KR100587949B1 - Anchor Bolt and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an anchor bolt that can be easily fastened material to the structure, in particular, the heat treatment of the finished medium-carbon steel SS45C to remove the stress after re-heating the entire anchor bolt in a rotary furnace to perform a phase deformation and rotary quenching By securing tempering and anti-rust coating, it is long enough to secure sufficient strength but not bent during the heat treatment process and can be used for special purposes. It's about bolts.

The present invention is an anchor bolt that can be easily fastened material to the structure, carbon 0.40 ~ 0.50Wt%, silicon 0.10 ~ 0.20Wt%, manganese 0.60 ~ 0.70Wt%, phosphorus 0.020Wt% or less, sulfur 0.015Wt% or less Machining process (S1) of forming the anchor bolt by machining the hot carbon steel containing hot or cold; A washing step of dipping the machined anchor bolt in a detergent for removing oil (S2); A preheating step (S3) of removing the stress by partially heat-treating the washed anchor bolt at about 250 ° C. for about 1 hour; A stress removing step (S4) of completely removing the stress generated by machining by heat-treating the anchor bolts partially removed from the stress in a heating furnace at 650 ° C. to 680 ° C. for 30 minutes; A medium heat process (S5) of starting the phase deformation evenly by heat-treating the anchor bolts from which the stress is completely removed in a rotary furnace of 700 ° C. to 720 ° C. for 15 minutes; A main heat process (S6) of completing the phase deformation by heat-treating the anchor bolts having the phase deformation started at about 880 ° C. for about 10 minutes; A diffusion step (S7) of rapidly lowering the temperature to about 800 ° C. such that the anchor bolt in which the phase deformation is completed is free of phase deformation in the diffusion furnace; Quenching step (S8) to pass through while rotating the cooling coil spraying the water-soluble oil of about 25 ℃ the anchor bolt is lowered temperature; The quenched anchor bolt is manufactured by heat treatment at about 650 ° C. to temper the steel plate to a suitable strength.

Anchor bolt, medium carbon steel, SS45C, stress relief, rotary furnace, antirust coating, quenching, tempering

Description

Anchor bolt for machine structure and manufacturing method thereof

1 is a cross-sectional view showing a state of use of the conventional anchor bolt for mechanical structure,

Figure 2 is a process diagram showing the manufacturing process of the anchor bolt for the mechanical structure according to the present invention,

3 is a graph showing the heat treatment temperature and time of the anchor bolt for the mechanical structure according to the present invention.

<Explanation of symbols for each major part of drawing>

S1: Machining Process S2: Washing Process

S3: preheating process S4: stress removing process

S5: Middle heat process S6: Main heat process

S7: Diffusion Process S8: Quenching Process

S9: Tempering process S10: Coating process

The present invention relates to an anchor bolt that can be easily fastened material to the structure, and more specifically, after removing the stress by heat-treating the medium-carbon steel SS45C finished machining and re-heat the entire anchor bolt in a rotary furnace to perform a phase deformation Rotating quenching, tempering and rust preventive coating process ensures sufficient strength but does not bend during heat treatment, so it is longer in length and can be used for special purposes. It relates to an anchor bolt for a mechanical structure.

In general, anchor bolts are anchor anchors on concrete floors or walls, and then anchor bolts are inserted into the anchor holes to insert the joints of objects to be fixed to the body of the bolts that are exposed to the outside. As the bolt is gradually discharged to the outside by an object installed in the conical bolt head portion to secure the installation pipe to the anchor installation hole by expanding the end of the installation pipe of the anchor bolt.

Specifically, as shown in FIG. 1, the conventional anchor bolt integrally constitutes the cutout portion 16-1 extending outwardly at the end of the bolt rod 10-1 to form the cutout portion 12-1. The bolt pipe 10-1 penetrates the bolt rod and fastens the nut 18 to the bolt rod 10-1. The anchor bolt is drilled to the concrete wall surface 20 by the drill tube 15-. After drilling the fastening hole 21 drilled larger than the diameter of 1) is inserted into the chain pipe (15-1) to which the bolt rod 10-1 is fastened.

The bolt rod 10-1 fastened to the nut 18 moves by tightening the fastened washer and the nut 18, and the integrated wedge unit 16-1 flows into the chain engine 15-1 so that The base 16-1 expands together with the cutout portion 12-1 by expanding the outer chain organ 15-1, and by this extension, the chain organ 15-1 is crimped and supported on the inner circumferential surface of the fastening hole 21. do.

