JPS5914292B2 - Method of using lubricants as heat transfer media for fluidized bed operations - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to fluidized beds, and more particularly, the present invention relates to fluidized beds and, more particularly, to the use of fluidized beds, which are conventionally used in fluidized bed operations to preheat workpiece parts as a step in some metal processing methods. It concerns a fluidized bed composed of graphite or other solid lubricants rather than refractory particles such as sand.

With the present invention, there is no need to coat the parts with a lubricant as a separate step, and the parts can be removed from the fluidized bed for continuous operation.

Conventionally, in the field of metal processing industry, there are many examples in which it is desired to heat processed parts using a fluidized bed.

For example, forging steel or aluminum parts is done at high temperatures.

Similarly, metal extrusion requires preheating.

Preheating of billets has been accomplished safely and economically in a fluidized bed.

However, one of the drawbacks of conventional fluidized beds is that they use refractory particles as the fluidizing medium, and particles of the fluidized bed that stick to the parts are often carried with them to the next work station.

Since many of the materials commonly used are alumina, silica grit or abrasive type particles, there was a great risk that such carried away material would damage the subsequent forging or extrusion die.

In the present invention, a fluidized bed can be used for the intended basic function of subjecting the part to heating by using solid particles selected from the group of lubricant-type materials, for example graphite; Problems associated with the presence of abrasive particles are eliminated.

In practice, graphite is often used to lubricate tools used in subsequent machining operations on a part, so any particles carried away from the fluidized bed contribute as a useful tool.

In one embodiment of the present invention, graphite is used as the particles of the fluidized bed.

Other examples of fluid bed lubricant type materials used in the present invention include, but are not limited to, zinc oxide and higher saturated fatty acid salts such as stearic acid type materials.

These materials are used as lubricants in the textile industry,
It can be used for heating and curing treatment of synthetic yarns.

In that case, these materials can also be used as lubricants in the subsequent weaving operation.

The heating temperature of the fluidized bed of the present invention is controlled so that the solid lubricant particles used in the fluidized bed do not dissolve within the fluidized bed.

For example, when graphite is used as the particles, the temperature within the bed is approximately 540°C (100°C) depending on the size of the particles.
It is possible to heat up to 0'F).

The dissolution that occurs is negligible and there is no loss of lubricating properties.

Also, for example, by utilizing nitrogen as the heated pressurized gas, the temperature can be raised to about 1200° C. (below 2200° C.) or higher.

Based on this effect, nitrogen and graphite are used to
Silver can be annealed at 1100"F).

When a portion of the fluidized bed using graphite and nitrogen, whose temperature had risen to approximately 845°C (1550'1 = -), was taken out and subjected to a compression quenching test, it was found that the graphite was hardly dissolved and its lubricating properties were It turned out that nothing was lost.

When using the particles in the textile industry, the temperature is approximately 316°C (6
00'F) is suitable.

The present invention improves a fluidized bed working method in which a member to be processed is immersed in a fluidized bed and heated prior to a modeling operation, in which solid lubricant particles are filled as a heat transfer fluid medium into a container forming the fluidized bed. The lubricant particles are used as a heat transfer medium, characterized in that the lubricant particles are heated and pressurized gas is passed through the lubricant particles to agitate the particles so that the metal member to be processed receives optimal heat transfer within the lubricant particles. This is accomplished using a fluidized bed method.

As described above, the present invention serves as a heat transfer fluid medium for providing good preheating in a fluidized bed, and when moving to the next step, it acts as a lubricant to prevent the movement of the metal body even if it sticks to the metal body to be processed. An improved method of fluidized bed using a fluidized medium containing lubricant solid particles having a lubricating effect is realized, which improves the processing efficiency of the fluidized bed and also improves the metal body to be processed as well as the tools used for processing. This has an excellent effect of preventing damage to the jig.

Claims (1)

[Scope of Claims] 1. In an improvement of a fluidized bed working method in which a member to be processed is immersed in a fluidized bed prior to a shaping operation and heated to a temperature lower than the melting point of solid lubricant particles, is filled with solid lubricant particles as a fluid medium that transfers heat to the part, and heated and pressurized gas is passed through the lubricant particles so that the part to be processed receives optimum heat transfer within the lubricant particles. A method of using a lubricant as a heat transfer medium for fluidized bed operation, characterized in that the particles are agitated. 2. The method of claim 1, wherein the solid lubricant particles used as a heat transfer medium in the fluidized bed are selected from the group consisting of graphite, zinc oxide, and salts of higher saturated fatty acids. 3. A method according to claim 1, characterized in that the particles are selected from the group consisting of stearate-type substances used as lubricants. 4. A method according to claim 1, characterized in that the particles are selected from the group consisting of stearate-type materials used as optical lubricants used in fiber manufacturing. 5. The method of claim 1, wherein the pressurized gas is air.