JPS63241138A - Steel code - Google Patents

Abstract

PURPOSE:To improve the corrosion resistant effect of the titled code and to suppress the lowering or fatigue characteristics of it under the corrosive conditions by specifying the compsn. of a hard steel wire which forms the steel code. CONSTITUTION:The steel code is produced by the hard steel wire contg. 0.60-1.10% C, 0.15-0.35% Si, 0.30-0.90% Mn, <=0.02% P, 0.01-0.04% S and 0.10-1.0% Cu. In this way, the corrosion resistant effect of the steel code is considerably improved and the high fatigue value can be obtd. at the time of leaving the element wire of the steel code and the twisted wire of the steel code under the environment where corrosion tends to occur. The generation of rust and drastic lowering of the strength of the steel code, etc., can be particularly improved in the case of using the same for a tire.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in steel cords for reinforcing rubber used as reinforcing materials for tires, belts, etc.

[Conventional technology and its problems]

Conventional steel cords are made by patenting a hard steel wire rod (for example, S W RS 72A) with a size of 5.5 mm, descaling it, and pre-treating it with a lubricating coating, and then drawing it using a die. Then, these processes are repeated to produce a wire of intermediate size.

Next, final patenting is applied to this intermediate wire under conditions that provide strong patenting strength and a metallographic structure suitable for wire drawing, and as a pre-drawing treatment, plus plating is applied to give the wire corrosion resistance as required. A steel cord strand made of ultra-fine hard steel wire is obtained. Steel cords were obtained by twisting a plurality of these strands together depending on the purpose of the tire.

However, conventional steel cords have a problem in that when steel cord strands or stranded steel cords are left in environments where they are susceptible to corrosion, their fatigue properties deteriorate and are still insufficient.

Particularly when used in tires, the steel cord may rust due to moisture in the rubber or moisture that has entered through cuts in the rubber while the car is running, resulting in a significant decrease in the strength of the steel cord. There is a problem in that the so-called separation phenomenon occurs in which the rubber material peels off.

[Means for solving problems]

The present invention solves the above-mentioned conventional problems.
0.60-1.10%, Si: 0.15-0.
35%, Mn: 0.30-0.90%, P:
0.02% or less, S: 0.01-0.04%, Cu
: A steel cord formed from hard steel wire containing 0.10 to 1.0%, especially a diameter of 0.40 m.
The present invention provides a steel cord made of ultra-fine hard steel wire with a diameter of 0.1 hm or less and 0.1 hm or more.

In addition, C is a basic component that controls the strength and ductility of steel cord, and if it is less than 0.60%, the strength will decrease,
Moreover, if it exceeds 1.10%, carbides will precipitate, toughness will decrease, and workability will deteriorate.

Sl has traditionally been added for the purpose of deoxidizing molten steel, and if it is less than 0.15%, the effect will be reduced, and if it exceeds 0.35%, the toughness will be reduced.

λ4n makes the structure of steel fine and ensures strength and toughness, and if it is less than 0.30%, the effect will decrease.
If it exceeds 0.90%, retained austenite increases during quenching, and hardness decreases.

Since P embrittles steel, it is preferably 0.02% or less.

When S exceeds 0.04%, the wire becomes brittle and the workability of fine wires is significantly reduced. Moreover, if it is less than 0.01%, the anticorrosion effect that is the objective of the present invention will decrease.

Cu is a more dangerous metal than H1 and does not cause hydrogen-generating corrosion and significantly improves the corrosion resistance effect, but if it is less than 0.10%, the effect decreases, and if it exceeds 1.0%, the toughness decreases. decreases. Preferably S: 0.015-0.03%
, Cu: 0.10 to 0.30%.

The present invention will be explained in detail below.

[Example 1] C: 0.75%, Si: 0.21%, Mn
: 0.57%, P7 0.004%, S: 0
．． The steel cord of the present invention is made of a hard steel wire containing Cu: 0.028% and Cu: 0.16%.

Incidentally, a steel cord wire for a tire with a diameter of 0.23 and a stranded wire are formed using the wire rod 5.5n+φ by the following processing steps.

