JP2632165B2 - Manufacturing method of cemented carbide brazing shear knife - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to a cutting line of a rolling line or a shear line of a non-ferrous metal plate such as a cold-rolled thin steel plate, a stainless steel thin plate, a silicon steel plate or aluminum. The present invention relates to a method for manufacturing a cemented carbide brazing shear knife to be used.

[Conventional technology]

Conventionally, long shear knives have used all steel products made of special steels such as SKD and SKH series. Cemented carbide brazing shear knives, in which a flat plate made of cemented carbide is brazed and fixed with one or a plurality of sheets, have been used.

This long cemented carbide brazing shear knife is manufactured by the following manufacturing method. Therefore, Japanese Utility Model Application Laid-Open No. 58-177224, FIGS. 4 and 5 (a) to (c). ), One of the metal bases (2) made of steel material
Usually, a flat plate (3) made of cemented carbide is brazed and fixed only to the corner portion or at most two corner portions.

Grooving is performed on the cemented carbide part of the base metal (2) member.

A long flat plate (3) made of cemented carbide is fitted and fixed to the groove via a flux / low material.

Then, as shown in FIG. 6, the base metal (2) is set on a feeding device such that the long flat plate (3) faces upward, and the width of the base metal (2) is moved while moving in the longitudinal direction. Then, the brazing material is continuously heated and melted by passing through a high-frequency heating coil (1) installed so as to surround the thickness direction, and then pressed until solidified by a crimping device (not shown) installed immediately after heating. Attach it.

Next, the bending caused by brazing is corrected.

Rough finish grinding, mounting hole processing and finish grinding are performed so that the long flat plate (3) becomes a corner portion, and the process is completed.

Also, although the composition of the cutting edge is completely different from the cemented carbide brazing shear knife targeted by the present invention, an edge portion serving as a cutting edge portion of the base material is subjected to groove processing, and the groove processed portion is formed with the base material. By effectively forming the metal layer having impact resistance through the intermediary alloy layer having fusibility and being integrally formed, the characteristics of the blade portion and the base material portion of the blade tool are effectively exhibited. As a prior art of the cutting tool in the machine tool as described above, there is one disclosed in Japanese Patent Application Laid-Open No. 56-139842.

A shear blade shown as an embodiment of a blade tool in this machine tool has three different types of special alloys or the like melted by an arc or gas or the like in three stages in a groove processing portion and laminated and welded to an appropriate thickness. The blade edge composition is completely different from that of a shear blade in which a long flat plate having a uniform composition is brazed and fixed to a groove processing portion.

Next, a cemented carbide 2 corner brazing shear knife (10
An example of the use of a shear knife using a shear knife (101) as the lower blade and a shear knife (101) made of all steel (SKD) as the upper blade will be described with reference to FIG.

Normally, cutting is performed by sandwiching the object between the upper and lower blades (101) and (100).
In order to increase the commercial value of the knife and extend the life of the knife itself,
Every time the blade edge is worn, chipped, repaired, inspected, etc., the knife blade is changed to a new blade or a polished blade according to the following procedure.

(A) Turn the upper blade tightening nut (121) to remove the upper blade tightening bolt (131), remove the upper blade (101), and remove the upper blade adjustment packing (111). Then, turn the lower blade tightening nut (120) to remove the lower blade tightening bolt (130), and remove the lower blade (100) and the lower blade adjustment packing (100) in this order.

(A) Thicknesses A, B, and C of the upper blade adjustment packing (111), the upper blade (101), the lower blade adjustment packing (110), and the lower blade (100)
And D. Then, a value [E− (A + B + C + D)] obtained by subtracting the sum of the above thicknesses from the distance E between the joining surfaces of the upper and lower blades (101) and (100) of the upper and lower holders (141) and (140) is obtained. A value 0.1x obtained by multiplying x by 0.1 is set as an optimal gap between the upper and lower blades (101) and (100) when cutting an object to be cut, and this 0.1x is assumed to be equal to the above value [E- (A + B + C + D)].

0.1x = E- (A + B + C + D) From this equation, the lower blade adjustment packing (11
0) and the lower blade adjusting packing (1)
Prepare 10).

(C) Then, insert the upper blade tightening bolt (131), attach the upper blade adjusting packing (111) and the upper blade (101), and turn and tighten the upper blade tightening nut (121). Then, the lower blade adjusting packing (110) and the lower blade (100) are attached, the lower blade tightening bolt (130) is inserted, and the lower blade tightening nut (120) is turned to tighten.

