JP2010042480A - Rolled bar surface polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolled bar surface polishing method for reliably polishing a rolled bar made of a stainless steel, a high alloy steel, or non-ferrous metals at high profile precision and dimensional precision with high yield. <P>SOLUTION: The rolled bar surface polishing method includes the following steps: a first step of inserting a rolled bar W2 fed along an axial direction to a clearance between a pair of grinding drums G1 and G2 which respectively have parallel rotating shafts S, are adjacent to each other, and rotate in the reverse direction to each other, and grinding the surface of the rolled bar W2 by rotationally driving the rolled bar in contact with the outer surfaces of the pair of grinding drums G1 and G2; and a second step of feeding a rolled bar W3 with the surface ground in the first step along the axial direction, and polishing the surface of the rolled bar W3 by inserting the rolled bar between the pair of polishing discs D1 and D2 which are arranged on the downstream side of the pair of grinding drums G1 and G2 on the both sides in the radial direction of the rolled bar W3, respectively have rotating shafts s along the radial direction of the rolled bar W3 and rotate in the direction of feeding the rolled bar W3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface polishing method for a rolled bar made of stainless steel, high alloy steel, or non-ferrous metal, and more particularly to a surface polishing method for reliably obtaining a rolled bar with high shape / dimensional accuracy and yield.

In general, the surface polishing of a rolled bar made of high alloy steel containing an Fe-Ni alloy is performed by a peeling process in which the periphery of the bar is rotated at a high speed while pressing a throw-away tip against the surface, or by a centerless grinder. (For example, refer to Patent Document 1).
JP-A-62-79954 (pages 1 to 3, FIGS. 1 and 2)

However, in the case of the peeling process, there is a problem that the yield loss of the rolled bar is increased because a grinding allowance of 0.8 mm or more is required in one peeling process for mechanical reasons.
Further, in the case of polishing by the centerless grinder, there is a problem that productivity is lowered because the grinding speed is relatively low, about 1 to 3 m / min.

On the other hand, when a rolled bar made of Cr-based stainless steel is peeled, it is rotated with respect to the feed direction in order to remove spiral cutter marks (wave lines) generated on the surface due to grinding by the tip. It is necessary to correct the clogging by passing between the drum-shaped roll and the drum-shaped roll having different axes. However, both ends of the rod after the straightening have a spindle shape that becomes thicker by about 0.1 mm than the original diameter due to internal residual stress due to being not restrained during the straightening. A large diameter part arises. Therefore, when high dimensional accuracy is required, the end including the large-diameter portion is cut from hot noodles to a length of about 5 to 10 cm, which has been a factor in reducing yield.
Furthermore, in order to improve the dimensional accuracy, a method of polishing with a centerless grinder after peeling processing is also performed, but the large diameter portion generated at the end cannot be removed even by the grinder, so that the yield reduction due to the cutting is reduced. It was a factor.

  The present invention solves the problems described in the background art, and the surface of a rolled bar that can reliably polish a rolled bar made of stainless steel, high alloy steel, or non-ferrous metal with high shape / dimensional accuracy and yield. It is an object to provide a polishing method.

Means for Solving the Problems and Effects of the Invention

In order to solve the above-mentioned problems, the present invention has been implemented by the inventors, and as a result, a rolling bar is provided by a pair of grinding wheel drums that are symmetrically arranged on both sides in the radial direction of the rolled bar to be surface-polished and rotate in the opposite direction. The idea is to polish the surface of the material.
That is, the surface polishing method for a rolled bar according to the present invention (Claim 1) is a method for polishing the surface of a rolled bar made of stainless steel, high alloy steel, or non-ferrous metal and rolled to a predetermined diameter. Then, the rolled rod material fed along the axial direction is inserted into a gap between a pair of grindstone drums whose rotation axes are parallel to each other and are arranged adjacent to each other and reversely rotate with each other. A first step of grinding the surface of the rolled bar by rotating it while making contact with the peripheral surface of the drum, and the rolled bar whose surface is ground in the first step is fed along the axial direction. A pair of polishing discs disposed downstream of the pair of grinding wheel drums and on both sides in the radial direction of the rolling bar, and having a rotation axis along the radial direction of the rolling bar and rotating about the rotation axis. The surface of the rolled bar Comprising a second step of grinding, and wherein the.

