KR101197431B1 - STEEL PIPE WITH A FUNCTION OF CONVEYING 600bar HIGH-PRESSURE CONCRETE AND THE METHOD OF MANUFACTURING THE SAME - Google Patents

Abstract

Disclosed is a concrete high pressure press tube improved by 1250 MPa tensile strength, 360 Hv hardness, 600 bar pressure resistance performance, and a manufacturing method thereof.
The method for producing a concrete high pressure pump according to the present invention, in weight%, carbon (C): 0.34 ~ 0.36%, manganese (Mn): 2.50% or less, phosphorus (P): 0.03% or less, sulfur (S): 0.03 % Or less, boron (B): 0.004% or less, Slitting step of slitting the heat-treated steel composed of the remaining iron (Fe) and other unavoidable impurities to the outer diameter width of the pressure vessel to form a skelp ; Leveling and edge milling steps to adjust flatness and polish edges while releasing the roll-shaped skelp; A roll forming step of forming the skelp through the leveling and edge milling into a multi-stage roll to form a pipe; A pressure pipe tube tube step of welding the pressure pipes by welding both edges of the skelp after the roll forming; (e) Press tube heat treatment to be heat-treated with tempered martensite structure suitable for conveying concrete at 600 bar pressure with a minimum tensile strength of 1250 MPa and a minimum hardness of 360 Hv. It includes; step.

Description

SPEEL PIPE WITH A FUNCTION OF CONVEYING 600bar HIGH-PRESSURE CONCRETE AND THE METHOD OF MANUFACTURING THE SAME}

The present invention relates to a high pressure concrete pipe and improved manufacturing method of 1250MPa tensile strength, 360Hv hardness, 600bar pressure resistance performance, the concrete is improved in pressure resistance and wear resistance to be able to press the concrete at a high pressure of 600bar when construction of high-rise building It is a technique regarding a high pressure pressure pipe and its manufacturing method.

Concrete pressurized pipe means a pipe member which carries concrete using pressure.

Concrete is a material with a higher specific gravity than water, so in order to effectively transport it to the upper level, it is necessary to secure mechanical properties of the steel pipe itself, which can endure very high pressure.

At present, there is an increasing interest in the construction of high-rise buildings, and according to this trend, there is an urgent need for a pressure pipe with improved pressure resistance and wear resistance that can effectively transport concrete to the height of a high-rise building.

To date, pressure pipes manufactured by heat-treating general structural steels (eg STK490) and heat-treated steel sheets (eg, S45C) have been on the market, but are superior to the conventional pressure pipes. There is an urgent need for the development of a pressure pipe that can have a pressure resistance characteristic.

An object of the present invention is to provide a high-pressure concrete concrete pressure pipe that can be pressed at a pressure of 600 bar by securing the mechanical properties of the tensile strength (TS) 1250MPa or more, hardness 360Hv or more, as the heat treatment of the heat-treated steel effectively.

Another object of the present invention is to properly present the composition ratio of the heat treatment steel grade necessary for manufacturing the above-mentioned concrete high pressure feed pipe, and to propose the appropriate heat treatment conditions so as to achieve the desired pressure resistance performance, suitable for the construction of high-rise buildings. The present invention provides a method for producing a concrete pressure pipe.

The problem to be solved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

According to the spirit of the present invention, (a) wt%, carbon (C): 0.34 ~ 0.36%, manganese (Mn): 2.50% or less, phosphorus (P): 0.03% or less, sulfur (S): 0.03% or less , Boron (B): less than 0.004%, the slitting step of slitting the heat-treated steel composed of the remaining iron (Fe) and other unavoidable impurities to the outer diameter width of the pressure vessel to form a skelp; (b) leveling and edge milling steps to adjust flatness and polish edges while releasing the rolled skelp; (c) a roll forming step of forming the skelp through the leveling and edge milling into a multi-stage roll to form a pipe; (d) a pressure pipe tube tube step of welding the pipes by welding both edges of the skelp after the roll forming; (e) Press tube heat treatment to be heat-treated with tempered martensite structure suitable for conveying concrete at 600 bar pressure with a minimum tensile strength of 1250 MPa and a minimum hardness of 360 Hv. It provides a concrete high pressure pressure pipe manufacturing method comprising a.

