JP4532438B2 - Manufacturing method of irregular cross section line - Google Patents

Description

  The present invention relates to a method for producing a modified cross-section line used as a part for a machine structure such as an automobile.

  Conventionally, in a manufacturing method in which a steel wire is drawn into a circular cross-section line or an irregular cross-section wire different from a circular cross-section using a wire drawing die, the surface of the steel wire rod is obtained by pickling in order to perform the wire drawing process smoothly. After removing the scale adhering to the steel, pickling and film treatment is performed to immerse the steel wire in a zinc phosphate solution to form a zinc phosphate film. In the wire drawing step, a dry lubricant containing a metal soap such as calcium stearate or sodium stearate is used.

  In addition to the above technique, a technique related to the removal treatment of the scale adhering to the surface of the steel wire rod has been proposed and put into practical use. For example, in the surface treatment of a steel wire rod disclosed in Patent Document 1, an ultrahigh pressure water jet of an abrasive jet method is used to remove scale adhered to the surface of the steel wire rod before the film formation treatment. By continuously injecting water and abrasives onto the surface of the steel wire rod, the scale is removed and innumerable fine irregularities are formed on the surface of the steel wire rod. Then, when the steel wire rod with the surface irregularity is treated with a zinc phosphate solution, a dense and highly adherent zinc phosphate coating is formed on the surface of the steel wire rod. In addition, the abrasive is composed of steelmaking dust generated in the steelmaking process by converter refining.

Here, low alloy steels such as CR steel, SCM steel and SNCM steel may be used for machine structural parts. For example, recently for automobiles, high strength of parts is demanded from the viewpoint of weight reduction. Low alloy steels containing small amounts of transition metals such as chromium (Cr), molybdenum (Mo) and nickel (Ni) are increasingly used.
Japanese Patent Laid-Open No. 7-80772

  However, in the conventional manufacturing method, smut (insoluble substance) may remain even if the scale can be removed by pickling. In this case, the formation of a zinc phosphate coating in the coating treatment after pickling may occur. Since it will be in an inadequate state, the problem that the uniformity and peeling resistance of a zinc-phosphate membrane fall will arise. In particular, the tendency is strong in the low alloy steel. In addition, some of these low alloy steels cannot be drawn with hot rolling as they are, so that heat treatment such as annealing may be performed after rolling. Tends to remain, and the state of the zinc phosphate film deteriorates.

When a wire material having such a film property is drawn, even if the degree of processing (for example, the area reduction ratio) does not cause a problem in a normal circular section, the area reduction ratio is locally increased in the drawing of an irregular section other than the circular section. Since there is a high portion, seizure is likely to occur in the portion, and the wire drawing die life (the amount of wire drawn before die baking is generated) is significantly lower than the wire drawing die life of the circular cross-section line. In that case, in order not to reduce the die life, it is necessary to reduce the wire drawing speed. As a result, there is a problem in that the productivity for producing the deformed wire is reduced.
On the other hand, in the surface treatment of the steel wire rod of Patent Document 1, since the abrasive is used, the surface roughness of the steel wire rod is deteriorated, and there is a problem that it cannot be used for a product having a severe surface roughness requirement. .

  An object of the present invention is to provide a method for producing a deformed cross-section wire capable of improving a drawing die life and a drawing speed in the drawing of a steel wire, particularly a low alloy steel.

Method for producing a modified cross-section wire according to claim 1 is a method of manufacturing a profiled section line for drawing the steel wire rod made of a low alloy steel material modified cross-section, prior to the irregular drawing process, the surface of the steel wire rod of a pickling step of removing the pickling scale, then a film forming step of forming a zinc phosphate coating with only immersing the steel wire in a zinc phosphate solution was added a predetermined chelating agent It is provided.