  According to this, when the rolling bar is driven and rotated between the peripheral surfaces of a pair of adjacent grindstone drums while being in contact with the peripheral surfaces, the axis of the rolling rod is not shaken. The entire surface is ground with a uniform cutting allowance according to the difference from the peripheral speed of the peripheral surface (first step). Moreover, when the polished rolled bar passes between a pair of rotating polishing disks located on the downstream side, the ground surface is smoothed by the pressing force of each surface of the disk. (Second step). Therefore, it is possible to reliably polish the surface of the rolled bar with high shape and dimensional accuracy having a required diameter, roundness, and surface roughness, and yield.

The high alloy steel includes, for example, 70 mass% Ni-30 mass% Fe (INCONEL), and the non-ferrous metal includes, for example, Ti-6 mass% Al-4 mass% V.
In addition, the rolled bar is fed in the axial direction so that the axis of the rolled bar is positioned below the rotational axes of the pair of grinding wheel drums used in the first step.
Further, the pair of grindstone drums used in the first step can approach or separate the rotation shafts of the drums according to the diameter reduction due to wear of the surface grindstone or the diameter of the rolled bar to be ground. .
In addition, the pair of polishing disks used in the second step are, for example, at least peripheral surfaces are made of cemented carbide, and their rotational axes are arranged at positions shifted from each other along the axis (feed) direction of the rolled bar. Has been.
In addition, the pair of polishing disks used in the second step may be further installed on the upstream side of the pair of grindstone drums used in the first step. At least the surface of the polishing disk is also made of a carbide such as WC.

In the present invention, when the rolled bar is made of stainless steel, the first step is that the peripheral speed of the peripheral surfaces of the pair of grindstone drums is 15 m / sec or more and is driven by the grindstone drum. The difference between the peripheral speed on the surface of the rolled bar to be rotated and the peripheral speed of the grindstone drum is 13 m / sec or more, and the grinding allowance of the rolled bar to be ground by the pair of grindstone drums is 0. A surface polishing method for a rolled bar (claim 2), which is 15 mm or more and is performed at a feed rate of the rolled bar of 20 m / min or less, is also included.
According to this, the rolling bar fed in the axial direction at a feeding speed of 20 m / min or less is 13 m / sec or more between the peripheral surfaces having a circumferential speed of 15 m / sec or more in the pair of grindstone drums. The entire surface is subjected to grinding with a grinding allowance of 0.15 mm or more by being driven and rotated while being in contact with the peripheral surface at a low peripheral speed (first step). Thereafter, the rolled bar has a smooth surface with a relatively high roundness (shape / dimension) and a surface roughness (Ra) of 0.8 μm or less because it is polished by the pair of polishing disks (second step). Surface polishing can be performed on the material with high yield.
Note that the peripheral speeds of the peripheral surfaces of the pair of grindstone drums are always larger than the peripheral speeds of the peripheral surfaces of the rolled bar that is driven and rotated, and the difference between the grindstone drums and the rolled bar is the peripheral speed. It is a difference. The grinding allowance is a measure of the minimum depth for grinding at one time. Further, when any one of the three numerical values (parameters) excluding the grinding allowance is lacking, the roundness and the surface roughness may be reduced, so these ranges are excluded.

Further, in the present invention, in the case where the rolled bar is made of high alloy steel or non-ferrous metal, the first step has a peripheral speed of 30 m / second or more on the peripheral surfaces of the pair of grinding stone drums. The difference between the peripheral speed on the surface of the rolled bar driven and rotated by the grindstone drum and the peripheral speed of the grindstone drum is 29 m / sec or more, and the grinding allowance of the rolled bar to be ground by the pair of grindstone drums Includes a method of polishing the surface of the rolled bar (claim 3), which is 0.2 mm or more and the feed speed of the rolled bar is 6 m / min or less.
According to this, the rolling bar fed in the axial direction at a feed speed of 6 m / min or less is 29 m / sec or more between the peripheral surfaces of the pair of grinding stone drums whose circumferential speed is 30 m / sec or more. The entire surface is subjected to grinding with a grinding allowance of 0.2 mm or more by being driven and rotated while being in contact with the peripheral surface at a low peripheral speed (first step). Thereafter, the rolled bar having a smooth surface with a relatively high roundness (shape / dimension) and a surface roughness (Ra) of 4 μm or less is subjected to polishing by the pair of polishing disks (second step). Thus, it is possible to polish the surface with a high yield.
The peripheral speed difference and the grinding allowance are the same as described above. In addition, when any one of the three numerical values (parameters) excluding the grinding allowance is lacking, the roundness and the surface roughness may be reduced, so these ranges are excluded.

