KR101310167B1 - Copper alloy material for pipe of high strength and high conductivity and the method for production same - Google Patents

Abstract

The present invention consists of 0.05 to 0.25 wt% iron (Fe), 0.01 to 0.05 wt% manganese (Mn), 0.015 to 0.07 wt% phosphorus (P), balance copper (Cu) and other unavoidable impurities A copper alloy material for high strength and high conductivity pipes having a weight ratio (Fe / P) of iron (Fe) and phosphorus (P) is 0.75 to 6.0.
In addition, the present invention includes 0.05 to 0.25% by weight of iron (Fe), 0.01 to 0.05% by weight of manganese (Mn), 0.015 to 0.07% by weight of phosphorus (P), and the balance of copper (Cu) Casting the billet so that the weight ratio (Fe / P) of iron (Fe) and phosphorus (P) is 0.75 to 6.0; Hot extruding said billet to obtain an elemental tube; Cold-rolling the hot-extruded element pipe to obtain a pipe material (cold pipe rolling step); Cold drawing the cold drawn tube; Winding the cold drawn tubular material in the form of a coil (level winding step); And heat treating the tubular material wound in the coil form.

Description

Copper alloy material for high strength and high conductivity pipes and a method of manufacturing the same {COPPER ALLOY MATERIAL FOR PIPE OF HIGH STRENGTH AND HIGH CONDUCTIVITY AND THE METHOD FOR PRODUCTION SAME}

The present invention relates to a copper alloy pipe for high strength and highly conductive pipes including copper, iron, manganese and phosphorus and a method for producing the same.

Copper or copper alloy material with excellent thermal conductivity is mainly used as a material for pipes used in piping equipment such as hot water heaters, air conditioners, refrigerators, refrigerators, and heat exchangers. Among them, copper phosphate (C1220) having excellent thermal conductivity, processability, heat resistance, and solderability has been mainly used.

On the other hand, in recent years the hot water heater, air-conditioning, Freon gas that was used as the heating medium gas in the exchanger to the sanitary equipment and heat exchanger of a refrigerator, etc., is restricted to its use is strictly due to the depletion of the ozone layer, instead of the use of environment-friendly refrigerant (CO ₂ gas or the like) is recommended have. However, the condensation pressure in the case of using such an eco-friendly refrigerant as the heat medium is more than twice as high as in the case of using freon gas. Therefore, in order for the pipes used in the plumbing and the heat exchanger to withstand the increased condensation pressure due to the use of the Freon gas replacement eco-friendly refrigerant, the thickness of the pipe must be further thickened or the pipe's strength is further improved. However, increasing the thickness of the pipe increases the weight of the total pressure-resistant heat transfer container, thereby increasing the total manufacturing cost. In addition, when the thickness of the pipe is increased, the member for fixing the pipe must also be increased in strength for structural reasons and to prevent vibration, thereby further increasing the manufacturing cost thereof. In addition, when the thickness of the pipe is increased, the processing amount of the drawing process during the manufacture of the pipe also increases, which also causes a cost increase.

Currently, Korean Patent Publication No. 10-2009-0087005 discloses a copper alloy tube including copper, tin, cobalt, phosphorus, zinc, nickel, etc. as a high strength copper alloy tube, but the copper alloy tube is used as a pipe for heat exchangers due to its low elongation. The following is a problem in terms of processability.

Accordingly, the present invention seeks to provide a copper alloy material having high strength and high conductivity, and also having good workability and a method for producing the same.

Copper alloy material for high strength and high conductivity pipe according to the present invention is 0.05 to 0.25% by weight of iron (Fe), 0.01 to 0.05% by weight of manganese (Mn), 0.015 to 0.07% by weight of phosphorus (P), the balance It is made of copper (Cu) and other unavoidable impurities, and the weight ratio (Fe / P) of iron (Fe) and phosphorus (P) is 0.75 to 6.0. The copper alloy material has a tensile strength of 295 MPa or more, an elongation of 35% or more, and an electrical conductivity of 81% IACS or more.

