JPH08954B2 - Annealing / drawing method for copper or copper alloy pipes - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drawing and / or annealing method for preventing alteration of the surface of a copper or copper alloy product. More specifically, it relates to a method of preventing sticking during unwinding of products shipped as softened and annealed after drawing and discoloration of the products shipped as drawn to dark brown during storage in the air. .

[Prior Art] When copper or copper alloy is used as a pipe / rod or a linear product,
Generally, cold drawing is performed, and bright annealing is performed for softening after drawing. Before annealing, the lubricant used during drawing is degreased and washed, and then placed in a bright annealing furnace. Since these products are charged into the furnace in a coiled or bundled state, the products are heated in the furnace in a state where the products are locally in contact with each other. At this time, when the heating temperature is relatively high, the contact portion causes a welding phenomenon (sticking), and when the contact portion is peeled off after cooling, deterioration or peeling occurs. Further, when drawing is performed after bright annealing, these deteriorated layers become scratches and remain on the product.

In addition, bright annealing may be performed without degreasing and cleaning the lubricant at the time of drawing, but the lubricant is carbonized and black rust occurs. However, since no welding phenomenon is observed where black rust occurs, in such a case, bright annealing was performed after applying light oil before the bright annealing.

Further, the product whose surface has been cold worked and hardened is shipped with the lubricant degreased and washed after drawing, or without degreasing and washing.

[Problems to be Solved by the Invention] As described above, conventionally, bright annealing was performed after degreasing / washing after drawing, or after applying light oil on the surface as it is, but there is no welding. However, in the case of bright annealing of copper or copper alloy, a welding phenomenon occurs during annealing, and in the subsequent process, a linear alteration layer caused by welding is detected by eddy current flaw detection, black rust due to carbonization or after annealing. However, the quality of the product was deteriorated due to the fact that it may be oxidized and discolored to dark brown depending on the environment. It has been known that the brown discoloration occurs both in the as-annealed and as-drawn parts, especially when the humidity is high, but it is desired to stabilize the quality without this preventive measure.

[Purpose] The present invention provides a method for preventing the above-described copper or copper alloy from being deposited during bright annealing and preventing discoloration when further drawing after bright annealing.

[Means for Solving Problems] The inventors of the present invention have conducted extensive research in order to solve the above problems. Among them, first, the cause of the above-mentioned welding and discoloration phenomenon was investigated.

And, when bright annealing occurs, welding occurs in circular tubes, rods,
When the wires are arranged in parallel or wound in a coil, these contact parts are in line contact, and this contact part deteriorates the flow of the atmosphere gas in the furnace. It was thought that the temperature would rise to a high temperature and cause welding.

That is, in the high temperature portion, the lubricant during drawing and the applied light fat are burned off, and the metals come into contact with each other, and the thermal expansion causes pressure to accelerate welding. It was also considered that the discoloration phenomenon was also caused by the fact that the lubricating oil burned off from the metal surface due to an unexpectedly high temperature during drawing.

Therefore, the inventors need to prevent metal contact in order to prevent this welding. For this purpose, it suffices to interpose a film that is stable even under high temperature conditions. It was found that the above is also effective, and completed the present invention.

That is, the present invention is a method of annealing and drawing copper or copper alloy pipe material, in which the drawn pipe material is annealed by applying a silicone oil or a mixed oil of a silicone oil and a light oil, and after the annealing, a silicone oil or silicone oil A method for annealing and drawing a copper or copper alloy pipe material, which comprises applying a mixed oil with a light oil and drawing it.

The silicone oil used in the present invention has a viscosity of 3000 cs or less at 25 ° C. and a specific gravity of 1.0 or less at 25 ° C., for example,
Examples include dimethyl silicone oil and the like.

The light oil used as a mixture with the silicone oil has a viscosity of 3 cs or less at 25 ° C. and a specific gravity of 1.0 or less at 25 ° C., and examples thereof include refined kerosene oil. In the case of mixed oil, silicone oil can be used in the range of 0.3 to 99% and light oil in the range of 1 to 99.7%.

