Stainless steel wire for superfine pen point steel and preparation method of stainless steel wire

Abstract

The invention provides a stainless steel wire for superfine pen point steel and a preparation method thereof, and belongs to the technical field of stainless steel materials. The stainless steel wire for the superfine nib steel comprises the following chemical components in percentage by mass: less than or equal to 0.05% of C, less than or equal to 1.00% of Si, less than or equal to 2.00% of Mn, less than or equal to 0.05% of P, more than or equal to 0.15% of S, more than or equal to 19.00% and less than or equal to 21.00% of Cr, more than or equal to 1.5% and less than or equal to 2.5% of Mo and the balance of Fe and inevitable impurities, according to the stainless steel wire rod for the pen point steel, on the basis that the mechanical property of the stainless steel wire rod is guaranteed, the finished product of 2.30 mm in the past is changed into the finished product of 1.30 mm at present, the diameter of the stainless steel wire rod for the pen point steel is greatly reduced, and the stainless steel wire rod has wide application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel materials, and in particular to a stainless steel wire for an ultra-fine pen tip steel and a preparation method thereof. Background Art

[0002] According to the different ink properties, ballpoint pens are divided into oil-based, water-based, pressure, roller and erasable varieties. A ballpoint pen is generally composed of a pen shaft, a refill and ink. The refill is composed of a ball, a ball seat, an oil tube, ink and a float. The ballpoint pen uses the ball located on the tip of the pen to slide in the ball seat, adhere to and carry the ink to transfer to the paper surface to complete the writing function.

[0003] At present, the nib material of high-end ballpoint pens is mostly stainless steel. When setting the stainless steel material for the nib, in addition to considering the corrosion resistance and wear resistance of the stainless steel material, the cutting performance of the stainless steel material should also be considered. At present, the design of stainless steel wire for nib steel with thicker diameter (2.3mm and above) has been mature. However, for ultra-fine stainless steel wire for nib steel below 1.5mm, it is difficult to ensure the wear resistance, corrosion resistance and cutting performance of the wire in the actual production process, and the production standards are not met. Summary of the invention

[0004] The invention aims to provide a stainless steel wire material for pen tip which has small diameter, good corrosion resistance, good wear resistance and is easy to cut.

[0005] To achieve the above-mentioned purpose, the first aspect of the present invention provides a stainless steel wire for ultra-fine pen tip steel and a preparation method thereof, wherein the chemical composition of the stainless steel wire for ultra-fine pen tip steel includes the following components by mass percentage: C≤0.05%, Si≤1.00%, Mn≤2.00%, P≤0.05%, S≥0.15%, 19.00%≤Cr≤21.00%, 1.5%≤Mo≤2.5%, and the balance is Fe and unavoidable impurities.

[0006] Preferably, based on the chemical composition by mass, 19.00%≤Cr≤21.00%, 1.5%≤Mo≤2.5%, the corrosion resistance of the stainless steel wire is improved, and S≥0.15%, the machinability of the stainless steel wire is improved.

[0007] The stainless steel wire material for the ultra-fine pen tip provided by the present invention has an S content of more than 0.15% and is easy to cut.

[0008] Mn combines with S to form MnS, which mainly exists in the form of inclusions. It is usually spherical or spindle-shaped particles, which are distributed at the grain boundaries or within the grains. It can improve the cutting performance of pen tip steel. During the cutting process, manganese sulfide inclusions can make the chips break easily, reduce tool wear, and make the cutting process smoother, thereby effectively improving the quality and precision of the machined surface.

[0009] Cr can form a dense and strongly adhesive chromium oxide protective film on the surface of the stainless steel wire used for pen tip steel, which ensures the corrosion resistance of the stainless steel wire used for pen tip steel, helps to stabilize the ferrite phase, and ensures that the material is mainly composed of ferrite, thereby giving the material good toughness and ductility.

[0010] Mo can significantly improve the pitting and crevice corrosion resistance of ferritic stainless steel in harsh corrosive environments such as those containing chloride ions.