(D) Upper and lower blades (101) and (100) when cutting the object to be cut
Measure with a thickness gauge whether there is an optimal gap between them.

[Problems to be solved by the invention]

Even with such a knife blade change, the surfaces where the knife can be used (for example, (103a) and (103b) in FIG. 7) are worn, chipped, repaired,
If it can no longer be used due to inspection, etc., replace all new or re-ground knives with a completely prepared knife usable surface with a completely different thickness in accordance with the above-mentioned a, b, c and d blade replacement procedures. Knives to be replaced may be performed. Unlike all-steel shear knives that can use four corners, cemented carbide brazed shear knives can only use at most two corners, so this knife is usually replaced once every two times. Become. However, on the actual work surface, the gap between the upper blade and the lower blade is set in units of 1/100 mm, so an appropriate gap cannot be obtained from the beginning, and the gap must be adjusted two to six times. Therefore, it takes a long time. Normally, it takes about 0.5 hours to change the blade on the opposite side of the same knife, but it will take 2.5 hours for the total replacement, and the drop in production rate due to the line stoppage during that time will be remarkable.

Re-grinding, maintenance,
The cost per unit, such as inspection and fare, is almost the same regardless of the number of corners where the knife can be used. If the number of usable knifes is small, the cost becomes higher.

Furthermore, the life of the currently used cemented carbide brazing shear knives is 1 year to 1.5 years per corner, and about 2 years to 3 years per piece for a shear knife having a two-corner usable surface. Life is long. Judging from this kind of knife life, the number of knives required for stable operation is at least two in addition to the shear knife in use (knives for grinding, sudden accidents of equipment during grinding, chipping of blades, etc.). Spare knives are needed)
The stock of substitutes will increase.

Next, in the conventional method of manufacturing a cemented carbide brazing shear knife described above, it is possible to melt and fix a long flat plate made of cemented carbide to the upper surface of the base metal, but if it is to be fixed to the lower surface, In addition, soldering defects such as flux withering and solder withering are likely to occur, and the soldering at one or two corners of the upper surface of the base metal is limited. Further, since the heating is partially performed for a very short time, there is a problem that temperature unevenness easily occurs, and the occurrence rate of brazing defects is high. For this reason, it must be said that it is extremely difficult to develop a method for manufacturing a cemented carbide brazed shear knife in which long plates made of cemented carbide are brazed and fixed to four longitudinal corners of the base metal. Was.

In addition, in the case of brazing at one corner or two corners on the upper surface, since the cross section is asymmetric in material, the difference in thermal expansion between the long plate made of cemented carbide and the base metal (alloys 5 to 5) 6
× 10 ^-6 / ° C, base metal 11-12 × 10 ^-6 / ° C), the bending after brazing is as large as 20 mm per 1000 mm at maximum, and many steps are required to correct this bending in the process after brazing. In addition to consuming man-hours, the bending also induces the occurrence of bending after cutting and use, and the troublesome work of removing the trouble that it must be removed frequently during re-grinding has been forced.

On the other hand, the shear blade disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 56-139842 has a metal layer directly welded to a groove processed portion formed on a shank material (base material), and a metal layer formed of the metal layer. A blade material intermediate layer which is weld-welded to the outside by, for example, welding of semi-high-speed steel, and a blade portion made of high-speed steel or high-alloy steel weld-welded to the outside of the blade material intermediate layer. The composition of the edge portion formed by the three-layer build-up welding has a very coarse dentite structure (dendritic crystal), and the present invention is a technical object of the present invention. When a large local impact stress acts like cold shear, cracks are likely to occur, and the propagation and expansion of the cracks are likely to lead to a large breakage accident. Also,
It is also difficult to eliminate any systematic defects such as slag entrapment and nesting during overlaying, and the risk of cracks originating from them is high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art.
The present invention aims to solve the above-mentioned problems by providing a new method of manufacturing a shear knife which has been made possible by the present inventors having completed the technique of brazing and fixing the corner once. Things.

[Means for solving the problem]

The present invention has the following means in order to solve the above technical problems.

