti): 0.03% or less, nitrogen (N): 40 ppm or less and the remaining iron (Fe) and inevitable impurities;
A hot rolling step of hot rolling the steel; And
A damping steel manufacturing method comprising a; cooling step of cooling the steel.
The method of claim 5, wherein
In the slab reheating step,
Slab reheat temperature (SRT) is 1150 ~ 1250 ℃,
In the hot rolling step,
Finish hot rolling temperature (FDT) is 950 ~ 1050 ℃ seismic damper steel manufacturing method characterized in that.
KR1020110051200A 2011-05-30 2011-05-30 Structural damper steel with low yield ratio and method of manufacturing the same KR20120132839A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102376475B1 (en) 2020-12-16 2022-03-17 주식회사 포스코 Concrete reinforcement seismic steel wire rod, and method of manufacturing the same
KR20220088225A (en) * 2020-12-18 2022-06-27 주식회사 포스코 Steel sheet for seismic damper having superior toughness property and manufacturing method of the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102376475B1 (en) 2020-12-16 2022-03-17 주식회사 포스코 Concrete reinforcement seismic steel wire rod, and method of manufacturing the same
KR20220088225A (en) * 2020-12-18 2022-06-27 주식회사 포스코 Steel sheet for seismic damper having superior toughness property and manufacturing method of the same

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