[Function] Silicone oil is used as the oil agent to be applied before bright annealing. The reason is that normal light oil is burned off when heated to a high temperature of 800 ° C, but silicone oil is 800% in a reducing atmosphere. It has been confirmed with an oil meter that the oil remains on the surface as oil until it is heated to ℃. Needless to say, 100% silicone oil can be used as the silicone oil, but since it is relatively expensive, it can be used as a mixture with other oils such as kerosene which dissolves at room temperature. It has been confirmed that addition of 0.3% of silicone oil can prevent welding, because the use of petroleum-based light oil as the other oil results in good dissolution of silicone oil.

When silicone oil remains on the surface of copper or copper alloy products after bright annealing, in addition to preventing welding in the furnace, it also prevents oxidative discoloration due to dew condensation of water vapor in the high temperature and high humidity environment of the product. There is also an action.

Further, when drawing after bright annealing, a lubricating oil is further applied, but when silicone oil remains after bright annealing,
The coefficient of friction during drawing is reduced, the temperature rise due to frictional heat is suppressed, the silicone oil remains as a film even after drawing, and there is an effect of preventing the above-described oxidative discoloration due to dew condensation.

Therefore, it goes without saying that the addition of silicone oil to the lubricating oil during drawing will enhance the above-mentioned action.

Example 1 Prevention of welding during annealing and prevention of discoloration after annealing The copper and copper alloys of the test materials 1 and 2 shown in Table 1 were used for the outer diameter 1
After drawing to 0.7 mm and wall thickness 0.48 mm and cutting to a length of 400 mm,
Silicone oil or a mixed oil of silicone oil and petroleum light oil was applied by spraying, 30 pieces were concentrically bound, and the mixture was placed in a bright annealing furnace in a reducing atmosphere.

The heating conditions are the same as those used in the manufacturing process. Copper pipes are 600 ° C x 30 minutes, and copper alloy pipes are 600 ° C x 30 minutes.
Hold for minutes.

After the unbundling, the surface condition was observed and the presence or absence of residual oil was investigated with an oil meter, and the results are shown in Table 2.

Further, the test pieces extracted from the furnace were allowed to stand in the atmosphere for 60 days without being in contact with each other, and the surface discoloration state was observed.

Prevention of discoloration after drawing The test piece annealed in Example 1 was drawn after applying a lubricant. The drawing condition was that the outer diameter was drawn from 10.7 mm to 9.52 mm.

The measured value of the temperature rise during drawing and the test piece after drawing were left in the air for 60 days without contacting each other, and the surface discoloration was observed. The results are shown in Table 2.

Example 2 Baking during Annealing Four types of test materials of copper and copper alloy shown in Table 1 were used for 10.7.
It was wound on a φ0.48 t 500 kg coil, coated with a mixed oil of silicone oil and light oil, wound on the coil, and placed in a bright annealing furnace. Annealing conditions were 600 ° C. × 10 minutes for copper and 600 ° C. × 10 minutes for copper alloy.

The welding condition was observed while the coil was rewound, but no welding occurred.

Further, these were wound on a coil and left in the atmosphere for 60 days, and observed while unwinding the discoloration of the surface, but it was confirmed that discoloration did not occur in any of them.

After bright annealing with discoloration after drawing, a drawn lubricant containing 7% of silicone oil was applied, drawn from 10.7φ to 9.52φ, wound on a coil and left in the air for 60 days. Discoloration was observed while rewinding this, but discoloration did not occur.

[Effects of the Invention] As is clear from the above results, by applying the silicone oil or the mixed oil containing the silicone oil before the annealing, no welding occurred during the annealing. Therefore, for example, in the case of a copper tube, the charge amount of the straight tube or the coil winding tube can be greatly increased, and the productivity can be remarkably improved.

By applying silicone oil or a mixed oil containing silicone oil to the material to be drawn after annealing, the drawing force during drawing is low, the silicone oil film remains after drawing, and discolors even if left in the atmosphere for a long time Things are gone.

In addition, as described above, the product after annealing and drawing has a film of silicone oil formed on the surface, which significantly improves slipperiness, improves workability during handling, and prevents scratches and bending. Can be increased.

Claims (1)

[Claims] 1. A method for annealing and drawing copper or copper alloy pipe material, wherein the drawn pipe material is coated with silicone oil or a mixed oil of silicone oil and light oil, annealed, and after annealing, further silicone oil or silicone oil and light oil. A method of annealing and drawing a copper or copper alloy pipe material, which comprises applying a mixed oil with an oil and then drawing.