In addition, according to the present invention, prior to the first step, the rolled bar material is preliminarily erased from the preliminary step 1 in which surface grinding is performed by peeling processing and the spiral wavy lines formed on the surface by the grinding. Therefore, a preliminary step 2 for correcting between a drum-shaped roll having a rotation direction different from each other and having a circumferential surface recessed in an arc shape and a drum-shaped roll having a circumferential surface swelled in an arc shape; The method of polishing the surface of the rolled bar (Claim 4) is also included.
According to this, even in the case of a rolled bar having a large-diameter portion at both ends by the preliminary steps 1 and 2, since the grinding by the first step and the surface polishing by the second step are performed, the large-diameter portion Or the diameters at both ends can be reliably within the tolerance range.
In addition, the large diameter part which arises at the both ends of the said rolling bar used as the object of preliminary | backup step 2 arises when the rolling bar | burr concerned concerned is peeled of the said preliminary | backup step 1, and the thickness followed the axial direction. The central part (maximum) of the spindle shape is about 0.1 mm, and the length is, for example, within 10 cm or 5 cm from the end face.

In the following, the best mode for carrying out the present invention will be described.
FIG. 1 is a schematic view showing a preliminary step 1 in which surface rolling by peeling processing is performed on a rolled bar W0 that is an object of the present invention to obtain a required diameter.
The rolled bar W0 that has been reduced in diameter to a predetermined diameter by hot rolling in advance is subjected to peeling (peeling) processing by the peeling machine 1 in order to remove the black skin on the surface layer. As shown in FIG. 1, between a plurality of transport rollers R, r arranged along the left-right direction, a motor and a rotation mechanism (not shown) are used to feed along the axial direction as shown by arrows in FIG. A holder 2 that swivels around the fed rolled bar W0 and circular or substantially triangular throw-away tips c1 and c2 attached to the tip of the holder 2 are disposed. As a result of the two-step surface grinding with the chips c1 and c2, the spiral wave streak BL remains on the surface of the rolled bar W1 whose diameter has been reduced in the preliminary step 1.

In order to remove the wavy lines BL generated on the surface of the rolled bar W1, as shown in FIG. 2, the rotation axes of the rolled bar W1 intersect with the feeding (axis) direction of the rolled bar W1 and are different oblique directions, Preliminary step 2 is performed in which the peripheral surface 5 passes between the drum-shaped roll 4 having a circular arc shape and the drum-shaped roll 6 having the circular peripheral surface 7 swelled in an arc shape. The drum-shaped roll 4 and the drum-shaped roll 6 are supported while receiving a radial pressure P so that the drum-shaped roll 4 and the drum-shaped roll 6 can be rotated by a support (not shown) and the peripheral surfaces 5 and 7 thereof approach each other.
As shown in FIG. 2, when the rolled bar W1 is inserted between the peripheral surfaces 5 and 7 of the hourglass roll 4 and the drum-shaped roll 6 that rotate in different directions, bending between the peripheral surfaces 5 and 7 and The rolled bar W2 in which the spiral wave streak BL is crushed can be obtained by the correction action that repeatedly receives the pressing force.