Method for producing a copper alloy material for high strength and high conductivity pipes according to the present invention is 0.05 to 0.25% by weight of iron (Fe), 0.01 to 0.05% by weight of manganese (Mn), 0.015 to 0.07% by weight of phosphorus (P), and Casting a billet including a remainder of copper (Cu), such that the weight ratio (Fe / P) of the iron (Fe) and phosphorus (P) is 0.75 to 6.0 (casting step); Hot extruding the billet to obtain an element tube (hot extrusion step); Cold-rolling the hot-extruded element pipe to obtain a pipe material (cold pipe rolling step); Cold drawing the cold drawn tube material (cold drawing step); Winding the cold drawn tubular material in the form of a coil (level winding step); And heat treating the pipe wound in the form of a coil (heat treatment step).

The copper alloy material for pipes produced by the manufacturing method according to the present invention described above has a tensile strength of 295 MPa or more, an elongation of 35% or more, and an electrical conductivity of 81% IACS or more.

The copper alloy material for pipes according to the present invention is excellent in strength and conductivity, and workability is improved. In addition, the copper alloy material for pipes according to the present invention has the advantage that the copper alloy material for pipes having a high strength at a low cost can be manufactured.

1 is a process flowchart showing a method of manufacturing a copper alloy material according to the present invention.
2 is an expansion test result of each sample prepared according to Examples and Comparative Examples.
3 is a corrosion test result of each sample prepared according to Examples and Comparative Examples.
4 is a tissue photograph of each sample prepared according to Examples and Comparative Examples.

High strength and according to the invention High conductivity  For pipe Copper alloy

Copper alloy material for high strength and high conductivity pipe according to the present invention is 0.05 to 0.25% by weight of iron (Fe), 0.01 to 0.05% by weight of manganese (Mn), 0.015 to 0.07% by weight of phosphorus (P), balance copper (Cu) and other unavoidable impurities, and the weight ratio (Fe / P) of iron (Fe) and phosphorus (P) is 0.75 to 6.0.

In the copper alloy material for high strength and high conductivity pipe according to the present invention, iron (Fe) forms a precipitate of fine dispersed particles such as Fe-P-based, and serves to improve the strength and conductivity of the copper alloy material.

Iron in the copper alloy material is included in the range of 0.05 to 0.25% by weight. When iron is contained in an amount less than 0.05% by weight, the fine precipitated dispersion particles are insufficient and sufficient strength and conductivity cannot be secured. On the other hand, when the iron exceeds 0.25% by weight, the strength and bending workability of the resulting product is rather reduced by coarsening of the precipitated dispersed particles.

In the copper alloy material for high strength and high conductivity pipe according to the present invention, manganese (Mn) serves to improve hot workability.

Manganese in the copper alloy material is included in the range of 0.01 to 0.05% by weight. When the content of manganese is less than 0.01% by weight, sufficient hot workability is not obtained. When the content of manganese is more than 0.05% by weight, coarse crystallized matter and oxides are formed to lower the bending workability, and the conductivity is further reduced.

In the copper alloy material for high strength and high conductivity pipes according to the present invention, phosphorus (P) serves to improve the strength or conductivity of the copper alloy by forming fine precipitates with iron as well as deoxidation.

Phosphorus in the copper alloy material is included in the range of 0.015 to 0.07% by weight. If phosphorus is contained at less than 0.015% by weight, fine precipitate particles are insufficient and sufficient strength and conductivity cannot be secured. Moreover, when content of phosphorus exceeds 0.07 weight%, as a Fe-P precipitated particle coarsens, strength and bending workability will fall, and hot workability will also fall.

In the copper alloy material for high strength and high conductivity pipe according to the present invention, copper (Cu) is included in the balance.

The copper alloy material for high strength and high conductivity pipes according to the present invention may contain an extremely small amount of other unavoidable impurities. Other unavoidable impurities do not affect the properties of the copper alloy material for high strength and high conductivity pipes according to the present invention.

In the copper alloy material for high strength and high conductivity pipe according to the present invention, the mass ratio of Fe and P is 0.75 to 6.0. When the mass ratio (Fe / P) of Fe and P is less than 0.75, excess P is dissolved in the Cu matrix, and the conductivity of the final copper alloy material is rather lowered. On the other hand, when the mass ratio (Fe / P) of Fe and P exceeds 6.0, the excess excess Fe is produced as crude single grain Fe particles, and the strength of the final copper alloy material is lowered. Therefore, the mass ratio (Fe / P) of Fe and P should be in the range of 0.75 to 6.0.

