JPH0481278A - Welding equipment - Google Patents

Abstract

PURPOSE:To stabilize and uniformize the quality of a weld zone by measurizing the base metal temperature and its variation at the time of welding and controlling the penetration quantity to base metal. CONSTITUTION:A traveling device A is constituted of a traveling carriage 1 in which a traveling motor is incorporated, a welding torch 2 mounted on this traveling truck 1 and a temperature detecting sensor 3. The welding torch 2 generates an arc on the weld zone of the base metal 8 to perform welding. A temperature detecting sensor such as an infrared thermometer is used as the detecting sensor 3. This infrared thermometer is held at a certain distance from the welding torch and measures continuously the base metal temperature at a point separated by a certain distance from the welding position during welding. A traveling speed control system B is constituted of a signal conversion part 4, an upper and lower limit temperature setting part 5, a proportional conversion part 6 and a voltage conversion part 7. Consequently, the speed of the traveling truck 1 in proportion to the base metal temperature is obtained and resultantly, the base metal temperature is fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a welding device for stabilizing the quality of a welded part.

(Prior art) Automation of conventional welding equipment involves controlling the torch positional relationship to control the bead sequence for welding inside the groove,
Or related welding conditions.

For example, welding current, voltage, speed, etc. have been sequentially controlled at stable values.

Generally, the amount of heat input during welding is used as an important factor when managing and evaluating the quality and characteristics of welded joints.

This amount of heat input is expressed by the following equation (1). In other words, heat input (J/cm) = 60 x welding current (A) x welding voltage (D) welding speed (cm/min) (By the way, as the heat input changes For example, since the amount of heat input to the base metal changes, the amount of base metal penetration and heat affected zone changes.In other words, the amount of change in the properties of the base metal before welding changes, resulting in a change in the welded joint. Efforts have been made to manage and evaluate the quality characteristics of welded joints based on these correlations, and to stabilize the output of welding equipment such as welding current, voltage, and speed in order to stabilize quality. Ta.

(Problem to be solved by the invention) However, even if the output of the welding device is stabilized and welding is performed with a constant amount of heat input, the temperature of the base material changes as welding progresses. There is a large difference in the amount of penetration between the welding process and the end of welding. Furthermore, even when welding is performed with the same amount of heat input, the amount of penetration varies depending on the thickness, size, etc. of the base metal. Furthermore, even if welding is carried out under the same conditions, the welding results often vary greatly depending on the season. In particular, for copper, aluminum, and their alloys, which have good thermal conductivity, the increase in base metal temperature due to welding has a large effect on the penetration depth, and even if the output of the welding equipment is constant, the quality will not be constant. There was a drawback.

However, changes in the amount of penetration not only lead to welding defects such as poor fusion, but also changes in the amount of dilution.
This is a serious problem that changes the performance of welded joints. Therefore, instead of simply controlling the output of the welding device, it is necessary to detect changes in the base material that receives heat and control the welding device.

Furthermore, in automatic TIG welding involving wire feeding, there is a problem in that the amount of wire fed usually has to be controlled so as to obtain a uniform amount of welding in order to prevent unevenness from occurring in the weld bead.

The present invention was made in view of the above circumstances, and its purpose is to measure the base metal temperature and the amount of change thereof during welding, thereby controlling the amount of penetration into the base metal and stabilizing the quality of the welded part. The object of the present invention is to provide a welding device capable of welding and uniformization.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a welding device equipped with a traveling truck, a welding torch, and a temperature sensor, in which an arc point is removed during arc welding of a base material. The welding speed is characterized in that the temperature of the base material in the vicinity is continuously measured and the welding speed is proportionally controlled based on the temperature of the base material. In addition, when the welding conditions of the base metal change, the upper and lower limit temperature setting section controls the welding speed to the minimum speed when the base metal temperature is below the minimum temperature setting, and the maximum speed when the welding speed is higher than the upper limit temperature setting. This is characterized by the provision of a proportional converter that can change the proportional coefficient and constant of the welding speed, which is proportionally controlled depending on the material temperature.

(Function) To stabilize the quality by controlling the amount of penetration into the base metal, the influence on the base metal side that receives the output from the welding equipment is measured, and the output of the welding equipment is adjusted according to the degree of influence. must be controlled.