However, during the straightening, the tensile and compressive residual stress due to the bending is generated inside the rolled bar W2. As a result, as shown in FIG. 3, large-diameter portions 8 are generated at both ends of the rolled bar W2 after the preliminary step 2 due to the occurrence of the residual stress by being not restrained in the bar W2. The large diameter portion 8 as a whole having a diameter approximately 100 μm thicker than the diameter D of the intermediate portion is substantially spindle-shaped, has a length of about 5 to 10 cm, and the diameter d of the end face 9 is smaller than the diameter D. It is.
In the present invention, the entire surface of the rolled bar W2 including the large-diameter portion 8 is uniformly ground (first step) with a polishing margin of about 0.1 to 0.2 mm, and immediately after that surface polishing (first step) 2 steps), a round bar (shape / dimension) having a relatively high surface roughness (Ra) of 1 μm or less and a smooth surface is polished with high yield.

FIG. 4 is a perspective view schematically showing the surface polishing apparatus 10 for performing the first and second steps of the present invention, and FIGS. 5 and 6 are side views showing a part of the apparatus 10.
As shown in FIGS. 4 to 6, the surface polishing apparatus 10 includes a pair of polishing disks d1 and d2, which are sequentially arranged along the feeding direction of the rolled bar W2 indicated by the oblique arrows in FIG. Grinding wheel drums G1, G2 and a pair of polishing disks D1, D2.
The pair of polishing discs d1, d2, D1, D2 are arranged so as to be shifted on both sides in the axial direction of the rolled bar W2, as illustrated in FIG. 5 showing the latter side surface arranged on the downstream side. It rotates around a rotation axis s along the radial direction of W2. As shown in FIG. 5, the shift amount of the pair of polishing disks D1, D2 (d1, d2) is slightly larger than the respective radii. The polishing discs D1 and D2 are made of a carbide such as WC at least on the surface, and the rolled bar W2 feeds a position slightly lower than each rotation axis s on a support blade (not shown) disposed in the gap between the two. It is polished while being fed. At this time, the rolled bar W2 is fed along the axial direction while being sandwiched and rotated by a pair of front and rear polishing disks D1, D2 (d1, d2), and the surface thereof is polished therebetween.

On the other hand, as shown in FIGS. 4 and 6, the pair of grindstone drums G1 and G2 are located on both sides in the radial direction of the rolled bar W2, the rotation axis S is parallel to each other, and the axial direction of the rolled bar W2 And rotate in opposite directions. In the gap between the grindstone drums G1 and G2, the rolled bar W2 is fed in the axial direction along the upper surface of the support blade b. At this time, the rolled bar W2 is in contact with the circumferential surfaces of the grinding wheel drums G1 and G2 rotating in the opposite directions, and is driven to rotate by these circumferential surfaces, and according to the difference from the circumferential speed of the grinding wheel drums G1 and G2. The surface is uniformly ground so as to have the same radius from the axis.
As shown in FIG. 6, the rolled bar W2 passing through the upper surface of the support blade b is located slightly below the horizontal line connecting the rotation axes S, S of the grindstone drums G1, G2. Also, the grinding wheel drums G1 and G2 can approach or separate the rotational axes S of the grinding wheel drums G1 and G2 by parallel movement in accordance with the diameter reduction due to wear of the surface grinding stone or the diameter of the rolled bar W2 to be ground. It is said that. Further, abrasive grains of a predetermined particle size made of fused alumina, silicon carbide, or diamond are uniformly distributed on the peripheral surfaces of the grindstone drums G1, G2.

As shown in FIG. 4, the rolled bar W2 having the large-diameter portions 8 at both ends is sandwiched between a pair of polishing disks d1 and d2 located on the upstream side of the grindstone drums G1 and G2 in the surface polishing apparatus 10. The surface is sent along the axial direction while rotating, and when passing through the gap between the pair of grinding wheel drums G1 and G2, the surface is made uniform according to the difference from the peripheral speed of the grinding wheel drums G1 and G2 while being rotated. Grinding with a proper thickness (first step). At this time, the rolled bar W2 is mainly ground by the grindstone drum G2 that rotates in the opposite direction, and the large-diameter portions 8 at both ends thereof are also eliminated, and the diameter is the same as or almost the same as the intermediate portion. .
As shown in FIG. 4, the rolled bar W3 ground to a predetermined diameter between the grindstone drums G1 and G2 is sandwiched between a pair of polishing disks D1 and D2 positioned on the downstream side and rotates along the axial direction. Sent. At this time, the ground surface of the rolled bar W3 is smoothed by the pressing force of each surface of the rotating polishing disks D1 and D2.
As a result, as shown on the right side of FIG. 5, when the rolled bar W2 is a rolled bar W4 having a required shape (diameter, roundness) and surface roughness, high shape and dimensional accuracy, In addition, it is possible to reliably perform surface polishing with a yield.