[0011] The second aspect of the present invention provides a method for preparing the aforementioned stainless steel wire for pen tip steel, which specifically comprises the following steps:

[0012] S1: Performing the first online bright annealing on the stainless steel wire with a diameter of 2.3 mm and meeting the standards of claim 1 or 2;

[0013] S2: Fine drawing of stainless steel wire;

[0014] S3: Performing a second online bright annealing on the stainless steel wire;

[0015] S4: The stainless steel wire is drawn for the first time;

[0016] S5: Drawing the stainless steel wire for the second time to obtain a stainless steel wire product with a diameter of 1.30 mm;

[0017] S6: Eddy current flaw detection, screen out the wires without internal damage, that is, the stainless steel wires for ultra-fine pen tip steel.

[0018] Preferably, the stainless steel wire is subjected to a first online bright annealing in a protective gas atmosphere, wherein the protective gas atmosphere is a nitrogen-hydrogen mixed gas with a volume ratio of 1:3, and the conveying flow rate of the protective gas is 1.2±0.5 m / h.

[0019] Preferably, in step S1, the first online bright annealing temperature is 800-860° C., and the holding time is 30-40 seconds per millimeter of effective diameter.

[0020] Preferably, in step S2, the surface reduction rate of fine drawing is 50-60%.

[0021] Preferably, in step S3, the second online bright annealing temperature is 800-860° C., and the holding time is 30-40 minutes per millimeter of effective diameter.

[0022] Preferably, the area reduction ratio of the first drawing is 15-20%.

[0023] Preferably, the area reduction ratio of the second drawing is 10-15%.

[0024] The beneficial effects of the present invention are as follows: by adjusting the content of relevant chemical elements in the stainless steel wire, the wire can be drawn to a diameter of only 1.3 mm while ensuring excellent wear resistance, corrosion resistance and easy cutting. The surface of the wire is bright, without defects such as black and yellow lines, pull marks, cracks, folds, and warping. The mechanical properties are excellent, specifically manifested as: tensile strength ≥ 780N / mm 2 , elongation 2~5%, hardness HV: 250~270. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation method and typical parameters of the present invention, and are not used to limit the parameter range described in the present invention. Reasonable changes derived therefrom are still within the scope of protection of the claims of the present invention.

[0026] It should be noted that the endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article.

[0027] Unless otherwise defined, all terms, symbols and other scientific terms used herein are intended to have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. In some cases, the terms with conventionally understood meanings are defined herein for the purpose of illustrating or facilitating reference, and such definitions herein should not be construed as indicating significant differences from conventional understandings in the art. The technical methods described or cited herein are generally well understood by those skilled in the art and are adopted by conventional methods. Unless otherwise stated, the use of commercially available reagents and instruments is carried out in accordance with the schemes and parameters given by the manufacturer.

[0028] In order to overcome the defects of the prior art, the specific embodiment of the present invention provides a stainless steel wire for ultra-fine pen tip steel and a preparation method thereof. The chemical composition of the stainless steel wire for pen tip steel includes the following components by mass: C≤0.05%, Si≤1.00%, Mn≤2.00%, P≤0.05%, S≥0.15%, 19.00%≤Cr≤21.00%, 1.5%≤Mo≤2.5%, and the balance is Fe and unavoidable impurities.

[0029] Among them, 19.00% ≤ Cr ≤ 21.00%, 1.5% ≤ Mo ≤ 2.5% in the wire improves the corrosion resistance of the stainless steel wire, and S ≥ 0.15% improves the machinability of the stainless steel wire.

[0030] In a specific embodiment of the present invention, a reasonable element equivalent ratio ensures the mechanical properties of the stainless steel wire for the ultra-fine pen tip steel.

[0031] The technical solution of the present invention is further described below through specific embodiments.