According to the present invention, the temperature of the base material at a certain distance from the welding torch is continuously measured with a thermometer in order to understand the degree of influence on the base metal side in the solution as a change in the base metal temperature. Since the welding speed is proportionally controlled based on the base metal temperature signal from this thermometer, there is no change in melt penetration in materials with good thermal conductivity, and quality is stabilized. Further, since the upper and lower limit temperature setting section or the proportional conversion section is provided, the output of the welding device can be easily adjusted in accordance with changes in base material temperature or changes in welding conditions.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram showing the relationship between the speed control system and wire control system of FIG. 1.

As shown in FIGS. 1 and 2, the welding apparatus of the present invention is comprised of a traveling device A, a traveling speed control system B, and a wire control system C.

The traveling device A includes a traveling truck 1 having a built-in traveling motor (not shown), a welding torch 2 mounted on the traveling truck 1, and a temperature detection sensor 3. The welding torch 2 performs welding by generating an arc in the welded portion of the base material 8, and the detection sensor 3 is a temperature detection sensor such as an infrared thermometer. This infrared thermometer is held at a certain distance from the welding torch and continuously measures the temperature of the base material at a certain distance from the welding position in the solution.

The traveling speed control system B includes a signal converter 4 and an upper/lower limit temperature setting unit 5.
, a proportional converter 6, and a voltage converter 7.

Since the base material temperature signal from the infrared thermometer may be an analog signal or a digital signal depending on the thermometer, the signal converter 4 is selected according to the traveling speed control system to be used. In other words, it performs D/A conversion or A/D conversion, and further amplifies the temperature signal level to the control system signal level.
Convert the ratio of input and output. In addition, the upper and lower limit temperature setting section 5
As shown in FIG. 3, the control range of the base material temperature is set.

The proportional converter 6 calculates the plate thickness, size, etc. of the base material, welding current,
When settings such as voltage change, the equation y=ax+c expresses the relationship between base material temperature and output (see equation (2) below)
This is to obtain matching of welding characteristics by changing the proportionality coefficient a and constant part C. The voltage conversion section 7 performs voltage conversion to obtain a motor drive voltage for the traveling bogie, and the voltage converted here is supplied to the motor 1a of the traveling bogie 1 to determine the traveling speed. As a result, the speed of the traveling trolley 1 is obtained in proportion to the base material temperature, and as a result, the base material temperature is made constant.

Further, the wire control system C includes a running speed detection encoder 9, a signal conversion section 10, an output section 11, and a wire supply motor 12. Detect the traveling speed with encoder 9,
A signal converter 10 converts a wire feed amount signal corresponding to the traveling speed. The output section 11 specifically obtains a voltage to be supplied to the wire feeding motor 12.

Next, the operation of this embodiment will be explained.

Generally, the relationship between base material temperature and running speed is expressed by the following linear equation.

y = a x + c (2) where y: Traveling speed, a: Proportionality coefficient This is extremely difficult as it varies depending on the size etc. Therefore, the relationship between the base material temperature and the running speed may be expressed by a linear equation roughly to some extent. This roughness is compensated for by the next upper and lower limit temperature setting section 5. That is, in the signal converter 4, the relationship between the base material temperature and the traveling speed of the welding device is set as shown by the straight line m in FIG. However, the actually required traveling speed deviates slightly near both ends of the straight line m. Therefore, as shown by the solid line n in Fig. 3, lower and upper temperature settings are set, and when the base material temperature is below the minimum set temperature, the running is stopped, and when the base material temperature is above the upper limit set temperature, the maximum speed of the equipment is set. Alternatively, the vehicle travels at a traveling speed corresponding to the case where the base material temperature is slightly higher than the range of the base material temperature to be controlled, and changes according to the relationship shown in FIG. 4 within the set temperature range of the upper and lower limits.

By the way, during welding, a hair arc is generated in the base material 8 from the welding torch 2, and the temperature of the base material increases, and the traveling speed of the traveling trolley 1 increases accordingly.

If the welding current and voltage are set to constant values, as the traveling speed increases, the heat source moves faster and the base material temperature decreases. If the base material temperature decreases, the running speed will also decrease.

