JPH0191955A - Method for welding stellite onto band saw blade - Google Patents

Abstract

PURPOSE:To improve the welding strength and processing efficiency of a stellite by lifting a band saw blade by dipping it into the stellite solution, then, forming the satellite small ball sticked to the blade tip with its pressurization from both sides. CONSTITUTION:The two drums 23, 23 vertically moving at the rotation stopping time as well as the intermittent rotation time are arranged and supported by bringing a band saw 1 between the drums 23, 23. The band saw 1 is stopped by intermittently feeding it on each one blade and the blade tip 3 is dipped in a stellite solution 19 for the specified time by lowering the band saw 1. In this case, the stellite small ball 25 stuck to the blade tip 3 is formed by pressurizing from both sides by a press die, etc., at the ascent time of the band saw 1. A stellite stuck to the blade tip 3 by melting it in advance under optimum temp. and conditions with pressurized forming. Consequently, the stellite welding strength to the band saw 1 and its processing efficiently are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an improved stellite welding method for improving the durability of band saw blade edges.

(bl) Background of the Invention As shown in Figure 6, the blade (2) of the band saw (11) used for lumber sawing has a blade edge (3) that is crushed into a thin curved shape in plan view, resembling an ear pick. .Then, since the wood fibers are also cut with the tip of the blade (4), both sides (
4a) It is desirable that (4a) be square like a shamisen. However, the side portion (4a) is severely abraded and becomes rounded in a short period of time as shown by the chain line, and becomes hard to cut within about one hour, especially when processing external materials.

Therefore, polish frequently and occasionally polish after overlaying on both sides (4
a) - (4a) needs to be squared, but if you polish the Stellite after welding it to the cutting edge, especially the tip,
Abrasion resistance is improved and pot life is extended by 2 to 3 times. Therefore, stellite welding is now common practice.

fe) Problems with the Prior Art Nowadays, this stellite welding is mostly done manually in the same manner as gas welding. This is usually done by supporting a band saw (11 vertically) and cutting edge (3) as shown in Figure 7.
Apply the stellite melt (5) to the part one blade at a time. In the case of manual work, it is possible to apply the minimum amount of stellite melt to the desired location. However, stellite (Fe, C.

The alloy, which contains about 3% Cr and 12% W and the rest is Co, is a cast-like brittle alloy with a high melting point (L 285° C.) and a small specific heat (0,094). Therefore, if the melting temperature is too high, it will sag, and if it is too low, it will become lumpy and the adhesion will be weak.
Temperature control is difficult, requires patience and skill, and is extremely inefficient. Furthermore, pour the melt onto the tip of the blade (4)
Since the material does not conform to the surface, post-processing is required to press it while it is hot, further reducing work efficiency.

Therefore, some devices have been proposed to automate these operations, such as automatic electric welding, but since stellite is brittle, it is difficult to handle and can break during feeding, and temperature control is also difficult. Also, if the amount of adhesion is small, the effect will be poor, and if it is too much, it will be removed by polishing and will be wasted, but it is quite difficult to accurately adhere a melt of an appropriate size to the narrow cutting edge portion.

Furthermore, the device itself is expensive, and expensive imported stellite is often wasted.

Moreover, in each of the above welding methods, the temperature of the Stellai I/molten material (5) adhering to the cutting edge (3) rapidly decreases as the cutting edge (3) absorbs heat, making it impossible to obtain sufficient adhesion strength. It has the drawback that it cannot be pressed cleanly, is easily peeled off due to strong peeling force or impact force during polishing or use, and has poor durability.

(dl Problems to be Solved by the Invention) Therefore, the present inventor considered the requirements required for stellite welding of the band saw blade edge, and found that the blade edge (3) could be strongly welded over the entire area, with particular emphasis on the tip. To this end, it was found that the temperature control of the stellite melt, the control of the position and amount of stellite to be deposited, the timing of applying pressure after deposition, etc. are important. The prerequisites for reducing costs are increasing processing capacity to increase speed, eliminating waste of melted stellite, and creating equipment that is inexpensive and easy to operate.

fe) Means for Solving the Problems In view of the above, the inventors have conducted various studies such as improving the conventional welding method and applying thermal spraying technology. However, the welding method is inconsistent with the above requirements,
With thermal spraying, the coating is too thin to withstand polishing.

Therefore, they continued their research and developed a technique in which they melted stellite in advance and dipped the edge of the bandsaw blade in the solution for a short time to weld it. (Then, the temperature can be easily and reliably controlled, and the necessary and sufficient amount of stellite can be attached to the cutting edge, and since the cutting edge is also heated, the temperature of the attached stellite can be rapidly cooled.) Moreover, the adhesion operation is extremely simple, and the subsequent pressing of the adhered stellite is also easy.In addition, since the melting temperature of stellite is higher than that of band saws (steel), a very small amount of the steel melts during immersion, resulting in stellite. Another major feature of the present invention is that the bonding strength of the two materials is greatly increased, resulting in strong welding.

(e) Structure of the invention.