Here, specific examples of the present invention will be described together with comparative examples.
It consists of SUS430 (stainless steel), INCONEL (70 mass% Ni-30 mass% Fe: high alloy steel), and Ti-6 mass% Al-4 mass% V (Ti-based alloy: non-ferrous metal), with a diameter of 24 mm. A plurality of rolled bars W0 are prepared and subjected to the peeling process (preliminary step 1) and the correction (preliminary step 2) under the same conditions, and a plurality of rolled bars W2 having a diameter of 23 mm and a length of 4 m are prepared. Made this book.
Next, surface rolling (first step) and surface polishing (second step) are performed on the rolled bar W2 using the surface polishing apparatus 10 having the same specifications, as shown in Table 1 (grinding drums G1, G2). ), The difference between the peripheral speed and the peripheral speed of the rolled bar W2, the grinding allowance, and the feed speed) were performed ten times for each example.

Of the rolled bar W4 of each example whose surface was polished, with regard to SUS430, the one with an average surface roughness (Ra) of 0.8 μm or less was regarded as good grinding (◯), and the one with a roughness greater than 0.8 μm was ground. The results are shown in Table 1 as “No” (×). Furthermore, for INCONEL and Ti-6% Al-4% V, the surface roughness (Ra) is 4 μm or less on average and the grinding is good (◯), and the one exceeding 4 μm is not grinding (x). Each is shown in Table 1.
On the other hand, in the example of the rolled bar W4 of each example, the large-diameter portions 8 at both ends are eliminated in the same manner as the diameter of the intermediate portion or the diameter is 10 mm or less. Table 1 shows examples in which removal of the end portion was thick (x).

According to Table 1, in SUS430, Examples 1-4 were good grinding, and the end part thickness was also good removal. This is because the circumferential speed on the circumferential surface of the grinding drums G1, G2 in the first step is 15 m / sec or more, and the difference between the circumferential speed on the surface of the rolled bar W3 and the circumferential speed of the grinding drums G1, G2 is 13 m. / Sec or more, and the grinding allowance of the rolled bar W3 is 0.15 mm or more, and the feed rate of the rolled bar W3 is estimated to be a result of being performed in an appropriate range of 20 m / min or less. .
On the other hand, in Comparative Examples 1 and 2, grinding was rejected, and the end thickening was also rejected. This is because, as shown by the underline in Table 1, in Comparative Example 1, the feed speed of the rolled bar W3 was too fast, 30 m / min, and the shaft center was shaken. In Comparative Example 2, the grinding wheel drum The peripheral speed on the peripheral surfaces of G1 and G2 is as low as less than 15 m / sec, and the difference between the peripheral speed on the surface of the rolled bar W3 and the peripheral speed of the grindstone drums G1 and G2 is too small at less than 13 m / sec. It is estimated that the shaft runout and the grinding speed were insufficient.

Further, with INCONEL and Ti-6% Al-4% V, Examples 5 to 7 and 8 to 10 were good in grinding and also excellent in removal of end thickness. This is because the circumferential speed on the circumferential surface of the grinding wheel drums G1 and G2 in the first step is 30 m / second or more, and the difference between the circumferential speed on the surface of the rolled bar W3 and the circumferential speed of the grinding wheel drums G1 and G2 is It is 29 m / sec or more, and it is estimated that the grinding allowance of the rolled bar W3 is 0.2 mm or more, and that the feed speed of the rolled bar W3 is 6 m / min or less.
On the other hand, in Comparative Examples 3 to 6, all were grinding failures and the end thickening was also rejection rejection. This is because, as shown by the underline in Table 1, in Comparative Examples 3, 5, and 6, the feed speed of the rolled bar W3 was too fast, 8 m / min, and the shaft center was swung. Comparative Example 4 Then, the peripheral speed on the peripheral surface of the grindstone drums G1 and G2 is as slow as 25 m / sec, and the difference between the peripheral speed on the surface of the rolled bar W3 and the peripheral speed of the grindstone drums G1 and G2 is 24.3 m / sec. Since it was too small, it is estimated that the grinding speed was insufficient.