As the material of the conventional anchor bolt, low carbon steel such as SS400 or SS20C was mainly used without a separate heat treatment, but the anchor bolt has a problem that is easily bent when a strong load is applied because its length is longer than that of a general bolt. The manufacture of the anchor bolt made of the material was required.

According to these demands, there have been attempts to manufacture high-strength anchor bolts by heat-treating medium carbon steel such as SS45C, but there are many difficulties in manufacturing long anchor bolts due to the problem that the anchor bolts themselves are long and deformed during heat treatment. There was, but the present invention solves this problem to produce a longer and straighter anchor bolt is not yet high strength and not bent.

The present invention has been made in view of the problems of the prior art as described above, after removing the stress by heat treatment of the medium-carbon steel SS45C finished machining, the entire anchor bolt is reheated in a rotary furnace to perform a phase deformation and rotary quenching, tempering And the anti-rust coating treatment, which ensures sufficient strength but does not bend during the heat treatment process, the length is longer and can be used for special purposes, and the production cost is cheaper than the high strength and the rust does not occur. The purpose is to provide.

The mechanical bolt anchor bolt of the present invention for achieving the above object contains carbon 0.40 ~ 0.50Wt%, silicon 0.10 ~ 0.20Wt%, manganese 0.60 ~ 0.70Wt%, phosphorus 0.020Wt% or less, sulfur 0.015Wt% or less Machining process of forming the anchor bolt by machining the medium carbon steel in hot or cold; A washing process of dipping the machined anchor bolt in a detergent for removing oil; A preheating process of removing the stress by partially heat treating the washed anchor bolt at about 250 ° C. for about 1 hour; Stress relief process to completely remove the stress caused by machining by heat-treating the anchor bolt in which the stress is partially removed in the heating furnace of 650 ℃ ~ 680 ℃ for 30 minutes, heat deformation of the anchor bolt from which the stress is completely removed Starting heavy heat process; A heat treatment step of completing the phase deformation by heat-treating the anchor bolt in which the phase deformation starts; A diffusion process of rapidly lowering the temperature to about 800 ° C. such that the anchor bolt in which the phase deformation is completed is free from phase deformation in the diffusion furnace; Quenching step of quenching the anchor bolt is lowered temperature; In the anchor bolt having a long length screw portion is manufactured through a tempering process to heat the quenched anchor bolt at about 650 ℃ to match the appropriate strength in use, 15 minutes in a rotary furnace of 700 ℃ ~ 720 ℃ in the medium heat process Phase deformation is started by heat treatment, and the anchor bolt in which the phase deformation starts in the main heat process is heat treated for about 10 minutes in a rotary furnace of about 880 ° C. to complete phase deformation, and water-soluble oil of about 25 ° C. is sprayed in the quenching process. By quenching while passing the cooling coil to rotate, the long length of the bolt is characterized in that it is manufactured not bent during the heat treatment process.

The anchor bolts for mechanical structures of the present invention are made of hot or cold carbon steel containing 0.40 to 0.50 Wt%, silicon 0.10 to 0.20 Wt%, manganese 0.60 to 0.70 Wt%, phosphorus 0.020 Wt% or less, and sulfur 0.015 Wt% or less. A machining process of forming an anchor bolt by machining; A washing process of dipping the machined anchor bolt in a detergent for removing oil; A preheating process of removing the stress by partially heat treating the washed anchor bolt at about 250 ° C. for about 1 hour; Stress relief process to completely remove the stress caused by machining by heat-treating the anchor bolt in which the stress is partially removed in the heating furnace of 650 ℃ ~ 680 ℃ for 30 minutes, heat deformation of the anchor bolt from which the stress is completely removed Starting heavy heat process; A heat treatment step of completing the phase deformation by heat-treating the anchor bolt in which the phase deformation starts; A diffusion process of rapidly lowering the temperature to about 800 ° C. such that the anchor bolt in which the phase deformation is completed is free from phase deformation in the diffusion furnace; Quenching step of quenching the anchor bolt is lowered temperature; In the anchor bolt manufacturing method having a long length screw portion is manufactured through a tempering process to heat the quenched anchor bolt at about 650 ℃ to match the appropriate strength in use, in the rotary furnace of 700 ℃ ~ 720 ℃ in the medium heat process Phase deformation is started by heat treatment for about 15 minutes, and the anchor bolt, which starts phase deformation in the main heat process, is heat treated for about 10 minutes in a rotary furnace of about 880 ° C. to complete phase deformation, and water-soluble oil of about 25 ° C. in the quenching process. By quenching while passing through the cooling coil to spray the, characterized in that the long length of the bolt is manufactured so as not to bend during the heat treatment process.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a process chart showing the manufacturing process of the mechanical bolt anchor bolt according to the present invention, Figure 3 is a graph showing the heat treatment temperature and time of the mechanical bolt anchor bolt according to the present invention.

