JPS63310977A - Plated high-carbon wire to be formed into precise spring - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the corrosion resistance of the Ni layer of an Ni plated high-carbon steel wire due to pinholes when the surface of a steel wire is plated with Ni to produce the Ni plates steel wire as stock for a precise spring, by plating the surface of the steel wire with Cu to form an underlayer before the Ni plating. CONSTITUTION:A Cu underlayer 5 of 1-5mum thickness is formed by plating on the surface of a high-carbon steel wire 1 as stock for producing a precise spring, an Ni layer 2 of 1-5mum thickness is formed thereon by plating on the underlayer 5 and the steel wire 1 is cold drawn to a prescribed diameter. Even when pinholes 3 are present in the Ni layer 2, Ni positioned above Cu in a aglvanic series acts as the anode, electric current flows from Ni to Cu at the parts of local cells 4 and a significant anticorrosive effect is electrochemically produced to prevent the corrosion of the Ni layer 2 due to the pinholes 3.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application This invention relates to a plated high carbon wire that is formed into precision springs.

Conventional technology The nickel-plated high carbon wire that is prepared for the purpose of being molded into conventional precision springs has many pinholes in the plating, and has significant drawbacks in the corrosion resistance of steel. Ta.

Problems to be Solved by the Invention This invention aims to reduce the decrease in corrosion resistance caused by pinholes in nickel plating.

20 Measures to Solve Problems By applying copper plating as the base plating for nickel plating, we have reduced the reduction in corrosion resistance of steel due to pinholes in nickel plating.

A comparison between the conventional nickel-plated high carbon wire, which is directly nickel plated on steel, and the plated high carbon wire of the present invention, which is copper plated as a base plating for the nickel plating, is explained based on the principle of corrosion resistance for steel. I will do it.

In Figure 2: At the former pinhole part C, a local battery occurs because steel, nickel, and outside air (including moisture) are in contact, and since steel is higher in the potential series than nickel, it becomes an anode. Therefore, current flows from the steel to the nickel, and corrosion of the steel is accelerated in the pinhole area.

In Figure 4: In the latter pinhole part, the ore becomes an anode because nickel is higher in the potential series than copper, so current flows from the nickel to the steel. Therefore, nickel plating has an electrochemical corrosion-resistant effect on steel plating.

1 Effect of the invention The conventional nickel-plated high carbon wire with a plating film thickness of 5 μm is 11:0, and the high carbon wire according to the present invention is plated with steel with a plating film thickness of 2 μm on the base and nickel plated on the surface with a plating film thickness of 8 μm. Let be ■.

Comparative results of salt spray tests based on the Japanese Industrial Standard JIS 2 2371 K for both products are shown below.

Based on the above results, it can be said that the plated high carbon wire ○ of this invention has significantly improved corrosion resistance compared to the conventional nickel plated high carbon wire ■.

[Brief explanation of the drawing]

1... High carbon wire (steel) 2... Nickel plating layer 8... Pinhole portion 4... Pole part Indicating the flow direction of battery current 5... Steel plating layer Patent applicant Marubishi Metals Kogyo Co., Ltd. Figure 1 Procedural Amendments July 1986 20 units - 1

Claims (1)

[Claims] After the base plating is copper plated with a thickness of 1μ to 5μ and the surface plating is coated with nickel with a thickness of 1μ to 5μ, which is intended to be molded into precision springs, it is further cooled to a predetermined wire diameter. High carbon wire that has been wire drawn.