[0032] Example 1

[0033] 1.3mm diameter ultra-fine pen tip steel made of stainless steel wire

[0034] S1: The stainless steel wire with a diameter of 2.3 mm and chemical composition including the following components by mass: C0.01%, Si0.4%, Mn1.1%, P0.03%, S0.32%, Cr20.4%, Mo1.8%, and the balance Fe and unavoidable impurities is subjected to the first online bright annealing, wherein the stainless steel wire is subjected to the first online bright annealing under a protective gas atmosphere, the protective gas atmosphere is a nitrogen-hydrogen mixed gas with a volume ratio of 1:3, the conveying flow rate of the protective atmosphere is 1.2±0.5m / h, the annealing temperature is 850°C, and the holding time per millimeter of effective diameter is 34 seconds;

[0035] S2: fine drawing of the stainless steel wire, wherein the area reduction rate of the fine drawing is 54%;

[0036] S3: performing a second online bright annealing on the stainless steel wire, wherein the stainless steel wire is subjected to a second online bright annealing under a protective gas atmosphere, the protective gas atmosphere is a nitrogen-hydrogen mixed gas with a volume ratio of 1:3, the conveying flow rate of the protective atmosphere is 1.2±0.5m / h, the annealing temperature is 850°C, and the holding time per millimeter of effective diameter is 34 seconds;

[0037] S4: The stainless steel wire is drawn for the first time, and the area reduction ratio is 18.39%;

[0038] S5: Drawing the stainless steel wire for the second time to obtain a stainless steel wire product with a diameter of 1.30 mm, and the area reduction rate of drawing is 13.77%;

[0039] S6: Eddy current flaw detection, screen out the wires without internal damage, that is, the stainless steel wires for ultra-fine pen tip steel.

[0040] Example 2

[0041] Mechanical properties testing

[0042] The mechanical properties of the stainless steel wire for the ultra-fine pen tip steel prepared in Example 1 were tested and compared with the stainless steel wire provided by the Chinese invention patent with publication number CN102828118A. The comparison results are shown in Table 1.

[0043] tensile strength Elongation HV(1 / 2 radius) diameter Example 1 <![CDATA[806N / mm 2 ]]> 3％ 263 1.3mm Existing wire <![CDATA[≥700N / mm 2 ]]> 3～6％ 240～280 2.3mm

[0044] It can be seen that the stainless steel wire provided in Example 1 reduces the diameter of the stainless steel wire while ensuring that the mechanical properties of the wire remain unchanged or slightly improved, and has broad application prospects.

[0045] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A stainless steel wire for an ultra-fine pen tip, characterized in that: The chemical composition of the stainless steel wire for the ultra-fine pen tip steel includes the following components by mass percentage: C≤0.05%, Si≤1.00%, Mn≤2.00%, P≤0.05%, S≥0.15%, 19.00%≤Cr≤21.00%, 1.5%≤Mo≤2.5%, and the balance is Fe and unavoidable impurities.

2. A method for preparing the stainless steel wire for the ultra-fine pen tip steel according to claim 1, characterized in that: The following steps are involved: S1: Performing the first online bright annealing on the stainless steel wire with a diameter of 2.3 mm and meeting the standards of claim 1 or 2; S2: Fine drawing of stainless steel wire; S3: Performing a second online bright annealing on the stainless steel wire; S4: The stainless steel wire is drawn in one pass for the first time; S5: Drawing the stainless steel wire for the second time to obtain a stainless steel wire product with a diameter of 1.30 mm; S6: Eddy current flaw detection, screen out the wires without internal damage, that is, the stainless steel wires for ultra-fine pen tip steel.

3. The preparation method according to claim 2, characterized in that: The stainless steel wire is subjected to the first online bright annealing in a protective gas atmosphere, wherein the protective gas atmosphere is a nitrogen-hydrogen mixed gas with a volume ratio of 1:3, and the conveying flow rate of the protective gas is 1.2±0.5 m / h.

4. The preparation method according to claim 2, characterized in that: In the step S1, the first online bright annealing temperature is 800-860° C., and the holding time is 30-40 seconds per millimeter of effective diameter.

5. The preparation method according to claim 2, characterized in that: In the step S2, the surface reduction rate of fine drawing is 40-60%.

6. The preparation method according to claim 2, characterized in that: In step S3, the second online bright annealing temperature is 800-860° C., and the holding time is 30-40 seconds per millimeter of effective diameter.

7. The preparation method according to claim 2, characterized in that: The surface reduction rate of the first drawing is 15-20%.

8. The preparation method according to claim 2, characterized in that: The surface reduction rate of the second drawing is 10-15%.