  In particular, this production method is based on the finding that by adding a chelating agent to a zinc phosphate solution, the smut on the surface of the steel wire is removed and the zinc phosphate film properties are improved. That is, in the manufacturing method of drawing a steel hot-rolled wire or heat-treated wire into a deformed cross-section wire, after removing the scale on the surface of the wire by pickling in the pickling / coating step performed before the deformed wire drawing step, By coating a steel wire with a zinc phosphate solution with a predetermined chelating agent added, the uniformity of the zinc phosphate coating, improvement in peel resistance and the amount of adhesion can be increased, and the wire drawing speed can be increased. The wire drawing die life can be extended.

  According to a second aspect of the present invention, there is provided a method for producing a modified cross-section wire, wherein a steel wire having a zinc phosphate coating formed in a deformed wire drawing step is drawn using a lubricant containing one or both of a tetrafluoroethylene resin and a melamine resin. It is characterized by doing.

  In the deformed wire drawing process, by using a wire drawing lubricant added with tetrafluoroethylene resin or melamine resin, the decrease in the amount of zinc phosphate coating on the surface of the steel wire after wire drawing is suppressed. This is based on the knowledge that the adhesion amount of the lubricant can be increased. That is, by adding one or both of a tetrafluoroethylene resin and a melamine resin to the lubricant used in the deformed wire drawing step, it is possible to prevent the direct contact between the wire and the die, because the above-described effect can be obtained. The effect of extending the die life and improving the drawing speed is further promoted.

According to the first aspect of the present invention, since the steel wire is provided with a film forming step of forming a zinc phosphate film only by immersing the steel wire in a zinc phosphate solution to which a predetermined chelating agent is added, the surface of the steel wire It is possible to form a high-quality zinc phosphate film that is difficult to peel off and has excellent uniformity. As a result, when deformed wire drawing having a complicated shape is performed, it is possible to achieve higher speed wire drawing and longer die life than before, and it is possible to improve the productivity of the deformed wire and reduce the manufacturing cost.

  According to the invention of claim 2, since the steel wire having the zinc phosphate film formed in the irregular wire drawing step is drawn using a lubricant containing one or both of a tetrafluoroethylene resin and a melamine resin, It is possible to prevent the zinc phosphate coating from decreasing, and to prevent the direct contact between the steel wire and the die by increasing the adhesion amount of the lubricant. For this reason, the extension of the die life and the improvement of the drawing speed can be further enhanced, which can greatly contribute to the improvement of the productivity of the deformed wire and the reduction of the manufacturing cost.

  The method for producing a modified cross-section wire according to the present invention includes a pickling step of removing the scale of the surface of the steel wire rod by pickling before the deformed wire drawing step, and then a predetermined chelating agent for the steel wire rod. A film forming step of forming a zinc phosphate film by treating with the added zinc phosphate solution.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and tables.
The present embodiment is an example in which the present invention is applied to a manufacturing method in which a steel wire is drawn into an irregular cross-section line having a different cross-section from a circular cross-section. FIG. 1 shows a method for producing a deformed cross-sectional wire in which a steel wire is drawn through a pickling step and a film forming step into a deformed cross-section having a complicated shape. In FIG. 1, reference numeral Pi (i = 1, 2, ...) shows each process.

  As shown in FIG. 1, first, in P1 (hot rolling step), a low alloy steel material SNCM220 (JIS G4103) is hot-rolled to form a hot-rolled wire. Next, in P2 (pickling process), after removing the scale adhering to the surface of the hot-rolled wire rod by pickling with hydrochloric acid, washing is performed with high pressure water in a high pressure shower. Next, in P3 (film formation step), the wire is immersed in a zinc phosphate solution to which a solution containing a predetermined chelating agent (EDTA: ethylenediaminetetraacetic acid) as a main component is added, and the zinc phosphate film is formed on the surface of the wire. To form. Next, in P4 (special wire drawing process), using a wire drawing lubricant, the wire is drawn through a wire drawing die to form a metal soap film on the zinc phosphate film, and then drawn into a circular cross-section wire. After that, a circular cross-section wire is rolled with a roll, drawn through a wire rod rolled into a die hole for an irregular cross-section, and drawn to produce an irregular wire 1 having a cross-sectional shape shown in FIG.