According to yet another aspect of the present invention, in weight%, carbon (C): 0.34 to 0.36%, manganese (Mn): 2.50% or less, phosphorus (P): 0.03% or less, sulfur (S): 0.03 % Or less, boron (B): 0.004% or less, and heat-treated steel composed of the remaining iron (Fe) and other unavoidable impurities slitting to the outer diameter width of the pressure pipe to form a skelp, The push tube constructed using concrete has a minimum tensile strength of 1250 MPa, a minimum hardness of 360 Hv, and a concrete heat-treated with tempered martensite structure to be suitable for conveying concrete at 600 bar pressure. Provide a high pressure pump.

According to the concrete high pressure pressure pipe of the present invention and a method of manufacturing the same, by using a heat treatment steel grade, by effectively quenching and tempering (tempering) heat treatment, such as better tensile strength (TS) and hardness (Hv) Since mechanical properties can be secured, there is an advantageous effect of providing a concrete high pressure pressure pipe required for the construction of a high-rise building.

In addition, according to the concrete high pressure pump and the manufacturing method of the present invention, in order to manufacture the above-mentioned concrete high pressure pump, it is possible to correctly present the composition ratio of the heat treatment steel species required, and to achieve the desired pressure resistance performance, The competitiveness can be improved.

1 is a flow chart showing a concrete high pressure pressure pipe manufacturing method according to an embodiment of the present invention,
2 is a structure photograph shown to explain the change in the structure before and after the heat treatment in the concrete high pressure pressure pipe according to an embodiment of the present invention,
Figure 3 is a tissue picture of Comparative Example 1 shown for comparison with an embodiment of the present invention.

Hereinafter, a description will be given of a preferred embodiment of a concrete high pressure pressure pipe according to the present invention and a manufacturing method thereof.

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. The present invention may, however, be embodied in 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, and will fully convey the scope of the invention to those skilled in the art. 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.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, with reference to the accompanying drawings it will be described in detail with respect to the concrete high-pressure pump and the manufacturing method according to a preferred embodiment of the present invention.

Improved concrete high pressure pump with 600 bar pressure resistance

Concrete high pressure pressure pipe according to the present invention is to pipe the pressure pipe using a carbonaceous heat-treated steel of 0.34 ~ 0.36% by weight of carbon so that the pressure resistance and wear resistance required for the concrete can be improved during construction of a high-rise building .

As the heat-treated tube is heat-treated by the manufacturing method according to the embodiment of the present invention, the tensile strength (TS) is 1250MPa or more, the hardness is to ensure the mechanical properties of 360Hv or more.

As a result, the concrete high pressure pressure pipe according to the present invention may have a pressure resistance characteristic of 600 bar.

Concrete high pressure pump according to the present invention, in weight%, carbon (C): 0.34 ~ 0.36%, manganese (Mn): 2.50% or less, phosphorus (P): 0.03% or less, sulfur (S): 0.03% or less , Boron (B): 0.004%, the remainder is prepared using a heat-treated steel composed of iron (Fe) and other unavoidable impurities.

Referring to the role and the content of each component included in the concrete high pressure pump according to the present invention as follows.

Carbon (C): 0.34 to 0.36 wt%

Carbon is an important element that allows martensite transformation to occur after heat treatment in subsequent processes, and serves to enhance the strength of the steel. In other words, austenite solid solution forms martensite structure during quenching heat treatment.

Such carbon may help to improve the martensite fraction as the content thereof increases, and it is preferable to add 0.34 to 0.36% by weight relative to the total weight of the concrete high pressure pump according to the present invention. More preferably 0.35% by weight.

