JPS637949A - Dot pin for dot printer - Google Patents

Abstract

PURPOSE:To obtain a dot pin extremely easy in wire drawing processing, having low specific gravity and excellent in abrasion resistance, toughness and corrosion resistance, by applying wire drawing processing to steel constituted of nitrogen, carbon, chromium, manganese, iron and inevitable impurities in a specific wt. percentage. CONSTITUTION:Nitrogen and carbon are elements necessary for strain aging effect and necessary in an amount of at least 0.4% or more. However, when both elements are contained in large quantities, processing becomes difficult and, therefore, the contents thereof is limited up to 1.5%. Chromium is an element necessary for reducing corrosion resistance and specific gravity and, when it is below 10%, the effect thereof is reduced and chromium is desirable contained in an amount of 13% or more. However, since processability becomes inferior when a large amount of chromium is contained, the content thereof is limited up to 25%. Manganese is an element necessary for enhancing abrasion resistance and reducing specific gravity and necessary in an amount of at least 10%, desirably, 15% or more. However, since processability becomes hard when a large amount of manganese is contained, the content thereof is limited up to 30%. The remainder is iron and, as inevitable impurities, there are sulfur, phosphorus and oxygen etc. but they are pref. as little as possible because these impurities cause poor processability or corrosion resistance.

Description

[Detailed description of the invention] [Field of application of the invention] (Industrial application field) The present invention relates to a dot pin for a dot printer.

(Prior art) A dot printer prints required characters, numbers, symbols, etc. by activating multiple dot pins for the printer.The printing speed is fast and printing is possible even when stacking multiple sheets of paper. It has characteristics. This dot pin for dot printers has good wear resistance, is lightweight, has high toughness and is hard to break, has good corrosion resistance, and has good wire drawability and easy heat treatment. is also required.

Currently, dot pins made of tungsten, cemented carbide, and sintered high-speed steel are generally used as dot pins for dot printers. However, tungsten dot pins have a high specific gravity of approximately 19.2,
Dot pins made of cemented carbide are difficult to manufacture into wire rods, have a high specific gravity of about 14, and are easily broken because they are sintered bodies. In addition, although sintered high-speed steel has the advantage of having a small specific gravity of approximately 8.15, it has poor workability, and furthermore, because the dot pins are hardened and have a diameter of 0.3+on+ or 0.2ma+, they are prone to deformation. In addition to these drawbacks, the part that is joined to the armature by brazing or welding is easily broken and has poor corrosion resistance.

(Problems to be Solved by the Invention) The present invention has been made in view of the above points, and it is very easy to draw the material of the dot pin into a wire.
The purpose of the present invention is to provide a dot pin suitable for use in dot printers, which has a small specific gravity and excellent wear resistance, toughness, and corrosion resistance.

[Structure of the Invention] (Means and Effects for Solving the Invention) The dot pin for a dot printer of the present invention has a total content of nitrogen and carbon of 0.4 to 1.5% by weight and 10 to 25% of chromium.
%, manganese 10 to 30%, the balance iron and incidental impurities. Here, the reason for limiting the composition and heat treatment temperature of the dot pin for a dot printer according to the present invention will be explained. Nitrogen and carbon stabilize the auste-poor composition and improve workability.
Further, it is an element necessary for increasing hardness through wire drawing and improving wear resistance, and for bringing out the strain aging effect, and it is necessary to contain at least 0.4%. However, since containing a large amount would make processing difficult, the content was limited to 1.5%.

Note that in consideration of corrosion resistance, nitrogen content is better than carbon content, so nitrogen content is preferably 0.4% or more.

Further, from the viewpoint of corrosion resistance, carbon content is preferably 0.3% or less.

Chromium is an element necessary for corrosion resistance and reduction of specific gravity.
If it is less than 0%, the effect will be small, and it is preferably 13% or more, more preferably 15% or more. However, the content of tampon was limited to 25% because it impairs processability. Manganese is an element necessary to improve wear resistance and reduce specific gravity, and it is necessary to contain at least 10%, preferably 15% or more. However, the content of too many mountains is limited to 30% because it impairs workability. In addition, in the alloy composition of the dot pin for dot printers according to the present invention, a small amount of silicon may be added as a deoxidizing agent during melting, and vanadium, tungsten, niobium, and austenite structures may be added to improve wear resistance. It is permissible to add small amounts of nickel, copper, cobalt for stabilization, and molybdenum to improve corrosion resistance.

Further, incidental impurities of the present invention include sulfur, phosphorus, oxygen, etc., but since these impurities impair workability and corrosion resistance, it is better to have as few as possible, and preferably the total amount is 0.
．． 1% or less is preferable. Next, strain aging treatment after stretching processing is effective in greatly improving the tensile strength and spring strength of the dot pin, as well as improving the hardness and Young's modulus, and this effect can be achieved by heating at 200°C or higher. can get. However, if the temperature is raised too high, it will soften, so a range of up to 600°C is preferable. Desirably 350 to 550°C, more preferably 450°C
~550°C is good. Note that it is possible to perform this strain aging treatment together with the nitriding treatment.

