JPS5929674B2 - Manufacturing method of stainless steel gimbal spring for magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a stainless steel spring that forms a golden coating on the stainless steel spring, and more particularly, to a method for manufacturing a gimbal spring for stably floating a magnetic head of a magnetic disk device. .

Gimbal springs are thin springs that support slider gimbals incorporating magnetic heads, and are usually made of stainless steel. Conventionally, gimbal springs are either (1) subjected to passivation treatment after spring annealing at 430°C x lh in vacuum, or (2) ) was immersed in a hot bath of chromic acid and sulfuric acid. In method (1) above, the reduction in plate thickness varies greatly depending on the freshness of the passivating solution, the external temperature, the sample position in the tank, etc., and as a gimbal spring, it increases the variation in elasticity and reduces the yield. is decreasing. (2
) method is also effective, but it is not preferable for small items such as gimbal springs and precision parts because it also reduces the plate thickness. In addition, both (1) and (2) require equipment for wet chemical treatment and anti-pollution measures, which are not preferable.

It is an object of the present invention to provide a method for manufacturing gimbal springs that eliminates the drawbacks of conventional methods and can form a beautiful golden-yellow film at low cost and with a simple process.

In the present invention, a thin stainless steel plate, which is a material for a gimbal spring, is annealed in an oxidizing atmosphere at a relatively low temperature of 360 to 400°C to form a golden yellow film. The present invention will be explained in detail with reference to Examples below.

As a stainless steel material, SUS304 specified by the JIS standard, consisting of 18 chromium and 8 nickel with the balance iron, was punched into a spring shape and annealed in an electric furnace at each temperature shown in the table below for 1 hour.

The table below shows the results of investigating the atmospheric annealing temperature, corrosion resistance, and color tone. The drawing also shows the relationship between annealing temperature, Vickers hardness, and tensile strength. In the figure, white circles and black circles indicate the hardness and tensile strength when the thickness is 40μ, and white triangles and black triangles indicate the hardness and tensile strength when the thickness is 5.1μ. Annealing temperature Sap color tone Corrosion resistance Evaluation level (°C) Le number IE10 Silver white passed (Gold material) 3005 Silver white passed △ 1 piece discolored 34010 Pale yellow △ Passed 1 piece discolored 3505 Pale yellow △ Passed 36010 Golden color Passed ○ 1 piece has discoloration 37010 Golden color ○ Ruga passed 38010 Golden color Passed 0 1 piece had discoloration 39010 Golden color ○ Ruga passed V-1 Town 1 From now on, corrosion resistance will decrease as the temperature increases In fact, it is known that mechanical properties increase up to approximately 450°C.

In other words, the temperature that satisfies the three conditions of spring annealing effect, corrosion resistance, and golden yellow coating on the surface is 360 to 400°C.
It is. The thickness of the film formed by annealing at 380°C is approximately 300λ, and as this thickness increases, corrosion resistance decreases, so the annealing time is approximately 30 minutes to 1 hour.

The above example was performed in the atmosphere, but similar results were obtained when the experiment was conducted in an atmosphere where the flow rate of nitrogen was 9 and the flow rate of oxygen was 1. Also, JIS standard SUS3l6
, 3O3, and 3Ol have obtained similar results, and an austenitic material is effective.

When the magnetic head was assembled and the spring constant was measured, it was found that the spring constant increased by about 5%, and the spring properties were improved.

Therefore, the magnetic disk device is resistant to external vibrations and the positioning accuracy of the magnetic head is improved. In addition, in this manufacturing method, batch processing or continuous processing can be performed with one electric furnace, and the temperature range is wide, so gimbal springs can be stably manufactured at low cost and with high yield. According to the present invention, a gimbal spring with a beautiful golden yellow film that is corrosion resistant and has high spring properties can be manufactured stably at low cost and with a high yield through a simple process.

[Brief explanation of drawings]

The drawing shows the relationship between hardness and tensile strength with respect to temperature when stainless thin plates of two thicknesses are annealed in an example of the present invention.

Claims (1)

[Claims] 1. A gimbal spring for a magnetic head made of stainless steel with a thickness of about several tens of micrometers was heated to 360 to 400 in an oxidizing atmosphere.
A method for manufacturing a stainless steel gimbal spring for a magnetic head, which comprises performing heat treatment at a temperature of 30° C. for about 30 minutes to 1 hour to form a low-temperature annealing and a golden film.