When the carbon content is less than 0.34% by weight, it is difficult to secure sufficient strength. When the carbon content is more than 0.36% by weight, it may adversely affect workability, and the weldability and toughness may be deteriorated.

Manganese (Mn): 2.50 wt% or less

Manganese is an effective element that raises the strength without lowering the toughness.

Manganese is an effective element that raises the strength without lowering the toughness.

In particular, as a solid solution strengthening element, it improves the hardenability of steel and contributes to improving the yield strength and tensile strength of carbon steel. In addition, manganese increases the depth of cure during the quenching heat treatment, but if excessively large amounts are contained, quenching cracks or deformation may be caused.

Therefore, in the case of the concrete high pressure pump according to the present invention, the content of manganese is preferably limited to 2.50% by weight. As a preferred embodiment, 2.50% by weight can be presented.

Boron (B): 0.004 wt% or less

Boron is an element that significantly increases the hardenability by only a small amount of addition, but when excessively added, Fe ₃ B forms and causes red brittleness. Therefore, it is preferable to add the limited to 0.004% by weight or less with respect to the total weight of the concrete high pressure pump according to the invention.

Phosphorus (P): 0.03 wt% or less

Phosphorus is an impurity element present in steel and is an advantageous element for improving strength and corrosion resistance. However, excessive addition may significantly impair the impact toughness, so it is desirable to keep the content as low as possible.

The phosphorus content is added to the total weight of the concrete high pressure pressure pipe according to the present invention is limited to 0.03% by weight or less.

Sulfur (S): 0.03 wt% or less

Sulfur, like phosphorus, is an impurity element present in steel.

In particular, since such sulfur forms an emulsion-based inclusions such as MnS, which can greatly inhibit the toughness and strength of the steel, it is advantageous to keep the content as low as possible.

Therefore, the content of sulfur is preferably limited to 0.03% by weight or less based on the total weight of the concrete high pressure pump according to the present invention.

The prepared heat-treated steel is slitting to the outer diameter width of the pressure feed pipe, and formed into a skelp.

Such a skelp can be manufactured into a concrete high pressure pressure pipe required for the construction of a high-rise building through the pipe work.

In the high pressure concrete pressure tube according to a preferred embodiment of the present invention, the targeted pressure resistance is 600 bar and should correspond to a tensile strength (TS) of 1250 MPa and a hardness standard of 360 Hv.

1 is a flowchart illustrating a method of manufacturing a concrete high pressure pressure pipe according to an embodiment of the present invention.

Hereinafter, with reference to Figure 1, it will be described in detail with respect to the manufacturing method of the concrete high pressure pump according to a preferred embodiment of the present invention.

First, in weight percent, carbon (C): 0.34 to 0.36%, manganese (Mn): 2.500% or less, phosphorus (P): 0.03% or less, sulfur (S): 0.03% or less, boron (B): 0.004% Hereinafter, a heat treatment steel composed of the remaining iron (Fe) and other unavoidable impurities is slitting to the width of the outer diameter of the pressure feed pipe to form a skelp (S100).

Next, leveling and edge milling to adjust the flatness and polish the edge while releasing the roll-shaped skelp are performed (S200).

When the leveling and edge milling is completed, the roll forming is performed to form a skelp into a multi-stage roll to form a pipe shape (S300).

Next, the pressure pipe is manufactured by welding both edges of the skelp after the roll forming (S400). At this time, preferably, electric resistance welding may be used as a welding method used for edge welding of both ends of the skelp.

Between the pressure tube manufacturing step (S400) and the pressure tube heat treatment step (S500) to be described later, more preferably, during the pipe work of the pressure tube, it may include the step of removing the beads formed on the weld surface.

The corrugated push tube is then heat-treated with tempered martensite tissue, suitable for pushing concrete at 600 bar pressure (S500).

