JPS63268533A - Upset welding method for link chain - Google Patents

Abstract

PURPOSE:To make heat amt. and inner length dimension constant by adjusting an upsetting pressure in two stages strong and weak, executing an upset welding in a short time, utilizing the inner length dimension of a ink being contracted by forming a welding crest and cutting a heating power source with a limit switch prior to the completion of welding. CONSTITUTION:A pair of electrodes 15, 17 interposing both sides of the weld zone of an alloy steel made link 35, the cylinder 21 pressurizing the link from the side and the electric power conductor 23 heating the weld zone with electrification are owned. A cylinder 14 and the cylinder 21 for upsetting are driven via a pressure reducing valve 6 from an air source 1 and solenoid valve 10. In the welding equipment equipped with the limit switch 22 worked by the front and back movements of the cylinder an electric power conductor 23 is connected to a secondary side of a welding transformer 25 and a flashing circuit 27 is connected to a primary side via a thyristor switch 26. The variable resisters 30, 31 adjusting the secondary side current in strong and weak two stages are connected to this flashing circuit 27 and the pressure to the weld zone by the cylinder is pressurized in two stages strong and weak to execute upsetting welding in short time. The control of these circuits are executed by a sequence circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a welding method for absent welding links of a structural alloy prepared tire chain.

[Conventional technology] In order for vehicles to drive safely on snowy roads, it is necessary to install tire chains and spiked tires to prevent slipping, but recently the problem of dust pollution caused by spiked tires scraping the road surface has been raised. As a result, the use of spiked tires is being regulated or banned.

On the other hand, the necessity and importance of link chains has been recognized due to the occurrence of serious accidents caused by sightseeing buses on frozen roads. The chain is approximately 4 in one ring bone.
2) It is difficult for a single driver to handle the chain due to its heavy weight, so it is difficult to handle the chain by a single driver, so it has been inconvenient to attach a tire chain for a single tire to a double tire.

``Problems to be solved by the invention'' The wire diameter is smaller than that of conventional tire chains (for example, diameter 5 dragons - 4 cranes, 10 dragons → 8 tm) without reducing the performance of the tire chain.
), there is a need to reduce weight (cross-sectional area ratio 273 or less) by using thinner materials, but this cannot be solved by improving manufacturing methods alone; it is necessary to improve the mechanical properties and impact resistance of the materials used. , it is necessary to replace it with one that has high fatigue resistance and a low low-temperature brittle transition temperature. However, from a cost perspective, expensive materials such as nickel and chromium molybdenum are not used, and manganese steel, which has the above-mentioned characteristics and is easy to bend and heat-treat, is relatively inexpensive. becomes.

Structural alloy steel generally contains less carbon (C) than mild steel wire rod.
) High chemical content of silicon (Si) and manganese (Mn) [Soft M: CJ, 05-0.15%, Si.
Pol <ml ~0.15%, Mn-0.25~0.60%
, Structural alloy steel: C=0.11~0.23%, Si・0
．． 15-0.35%, Mn=0.90-1.50%],
To weld this, a preheating current is sent to the welding part using the Furanotsuyu welding method, and then a high heating current is sent to generate sparks, which removes carbon, silicon, manganese, etc. in the welding part material.
Complete welding was not possible unless upset pressure was applied after other impurities were scattered and removed and sufficient Joule heat was applied for fusion.

In this case, not only is there a loss of time for generating sparks, but also a large heating current is diverted to the back 36 of the link 35 shown in FIG. 7 and becomes high temperature as shown in FIGS. When the link is softened, one end of the link is hooked to the hooking part 91, and the pressing part 92 is pressed from the other end to apply upset pressure, the link becomes an oval shape (Fig. 9) and has an inner length of M. If the shrinkage is large (L>M>, there may be slight unevenness in energization due to the condition of the processed wire skin, the inner length will vary even if there is a timing shift in the operation of the pressurizing device, and the welding strength will be reduced due to deformation of the welded part 37) A decrease in

If the link is divided into two parts (FIG. 11), no split flow will occur, but it will be difficult to automate link welding. In addition, the generated spark-like iron powder contaminated the machinery and equipment, causing poor insulation of electrical circuits, resulting in many problems such as protecting workers' eyes, making work clothes fireproof, and deteriorating the working environment. Furthermore, because the welded part 37 becomes close to pure iron due to the flash action, there is damage due to a decrease in strength during pattern processing after the welding process of the ground contact part of the tire chain (cross chain), and the machine after carburizing heat treatment due to surface hardening. In order to compensate for this, a large welded area had to be left, making it unsuitable for tire chains, and the mechanical structure was complicated, requiring direct current welding, resulting in an expensive device.