The present invention consists of a step of melting stellite in a container (for example, a crucible) with a suitable capacity, a step of intermittently transferring a band saw to sequentially immerse the cutting edge in the melted stellite (stellite melt), and a step of sequentially immersing the cutting edge in the melted stellite (stellite melt). It consists of the steps of pressing the blade edge pulled up from inside with a press die, hammer, etc. from both sides, and press-forming the adhered stellite melt so that it follows the shape of the blade edge (3). The melting process requires temperature control and liquid level control. Further, in the dipping process, it is necessary to control the dipping time and dipping depth (the amount of vertical movement of the cutting edge (3)).

The cutting edge can be immersed by moving the cutting edge or the band saw itself up and down, or by moving a container containing a solution up and down toward the cutting edge. The temperature of the stellite solution is preferably about 1.300 to 1.450°C, particularly about 1.400°C, which is somewhat higher than the melting point, because if the temperature of the stellite solution is too high, the molten stellite will form a thin film, and if it is too low, it will become lumpy. Furthermore, even if the immersion time is long, the adhesion strength will not be improved, and on the contrary, the steel will melt, which is undesirable. About 1 to 3 seconds is sufficient. The amount of adhesion is determined by the depth of the cutting edge to be immersed and the temperature of the Stellite solution.

(f) Embodiments Next, the present invention will be described in detail based on embodiments shown in the drawings.

Figure 1 shows a stellite welding device (6
) - Show an example. This device (6) is composed of a furnace body (7), a temperature control section (8), a pressurizing section (9), a band saw drive section (!), etc.

The furnace body (7) is made of stellite (usually 2 to 3 IIIll
φ.

A furnace core tube (12) and a heating element (13
), and the entire surrounding area except the top is covered with firebrick (1
4) It is surrounded by... The temperature control section (8) is
For example, it consists of a temperature indicating controller (16) connected to a thermocouple (15) built into the furnace body (7), a mercury relay (1?), a transformer (18), etc., and the stellite solution in the crucible (I1). (19) functions to keep the temperature constant. Furthermore, a stellite rod supply device (20) and a liquid level detector (21) are arranged at the top of the furnace body (7).

The crucible (11) has a diameter that is necessary and sufficient for the tip of one bandsaw blade (2) to enter and exit. If the diameter is too large, the front and rear blades (2) will get in the way and the blade tip (3) will not fully enter the stellite solution (19). On the other hand, if it is too small, the base of the cutting edge (3) will get in the way and will not be able to enter the Stellite solution (19).
Fluctuations in temperature and liquid level become large. Incidentally, the dimensions of the bandsaw blade (2) are usually the thickness d of about 211III+, the height D (dimension between the peak and the bottom of the valley) of about 12mm, and the distance between the peaks of about 25 to 30III+ (Fig. 5). ).

Therefore, the diameter of the crucible (11) is preferably about 20 to 30 mII+, particularly about 25 mm. Depth is 20-3
Approximately 0 mm is sufficient. Note that the upper edge of the crucible (11) protrudes somewhat from the brick surface. This is because the front and rear blades (
This is to prevent the tip of 2) from colliding with the brick surface.

Instead of the protruding upper edge of the crucible (11), a recess (22) may be provided in the brick surface or the like on which the front and rear cutting edge tips come into contact.

The band saw drive unit (10) consists of two drums (23) and (23) that rotate intermittently and move up and down when the rotation stops, and the band saw (1) is hung between the drums (23) and (23). I fully support it. In addition, the type and structure of the stellite rod feeding device (2) does not matter as long as it can feed the stellite rods (24) in predetermined amounts into the crucible (!1), such as a conventional automatic welding machine. This delivery may be controlled by the output of the liquid level detector (21).

Therefore, while the band saw Tl) is being intermittently fed one blade at a time and stopped moving forward (solid line in Figure 1 (b)), the band saw (11) is lowered and the cutting edge (3) is moved to the stellite for a predetermined period of time, for example, about 2 seconds. Immerse in solution (19) (dashed line in Figure 1). Next, when the band saw (1) is raised, the cutting edge (3) will have the shape shown in Figure 2 (a).
The molten stellite adheres in the form of small spheres. This is due to the bulging of the tip side portions (4a) of the cutting edge. Simultaneously with the rise of the band saw (1), the band saw blade (3) is advanced by one blade, and the next band saw blade (3) is similarly immersed in the stellite solution (19).

Next, the stellite small balls (25) are pressurized and welded tightly to the entire surface of the cutting edge. Pressurize with Stellite small balls (25)
It is most preferable to carry out this process while the crucible is hot, particularly immediately after it has been lifted from the crucible (11). This pressurization can be done, for example, in Figure 2 (
Press mold (2G)/(2
6) Apply pressure from both sides. After pressurizing, stellite pellets (
25) completely adheres to the shape of the cutting edge (3) as shown in FIG. 2(b). Thereafter, the shape of the cutting edge (3) is adjusted by polishing as shown in FIG. 2(C). The symbol (27) is the welded stellite.