On the other hand, the copper alloy material for high strength and high conductivity pipe according to the present invention has a tensile strength of 295MPa or more. Therefore, even if an environmentally friendly refrigerant is used instead of the freon gas as the heat medium, the pressure resistant heat transfer vessel made of the copper alloy material for pipes according to the present invention can withstand the condensation pressure of the environmentally friendly refrigerant because the tensile strength of the copper alloy material is 295 MPa or more.

In addition, the copper alloy material for pipes according to the present invention has an electrical conductivity of 81% IACS or more. Therefore, the copper alloy material for pipes according to the present invention is suitable for replacing phosphoric acid copper used as a material for pressure-resistant heat-transfer containers such as pipes used in existing plumbing facilities such as hot water heaters, air conditioners, freezers, refrigerators, and heat exchangers.

The copper alloy material has an elongation of at least 35%. Therefore, the copper alloy material for pipes according to the present invention has excellent bendability and excellent workability, and is suitable for improving the ability to plastic deformation when the metal tube is press-fitted and expanded.

In the conventional copper alloy material for heat exchangers, when the tensile strength is improved to high, the electrical conductivity and the elongation are lowered, and when the electrical conductivity or the elongation is improved, the tensile strength and the electrical conductivity and the elongation are difficult to improve at the same time. As described above, by controlling the composition of the copper alloy material for the heat exchanger and the content range of the components, it is possible to produce a copper alloy material having high strength, high conductivity and excellent workability.

High strength and according to the invention High conductivity  Manufacturing method of copper alloy material for pipe

Disclosed is a method for producing a copper alloy material for high strength and high conductivity pipes according to the present invention.

The copper alloy material according to the present invention is billeted with 0.05 to 0.25% by weight of iron (Fe), 0.01 to 0.05% by weight of manganese (Mn), 0.015 to 0.07% by weight of phosphorus (P), and the balance of copper (Cu) Casting step (casting step) (S100); Hot extrusion of the obtained billet to obtain an element pipe (hot extrusion step) (S200); Cold-rolling the hot-extruded element pipe to obtain a pipe material (cold pipe rolling step) (S300); Cold drawing the cold drawn tube material (cold drawing) (S400); Winding the cold drawn tubular material in the form of a coil (level winding step) (S500); And it is manufactured by the step (heat treatment step) (S600) of heat-treating the tube wound in the coil form.

In the casting step (S100), the billet is 0.05 to 0.25% by weight of iron (Fe), 0.01 to 0.05% by weight of manganese (Mn), 0.015 to 0.07% by weight of phosphorus (P), the balance of copper ( Cu) is melted and cast. In the billet casting step, other unavoidable impurities may be included in a very small amount. Other unavoidable impurities do not affect the properties of the copper alloy material for high strength and high conductivity pipes according to the present invention. The billet may be manufactured in an appropriate size and shape according to the use, in the present invention can be manufactured by applying a semi-continuous casting in the electric furnace in a cylinder (pipe) of approximately Φ207 to Φ280. In the casting step, the casting temperature is approximately 1100 to 1350 ° C., and the casting speed is approximately 100 mm / min to 150 mm / min.

Then the billet obtained in the previous step is hot extruded (S200). The hot extrusion step (S200) is carried out in the range of about 770 ℃ to 900 ℃ by cutting the cast billet obtained in the previous step to an appropriate size. If the temperature range is lower than the recrystallization temperature, especially if the surface of the material is lower than the inner surface, the shear zone formed by the displacement of the center portion is generated inside the boundary surface, so that piping (extrusion defect) occurs, and the temperature is exceeded. In this case, recrystallization often occurs, and out of the region where the fine grain structure is formed, abnormal grains such as overgrowth occur, and coarse crystals occur in a ring shape in the cross-sectional structure.

For example, the copper alloy material for high strength and high conductivity pipes according to the present invention may be cut at 10 ° C. at about 900 ° C. in order to cut the cast billet obtained in the previous step to a length of about 640 L to 800 L to reduce the extrusion rate to about 90%. Heat treatment for minutes to prepare a pipe (pipe) to a thickness of 12 to 15 to the outer diameter of Φ 120 to Φ 130.

After the cold tube rolling step (S300) is carried out. The cold tube rolling step (S300) is obtained by pipe-rolling the tube material obtained in the previous step to an outer diameter of approximately Φ35 to Φ90 and a thickness of 2.8t to 3.1t. The feed rate is then about 9.52 mm / stroke to 11.2 mm / stroke.

