JPS6020086A - Treatment of inside wall of stainless steel heat pipe - Google Patents

Abstract

PURPOSE:To improve the wettability by water and thermal stability of the inside wall of stainless steel heat pipe by a method wherein oxide layer is formed on said inside wall by heating the inside wall in hydrogen gas flow moistened with steam at a high temperature of 800-1,200 deg.C for 3-60min. CONSTITUTION:Hydrogen gas flow moistened with steam is led from a hydrogen gas cylinder 4 and a humidifier 5 in a furnace body 1. The interior of the furnace body 1 is heated by means of a heater 6 up to a high temperature of 800- 1,200 deg.C. A stainless steel heat pipe 8 is left in the furnace body 1 for 3-60min in order to form oxide layer on the inside wall of the stainless steel heat pipe 8. Thus, the favorable wettability by water and at the same time the thermal stability are given to the inside wall of the stainless steel heat pipe 8.

Description

[Detailed Description of the Invention] The present invention relates to a method for treating the inner wall of a stainless steel heat pipe.Generally, it is necessary to use a heat pipe at a water drop position or to draw a large capillary force against the storage force. At the same time, the relationship between the heating medium and the inner wall of the heat exchanger becomes a very important factor.
For this reason, Hevipe strings are often made from gilt bronze or porous quick 755 strings, or IL-type lifting stands, or 0-merge (open-walled) strings or artery tubes. However, there are many problems in both the construction and construction of these heat pipes, and it is not desirable to change them. As heat vibs are increasingly being used at high temperatures, materials that are stable in terms of heat resistance are also desired.

The current thinning treatment methods applied to improve the wettability of the inner wall of heat pipes include forming mechanical grooves during extrusion molding of τ pipes, surface roughening by mechanical sandblasting, etc. There are surface treatment methods such as chemical corrosion using strong acid solutions and etching solutions, and electrolytic surface treatment methods such as anodic oxidation and electrolytic plating. Although the contact between the surface and the heating medium has been attempted, it has not been possible to apply the well-known techniques of pre-treatment of plating and pre-treatment of contact surfaces.

Especially if heat & is water/b, 1 of the water on the metal surface? Renability χ
In contrast, the most promising method is to apply a chemical conversion treatment to the metal surface, or to apply a gold maple oxide film using electrodeposition plating, which relies on affinity due to hydrogen bonding. However, within the historical temperature range or 500℃ above room temperature,
In the case of = I, the gold-burm oxide layer has high heat resistance,
In addition, there is a problem with the denseness of the membrane or the lack of women. In addition, when the heat pipe material is a stainless steel base metal, there are surface treatment methods such as chemical conversion treatment with chromate under strong alkali or strong acid, but these also have problems in terms of the production environment. I was standing there.

The present invention has been made in view of the above-mentioned drawbacks, and has the following features: It is a metal oxide film that is stable in heat resistance and does not have to worry about peeling, and is formed on the inner surface of a stainless steel heat bike. The purpose of this product is to greatly improve the flexibility with water, and to improve the start-up performance and stability of a 6-heat vip that can be installed horizontally or on a reverse slope. The inner wall of the heat pipe is made of stainless steel pipe string material with stainless steel threads containing chromium and nickel 2, and is heated to a high temperature of 800°C to 1200°C for 5 to 60 minutes in a steam humidified hydrogen atmosphere to reflect oxidation. Pregnant form is weak! :
A specific embodiment of the present invention will be explained below based on FIGS. 1 and 2.

Figure 1 (a) is a cross-sectional view of a plain heat vibrator, (1
)) is a heat weigl r side view of the inner diameter type heat pipe, and (C) is the inner wire mesh type heat pipe.
) and (b).First, see Figure 7(a).
As a pre-treatment before sharpening the K-bottom, both ends must be opened and the inner periphery of the stainless steel tube for the heat pipe must be treated with degreasing, thorough washing, electrolytic polishing, etc. according to the requirements. Let's do it. Preferably, as shown in FIG. 1(b), the circumferential surface is subjected to sandblasting treatment 4 in order to increase the capillary force and improve the elasticity.
It is recommended to roughen the surface by a few microns.

