JP4577310B2 - Quenching method and apparatus used therefor - Google Patents

Description

  The present invention relates to a quenching method for carburizing and quenching steel parts such as gears and bearings, and a quenching apparatus used therefor.

2. Description of the Related Art Conventionally, as a quenching apparatus, an apparatus equipped with an oil tank containing a coolant and an agitator that stirs the coolant so that an upward flow is generated in the coolant in the oil tank is known.
As the coolant, an appropriate oil type and an appropriate oil temperature are selected depending on the mass, shape, hardenability, and the like of the steel material part. Further, the cooling capacity is adjusted by stirring at an appropriate flow rate.
When the treated product is immersed in the agitated coolant, the cooling rate varies between the sun and the shade on the opposite side of the treated product that are directly hit by the coolant flow, resulting in carburizing quality (surface hardness). , Effective hardened layer depth, internal hardness, etc.) and heat treatment strain variation.
In addition, several tens of processed products are processed together by a tray, a jig or the like. For this reason, in addition to the processed product itself, the flow of the coolant is blocked by the tray, jig, etc., resulting in variations in the flow velocity within the tray, which is also a cause of variations in heat treatment strain.
This invention solves all the above-mentioned problems, reduces the variation in the cooling rate of the coolant with respect to the treated product, and can suppress the variation in carburizing quality and heat treatment strain, and the quenching apparatus used therefor Is intended to provide.

In the quenching method according to the present invention, the quenching oil in the oil tank is agitated to equalize the oil temperature, the agitation is stopped, and the treated product is immersed in the quenching oil in the oil tank for 2 to 10 seconds. The processed product is swung vertically and / or horizontally in a cycle.
In the quenching method according to the present invention, the flow rate of the quenching oil with respect to the treated product can be made uniform by swinging the treated product in the quenching oil whose stirring is stopped. If the treated product is immersed in the quenching quenching oil, the cooling rate varies between the sun and the shade on the opposite side of the treated product, but there is no concern in this invention. Therefore, the variation in the cooling rate of the coolant with respect to the processed product can be reduced, and the variation in the carburizing quality and the heat treatment strain can be suppressed. Moreover, since the oscillation cycle is 2 to 10 seconds, optimal cooling can be achieved.
In another quenching method according to the present invention, the quenching oil in the oil tank is agitated to equalize the oil temperature, and then the stirring is stopped and the treated product is immersed in the quenching oil in the oil tank. When the size in the horizontal direction is larger than the size in the vertical direction, the processed product is swung in the vertical direction, and the size in the horizontal direction is smaller than the size in the vertical direction of the processed product. The product is swung horizontally.
In another quenching method according to the present invention, the vertical or horizontal rocking direction is selected depending on the shape of the processed product, so that optimum quenching can be performed.
The quenching apparatus according to the present invention includes a vertical swinging means for swinging a treated product in a vertical direction while the treated product is immersed in the quenching oil in the oil bath, and a treated product immersed in the quenching oil in the oil bath. In this state, a horizontal swinging means for swinging the processed product in the horizontal direction is provided.
In the quenching apparatus according to the present invention, the flow rate of the quenching oil with respect to the processed product is made uniform by swinging the processed product in the quenching oil using either one of the vertical rocking means and the horizontal rocking means. be able to. Therefore, the variation in the cooling rate of the coolant with respect to the processed product can be reduced, and the variation in the carburizing quality and the heat treatment strain can be suppressed.
Furthermore, if the quenching apparatus is provided with a control means for controlling the vertical swing means and the horizontal swing means so that the vertical and horizontal swing periods are 2 to 10 seconds, optimal cooling can be achieved. it can.
Further, in the quenching apparatus, when the vertical swing means includes a pair of elevating rails that straddle the tray loaded with the processed products and a fluid pressure cylinder that elevates the elevating rails, the elevating speed of the elevating rails Further, by changing the stroke, the vertical oscillation period, stroke, and the like can be easily changed.
Further, when the laterally swinging means includes a roller row composed of a plurality of parallel rollers and receiving the tray, and a pushing mechanism for pushing the tray received by the roller row, with a simple mechanism, The processed product can be swung laterally.
In addition, when the pushing mechanism includes a fluid pressure cylinder disposed so that the tip of the piston rod can be brought into contact with one end of the tray, and a spring that elastically supports the other end of the tray, By changing the operation speed and the stroke, the horizontal oscillation cycle, the stroke, and the like can be easily changed.
In addition, when the lifting rail and the roller train intersect with each other, and there is a gap that allows the lifting rail to pass between the adjacent rollers in the roller train at the intersection, the passage passes through the clearance. By raising and lowering the elevating rail so as to make it happen, the tray can be delivered between the elevating rail and the roller train.