The effects of the present invention were confirmed by Examples 1 to 10 as described above.
In the case of INCONEL, as shown in Table 1, the peripheral speed on the peripheral surface of the grindstone drums G1 and G2 in the first step is 35 m / second or more, and the peripheral speed on the surface of the rolled bar W3 and the grindstone drum G1. , G2 and the peripheral speed may be 34 m / sec or more.
The rolled bar is made of stainless steel other than Cr-based stainless steel, high alloy steel other than INCONEL, Ti alloy other than Ti-6% Al-4% V, and other non-ferrous alloys. It is good as a thing.
Furthermore, the surface polishing method for a rolled bar according to the present invention may be configured such that the preliminary steps 1 and 2 are omitted and only the first and second steps are performed.

Schematic which shows the preliminary step 1 in this invention. Schematic which shows the preliminary step 2 in this invention. Schematic which shows the edge part of the rolling bar obtained by the said preliminary steps 1 and 2. FIG. Schematic which shows the surface polishing apparatus which performs the 1st, 2nd step in this invention. Schematic which shows the grinding | polishing disc in the said surface grinding | polishing apparatus. Schematic which shows the grindstone drum in the said surface polishing apparatus.

Explanation of symbols

4 ......... Drum-shaped roll 6 ............... Drum-shaped roll 8 ............... Thick diameter part 10 ......... Surface polishing equipment W1-W4 ... Rolled bar G1, G2 ... Whetstone drum D1, D2 ... Abrasive disc

Claims (4)

A method of polishing a surface of a rolled bar made of stainless steel, high alloy steel, or non-ferrous metal and rolled to a predetermined diameter,
The above-mentioned rolled bar fed along the axial direction is inserted into a gap between a pair of grinding wheel drums whose rotation axes are parallel to each other and arranged adjacent to each other and reversely rotate with each other. A first step of grinding the surface of the rolled bar by rotating it while being in contact with the peripheral surface;
The rolled bar whose surface has been ground in the first step is fed along the axial direction, arranged downstream of the pair of grindstone drums and on both sides in the radial direction of the rolled bar, and a rotating shaft is involved. A second step of polishing the surface of the rolled bar by inserting between a pair of polishing disks that rotate along the radial direction of the rolled bar and about the rotation axis,
A method for polishing a surface of a rolled bar. In the case where the rolled bar is made of stainless steel,
In the first step, the peripheral speed of the peripheral surfaces of the pair of grinding wheel drums is 15 m / second or more, and the peripheral speed of the surface of the rolled bar driven by the grinding wheel drum and the peripheral speed of the grinding wheel drum And the grinding allowance of the rolled bar to be ground by the pair of grinding wheel drums is 0.15 mm or more, and the feed speed of the rolled bar is 20 m / min or less. Done in
The method for polishing a surface of a rolled bar according to claim 1. In the case where the rolled bar is made of high alloy steel or non-ferrous metal,
In the first step, the peripheral speed of the peripheral surfaces of the pair of grinding wheel drums is 30 m / second or more, and the peripheral speed of the surface of the rolled bar driven by the grinding wheel drum and the peripheral speed of the grinding wheel drum And the grinding allowance of the rolled bar to be ground by the pair of grinding wheel drums is 0.2 mm or more, and the feed speed of the rolled bar is 6 m / min or less. Done in
The method for polishing a surface of a rolled bar according to claim 1. Prior to the first step, the rolling rods have different rotation axes in order to eliminate the preliminary step 1 in which surface grinding is performed in advance by peeling and the spiral wavy lines formed on the surface by grinding. Preliminary step 2 for correcting between a drum-shaped roll having an oblique direction and a circumferential surface recessed in an arc shape and a drum-shaped roll having a circumferential surface swelled in an arc shape.
The method for polishing a surface of a rolled bar according to any one of claims 1 to 3.

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