Further, the higher the wire drawing processing rate, the better, and the drawing processing rate is preferably 50% or more. Furthermore, 1000% before or during the wire drawing process.
It is possible to perform solution treatment in which the material is heated to ~1100°C and then rapidly cooled, and this solution treatment makes the material uniform.

Melting can be done by conventional methods such as conductive melting or arc melting, but dot pins for dot printers have a diameter of 0.
Since it is extremely thin (3w1IIl or 0.2+am), it is desirable to make it from a clean steel ingot by remelting it by electroslag remelting or consumable electrode type arc melting to avoid nonmetallic inclusions.

(Example) An alloy having the chemical composition shown in Table 1 was melted in a high frequency induction melting furnace and then cast into a mold to obtain an ingot. Note that a master alloy of iron-chromium-nitrogen was used for nitrogen. Next, after heating this ingot to 1150-1200°C, forging,
A material with a diameter of 5.5111ffi was obtained using a mold roll.

The following is a margin: Table 1 Next, after heating to 1050°C, solution treatment by rapid cooling was performed, and expansion and contraction processing was performed at room temperature to obtain a wire rod with a diameter of 0.27 mm. As a result, whereas conventional dot pins made from sintered high-speed steel have poor wire drawability and require intermediate annealing 10 to 15 times, the ones according to the present invention have good wire drawability.
Since the wire could be easily drawn to a maximum area reduction rate of 98%, intermediate annealing was only required 5 to 6 times, and the time required for wire drawing and the number of intermediate annealings were significantly reduced.

Next, a test piece was taken from the wire with a diameter of 0.27 m that was made in this way, and the specific gravity was measured.The specific gravity of Alloys 1 to 4 according to the present invention was about 7.6, compared to the conventional tungsten dots. Specific gravity of pin: 19.2° Specific gravity of cemented carbide dot pin: 14. Specific gravity of sintered high speed steel dot pin 8.1
It was the smallest and lightest compared to No. 5. Therefore, when the dot pin according to the present invention is used, it becomes possible to increase the speed of the dot printer. The electromagnet that drives the dot pins can be made smaller. It can be seen that various advantages such as reduction in power consumption can be obtained. In addition, a test piece was taken from this wire with a diameter of 0.27++ m, and a commercially available sintered high-speed steel IJ
Corrosion resistance was evaluated by using a dot pin of O.3n++n as a comparison material by immersing it in water, taking it out, and leaving it in the air at room temperature. As a result, commercially available dot pins made of sintered high-speed steel rusted over the entire surface in one day, whereas alloys 1 to 1 according to the present invention
The wire rod No. 4 showed no rusting and exhibited excellent corrosion resistance. When alloys 1 to 4 according to the present invention were left in artificial seawater for two months, alloys 1 to 3 did not rust, but alloy 4 did.

Next, the diameter of the dot pin material according to the present invention is 0.27 mm.
．． A test piece was taken from a ms wire rod, subjected to strain aging treatment, and then subjected to hardness measurement, tensile strength measurement, and bending test.

The test results are shown in Table 2.

As is clear from Table 2 below, it can be seen that the aging treatment improves hardness and wear resistance. It also improves tensile strength,
It can be seen that even when the force applied to the bottle during printing increases, it becomes difficult to bend.

Furthermore, when a commercially available dot pin made of sintered high-speed steel was subjected to a 3R bending test, it broke at an angle of 70 to 80 degrees, indicating that the dot pin according to the present invention has an excellent property of being difficult to break.

Next, dot pins were manufactured from wire rods of alloys 1 to 4 with a diameter of 0.271111. Next, the tip of this dot pin was ground to a diameter of 0.2IllII, then brazed to an armature, and installed in a commercially available dot printer for a printing test. For comparison, a printing test was also conducted on a commercially available dot pin made of sintered high-speed steel with the same dimensions. As a result, the wear m of the dot pin after printing 50 million dots was 36 microns for the commercially available sintered high-speed steel dot pin, whereas the wear amount of the dot pin according to the present invention was 1
The wear amount was 2.about.17 microns, which was about 172 microns or less, indicating excellent wear resistance.

[Effects of the Invention] As explained above, since the dot pin for a dot printer according to the present invention has a smaller specific gravity than the conventional dot printer bin, it is possible to speed up the dot pin, save energy, and reduce the size of the dot pin. It has excellent corrosion resistance and toughness, which eliminates breakage during use, and excellent abrasion resistance, which enables stable printing over a long period of time.
It is extremely useful industrially as it can shorten the steps required for manufacturing.

Claims (3)

[Claims] (1) Total nitrogen and carbon content in weight% is 0.4-1.5%
, 10-25% chromium, 10-30% manganese, the balance iron and incidental impurities, and the dot pin is made by wire drawing. (2) The dot pin for a dot printer according to claim 1, which contains nitrogen in an amount of 0.4% or more by weight. (3) The dot pin for a dot printer according to claim 1 or 2, which is subjected to strain aging treatment at 200°C to 600°C after wire drawing.