The welding of the structural alloy steel by the upset welding method includes:
Higher heating current than mild steel welding [30-40% more than mild steel
Increase (soft line: @150 to 20 OA per area 11 m1)
, alloy #tJ wire: cross-sectional area 250-300A per layer)
), complete welding cannot be achieved, and it is necessary to complete welding in a short time to prevent deformation of the link due to backflow, but since it is a resistance welding method, reducing the pre-pressure will reduce the contact resistance Joule heat. It is larger and the extraction current can be reduced accordingly (same as mild steel wire or 10% more).

The high force required for fusion welding is 28'r! If welding is completed in the same flow, oxygen in the air and oxygen in the material will react with carbon in the material in the molten metal heated to over 1500°C, producing carbon dioxide gas, and iron, silicon, and manganese will be produced. etc. will oxidize and become impurities, and if pressurization is continued with pre-pressurization, feather-like burrs 33 will occur in the weld (Fig. 1θ), and impurity gas and impurities will remain in the weld, making the particles coarser and reducing strength. In extreme cases, the fracture surface becomes bluish and rough and breaks at the weld, as shown in Figure 12.13, or at the boundary of the weld, as shown in Figure 14, and the tensile strength decreases. The material strength of the welded part of a fully welded link is A or less.

In this case, when the cam performs the pressurizing operation, the first pressurizing and the second pressurizing
For both pressurization, there are differences in the melting point temperature due to the chemical content of the material to be processed, uneven current conduction due to the surface skin of the material and electrode contact conditions and dirt, and differences in the time it takes to reach the melting point temperature due to the shape and dirt of the cut surface of the welded part. coming out. If a constant pressurizing action is applied at this time, if the temperature rises quickly, the welded part will become an overheated structure and may melt and fall off, and if the temperature rises slowly, incomplete welding may occur. There are problems such as the occurrence of

"Means for Solving the Problems" In view of the above-mentioned problems in the conventional methods, the present invention includes a pair of electrodes that sandwich both sides of the welded part of an alloy steel link, and a pair of electrodes that sandwich the sandwiched links on both sides. a cylinder that is pressurized from
In a link chain welding device that has a power conductor that heats the welding part by energizing it and is equipped with a limit switch that is activated by the back and forth movement of the cylinder, the power conductor that connects to the electrode is connected to the secondary side of the welding transformer, An ignition circuit is connected to the primary side via a silisk switch, and a variable resistor is connected to this ignition circuit to adjust the secondary current in two stages of strength and weakness.
The present invention is characterized in that upset pressure applied to the welding part by the cylinder is applied in two stages of 6-strong to perform upset welding in a short time.

``Function'' When the cylinder is actuated to apply upset pressure while holding the welded part of the link, the welded part of the link whose hardness decreases in proportion to the degree of heating of the power equipment, has a quick response to pressure. The movable pressurizing part, which is advanced at a constant pressure as the temperature of the connecting part rises, is advanced in two steps to form a welded joint, and both ends of the link, which has become flexible, are exposed to the outside. Taking advantage of the fact that the ceramic dimensions of the link shrink due to extrusion, a limit switch is activated to turn off the heating current before welding is completed, and forging is performed during the subsequent holding time to reduce the amount of heat given to the welded area and the welded area. The size and internal length of the link can be made constant.

"Embodiment" An embodiment of the present invention will be described based on FIG. through the 1.2.3 pressure reducing valve 6.7.8 respectively.
．． Connect the three electric valves 10, 11, and 12.

One of the first electromagnetic valves 10 is connected to each front end of a pair of cylinders 14, and the other is connected to each rear end of the same cylinder, and each cylinder 14 is connected to a pair of movable electrodes 15 for clamping. each piston 16 is housed so that it can move forward and backward,
A fixed electrode 17 is provided opposite each movable electrode 15, respectively.

A movable pressurizing section 19 is provided so as to be movable forward and backward, facing the fixed pressurizing section 18 installed on an example of the fixed electrode 17, and the movable pressurizing section 1
The piston 20 connected to 9 is connected to the cylinder 2 for upset.
It is housed so that it can move forward and backward within the interior.

One side of the second solenoid valve 11 and the cylinder 21 for absethe throat
and the other and the rear end of the cylinder 21, and further connect the rear end of the cylinder 21 and the third solenoid valve 1.
Connect 2. Note that a limit switch 22 is provided facing the movable pressure section 19 for adjusting the forward position of the movable pressure section 19 and for turning off the heating current.

A power conductor 23 is provided on the secondary side of the welding transformer 25 to which movable/fixed electrodes 15, 17 for clamping are connected and the welding portion 37 is heated by electricity. In addition, an ignition circuit 27 is connected to the primary side of the welding transformer 25 via a heating current control switch 26 formed by a pair of thyristors, a resistor R, and a capacitor C. An ignition circuit transformer 29 is provided between the power source 28.