Thereafter, the product obtained in the previous step is cold drawn (S400). The cold drawing step S400 is not limited thereto, and for example, a hollow, a plug, a floating plug, and a mandrel drawing method may be used. In the cold drawing step, the tube material obtained in the previous step is tube-rolled to an outer diameter of approximately Φ4 to Φ22.2 and a thickness of 0.25t to 0.41t.

Next, the level winding step S500 is performed. The level winding step (S500) is a process of winding the obtained cold drawn tubular material to a drum after washing, calibrating, ECT inspection, and performing a defect mark, and the line speed is 350 m / min to 500 m / min. to be. Through this step, the non-uniform curvature may be maintained at a constant tension according to a plurality of drawing processes.

Thereafter, a heat treatment step S600 is performed. The heat treatment step (S600) is performed for 3 hours to 6 hours in the range of 450 ℃ to 650 ℃ to control the characteristics such as tensile strength, elongation, electrical conductivity of the copper alloy with improved strength according to the work hardening. Process oil remaining in the inner surface of copper pipe (pipe made of copper alloy material) may cause the refrigerant circuit failure or deteriorate the refrigerant.In the process of annealing, inert gas mixed with nitrogen and hydrogen is added to discharge residual oil to the outside to remove. (purging), the residual amount is managed to less than 0.1mg / m.

The present invention will be described in detail through the following examples.

Example

Example  One

Copper alloy pipes (pipes) made of a copper alloy material for high strength high conductivity pipes according to the present invention were prepared with the composition shown in Table 1 below. A billet was obtained by semi-continuous casting in an electric furnace with 0.05 wt% Fe, 0.05 wt% Mn, 0.015 wt% P and the balance copper (S100). The obtained billet was cut to a length of 640 L, and then hot-extruded at 800 ° C. to obtain a pipe material having a thickness of 15 t at an outer diameter of Φ 120 (S200). Subsequently, the tube material was cold rolled to obtain a tube having an outer diameter of φ 58 and a thickness of 2.8 t (S300). Thereafter, the cold rolled tube obtained was cold drawn to a thickness of 0.35 to an outer diameter of 0.35 and a thickness of 0.35 by a floating plug drawing method (S400). The cold drawn tube was rewound in a coiled manner (S500). Subsequently, the obtained product was heat-treated at 600 ° C. under an atmosphere of 95% nitrogen and 5% hydrogen (S600). The final copper alloy tube was cut to a size of 9.52 x 0.3 t x 30 l to prepare a specimen (sample 1).

Example  2 to 4

Samples were prepared by preparing copper alloy tubes as described in Example 1, except that the composition of the billet was changed as described in Table 1 below (Samples 2 to 4, respectively).

Comparative example  1 to 4

Except for changing the composition of the billet as described in Table 1 below, the copper alloy tube was prepared as described in Example 1 to prepare a specimen (samples 5 to 8 each in turn).

Comparative example  5 and 6

Copper phosphate (C1220) was used to prepare copper alloy tubes with the specifications and components listed in Table 1 to prepare specimens (samples 9 and 10, respectively, in turn).

division sample Specification (mm)
(Outer diameter X thickness) Ingredient (% by weight) Cu Fe P Mn Example 1 One 9.52ΦX0.3t Honey. 0.05 0.015 0.05 Example 2 2 9.52ΦX0.3t Honey. 0.08 0.04 0.03 Example 3 3 9.52ΦX0.3t Honey. 0.14 0.037 0.02 Example 4 4 9.52ΦX0.3t Honey. 0.25 0.07 0.01 Comparative Example 1 Copper alloy 5 9.52ΦX0.3t Honey. 0.05 - - Comparative Example 2 6 9.52ΦX0.3t Honey. 0.15 - 0.08 Comparative Example 3 7 9.52ΦX0.3t Honey. 0.35 0.1 0.03 Comparative Example 4 8 9.52ΦX0.3t Honey. 0.08 0.03 - Comparative Example 5 Intal Shandong
(C1220) 9 9.52ΦX0.3t Honey. 0.025 - - Comparative Example 6 10 9.52ΦX0.35t Honey. 0.026 - -

Honey. = Balance, balance

Tensile strength (TS), elongation (El, elongation), electrical conductivity (EC), expansion test (expansion test), pressure test , Corrosion test was performed and the results of each test are shown in Table 2.

