JPH0250981B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a wire for dot printers, which is extremely easy to draw into ultra-fine wires, can be easily heat treated, and has excellent toughness and wear resistance. It is related to. Dot printers operate multiple wires to print predetermined characters or numbers, and are characterized by extremely fast printing speeds. Printed wires are required to have high abrasion resistance, high toughness, high fatigue strength, easy wire drawing and heat treatment, and good corrosion resistance. Currently, hardened ultrafine high-speed steel wires are mainly used for print wires. High-speed steel wire is manufactured by repeatedly drawing and drawing wire into ultra-fine wire, quenching and tempering it, and then cutting it. However, a long wire-drawing process is required to make high-speed steel wire into ultra-fine wire. This has the disadvantage of increasing the price. Also, although it has excellent wear resistance, it lacks toughness and may break during use. The present invention was made in view of these problems, and it provides a dot that is extremely easy to draw into ultra-fine wire, easy to heat cure, and has excellent strength and wear resistance.・The purpose is to provide wire for printers. That is, the present invention provides C0.04~0.20%, Si0.10% or less, Mn0.10% or less, Ni16.0~19.0%, Mo3.0~
6.0%, Co7.0~13.0%, Al0.05~0.20%, Ti0.50
It is composed of steel with ~1.90% balance iron and impurities, and after the wire drawing coil is subjected to solution treatment by heating it to approximately 820℃ and cooling it with water, the area reduction rate is approximately
Wire drawing to 90%, then solution treatment,
Next, the process of drawing the wire with an area reduction rate of about 90% is repeated to make the diameter thinner, and finally the wire is drawn with an area reduction rate of about 90% to make the wire into a predetermined size of around 0.3 mm in diameter. After that, 3 hours (hours) at around 480℃
By performing pre- and post-aging treatments and precipitation hardening to Hv700 or higher, it has excellent performance in both toughness and wear resistance. Next, the reasons for limiting the composition of the wire for dot printers of the present invention will be described. C combines with Ti to form a hard special carbide, TiC, and is effective in improving wear resistance, but if it is less than 0.04%, the effect is small;
If it exceeds 0.20%, it will damage the toughness, so 0.04 to 0.20
%. Si and Mn have a deoxidizing effect, but
If it exceeds 0.10%, the toughness decreases, so each
It was set to 0.1% or less. Ni is necessary to form a martensitic structure and to stabilize martensite up to the aging temperature, but if it is less than 16%, the effect will be small, and if it exceeds 19%, retained austenite will appear, so 16.0~ It was set at 19.0%. Mo is necessary to form an intermetallic compound and cause precipitation hardening by aging treatment, but if it is less than 3%, the effect will be small, and if it exceeds 6%, the toughness will decrease, so it is set at 3.0 to 6.0%. Co has the effect of accelerating precipitation hardening due to Mo, but if it is less than 7%, the effect is small, and if it exceeds 13%, the improvement in the effect is small, so it is set at 7.0 to 13.0%. Al was added as a deoxidizing agent and also improved the age hardening properties, so it was set at 0.05 to 0.20%. Ti is an intermetallic compound
It is necessary to form Ni ₃ Ti and cause precipitation hardening, and also combines with C to form a special carbide to improve wear resistance, but if it is less than 0.50%, the effect is small, and if it exceeds 1.9%. 0.5 because the toughness decreases.
~1.9%. Steel with this composition undergoes water-cooling solution treatment at approximately 820°C to become low-carbon martensite with dispersed special carbide TiC, and has a relatively soft hardness of H _R C30 to 35, making it easy to draw and draw. Cold drawing with an area reduction of up to 95% is possible without intermediate solution treatment. In this manner, after performing cold wire drawing with a strength of 70% or more in area reduction, aging treatment at 480° C. for 3 hours results in precipitation hardening to a high hardness of _HV 700 to 750. In other words, steel with this composition has a H _V of 700~ due to precipitation hardening.
750, which has a structure in which hard special carbide TiC particles are dispersed in the low carbon martensite matrix.
It can have both toughness and wear resistance. Next, the effects of the present invention will be explained using examples.
Table 1 shows the chemical composition of the wire of the present invention and the wire made of SKH9.

[Table] Symbol A indicates a wire having a composition according to the present invention, and symbol B indicates a SKH9 wire. symbol B
SKH9 can be cold drawn without intermediate annealing with an area reduction rate of 30 to 40%, so intermediate annealing is required 12 to 6 times to draw SKH9 from 5.5 mmφ to 0.3 mmφ wire. . On the other hand, steel with symbol A can be drawn without intermediate solution treatment up to an area reduction of approximately 90%, so the intermediate solution treatment required to draw from a 5.5 mmφ coil to a 0.3 mmφ wire is as follows: Only 3 times. In this way, symbol A is very easy to draw into a wire.

[Table] Table 2 shows the heat treatment hardness of the 0.3 mmφ wire and the breakage rate after performing the hammering test 10 ⁶ times as a printed wire. In other words, symbol A is a wire drawn coil that is solution-treated at 820°C, then cold-drawn with a 90% reduction in area to a diameter of 0.3 mm, and then subjected to aging treatment at 480°C for 3 hours (hours). Precipitation hardened to H _V 730. As a result of the hammering test of these printer wires with symbol A and symbol B ¹⁰⁶ times, the breakage rate of symbol B was 15
%, whereas symbol A has a breakage rate of 0%, indicating that the wire of the present invention has excellent toughness. In addition, the wear resistance of symbol A is almost as good as symbol B. As explained above, the present invention has C0.04 to 0.20%,
Si0.10% or less, Mn0.10% or less, Ni16.0~19.0%,
Mo3.0~6.0%, Co7.0~13.0%, Al0.05~0.20%,
This wire for dot printers is characterized by being formed from a drawn coil of steel with Ti0.50 to 1.90% balance iron and impurities, and has excellent performance in toughness and wear resistance. be.

Claims (1)

[Claims] 1% by weight, C0.04-0.20%, Si0.10% or less,
Mn0.10% or less, Ni16.0~19.0%, Mo3.0~6.0%,
Co7.0~13.0%, Al0.05~0.20%, Ti0.50~1.90
A wire for dot printers having excellent toughness and wear resistance, characterized in that it is formed from a drawn coil of steel, the balance being iron and impurities.