In a method for manufacturing a super-high alloy brazing shear knife in which a long plate made of cemented carbide is brazed and fixed to four longitudinal corners of a base metal, grooves are machined at the four longitudinal corners of the base metal, After fitting and fixing a long flat plate made of cemented carbide through the flux / low material into the groove portion, the metal plate is set up so that the width direction of the base metal is vertical, and the inside of the high-frequency heating coil is vertically aligned. In the direction of heating to melt the brazing material and press the long flat plate made of cemented carbide against the base metal to fix it to the base metal. This is a method for manufacturing a cemented carbide brazing shear knife characterized by grinding to come to a part.

[Action]

In the shear knife of the present invention, a long flat plate made of a cemented carbide is brazed to each of the four corners in the longitudinal direction. Therefore, if the first corner becomes unusable due to wear or chipping, the shear is not used. It is only necessary to flip the knife up, down, left and right to use the next new corner as the cutting edge, and by repeating this, four corners can be used, so the life per one can be extended to about twice or four times the conventional one. Become.

In addition, a cemented carbide exhibiting excellent mechanical properties formed by powder metallurgy is brazed using silver brazing or the like, so the cemented carbide itself does not change systematically at all, A shear knife with a cutting edge can be obtained while maintaining the excellent properties of the cemented carbide at all four corners.

Further, since the long flat plate is brazed to the left and right sides of the base metal, the flux or the brazing material due to the outflow of the flux or the brazing material does not occur, and the four corners can be brazed at the same time. Further, since the base metal is erected so that the width direction thereof is vertical, and then passed through the high-frequency heating coil in the vertical direction, the coil is moved in the longitudinal direction of the base metal moving in the vertical direction. Heating is performed over the entire length of the base metal in the wound state, and the heating rate is reduced. Therefore, the temperature unevenness of the bonding surface is reduced. In addition, since four corners are simultaneously bonded, the occurrence of bending after brazing and fixing is very small, and the occurrence of bending after cutting and use is extremely reduced.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a shear knife according to one embodiment of the present invention. This shear knife has a length of 2000mm, a width of 100mm, and a thickness of 25mm.
A long plate (3) made of cemented carbide of abrasion-resistant and impact-resistant tool grade of 15 mm in width, 6 mm in thickness and 6 mm in thickness was brazed and fixed at a time by the following method, and manufactured.

First, grooves are provided in advance at four corners equidistant from a longitudinal center line YY passing through the center point of the rectangular cross section of the base metal (2) having a rectangular parallelepiped cross section, and the flux is formed therein.・ Fit a flat plate (3) made of cemented carbide through a brazing material. As shown in Fig. 2, the work thus produced is set so that its width direction is vertical.
It is installed on a carriage (not shown) having a lifting device. Then, the high-frequency heating coil (1) is fixed in a state of being wound in the longitudinal direction of the work, and the entire work is heated while the work on the table is raised and lowered in the vertical direction by the elevating device. When the brazing material melts and reaches the optimum temperature for brazing, a long flat plate (3) made of cemented carbide at the four corners is pressed by a crimping device (not shown) until the brazing material solidifies, thereby securing the brazing material. Aim. Thereafter, a mounting portion (5) is formed in the center portion of the alloy (2), and the blade edge (6) is located at the same predetermined position when the mounting portion (5) is mounted on the knife holder by inverting left, right, up and down via the mounting portion (5). Each edge (6) is formed by grinding so that it is positioned.

The shear knife made in this way has no flux withering or low withering, and the long flat plate (3) can be fixed in a state where the work is completely fixed. The parts can be simultaneously brazed. Further, since the heating rate is lower than that of the conventional method, the temperature unevenness of the bonding surface is reduced due to the heat conduction during that time, and the occurrence rate of brazing defects is reduced. Furthermore, when a long flat plate made of cemented carbide is brazed to only one corner as in the conventional case, after the brazing process,
It is normal that a large distortion of 20 mm occurs, but the distortion after the brazing process of the one manufactured in the present example is a maximum of 1000 mm.
It was 1 mm per mm, which eliminates the need to use a wasteful nerve to remove strain, and has given good results to subsequent machining.

The following table shows the results of comparison between the shear knife of the present embodiment and a conventional shear knife of the same dimensions in which a long flat plate made of cemented carbide is attached to two longitudinal corners.