As shown, the mechanical bolt anchor bolt according to the present invention in the anchor bolt that can easily fasten the material to the structure, carbon 0.40 ~ 0.50Wt%, silicon 0.10 ~ 0.20Wt%, manganese 0.60 ~ 0.70Wt%, phosphorus Machining process (S1) of forming the anchor bolt by machining the medium carbon steel containing 0.020Wt% or less, sulfur 0.015Wt% or less hot or cold; A washing step of dipping the machined anchor bolt in a detergent for removing oil (S2); A preheating step (S3) of removing the stress by partially heat-treating the washed anchor bolt at about 250 ° C. for about 1 hour; A stress removing step (S4) of completely removing the stress generated by machining by heat-treating the anchor bolts partially removed from the stress in a heating furnace at 650 ° C. to 680 ° C. for 30 minutes; A medium heat process (S5) of starting the phase deformation evenly by heat-treating the anchor bolts from which the stress is completely removed in a rotary furnace of 700 ° C. to 720 ° C. for 15 minutes; A main heat process (S6) of completing the phase deformation by heat-treating the anchor bolts having the phase deformation started at about 880 ° C. for about 10 minutes; A diffusion step (S7) of rapidly lowering the temperature to about 800 ° C. such that the anchor bolt in which the phase deformation is completed is free of phase deformation in the diffusion furnace; Quenching step (S8) to pass through while rotating the cooling coil spraying the water-soluble oil of about 25 ℃ the anchor bolt is lowered temperature; The quenched anchor bolt is manufactured by heat treatment at about 650 ° C. to temper the steel plate to a suitable strength.

In addition, after the tempering step (S9) is prepared by further comprising a coating step (S10) of coating the film to prevent rust generated in the anchor bolt has a suitable strength.

The mechanical bolt anchor bolt according to the present invention contains 0.40 to 0.50 Wt% of carbon, 0.10 to 0.20 Wt% of silicon, 0.60 to 0.70 Wt% of manganese, 0.020 Wt% or less of phosphorus, and 0.015 Wt% or less of sulfur. The reason for limitation is described in detail below.

The reason for limiting the content of carbon (C) to 0.40 to 0.50Wt% is that if the content is less than 0.40Wt%, it is difficult to secure sufficient tensile strength as a high strength bolt steel after heat treatment, and the content exceeds 0.50Wt%. This is because it is difficult to secure elongation after heat treatment, and cracks are easily generated during quenching, and have a detrimental effect on decarburization of the furnace, permanent deformation during bolting, fatigue characteristics, and carbonitride distribution.

The reason for limiting the content of silicon (Si) to 0.10 to 0.20Wt% is that it is difficult to secure the strength when the content is less than 0.10Wt%, delayed fracture resistance, surface corrosion characteristics, impact toughness, permanent deformation during bolting, etc. This is because it adversely affects, and if the content exceeds 0.20Wt%, the microstructures become inhomogeneous and the quality characteristics of the final product are degraded.

 The reason for limiting the content of manganese (Mn) to 0.60 ~ 0.70Wt% is that when the content is added less than 0.60Wt%, the segregation zone due to manganese segregation is hardly formed, but the stress relaxation effect is improved by solid solution strengthening. This is because it is difficult to expect, and when the content exceeds 0.70 Wt%, tissue heterogeneity due to manganese segregation adversely affects the bolt characteristics.

The reason for limiting the content of phosphorus (P) to less than 0.020Wt%, the content of sulfur (S) to less than 0.015Wt% is because the phosphorus segregates at the grain boundaries and lowers the toughness to limit the upper limit to 0.02Wt% Sulfur is a low melting point grain boundary segregation to lower the toughness and form an emulsion to adversely affect the delayed fracture resistance and stress relaxation characteristics, limiting the upper limit to 0.015Wt%.

The medium-carbon steel containing the above components is first subjected to a hot or cold machining process (S1) and a washing process (S2). In the machining process (S1), a steel of a desired shape is formed through drawing, rolling, and rolling. It is prepared to form a screw thread on the surface to complete the shape of the anchor bolt, in the washing step (S2) to remove the oil remaining on the surface by immersing the steel after the machining step (S1) in the oil removal cleaner.