Figure 2 is a systematic diagram of the wet sanding treatment equipment.

The humidity temperature is increased to 800°C by the heater heating element 6 in the heating furnace body 1.
The workpiece outlet 5 of the furnace body 1 is partitioned with a shutter 2.2 to avoid air leakage. Mixed reduction of 4 hydrogen gas 1 Add raw scum and 24 people f
In the case of 1'f: In order to avoid any air from entering the furnace, hydrogen gas is injected into the furnace, and at the shutter 2.2 the hydrogen flame 10.10 burns and the air is removed. Due to the heavy consumption of oxygen inside the furnace body 1, the inside of the furnace body 1 is brought into a strong reducing state along with the high temperature.

Roughly, saturated steam is added into the furnace body 1 by bubbling the moisture chamber 5 against the hydrogen gas LVc.
Here, the shutter 2 and the stainless steel furnace body 1
If the hydrogen gas is left for 60 to 90 minutes, the strong reducing nature of the hydrogen gas will prevent the formation of a brittle oxidized film, and it will react with water vapor to form a black to gray velvety gold-knit oxide film as described below.

H, 0+ M −) MO+ (water vapor) (gold pA) C gold pA film) (hydrogen) When the metal is stainless steel, the component of the metal film is Fe5tal
Cr filter Os, NiO is concentrated and ash.

This metal oxide broken film has a thickness of 1 to 10 μm and a surface thickness of less than 1 μm.The film structure is fine and concave, and it is highly resistant to cracking. There is no change at all between 500°C and 500°C.

However, when heat-treated stainless steel in full atmosphere, the fermented material is extremely brittle and cannot withstand one cycle of use at all, and if the zero heat knitting temperature is below 800°C, the reaction time will be several hours or more. This results in a lack of practicality.The most preferred conditions of the present invention are 6 to 60 minutes of stirring at 800°C to 1200°C.

According to experiments, due to the peeling of the coating, there must be a correlation and restriction between the treatment mudness and treatment time, and when the treatment temperature is 1200℃, 1
minutes or less, 6 minutes or less at 1100°C, 10 minutes or less at 1ooo°C, 20 minutes to 5 minutes at 900°C, 800°
G (D time is confirmed to be 60 to 20 minutes.

times, Ayo #) If 10j is long during reaction, the thickness of the gold-containing film will be 1
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Therefore, since the X brother has the above configuration, the (+f
It has excellent properties, and is stable to JJ, so there is no fear of flaking.It is a reed, and it is a non-polluting treatment method, so there is no need to worry about wastewater treatment.

4. Concave bend] Single 7+: Tomei Figure 1 shows 11. of each heat vibrator wick. f[quadruple,
Figure 2 is a schematic diagram of the mixed oxidation treatment equipment.

Explanation of symbols 1 High temperature furnace body -2 Shutter 6 Work population 4 Hydrogen gas 5 Humidification device 6 Calorie heating element 7 Cooling water rack 7 8 Work such as heat vibrator 9
Nitrogen gas 10 Hydrogen flame 11 Cold mowing water inlet

Claims (1)

[Claims] 1. Chromium or nickel? The oxidized film was formed on the r + J stainless steel base metal pipe π material and the inner wall of the heat vibrator by heating it through a sieve at 800°C to 1200°C for 6 to 60 minutes under water vapor power and water infiltration system vIL. What he did was sexual desire and how to treat the inner wall of the stainless steel heat pipe. 2. An oxide film is formed on the body of the button which has been mechanically modified by sandblasting. Inner wall treatment of the stainless steel heat pipe shown in TM 0 6, version version 11!
i. A method for treating the inner wall of a stainless steel heat pipe as described in Sections 1 and 2 of Mr. Ice.