Wire rod - Primary baking wire - Pickling - Primary wire drawing - Secondary baking wire - (1!1
210.23+l) By the way, the patenting conditions for imparting good wire drawability to the steel cord of this example have a slight adjustment range depending on the amount of Cufi, but by adding Cufi,
T, T, 7 Raise the nose of the curve and move it to the long time side at the same time. In other words, T.

It is expected that the shape will be obtained by translating the T,7 curve to the upper right. Therefore, it is necessary to use good wire drawing processing and patenting conditions that ensure crystal grains and lamella spacing to return sufficient strength after processing.For example, if conventional heat treatment conditions are used, bainite, marten, There is a possibility that structures such as sites that impede the wire drawing process may be generated in pearlite. Therefore, in the present invention, during heat treatment, the lead patenting temperature was set 35°C higher than when using conventional wires to achieve pearlite transformation.

Further, in this example, V may be added in a trace amount of about 0.001%.

[Example 2] C: 0.82%, Si: 0.19%, Mn
: 0.52%, P: 0.004%, S:
The steel cord of the present invention is made of a hard steel wire containing Cu: 0.023% and Cu: 0.25%.

Note that the steel cord wire and the stranded wire are formed by substantially the same processing steps as in Example 1.

[Example 3] C: 0.87%, Si: 0.20%, Mn
: 0.55%・, P: 0.004%, S:
The steel cord of the present invention is made of a hard steel wire containing Cu: 0.03% and Cu: 0.30%.

Note that the steel cord wire and the stranded wire are formed by substantially the same processing steps as in Example 1.

(Operation) Comparative Example 1 (B) of the above Example 1 (^) (S W R
572A base component) C: 0.70-0
．． 74%, Si: 0.15-0.30%, Mn
: 0.40-0.60%, P: 0.02% or less, S
: Comparative Example 2 (D
) (Components based on SW RS 82A) C: 0.80~0.85%, Si: 0.15~
0.30%, Mn=0.40~G, 6Q%, P:Q, 0
Using steel cord wire containing 2% or less, S: 0.005% or less, Cu: 0.05% or less, and stranded wire, 80°C x 80% RHt'O time, 4 hours, 8 hours,
16-hour flF trench +: A fatigue test was conducted using a Hunter set fatigue testing machine.

Figures 1 and 2 show Example 1 (A) and Comparative Example 1 (
Stress σ of B) steel cord wire (wire diameter 0.23 m) and stranded wire (1x 12 K O, 23 + 1) =
This is a graph showing the fatigue test results in the case of 150 kg/mm2, and shows the percentage when the value before corrosion of Comparative Example 1 (B) (in the case of 0 standing time) is taken as 100%, and this Example 1 shows the It can be seen that the rate of decline over time is low, and the influence of corrosion is small.

In addition, Fig. 3 shows the fatigue test results when the steel cord wires of Example 2 (C) and Comparative Example 2 (D) were used and the stress σ = 150 kg/2. In this case, the corrosion resistance was higher than that of Comparative Example 2. It turns out to be extremely good.

This means that the steel cord of the present invention has S: 0.01 to 0.
．． 04%, Cu: 0.10 to 1.0% was added to form a CuS protective film on the wire surface, and due to the corrosion-resistant effect of Cu, a high fatigue value could be obtained under the above corrosion conditions. .

〔Effect of the invention〕

The steel cord of the present invention has a C: 0.150 to 1.10.
%, Si: 0.15-0.35%, Mn:
0.30-0.90%, P: 0.02% or less, S:
0.01-0.04%, Cu: 0.10-1.0%
Since it is formed from a hard steel wire containing , the corrosion resistance effect is significantly improved.

[Brief explanation of drawings]

Fig. 1 is a comparison graph showing the fatigue test results of steel cord strand A of one example of the present invention and comparative example B, Fig. 2 is a comparison graph showing the fatigue test results of the same steel cord twisted wire, and Fig. 3 shows a comparative graph showing the fatigue test results of steel cord wire C according to another example of the present invention and a comparative example. Figure 1: ti time (h) Figure 3: t i! L d3 rA (h) Figure 2 & 1 polymerization amount (h)

Claims (1)

[Claims] C: 0.60-1.10%, Si: 0.15-0.35
%, Mn: 0.30-0.90%, P: 0.02% or less, S: 0.01-0.04%, Cu: 0.10-1.0
A steel cord characterized in that it is formed from a hard steel wire containing %.