Then, the preheating step (S3) and the stress removing step (S4) is subjected to, in the preheating step (S3) to remove the stress generated by machining by heat-treating the steel from the oil for about 1 hour at about 250 ℃. In the stress removing step (S4), the steel from which the partial stress is removed is reheated for about 30 minutes in a heating furnace at 650 ° C. to 680 ° C. to completely remove the stress generated by the machining.

Next, the intermediate heat process (S5), the main heat process (S5) and the diffusion process (S7) are sequentially performed, and the medium heat process (S5) is about 15 minutes in a rotary furnace of 700 ° C to 720 ° C from which the stress is completely removed. Heat deformation is evenly started to start phase deformation, and in the heat treatment step (S6), the steel in which the phase deformation starts is heat-treated and rotated for about 10 minutes in a rotary furnace of about 880 ° C. to complete the phase deformation evenly as a whole. In S7, the temperature is rapidly lowered to about 800 ° C. so that there is no phase deformation in the diffusion furnace.

In the medium heat process (S5) and the main heat process (S5) by using a rotary furnace that rotates the entire anchor bolt at a constant speed at the same time as the heat treatment to induce the phase deformation is uniformly generated throughout the steel as the steel is bent during the heat treatment process Overcome the problem

Then, the quenching process (S8) and the tempering process (S9) is passed, and in the quenching process (S8), the steel lowered to 800 ° C is passed while rotating a spray-type cooling coil spraying water-soluble oil at about 25 ° C, and tempering. In step (S9), the quenched steel is disposed at a suitable interval of about 3 mm to 5 mm at about 650 ° C., and then heat-treated to achieve a suitable strength in use.

The quenching process (S8) also overcomes the problem that the steel is bent during the heat treatment process by inducing the phase deformation to be uniformly generated throughout the steel by passing the spray cooling coil while rapidly rotating the entire anchor bolt.

Finally, the coating step (S10) is to be passed through the tempering step (S9), and the coating is coated with zinc to prevent rust from having a suitable strength.

The action of the mechanical bolt anchor bolt of the present invention manufactured as described above will be described below with specific examples.

Example

It was prepared using steels having the composition of the composition shown in Table 1, Inventive Examples (1 to 4) is to satisfy the component range of the present invention, Comparative Examples (1 to 2) is a conventional out of the component range of the present invention Of things.

C (Wt%) Si (Wt%) Mn (Wt%) P (Wt%) S (Wt%) Inventive Example 1 0.47 0.16 0.62 0.018 0.009 Inventive Example 2 0.43 0.15 0.65 0.017 0.008 Inventive Example 3 0.43 0.18 0.68 0.019 0.012 Inventive Example 4 0.44 0.19 0.66 0.020 0.008 Comparative Example 1 0.17 0.18 0.58 0.022 0.008 Comparative Example 2 0.18 0.18 0.54 0.019 0.004

In order to evaluate the tensile strength, yield strength, etc. for the materials prepared as described above, the tensile test piece was used in the KS standard (KS B 0801) No. 4 test piece, the results are shown in Table 2 below.

Tensile Strength (N / mm ² ) Yield strength (N / mm ² ) Elongation (%) Cross section reduction rate (%) Inventive Example 1 857 642 22 53 Inventive Example 2 845 627 25 61 Inventive Example 3 849 630 24 59 Inventive Example 4 851 635 21 52 Comparative Example 1 468 337 37 89 Comparative Example 2 471 343 34 82

As shown in Table 2, when manufacturing the anchor bolt with SS45C of the present invention (1-4) compared to the conventional SS400 material of Comparative Examples (1-2), tensile strength, yield strength significantly increased, elongation and cross section As the reduction rate is reduced, it is possible to produce high strength anchor bolts suitable for special purposes.

Therefore, after machining medium carbon steel containing 0.40 ~ 0.50Wt% of carbon, 0.10 ~ 0.20Wt% of silicon, 0.60 ~ 0.70Wt% of manganese, 0.020Wt% of phosphorus and less than 0.015Wt% of sulfur, By sequential phase deformation, rotary quenching, and tempering in rotary furnaces, it is possible to produce longer anchor bolts because they do not bend during heat treatment while having sufficient strength to be used even for special purposes requiring high strength. .

