JPS6135276B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a coil spring that has excellent corrosion resistance and maintains a beautiful luster. Plated steel coil springs are often plated for aesthetics and corrosion protection.
Springs are essential parts for automobiles, home appliances, and various machines. Conventionally, to manufacture such plated steel coil springs, cold drawn high carbon steel wire for springs is processed in the following order: spring forming → bluing treatment → metal plating → baking treatment. was manufacturing. Most of this metal plating is galvanized, with the primary objective of providing high corrosion resistance, and is usually followed by a chromate treatment. However, the coil springs manufactured in this manner easily develop white rust on the zinc when subjected to, for example, a salt spray test, and then red rust appears on the iron base. The present invention solves the above-mentioned drawbacks, and by applying a special lacquer treatment to the nickel-coated steel wire spring, it not only prevents the occurrence of red rust on the iron base but also maintains the beautiful metallic luster inherent to nickel. The present invention aims to provide a steel wire coil spring with excellent corrosion resistance such as salt spray resistance. In the present invention, a nickel-coated steel wire is spring-formed and blued, and then a solution (hereinafter referred to as
This is a nickel-coated steel wire spring with excellent corrosion resistance that is made by immersing it in a special lacquer treatment solution and then drying it. Therefore, the cross section of this spring wire has the steel wire 1 in the center, as shown in the drawing, and the nickel wire on top of it.
It has a coating layer 2 and a special lacquer treatment coating 3 thereon. The nickel-coated steel wire used in the present invention is a wire that is cold-drawn to the final wire diameter after applying a nickel coating such as nickel plating to a high-carbon steel wire for springs, and the nickel coating is work-hardened. By carrying out this process at the stage where the material is not yet coated, it prevents the deterioration of properties due to metal plating in the conventional spring shape, and it is a metal-plated steel wire with excellent mechanical properties and no risk of embrittlement due to aging. The nickel layer thickness at the final wire diameter is usually 0.1~
It is 20μ. The present invention uses such a steel wire, and in addition to the above-mentioned excellent effects, it has much better protection than zinc chromate, nickel plating, tin plating, and other various platings applied to conventional bare steel wire springs. This provides a spring that has rust resistance and a beautiful metallic luster. Petroleum-based sulfonates are often used as surfactants, and they form an intermediate layer between the metal and the wax or lactone, strengthening the bond between the wax and the metal, making it stable for long periods of time. It provides excellent corrosion resistance. Furthermore, wax and lactone have almost the same effect, and in the case of the present application, it is thought that they form a dense water-permeable film layer on the surface of the plating layer. The present invention will be explained below using examples. Example After forming a 0.8% C nickel coated steel wire for a spring, a nickel coated steel wire spring subjected to a bluing treatment, and after forming a 0.8% C hard steel wire into a spring, bluing treatment, Zn plating, chromate treatment, Furthermore, a Zn chromate-treated spring that was subjected to baking treatment was created. The bluing treatment conditions are 400℃×
The baking conditions were 200°C for 3 hours, and a ventilated electric furnace was used in both cases. Nickel coating thickness and
The Zn coating thickness of the Zn chromate treated springs is approximately 5 to 6μ, and the spring specifications are all wire diameter 2.3
m/mφ, coil center diameter 22.85m/m, effective number of turns
It had 19.5 volumes and a free length of 83.0 m/m. In addition to these springs, the above two types of springs were each treated with the following special lacquer solution. This treatment involves applying a special lacquer solution to the spring for approximately 30 minutes.
After soaking for 2 seconds and taking out, about 50 ml to speed up drying.
It was dried with warm air at ℃ for about 5 minutes. This special lacquer liquid contains petroleum-based sulfonates and
Hyonic RP-303 by Hyonic Chemical Industry Co., Ltd. is a compound containing wax lactone dissolved in a mixed solution of mineral spirits and petroleum.
(Trademark), and there is no problem in terms of harm to the human body or pollution. As long as the composition of this special lacquer liquid has sufficient drying properties and osmotic pressure against pinholes etc. after being applied to the spring, slight fluctuations in the composition are not a problem, and after drying it is colorless and transparent. It is characterized by Table 1 shows the results of a salt spray test on the four types of springs described above. Test conditions are JIS Z
2371, and continuous spraying was performed for 72 hours.

[Table] From the table, the Ni-coated steel wire spring of the present invention + special lacquer treatment shows almost no rust and retains a beautiful luster for a long time, whereas all other products rust. , it can be seen that the salt water spray resistance is extremely excellent. In addition, in normal atmospheric exposure tests, the springs of the present invention showed almost no change, and the nickel-coated steel wire springs and the zinc chromate-treated springs showed no significant difference after 700 hours, and both developed uneven gloss. do. It goes without saying that zinc chromate treated springs have better corrosion resistance than Sn plating or Ni plating. The special lacquer-treated coating on the steel wire spring of the present invention has corrosion resistance in itself and covers the pinholes in the nickel coating layer, preventing rust from forming through the pinholes, resulting in corrosion resistance such as salt spray resistance. is good. In addition, the special lacquer treatment is simpler than any coating treatment for bare springs because the spring is immersed and can be air-dried unless there is a particular hurry, so the manufacturing process is simple. Also, this film is transparent and has nickel inside.
Because it has layers, it has a beautiful surface and retains its beauty for a long time. As described above, the present invention involves coil-forming a nickel-coated steel wire, bluing it, and then subjecting it to a special lacquer treatment. Since it is much cheaper and easier to treat, it is possible to treat nickel-coated steel wire springs more easily than zinc chromate treatment of bare steel wire, and there is no need for subsequent baking treatment. Without,
It has the effect of providing a coil spring that has excellent mechanical properties, has an extremely low hydrogen gas content, has good corrosion resistance, and retains a unique beautiful metallic luster.

[Brief explanation of the drawing]

The figure is a diagram showing a line cross section of the spring of the present invention. 1... Steel wire, 2... Nickel coating layer, 3... Special lacquer treatment coating. 〓〓〓〓〓

Claims (1)

[Claims] 1 After spring-forming and bluing a nickel-coated steel wire, it is immersed in a solution containing a composition mainly composed of petroleum-based sulfonates, waxes, and lactones dissolved in a mixed solvent of mineral spirits and petroleum. A method for manufacturing a nickel-coated steel wire spring with excellent corrosion resistance, which is produced by drying it.