As is clear from this table, the blade replacement time of the shear knife of the present invention is half that of the conventional product, and the downtime of the production line can be shortened accordingly. In addition, the grinding cost per wheel is the same for both, but the corner where the knife of the present invention can be used is 2
Since it is twice as expensive, the cost per corner is half that of the conventional product. The same is true for fares. Further, considering the life of one knife based on the conventional product having two corners, the product of the present invention has twice the four corners, so that the life is also doubled. In addition, the product of the present invention is superior in unit price per corner, number of units purchased per year, and cost. Although not shown in this table, since four corners can be used in the product of the present invention, a total of two knives in use and knives being ground out can be covered. As a result, spare knives are not required, and the inventory of knife replacements can be reduced.

FIG. 3 is a perspective view showing another embodiment of the shear knife according to the present invention in which a relief groove (4) for cutting is machined in the base metal (2).

〔The invention's effect〕

As described in detail above, according to the present invention, the length 4
It is now possible to obtain a shear knife with a long flat plate made of cemented carbide brazed at the corner, and the knife knife replacement time has been shortened. Knife wear, grinding due to chipping, maintenance and inspection・ Fares and other expenses can be reduced, and the life of each knife can be prolonged, and the inventory of multiple substitutes can be reduced.

In addition, a complicated strain caused by an imbalance in internal stress after use, which has been a problem in the case of a conventional shear knife in which a long flat plate made of cemented carbide is brazed and fixed to only one or two corners. There is almost no occurrence, and a troublesome strain removal operation is also reduced.

Further, the edge portion is formed by overlay welding in which a special alloy or the like is melted and welded with an arc or a gas or the like over three steps to a groove processed portion provided on an edge portion serving as a cut portion of the base material. It was formed by powder metallurgy without causing the material itself to have a coarsened structure and reduced mechanical properties, such as the shear blade shown in No. 56-139842. It is possible to obtain a shear knife with a cutting edge having excellent characteristics of the cemented carbide at all four corners without changing the structure of the cemented carbide having excellent mechanical characteristics.

[Brief description of the drawings]

FIG. 1 is a perspective view of a shear knife according to one embodiment of the present invention, FIG. 2 is an explanatory view showing a method of manufacturing the shear knife,
FIG. 3 is a perspective view showing another embodiment of the present invention, FIG. 4 is an explanatory view showing an example of a conventional cemented carbide brazing shear knife, and FIGS. FIG. 6 is a sectional view showing another example of a shear knife structure, FIG. 6 is an explanatory view showing a conventional method of manufacturing a shear knife, and FIG. 7 is an explanatory view showing a use example in which a conventional shear knife is used as a lower blade. It is. In the figure, (1) is a high-frequency heating coil, (2) is a base metal, (3)
(103a) (103b) is a long flat plate, (4) is a relief groove, (5)
Indicates an attachment portion, (6) indicates a cutting edge, and (100) and (101) indicate shear knives.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masakatsu Hanya 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Yoshinobu Fujisawa 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Toshihiro Terao 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Hajime Segawa 12th, Kayazawa, Kamiyazawa, Rifu-cho, Miyagi-gun, Miyagi Prefecture 193 (72) Inventor Tamio Sasaki 2-8-11 Odairo, Tagajo City, Miyagi Prefecture (72) Inventor Katsushi Saito 42-6, Matsugahama-cho, Shichigahama-cho, Miyagi-gun, Miyagi Prefecture (72) Inventor Masao Sekiguchi Naka-ku, Hiroshima City, Hiroshima Prefecture 9-17-701 Nishi-Tokaichi-cho Joint Panel Referee Masahiko Goto Referee Isao Kirimoto Referee Kunio Toyohara (56) References JP-A-56-139842 (JP, A) Shokai Sho58 177224 (JP, U)

Claims (1)

(57) [Claims] 1. A method of manufacturing a super-high alloy brazing shear knife in which a long flat plate made of cemented carbide is brazed and fixed to four longitudinal corners of a base metal. After processing the groove, a long flat plate made of cemented carbide is fitted and fixed in the groove via a flux / low material, and then this is set up so that the width direction of the base metal is vertical, and then high-frequency heating is performed. The inside of the coil is moved in the vertical direction to heat and melt the brazing material, and the long flat plate made of cemented carbide is pressed against the base metal and fixed there, and thereafter, the long plate made of cemented carbide is fixed. A method of manufacturing a cemented carbide brazing shear knife, characterized in that a shaping plate is ground so as to come to a longitudinal corner.