The above-described characteristic diagram in FIG. 3 shows the relationship between the base material temperature, that is, the temperature signal detected by the temperature detection sensor 3, and the traveling speed of the traveling truck 1. In other words, the speed of the traveling trolley 1 is controlled to keep the base material temperature constant while moving on the dotted line m, but if this continues, the range of the base material temperature will become wider, so upper and lower limits are set to forcibly limit the temperature range. A temperature setting section 5 is provided, and the speed of the traveling trolley 1 is controlled along the solid line n. In other words, the traveling trolley 1 is set to have a minimum speed of zero when the temperature is below the lower limit temperature setting, and a maximum speed when the temperature is higher than the upper limit temperature setting. Therefore, the upper and lower temperature limit setting section 5 may be set with respect to the signal of the temperature detection sensor 3, or may be set with respect to the output voltage of the voltage conversion section 4. As a result, when the temperature is below the lower limit temperature setting, the traveling trolley 1 stops and waits for the base material temperature to rise, and when the temperature exceeds the lower limit temperature, the traveling speed increases according to the traveling characteristic shown by the solid line n in FIG. 3. When the temperature exceeds the upper limit setting, the base material temperature rapidly decreases because the vehicle runs at maximum speed. Further, if the temperature falls below the lower limit temperature setting, the traveling truck will stop, so the base material temperature will rise rapidly. By repeating these operations, the base material temperature can be maintained more accurately.

In this embodiment, by controlling as described above, the temperature of the base material during welding can be kept constant from the start to the end of welding. If the base material temperature is constant, the amount of penetration can be easily controlled, and as a result, the amount of penetration can be easily controlled even when the material has good thermal conductivity.

In addition, the temperature distribution was calculated using multiple infrared thermometers,
It is also possible to calculate base material temperature measurement points for optimal control. Furthermore, the traveling speed can be detected by using a photoelectric switch, a proximity sensor, etc. without using an encoder.

Further, the welding current may be controlled by a signal from a base material temperature detection sensor. In this case, the higher the temperature of the base material, the more easily the melt penetrates, so the coefficient a must have a negative slope.

In the above explanation, we have explained the case where there are large changes in the numerical welding conditions, but if the welding conditions are relatively stable,
Further, when the welding temperature range is within the appropriate range, the accuracy of the welded part can be maintained sufficiently by controlling the welding speed according to the base material temperature without providing the upper and lower limit setting section and the proportional conversion section.

[Effects of the Invention] As explained above, according to the present invention, the base metal temperature is kept constant, so as the welding work progresses, the base metal temperature increases and the penetration amount and dilution amount change. This eliminates the disadvantage of conventional devices. Therefore, there is no change in penetration especially in materials with good thermal conductivity, and the quality of the welded part is stabilized.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a block diagram showing the relationship between the speed control system and wire control system in Fig. 1, and Fig. 3 is a case where upper and lower limit temperatures are set. FIG. 4 is a characteristic diagram showing the relationship between base material temperature and traveling speed. FIG. 4 is a characteristic diagram showing the relationship between base material temperature and traveling speed. 1... Traveling trolley 2... Welding torch 3... Temperature detection sensor 4... Signal conversion section 5... Upper/lower limit temperature setting section 6... Proportional conversion section 7... Voltage conversion section 8 ... Base material 9 ... Encoder 10 ... Signal conversion section 11 ... Output section 12 ... Wire feeding motor A ... Traveling device B ... Traveling speed control system C ... Wire Control System (11733) Agent Patent Attorney Yoshiaki Inomata (and 1 other person) Fig.

Claims (2)

[Claims] (1) In a welding device equipped with a traveling trolley, a welding torch, and a temperature sensor, the base metal temperature near the arc point is continuously measured during arc welding of the base metal, and the welding speed is proportionally controlled based on this base metal temperature. A welding device characterized by being configured as follows. (2) When the welding conditions of the upper/lower limit temperature setting section and the base metal change, the welding speed is controlled to be the lowest speed when the base metal temperature is below the lower limit temperature setting, and the welding speed is the highest speed when the upper limit temperature setting is higher than the upper limit temperature setting. 2. The welding apparatus according to claim 1, further comprising a proportional conversion section capable of changing a proportional coefficient and a constant of a welding speed that is proportionally controlled based on base material temperature.