At this time, the heat treatment step (S500) is a step of transforming the tempered martensite structure in order to improve the strength and pressure resistance performance of the pressure vessel was a ferrite + pearlite structure before heat treatment.

First, the prepared pressure feed tube is subjected to normalizing which heats up to the austenite transformation point.

Next, a quenching step (S520) of quenching the heated feed tube is performed. Subsequently, a tempering step S540 of re-heating the quenched pressure feed pipe and performing slow cooling is performed.

Here, normalization of the pressure feed pipe is performed in order to refine the welded structure of the pressure feed pipe that is formed through electrical resistance welding and to homogenize the internal and external textures of the pressure feed pipe.

In particular, through this normalization, the pressure vessel is heated to a uniform austenite structure to ensure a standardized structure. To this end, it may be heated to 900 ~ 1000 ℃ preferably a stable solid solution temperature of austenite.

Next, the quenching heat treatment step (S520) is performed. Quenching is one of heat treatment methods for steel, and refers to a heat treatment method for steel commonly referred to as quenching as a method of quenching a steel material heated at high temperature.

The quenching heat treatment in this step is to quench the pressure pipe heated to 900 ~ 1000 ℃, preferably the heated pressure feed through the water pressure of the cooling water (for example, water) injected at a high pressure of 2.4 ~ 2.6 kg / ㎠ pressure Cool the tube quickly.

By the quenching heat treatment, the pressure pipe is improved in hardness, but the brittleness appears, so that the tempering heat treatment step (S540) to remove the internal stress in accordance with the purpose of use of the concrete high pressure pressure pipe.

In the tempering heat treatment step (S540), the pressure pipe after the quenching heat treatment is reheated and then cooled slowly.

And here, although the temperature at the time of tempering is preferable that it is 490-510 degreeC, it improves the low-temperature impact toughness of a pressure feed pipe, and suppresses a hardness variation.

And through this tempering heat treatment, the pressure pipe is reinforced from the ferrite + pearlite structure to the tempered martensite structure before the heat treatment, it can be improved pressure resistance and wear resistance.

And, more preferably, it may further comprise the step of performing a straightness and diameter size correction for the pressure-reducing pipe generated during the heat treatment.

The equipment required to perform the straightness and diameter size calibration for the pressure pipe is a tube pipe straightener, which is not significantly different from the equipment used in general, detailed description of the equipment will be omitted.

Through all the above-mentioned steps, the concrete high-pressure pressure pipe according to a preferred embodiment of the present invention can withstand the internal pressure of 600 bar, it is possible to meet the target tensile strength 1250MPa and hardness 360Hv standards.

These results will be described in detail through the following examples.

Example

The concrete high pressure pump according to the present invention, through the above-described manufacturing method, while ensuring a tensile strength of 1250MPa, while ensuring a minimum hardness of 360Hv, it is manufactured to be suitable for conveying concrete at a pressure of 600bar. .

Hereinafter, preferred embodiments of the present invention will be described in comparison with Comparative Examples 1, 2, and 3 through the following [Table 1].

[Table 1]

This embodiment uses a carbon-treated heat-treated steel grade of 0.35% by weight, and in Comparative Examples 1 and 3 was used as a non-heat treated steel grade as STK 490 similar steel, in the case of Comparative Example 2 a high-carbon heat-treated steel grade as S45C-like steel It is used.

Each product specification has a similar shape to each other in diameter and thickness as disclosed.

Figure 2 is a tissue photograph showing a comparison of the structure before and after the heat treatment of this embodiment.

In the case of Figure 2 (a), as can be confirmed through the tissue picture, the ferrite, pearlite structure is confirmed.

And when the quenching and tempering heat treatment according to the present invention of Figure 2 (a), as can be seen in Figure 2 (b) it can be seen that transformed into a tempered martensite (tempered martensite) tissue.

On the other hand, the following [Table 2] shows the mechanical properties of the Examples and Comparative Example 1 compared to the composition in the above [Table 1].