FIG. 1 is an explanatory view of a processed product in which the packing form is flat.
FIG. 2 is an explanatory view of a processed product having a sword rack. .
FIG. 3 is a vertical longitudinal sectional view of the quenching apparatus.
FIG. 4 is a horizontal cross-sectional view of the quenching apparatus.
FIG. 5 is a cycle diagram of swing quenching.
FIG. 6 is a table showing the relationship between the rocking speed of the quenched product and the internal hardness.
FIG. 7 is a table showing the relationship between the fluctuation cycle of the quenched product and the variation in internal hardness.
FIG. 8 is a table showing the quenching results of the gears based on the difference in the packing form.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 and FIG. 2 show the packing state of a ring-shaped processed product S such as a gear. In FIG. 1, a plurality of vertical bar jigs J1 are erected on the upper surface of the tray T1 (also in a direction perpendicular to the paper surface). Each jig J1 is covered with a plurality of processed products S at a predetermined interval. This is called a flat packaging. In FIG. 2, a pair of posts P are erected on both ends of the upper surface of the tray T2. A horizontal bar-like jig J2 is secured to both posts P with a vertical gap (also in a direction perpendicular to the paper surface). Each jig J2 is covered with a plurality of processed products S at a predetermined interval. This is referred to as a sword rack.
In the case of flat packaging, the outer diameter of the processed product S, that is, the lateral direction (left and right or front and rear) of the processed product S is larger than the thickness of the processed product S, that is, the size of the processed product S in the vertical direction (vertical direction). Etc.) is large. In the case of a sword-packed package, the size relationship is the opposite of that of a flat-packed package.
Hereinafter, the processed product S in both packages is referred to as a workpiece W including the trays T1 and T2 and the jigs J1 and J2.
3 and 4, the quenching apparatus includes an oil tank 11 that stores the quenching oil O, and a stirrer that stirs the quenching oil O so that an upward flow is generated in the quenching oil O in the oil tank 11. 12, the vertical swinging means 13 for swinging the work W in the vertical direction with the work W immersed in the quenching oil O in the oil tank 11, and the work W being immersed in the quenching oil O in the oil tank 11 In this state, there is provided horizontal swinging means 14 (illustrated as the left-right direction in FIGS. 3 and 4) for swinging the workpiece W in the horizontal direction.
The oil tank 11 is partitioned into a left processing chamber 22 and a right stirring chamber 23 by a vertical partition wall 21. An entrance / exit 24 is provided on the upper left side wall of the processing chamber 22.
The stirrer 12 includes a vertical rotation shaft 31 extending vertically through the liquid level of the quenching oil O in the stirring chamber 23, a motor 32 connected to the upper end of the rotation shaft 31, and a lower end of the rotation shaft 31. An attached screw 33 and a rectifying duct 34 provided so as to penetrate the partition wall 21 are provided.
The rectifying duct 34 extends downward from a position surrounding the screw 33 and is opened upward near the center of the bottom surface of the processing chamber 22. A downward flow of the quenching oil O is generated in the stirring chamber 23 by the rotation of the screw 33, and this is guided by the rectifying duct 34 so as to flow upward in the processing chamber 22.
The vertical swinging means 13 includes a vertical guide rail 41 provided on the rear side wall of the oil tank 11, a lifting body 42 that is moved up and down along the guide rail 41, and a pair of left and right protruding forward from the lifting body 42 and extending parallel to each other. And a vertically swinging fluid pressure cylinder 44 having a piston rod connected to the lifting body 42 and mounted vertically downward on the top wall of the oil tank 11.
In the quenching oil O, the lateral rocking means 14 includes a pair of front and rear roller rows 52 including a plurality of parallel rollers 51 that extend parallel to each other and are arranged in the left-right direction so as to intersect with the lifting path of the lifting rail 43. A laterally oscillating fluid pressure cylinder 53 having a piston rod with the tip of the piston rod facing the left end of the roller row 52 and penetrating through the left side wall of the oil tank 11, and the roller row 52 extending in the left-right direction. In addition, a compression coil spring 54 having a right end fixed to the partition wall 21 is provided.
Among the rollers 51 of the roller row 52, the roller 51 in a portion that intersects with the lifting path of the lifting rail 43 has a gap C that allows the lifting rail 43 to pass between adjacent ones.
The workpiece W is a heating chamber (not shown), and carburizing, carbonitriding, or the like is performed as necessary.
The quenching oil O is maintained at a temperature suitable for the steel type to be stirred and processed by the stirrer 12. Stirring is stopped after the oil temperature is equalized. The stirring time necessary for equalizing the oil temperature is experimentally determined in advance.
The elevating rail 43 is kept on standby at the upper limit of its elevating stroke. The workpiece W carried into the processing chamber 22 by a conveying means (not shown) is placed on the lifting rail 43. When the piston rod of the vertically oscillating fluid pressure cylinder 44 is advanced, the elevating rail 43 is lowered. The workpiece W is immersed in the quenching oil O.
While the workpiece W is immersed in the hardened oil O in the oil tank 11, the workpiece W is swung in the vertical or horizontal direction. Depending on the loading state of the work W, the vertical and horizontal swing directions are selected. Is done. In the case of a flat package, the swing direction is vertical. In the case of a sword rack, the horizontal direction is selected as the swing direction.
When the swinging direction is vertical, the elevating rail 43 is lowered to the upper side of the roller row 52. By repeatedly expanding and contracting the piston rod of the vertically swinging fluid pressure cylinder 44, the work W is swung in the longitudinal direction together with the lifting rail 43.
When the swinging direction is horizontal, the elevating rail 43 is lowered to below the roller row 52. When the elevating rail 43 passes through the gap C between the rollers 51, the workpiece W is transferred from the elevating rail 43 to the roller row 52.
When the work W is transferred, the piston rod of the laterally oscillating fluid pressure cylinder 53 is retracted. The transferred work W is received in a state of straddling both roller rows 52.
When the workpiece W is received by both the roller rows 52, the piston rod of the laterally oscillating fluid pressure cylinder 53 is advanced, and the tip thereof is brought into contact with the left end of the workpiece W. The left end of the spring 54 is brought into contact with the right end of the workpiece W.
This time, the piston rod of the laterally oscillating fluid pressure cylinder 53 is expanded and contracted. Then, the workpiece W is swung in the lateral direction while expanding and contracting the spring 54. After the lapse of a predetermined time, the expansion and contraction of the piston rod of the laterally oscillating fluid pressure cylinder 53 is stopped, and the piston rod is retracted.
The elevating rail 43 is raised by retracting the piston rod of the vertically swinging fluid pressure cylinder 44. When the elevating rail 43 passes through the gap C between the rollers 51, the workpiece W is transferred from the roller train 52 to the elevating rail 43, is lifted together with the elevating rail 43, and is pulled up from the quenching oil O.
The advance / retreat speed of the vertical or lateral swing piston rod can be adjusted by a speed controller.
Next, a test was performed to set a preferable swing condition, which will be described. Quenching was performed from 850 ° C. using a test piece having a diameter of 25 mm and a length of 10 mm.
FIG. 5 shows a cycle diagram of swing quenching. FIG. 5 shows the case of vertical oscillation, but in the case of horizontal oscillation, the top and bottom in FIG.
In FIG. 5, a time T / 2 that elapses from the start of the rising stroke to the start of the next lowering stroke, and a time T that elapses from the start of the lowering stroke to the start of the next rising stroke. Is equal to / 2. The time T that elapses from the start of the rising stroke to the start of the next rising stroke is defined as the swing time. The swing time T includes a stroke stop time.
FIG. 6 shows the relationship between the rocking speed V and the variation in the internal hardness of the test piece. As the swing speed V increases, the internal hardness of the test piece increases.
FIG. 7 shows the relationship between the oscillation period T and the variation in the internal hardness of the test piece. FIG. 7 shows that the oscillation period T is preferably 10 seconds or less. Moreover, from the same figure, Preferably, the rocking | swiveling period T is 2 second or more.
FIG. 8 shows an example in which swing quenching is applied to a gear part. The gear parts were made of two materials, SCr and SCM. In any of the two types of gears, it can be seen that lateral swing is preferable when the load is a sword hook, and vertical swing is preferable when the load is flat.
In the above description, the swinging direction is described as vertical or horizontal. In particular, the lateral direction is not limited to the left and right shown in FIGS. 3 and 4, and may be front and rear, or may be intermediate between the front and rear and left and right.