The secondary current of the welding transformer 25 is connected to the ignition circuit 27 with two
Two variable resistors 30 and 31 that are adjusted in stages are connected in parallel, and the fifth relay piece 51a is a closed contact, the fifth relay piece 51b is an open contact, and the fourth relay piece 50a is an indirect point. A circuit 32 is formed. Note that the variable resistors 30' and 31° may be connected in series as shown in FIG.

To explain the sequence circuit shown in FIG. 2, a main switch 45 and a fuse 4 are connected to a control circuit 42 connected to a control power source.
4 and the pilot lamp 43. The foot switch 46, the third branch 70, the ninth relay piece 55a as a closing contact, and the first relay 47 are connected to the control circuit 42, and the first relay pieces 4, 7a as an open contact and the third branch are connected to the control circuit 42. The fourth branch part 71 connected to the part 70 is connected to the ninth relay piece 55b, which is a closing contact, and the first timer 61.

Between the fourth branch part 71 and the control circuit 42, an eighth relay piece 54a and a second relay 48, which are closed contacts, and a first timer piece 61a, a fifth branch part 72, and a second timer 62 are provided. , furthermore, the fifth branch part 72 and the eighth relay piece 5 which is a closing contact.
4b and the third relay 49 are connected.

Between the fourth branch part 71 and the control circuit 42, a second timer piece 62a, a sixth branch part 73, and a third timer 63 are provided, and a seventh relay piece 53a, which is a closing contact, is connected to the sixth branch part 73. The fourth relay 50 is connected, and the fourth timer 64 is also connected.

Further, a third timer 63a and a fifth relay 51 are connected between the fourth branch part 71 and the control circuit 42, and further, a fourth timer piece 64a and an eighth relay piece 54C, which is a closing contact, and a sixth relay 52 are connected. Connect the limit switch 22 and the eighth
The branch part 75 connects the ninth relay piece 55c, which is a closing contact, with the seventh relay 53, and also connects the seventh relay piece 53, which is an opening contact.
b and the ninth branch part 76 connected to the eighth branch part 75 and the fifth timer 65, and the fifth timer piece 65a
The eighth relay 54 and the ninth relay 55 are connected.

In parallel with the control circuit 42, a second relay piece 48, which is an indirect point, is connected.
a, the first solenoid valve IO2 for clamp pressurization, the third relay piece 49a which is also an open contact, the second solenoid valve 11 for upset first pressurization, and the sixth relay piece 52a which is an open contact.
and the third solenoid valve 12 for the second pressurization of the absent are connected, respectively.

Next, to explain the operation of this embodiment, the main switch 45 is turned on to energize the circuit, the link 35 is positioned between the clamping electrodes 15 and 17, and one end is fixed to the pressurizing part 18.
When the foot switch 46 is operated by touching the foot switch 46, the first relay 47 is activated and the first relay piece 47a is ONL. 2 relay 48 is activated and the second relay piece 48 is activated.
a is turned ON to switch the ttm valve 10 for clamp pressurization, move the movable electrode 15 connected to the piston 16 in the cylinder 14 forward, clamp both end pieces 34 of the link 35, and start clamp pressurization.

When the first timer 61 times up, the first timer piece 61a turns ON and the second timer 62 for the first (initial) pressurization starts a time-limited operation, and the third relay 49
, and turns on the third relay piece 49a to close the second solenoid valve 1.
1, actuate the cylinder 21, and move the movable pressing part 1.
9, and start the absent first pressurization (40 to 60% strength of the second pressurization described later).

The link 35, which is first pressurized by the movable pressurizing section 19 that has moved forward due to the operation of the cylinder 21, continues to be pressed with a weak upset first pressurizing force until the second timer 62 times up.

When the second timer 62 amplifies the time, the third timer 6
3 starts the time-limited operation, and operates the fourth relay 50 to ONL the fourth relay piece 50a (FIG. 1), which is the joint point, and connects the fourth relay piece 50a (FIG. 1), which is the contact point, to the primary side of the welding transformer 25. 5
The voltage of the first variable resistor 30 is applied via the relay piece 51a to close the ignition circuit 27, ignite the thyrisk switch 26, and apply a higher primary voltage to the power conductor 23 on the secondary side of the welding transformer 25. is energized, and a strong first heating current X (for example, 250 to 3 QOA per cross-sectional area l-1 of the alloy steel wire) is sent to the welded portion of the link 35 via the movable and fixed electrodes 15 and 17. Therefore, until the third timer 63 times up, the welded portion 37 is heated by a large current and reaches a high temperature due to the large contact resistance of the cross section due to the weak first upsetting force and the specific resistance of the material.