[Table 2]

And, the tissue picture of the Example and Comparative Example 1 according to the present invention can be confirmed through Figure 3, Figure 3 (a) is a tissue picture of the pressure-conducting tube manufactured according to the present invention, Figure 3 (b ) Is a structure photograph of Comparative Example 1 of [Table 1] and [Table 2].

As can be seen through the Figure 3, it can be seen that the structure between the Example and Comparative Example 1 is different from each other.

In particular, in the case of the embodiment of the present invention of Figure 3 (a), it can be seen that formed of a tempered martensite tissue (tempered martensite) tissue.

By such a tempered martensite structure, the tensile strength of the pressure pipe according to the present invention was rapidly increased to 1250 MPa, hardness 360 Hv, it was confirmed that the mechanical properties significantly improved compared to Comparative Example 1.

On the other hand, using the embodiment of the present invention, as a result of performing a hydraulic test, it was possible to obtain a result that the present invention is suitable for conveying concrete at a pressure of 600 bar as the target.

In summary, the high-pressure concrete pipe of the present invention is a high-pressure non-heat treated steel grade (e.g. STK 490) or a high-carbon heat-treated steel grade (e.g. S45C) in place of the heavy carbon steel heat treated steel (e.g., carbon weight% 0.34 ~ 0.36) I use it. Then, quenching and tempering heat treatment are performed under appropriate conditions.

As a result, it was possible to manufacture a pressure feeding tube having improved tensile strength (TS) of 1250 MPa and hardness of 360 Hv, and improved pressure resistance performance suitable for high pressure concrete feeding of 600 bar.

So far, concrete embodiments of the high pressure concrete pressure pipe of the present invention and a method of manufacturing the same have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

In other words, the foregoing embodiments are to be understood in all respects as illustrative and not restrictive, the scope of the invention being indicated by the following claims rather than the foregoing description, and the meanings of the claims and All changes or modifications derived from the scope and the equivalent concept should be construed as being included in the scope of the present invention.

S100: Slitting Step
S200: Leveling and Edge Milling Steps
S300: Roll Forming Step
S400: pressure pipe tube step
S500: heat treatment step
S520: quenching step
S540: Tempering Step

Claims (5)

(a)% by weight, carbon (C): 0.34 to 0.36%, manganese (Mn): 2.50% or less, phosphorus (P): 0.03% or less, sulfur (S): 0.03% or less, boron (B): 0.004 A slitting step of slitting a heat-treated steel composed of% or less, remaining iron (Fe) and other unavoidable impurities to an outer diameter width of a pressure pipe to form a skelp;
(b) leveling and edge milling steps to adjust flatness and polish edges while releasing the rolled skelp;
(c) a roll forming step of forming the skelp through the leveling and edge milling into a multi-stage roll to form a pipe;
(d) a pressure pipe tube tube step of welding the pipes by welding both edges of the skelp after the roll forming;
(e) Press tube heat treatment to be heat-treated with tempered martensite structure suitable for conveying concrete at 600 bar pressure with a minimum tensile strength of 1250 MPa and a minimum hardness of 360 Hv. Including;
In step (e),
(e-1) a normalizing step of heating the pressure feeding tube formed in step (d) to an austenite transformation point;
(e-2) quenching to quench the heated pressure feed tube; And
(e-3) a tempering step of slow cooling after reheating the quenched pressure feed pipe;
In the step (e-2), the quenching of the pressure pipe is carried out by a water cooling method with water of 2.4 ~ 2.6 kg / ㎠ pressure,
In the step (e-3), the tempering of the pressure tube is heat-treated at a rate of 5 m / min at a temperature of 490 ~ 510 ℃, and then the air pressure manufacturing method of the concrete, characterized in that the air cooled to room temperature .
delete delete The method of claim 1,
After the step (e)
And performing straightness and diameter size correction with respect to the pressure tube in which deformation occurs during the heat treatment. delete

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