In addition, the time required for raising and lowering the band [(1) depends on the structure of the device, but 2 to 3 seconds is sufficient; the time required for pressurization is 1 to 2 seconds, and the immersion time is 1 to 2 seconds. In the end, one cycle is completed in about 4 to 7 seconds. Therefore, it takes only about 23 to 39 minutes to process 11 bands (334 blades) with a total length of 10 m, each provided with blades (2)... at 30III1 intervals. Automatic stellite explosion of the band saw (1) is completed in about 30 to 45 minutes, including the setting time of the band saw (1).

Next, FIG. 3 shows an example in which gas is used as a heat source for melting stellite. In this example, a radiation type high temperature liver (28) is used as the temperature needle, and the temperature of the stellite solution (19) is controlled by adjusting the gas amount of the gas burner (29) using its output. Other structures are the same as in the previous example.

FIG. 4 shows a modification in which the upper part of the furnace body (7) shown in FIG. 1 is covered with a heat insulating lid (3).
) has the advantage that stellite melting during startup can be done in a short time because the heat retaining performance of Furthermore, there is a groove (31) into which the bandsaw (1) enters and exits the heat insulating lid (3), a through hole (32) into which the Stellite rod supply device (20), and a liquid level detector (2) are inserted (33). By providing the above, the band saw (1) can be processed with the heat insulating cover (30) attached, so that the temperature is constant, good stellite explosion bonding can be achieved, and heating costs can be reduced.

Next, FIG. 5 shows an example of a stellite welding device (34) having a different mechanism from each side. In addition to the crucible (11), this device (34) is equipped with a small crucible (35) that goes in and out of the crucible (1) to fill it with a stellite solution (19) and immerse the band saw blade tip (3), and also includes a band saw drive unit. (The difference is that 1 does not move up and down. The small crucible (35) is supported by drive arms (36) and (3G) made of a material with excellent strength and heat resistance.

The small crucible (35) used is one that is somewhat smaller in efficiency than the crucible (11) in the previous example. Therefore, the crucible (11) used has a size that allows the small crucible (35) to freely move in and out, for example, a diameter of about 40 to 100 mm.

Therefore, the band saw (1) is fed intermittently one blade at a time (band saw fl)
While the is stopped, the small crucible (35) is raised and the cutting edge (3) is poured into the stellite solution (19) for a predetermined period of time, e.g. about 2 seconds.
Soak in. Next, the small crucible (35) is lowered.

Simultaneously with the descent, move the band & 1g (11 forward by one blade length and immerse the next cutting edge (3) in the stellite solution (+9) in the same way.During dipping, the stellite globules attached to the previous cutting edge (3) Since the pressurization (25) can be performed, the processing time can be shortened compared to the case of the above example.

fh) Effect As described in detail above, in the present invention, when explosively adhering stellite to a band saw blade tip, stellite is heated and melted in advance in a furnace with an open top, and the band saw blade tip is placed in this stellite melt. After being immersed for a few seconds and pulled up, the stellite beads attached to the cutting edge are press-molded from both sides so that the sides of the tip of the cutting edge bulge during high temperatures.

Therefore, unlike conventional welding methods, there are no inconveniences due to variations in the melting temperature of the stellite rod or temperature differences with the band saw, and the appropriate amount of molten stellite can be explosively bonded to the required location, greatly improving bond strength and processing. This has various effects such as time reduction and freeing the worker from complicated manual work.

[Brief explanation of the drawing]

FIG. 1 is a schematic view showing an example of a stellite welding device used in the method of the present invention, fa) is a plan view, (b) is a longitudinal sectional view,
FIG. 2 is a cross-sectional view of the cutting edge of the band saw, with (a) showing the state after immersion and before pressurization, (b) after pressurization, and (C) after polishing. Figure 3 is a schematic sectional view of the furnace body showing another heating method, Figure 4 (al is a front view showing a modified example of the furnace body), (b) is a side view, and Figure 5 (a) is a A front view showing the method, (b) is a sectional view taken along the line A-A of the same figure (al), FIG.
FIG. 7 is an enlarged cross-sectional view taken along the line B-B in FIG. ■...Band saw 2...Blade 4...Blade tip 6, 34...Stellite welding device 7...
・Furnace main body 9... Pressure section 11... Crucible 19... Stellite melt 20... Stellite rod supply device 25...
・Stellite small ball 26... Press 27... Exploded Stellite 30... Insulating lid body 35... Small crucible

Claims (1)

[Claims] 1. Stellite is heated and melted in a furnace with an open top, and the tip of the band saw is immersed in the stellite melt for a few seconds and pulled out. A method for welding stellite to a bandsaw blade edge, which is characterized by press forming from both sides so that the side part of the tip of the blade bulges during high temperature. 2. The method for welding stellite to a band saw blade tip according to claim 1, wherein the band saw blade tip is dipped into the stellite melt by moving the band saw up and down. 3. The band saw blade tip is immersed in the stellite melt by filling a small crucible that goes in and out of the furnace with the melt and moving the small crucible up and down. Stellite welding method.