  Next, a wire drawing test was conducted for the purpose of confirming the improvement effect of the conditions for forming the zinc phosphate coating in the coating formation step (P3). Specifically, in the film formation step (P3), the amount of the chelating agent as a main component (Axelene 110 manufactured by Nippon CB Chemical Co., Ltd.) added to the zinc phosphate solution was changed in three ways to form a film. Went. Further, in the above-described irregular wire drawing step (P4), wire drawing is performed using a wire drawing lubricant (S45 manufactured by Kyoeisha Chemical Co., Ltd.) not containing tetrafluoroethylene resin or melamine resin, and the wire drawing speed is increased. The wire drawing speed at which seizure occurs on the surface of the irregular cross section (hereinafter, wire drawing limit speed) was determined.

  Table 1 shows the state of formation of the zinc phosphate coating on the surface of the wire after the coating treatment under the above conditions (the coating crystal formation area ratio), the amount of zinc phosphate coating deposited, and the zinc phosphate coating with a modified cross-section line after wire drawing The results of comparing the adhesion amount of the wire and the adhesion amount of the wire drawing lubricant are shown.

  According to this result, Examples A to C in which a chelating agent was added to a zinc phosphate solution had a higher film crystal formation area ratio than Comparative Example D, and the amount of zinc phosphate coating deposited was about 1.8. Doubled and a high drawing limit speed is obtained. This is considered to be due to the fact that in Examples A to C, the zinc phosphate coating was uniformly formed over the surface of the wire with a highly dense surface property and the amount of adhesion increased. That is, it can be seen that the use of a chelating agent is extremely effective for removing smut and forming a zinc phosphate film.

  As shown in FIG. 3, the second embodiment draws a steel wire rod harder than the SNCM 220 of the first embodiment into a deformed cross section having a complicated cross section through a spheroidizing annealing process, a pickling process, and a coating process. In FIG. 3, reference symbol Pi (i = 11, 12,...) Denotes each step.

  First, in P11 (hot rolling process), SCM435 (JIS G4105), which is a low alloy steel material, is hot-rolled to form a hot-rolled wire. Next, in P12 (pickling process), after removing the scale adhering to the surface of the hot-rolled wire rod by pickling with hydrochloric acid, the plate is washed with water and high pressure water in a high pressure shower. Next, in P13 (annealing step), the cleaned wire is heated to 760 ° C. in a heat treatment furnace, held for a certain time, and then gradually cooled and softened (spheroidizing heat treatment). Next, in P14 (pickling process), the scale on the surface of the wire generated by the heat treatment is removed by pickling with hydrochloric acid, followed by washing with high pressure water in a high pressure shower.

  Next, in P15 (film forming step), the wire is immersed in a zinc phosphate solution to which a solution containing a predetermined chelating agent as a main component is added, and a zinc phosphate film is formed on the surface of the wire. Next, in P16 (special wire drawing process), using a wire drawing lubricant, the wire rod is drawn through a wire rod to form a metal soap film on the zinc phosphate film, and then drawn into a circular cross-section wire. After that, a circular cross-section wire is rolled with a roll, drawn through a wire rolled into a die hole for a deformed cross section, and drawn to produce a deformed wire 2 having a cross-sectional shape shown in FIG.

  Next, a wire drawing test was conducted for the purpose of confirming the effect of improving the wire drawing conditions in the irregular wire drawing step (P16). Specifically, in the film formation step (P15), the solution containing the chelating agent used in Example 1 as a main component is added to the zinc phosphate solution to perform film treatment, and in the deformed wire drawing step (P16). The wire drawing lubricant added with tetrafluoroethylene resin (W350F manufactured by Kyoeisha Chemical Co., Ltd.) and the wire drawing lubricant added with melamine resin (AFCO 108 manufactured by Yoko Sangyo Co., Ltd.) were used in Example 1. Drawing was performed using a drawing lubricant, and the drawing limit speed was determined.

  Table 2 shows the state of formation of the zinc phosphate coating on the surface of the wire after the coating treatment under the above conditions (crystal formation area ratio), the amount of zinc phosphate coating deposited, and the zinc phosphate coating with a deformed cross-section line after wire drawing. The result of comparing the adhesion amount and the adhesion amount of the lubricant is shown.