In addition, the production cost is low compared to the excellent strength and the anti-rust coating treatment as a post-treatment, so that the rust does not easily occur even in the long-term use can further increase the safety of the structure.

The mechanical bolt anchor bolt of the present invention configured as described above is subjected to heat treatment of SS45C after machining to remove stress, and then the entire anchor bolt is reheated in a rotary furnace to perform phase deformation and rotary quenching, tempering and rust prevention coating treatment. By doing so, while ensuring sufficient strength does not bend in the heat treatment process, the length is longer and can be used for special purposes, and the production cost is low compared to high strength, and does not occur rust does not produce a useful effect that can be used safely for a long time.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various changes or modifications can be made within the spirit and scope of the present invention, and such changes or modifications are to the accompanying patents. Will have to belong to the claims.

Claims (3)

Forming anchor bolts by hot or cold machining of heavy carbon steel containing 0.40 ~ 0.50Wt% carbon, 0.10 ~ 0.20Wt% silicon, 0.60 ~ 0.70Wt% manganese, 0.020Wt% phosphorus or less, 0.015Wt% sulfur Machining process (S1); A washing process of dipping the machined anchor bolts into a detergent for removing oil and washing them (S2); A preheating step (S3) of removing the stress by partially heat-treating the washed anchor bolt at about 250 ° C. for about 1 hour; The stress bolt is partially heat-treated in the 650 ℃ ~ 680 ℃ heating furnace for about 30 minutes to remove the stress generated by the machining to remove the stress (S4), the anchor bolt from the stress is completely removed A middle heat process (S5) for starting phase deformation; A heat treatment step (S6) of completing the phase deformation by heat-treating the anchor bolt in which the phase deformation starts; A diffusion step (S7) of rapidly lowering the temperature to about 800 ° C. such that the anchor bolt in which the phase deformation is completed is free of phase deformation in the diffusion furnace; Quenching step (S8) to quench the anchor bolt is lowered temperature; In the anchor bolt having a long length screw portion is manufactured through a tempering process (S9) to heat the quenched anchor bolt at about 650 ℃ to meet the appropriate strength in use, In the middle heat process (S5) to start the phase deformation by heat treatment for about 15 minutes in a rotary furnace of 700 ℃ ~ 720 ℃, 10 minutes in a rotary furnace of about 880 ℃ to start the phase deformation in the main heat process (S6) After the heat treatment to complete the phase deformation, and quenching while passing through the cooling coil for spraying water-soluble oil of about 25 ℃ in the quenching step (S8), characterized in that the long length of the bolt is manufactured so as not to bend during the heat treatment process Long anchor bolts for machine structures. delete Forming anchor bolts by hot or cold machining of heavy carbon steel containing 0.40 ~ 0.50Wt% carbon, 0.10 ~ 0.20Wt% silicon, 0.60 ~ 0.70Wt% manganese, 0.020Wt% phosphorus or less, 0.015Wt% sulfur Machining process (S1); A washing process of dipping the machined anchor bolts into a detergent for removing oil and washing them (S2); A preheating step (S3) of removing the stress by partially heat-treating the washed anchor bolt at about 250 ° C. for about 1 hour; The stress bolt is partially heat-treated in the 650 ℃ ~ 680 ℃ heating furnace for about 30 minutes to remove the stress generated by the machining to remove the stress (S4), the anchor bolt from the stress is completely removed A middle heat process (S5) for starting phase deformation; A heat treatment step (S6) of completing the phase deformation by heat-treating the anchor bolt in which the phase deformation starts; A diffusion step (S7) of rapidly lowering the temperature to about 800 ° C. such that the anchor bolt in which the phase deformation is completed is free of phase deformation in the diffusion furnace; Quenching step (S8) to quench the anchor bolt is lowered temperature; In the anchor bolt manufacturing method having a long length screw portion is manufactured through a tempering process (S9) to heat the quenched anchor bolt at about 650 ℃ to match the appropriate strength in use, In the middle heat process (S5) to start the phase deformation by heat treatment for about 15 minutes in a rotary furnace of 700 ℃ ~ 720 ℃, 10 minutes in a rotary furnace of about 880 ℃ to start the phase deformation in the main heat process (S6) After the heat treatment to complete the phase deformation, in the quenching process (S8) by quenching while passing through the cooling coil for spraying water-soluble oil of about 25 ℃, characterized in that to produce a long length of the bolt does not bend during the heat treatment process Long length anchor bolt manufacturing method for the machine structure.

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