Next, when the third timer 63 times up, the fifth timer 63 times up.
When the relay 51 operates, the fifth relay piece 51a is turned OFF, and the fifth relay piece 51b, which is another closed contact, is turned ON, and the lower primary voltage due to the voltage of the second variable resistor 31 is transferred to the Cyrisk switch 26. The primary side of the welding transformer 25 is energized, and the first heating is performed by a second heating electric current which is 40 to 60% weaker than the current.
'v to link 35. A high heating current is applied for a very short period of time (0.15 to 0.2 seconds) as needed to melt the metal, then cut off just before a flash occurs and instantly switched to a weaker heating current to continuously rise the molten metal. It suppresses the temperature of the link to prevent overheating and melting and falling off, and also prevents flow splitting at the back of the link.

When the fourth timer 64 times up, the fourth timer piece 64a turns ONL, and the sixth relay 52 operates, turning the sixth relay piece 52a ONL and the 31st! Switch the L magnetic valve 12,
The cylinder 21 has an upsetting second pressing force that is approximately twice as strong as the first pressing force (for example, 25
~ 35 kgf) and continue to press the link 35 until the time amplifier of the fifth timer 65, the welding part 37 will push out impurity gas and impurities by the strong second pressurization to form the welding part 39, and the link When the movable pressurizing part 19 advances to a certain position by the operation of the cylinder 21, the limit switch 22 is activated, the seventh relay 53 is activated, and the seventh relay piece 53a of the closing contact is activated. Then, the fourth relay 50 is set to 0FFL, and the ill'i to the primary side of the welding transformer 25 is cut off by the sirisk switch 26, and the heating is completed. At the same time, the fifth timer 65 starts a time-limited operation via the other seventh relay piece 53b, and during the set time of the fifth timer 65, the welded part 37 of the link is applied with a strong second upsetting force by the cylinder 21. Press to forge molten metal.

The fifth timer 65 performs time amplification and the fifth timer piece 6
When 5a is turned on, the eighth relay 54 is activated and turns off the second relay 48, third relay 49, and sixth relay 52,
The cylinder 14 returns to move the movable electrode 15 back and link 3
At the same time, the ninth relay 55 is activated and the ninth relay pieces 55a, 55b, and 55c are turned off, and the foot switch 46 is turned off and the control circuit returns to its original state and is fully operational. complete.

``Effects of the invention'' ■ For link welds whose hardness decreases in proportion to the degree of heating, the upset pressure is adjusted to 6-strong and 2-step to perform absent welding in a short time, and constant pressure eliminates impurity gas. In addition to pushing out impurities to the outside, the welding area is formed and the ceramic dimensions of the ink shrink as the welding area is pushed out.The limit switch is activated to turn off the heating current before welding is completed, so a timer is not required. Furthermore, the amount of heat given to the welding part, the size of the welding part, and the ceramic dimensions of the link can be made constant.

■ By completely welding without flash using the absent welding method, welding time can be shortened by simply adding some parts without fundamentally changing the mechanical equipment, and deformation due to shunt to the back of the link can be avoided. It is possible to prevent large changes in the chemical components of the welded part and increase the durability of the link.

■Absent welding is a resistance welding method, and if the pre-pressure is reduced, the welding resistance Joule heat in the cross section of the link weld increases, and the heating current can be reduced.

■ Being lightweight, it is easy for women to handle, and tire chains for large buses can also be made lighter, making tire chains easier to handle and easier to install.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is an overall circuit diagram, Fig. 2 is a sequence circuit diagram, Fig. 3 is a schematic diagram of processing operations, and Fig. 4 is a pressurized state of a clamped link. 5 is a front view of the same, FIG. 6 is an adjustment circuit diagram showing another embodiment, FIG. 7 is a plan view of the link before welding, and FIG. 8 is a plan view of the link after welding. , FIG. 9 is a plan view showing a defective welding condition, FIG. 10 is a sectional view showing another defective welding condition, FIG. 11 is a plan view of the divided link, and 12th to 1st
FIG. 4 is a plan view of each broken link. 14.21--Cylinder, 15.17--Electrode, 22--Limit switch, 23- Power conductor, 25--Welding transformer, 26--Sirisk switch, 30, 31...variable abrasive, 35...
Link. Patent issuer Kazuo Muraoka Electric Industry LLC Representative Patent Attorney 1) Figure 7 Figure 8 Figure 2

Claims (1)

[Claims] A pair of electrodes sandwiching both sides of the welded part of the alloy steel link;
In a link chain welding device that has a cylinder that applies pressure to the sandwiched link from the side, a power conductor that heats the welded part, and a limit switch that is activated by the back and forth movement of the cylinder, the secondary side of the welding transformer is A power conductor connected to the electrode is connected, an ignition circuit is connected to the primary side via a thyristor switch, a variable resistor is connected to this ignition circuit to adjust the secondary side current in two stages of strength, and the A link chain upset welding method characterized in that upset welding is performed in a short time by applying upset pressure to the welded part by a cylinder in two stages, weak and strong.