  According to this result, Examples E to G have a higher film crystal formation area ratio than that of Comparative Example J using a lubricant to which a tetrafluoroethylene resin is added, and the amount of zinc phosphate coating deposited is also about Doubled, a high drawing limit speed is obtained. This is presumably because the zinc phosphate film was uniformly formed and the amount of adhesion was increased. Moreover, it turns out that wire drawing property is inferior only by using the lubricant which added the tetrafluoroethylene resin.

Examples F and G have higher wire drawing limit speed and excellent seizure resistance than Example E using a wire drawing lubricant that does not contain tetrafluoroethylene resin or melamine resin. This is presumably because the amount of decrease in the amount of adhesion of the zinc phosphate film due to wire drawing is small, that is, the peel resistance of the zinc phosphate film is high, and the amount of adhesion of the lubricant is increased.
Further, Example F and Comparative Example H were drawn at a drawing speed of 30 m / min, and the drawing die life was obtained. As a result, it can be seen that the die life of Example F is about 5 times longer than that of Comparative Example H, and the wire drawing property is remarkably superior to the conventional example. That is, it is considered that the extension of the wire drawing die life has been drastically improved by the synergistic action of the increase in the adhesion amount of the zinc phosphate film and the increase in the adhesion amount of the lubricant.

  According to the modified cross-section wire manufacturing method of this example, before the deformed wire drawing step, the surface scale of the steel wire rod is removed by pickling, and the steel is added to the zinc phosphate solution to which a predetermined chelating agent is added. Because it has a film forming process that immerses the wire rod, dissolves the smut adhering to the surface of the steel wire rod, and forms a zinc phosphate coating, it improves the peel resistance of the zinc phosphate coating and the amount of adhesion Even if the wire drawing speed is increased and the wire drawing speed is increased, the life of the wire drawing die can be extended.

  The steel wire with a zinc phosphate coating formed in the special wire drawing process is drawn using a lubricant containing either tetrafluoroethylene resin or melamine resin. Even when deformed wire processing is performed, compared to the manufacturing method of the comparative example, the wire drawing speed and wire drawing die life at the time of deformed wire processing are improved, and the deformed wire processing cost can be greatly reduced.

Next, a modified form in which the embodiment is partially modified will be described.
1] In the deformed wire drawing step of the embodiment, a lubricant containing both a tetrafluoroethylene resin and a melamine resin may be used.
2] In the manufacturing method of the embodiment, in addition to the irregular cross-section line of the illustrated cross-section shape, other complicated cross-section shapes such as an H-shape, a spline tooth shape, and a cross-sectional shape in which four vertical grooves are formed on the outer surface of the cylinder The present invention can also be applied to the production of irregular cross-section lines.
3] In addition, various modifications other than the matters disclosed in the above embodiments can be implemented without departing from the spirit of the present invention.

It is a figure which shows the process of the manufacturing method of an irregular cross-section line. It is a figure which shows the cross-sectional enlarged view of the deformed line manufactured by the manufacturing method shown in FIG. It is a figure which shows the process of the manufacturing method of an irregular cross-section line. It is a figure which shows the cross-sectional enlarged view of the deformed line manufactured by the manufacturing method shown in FIG.

1, 2 irregular cross section line

Claims (2)

In the method for producing a deformed cross-section wire in which a steel wire made of a low alloy steel material is drawn into a deformed cross-section,
Before the irregular drawing process,
A pickling step of removing by pickling the scale of the surface of the steel wire rod,
Next, a film forming step of forming a zinc phosphate coating with only immersing the steel wire in a zinc phosphate solution was added a predetermined chelating agent,
The manufacturing method of the irregular cross-section line characterized by the above-mentioned. The steel wire having the zinc phosphate film formed in the deformed wire drawing step is drawn using a lubricant containing one or both of a tetrafluoroethylene resin and a melamine resin. The manufacturing method of the unusual cross-section line of description.