Tensile strength and elongation in accordance with KS B 0802, thermal and electrical conductivity-related electrical conductivity in accordance with KS D 0240, expansion test in accordance with KS B ISO 8493, pressure resistance test in accordance with KS B 6730, corrosion test in KS D 9502 Measured according to.

Tensile strength test was carried out to measure the strength of the manufactured copper alloy tube, elongation was used as an indicator of workability, electrical conductivity is used to measure the conductivity of the copper alloy tube, it is also an indicator of the conductivity of the heat exchanger. . Expansion test is used to determine the capacity for plastic deformation when pressurizing and expanding a circular section of metal pipe. Pressure test is a test conducted to measure the pressure that can withstand the copper alloy tube. This is important because it measures the pressure it can withstand.

division sample
number TS
(MPa) Hand
(%) EC
(% IACS) Expansion test
(X1.4 times) Withstand pressure test
% Of DP Corrosion test Example 1 One 295 38 86 ○ 120 Good Example 2 2 297 37 82 ○ 120 Good Example 3 3 298 36 83 ○ 125 Good Example 4 4 301 35 81 ○ 127 Good Comparative Example 1 5 260 41 88 ○ 105 Good Comparative Example 2 6 280 34 75 ○ 110 Good Comparative Example 3 7 315 33 80 X 130 Good Comparative Example 4 8 290 38 84 ○ 120 Good Comparative Example 5 9 240 43 83 ○ 100 Good Comparative Example 6 10 245 43 82 ○ 120 Good

As can be seen in Table 2, Samples 1 to 4 prepared according to the Example, unlike Samples 5 to 10 prepared according to the Comparative Example, evenly obtained good results in all items such as tensile strength, conductivity and elongation. Samples 5 to 10 prepared according to the comparative example show results that are not as standard in other tests, although excellent results are obtained in certain tests among the tests performed above. For example, in the case of Sample 7 according to Comparative Example 3, good results were obtained in the tensile strength and withstand pressure tests, but the elongation was low, and the bursting phenomenon was observed in the expansion test.

As can be seen in Table 2, Samples 1 to 4 prepared according to the Examples showed excellent pressure resistance of 120% or more in the pressure resistance test.

From the above results, it can be seen that the copper alloy material according to the present invention has the effects of tensile strength, electrical conductivity, and elongation, which are difficult to be compatible with conventional copper alloy materials for pipes, at the same time. In addition, since the copper alloy tube made of the copper alloy material according to the present invention exhibits excellent pressure resistance in the pressure resistance test, it is well suited for piping equipment and heat exchanger pipes suitable for use of environmentally friendly refrigerants.

Further, as can be seen in the manufacturing method, the copper alloy material for pipes according to the present invention has high tensile strength and electrical conductivity and excellent workability, even though only one heat treatment is performed, unlike the conventional manufacturing process requiring heat treatment two or more times. Can be secured at the same time.

Claims (4)

0.05 to 0.25 wt% iron (Fe), 0.01 to 0.05 wt% manganese (Mn), 0.015 to 0.07 wt% phosphorus (P), balance copper (Cu), and other unavoidable impurities. A weight ratio (Fe / P) of iron (Fe) and phosphorus (P) is 0.75 to 6.0, and has a tensile strength of 295 MPa or more, an elongation of 35% or more, and an electrical conductivity of 81% IACS or more. delete 0.05 to 0.25 wt% iron (Fe), 0.01 to 0.05 wt% manganese (Mn), 0.015 to 0.07 wt% phosphorus (P), and the balance copper (Cu) to iron (Fe) and phosphorus Casting the billet so that the weight ratio (P / P) of (P) is 0.75 to 6.0,
Hot-extruding the billet to obtain a tube
Cold-rolling the hot-extruded element pipe to obtain a pipe material (cold pipe rolling step),
Cold drawing the cold drawn tube material;
Winding the cold drawn tubular material in the form of a coil, and
A method for producing a copper alloy material for pipes comprising a heat treatment step of heat-treating the pipe wound in the coil form. The method of claim 3, wherein
The copper alloy material has a tensile strength of 295 MPa or more, elongation of 35% or more, and electrical conductivity of 81% IACS or more.

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