  The quenching method according to the present invention is suitable for quenching in order to carburize and quench steel parts such as gears and bearings.

Claims (3)

With the treated product immersed in the hardened oil in the oil tank, the vertical swinging means for swinging the treated product in the vertical direction and the treated product immersed in the hardened oil in the oil tank A horizontal swinging means for swinging in the horizontal direction ,
The vertical swing means includes a pair of lifting rails that straddle a tray loaded with processed products, and a fluid pressure cylinder that lifts and lowers the lifting rails.
The lateral rocking means includes a roller row made up of a plurality of parallel rollers and receiving a tray, and a pushing mechanism for pushing the tray received by the roller row, and the pushing mechanism is a tip of the piston rod. A quenching apparatus comprising: a fluid pressure cylinder disposed so that the end of the tray can be brought into contact with one end of the tray; and a spring that elastically supports the other end of the tray . The quenching apparatus according to claim 1 , further comprising a control means for controlling the vertical rocking means and the horizontal rocking means so that the vertical and horizontal rocking cycles are 2 to 10 seconds. 3. The gap according to claim 1 , wherein the lifting path of the lifting rail intersects with the roller train, and a gap through which the lifting rail can pass is formed between adjacent rollers of the roller train at a location where the lifting train crosses the lifting path. Quenching equipment.

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