JPH11226731A - Pushing into term heat input control method of stud welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of a welding defect due to an excessive heat input. SOLUTION: A standard heat input quantity for a whole short circuit term at the time of starting a pushing into short circuit up to a short circuit voltage detection start point of time t91 is before hand set before a welding start. Then, because a steel plate installed on a steel frame waves, a clearance between the steel plate and the steel frame is generated, in the case that the clearance becomes larger than a value expected beforehand and the pushing into term is lengthened, pushing into short circuit voltage average values Vs (Δt) for every detection internal are measured from a short circuit voltage detection start point of time, by integrating the heat input average values for the every detection interval which are the product of the pushing into short circuit voltage average values for the every detection interval and the pushing into short circuit current values Is for the detection term, a short circuit term integration heat input quantity is calculated, at the point of time t9n when the short circuit term integration heat input quantity reaches a standard heat input quantity for the whole short circuit term, the pushing into short circuit current is interrupted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stud welding method in which a stud is pulled up to generate an arc, and after a predetermined time, the stud is pressed against a material to be welded to cause a short circuit. The present invention relates to a method for controlling heat input during a pressing period.

[0002]

2. Description of the Related Art Stud welding applications include building construction,
2. Description of the Related Art In construction work and the like, there is upper plate penetration welding in which a thin steel plate is disposed on a structure in which steel frames such as H-shaped steel and I-shaped steel are assembled, and a steel plate (deck plate) is fixed on the steel frame by stud welding. FIG. 1 is a diagram showing a positional relationship between a steel plate and a steel plate when a steel plate is wavy and a gap (clearance) is generated between the steel plate and the steel plate when the steel plate is disposed on the steel plate. In the same figure, when the steel plate Wb is arranged on the steel frame Wa, when the thickness Dp of the steel plate is a thin plate such as 1.2 [mm], for example, the steel plate Wb is wavy, and the steel frame Wa and the steel plate Wb A gap (clearance) Dc is generated between them.

[0010]

FIG. 2 is a steel plate / stud positional relationship diagram showing the positional relationship between the steel plate and the stud tip when there is a gap between the steel frame and the steel plate. Figure (A)
Is that the tip of the stud S immediately after the start of the stud welding is a steel plate W
b is a welding start positional relationship diagram showing a state in contact with b,
The position at which the tip of the stud S contacts the steel plate Wb is defined as the reference point P.
And FIG. 6B is an arc generation positional relationship diagram showing a state in which an arc is generated by pulling up the stud tip, and the stud tip is pulled up from the reference point P in FIG. In position.

FIG. 2C is a short-circuit position relationship diagram showing a state in which a command to push in the stud is issued after a preset time has elapsed from the start of welding and the tip of the stud is pushed in to short-circuit. The tip of the stud is located at a position pushed in by a pushing distance Dd from the reference point P in FIG. FIG. 3D is a diagram showing the time course of the tip position of the stud S from the start of welding to the end of welding, in which the vertical axis indicates the amount of movement M of the tip of the stud, and the reference numeral in FIG. ) Indicates the position of the tip of the stud, reference numeral indicates the position of the tip of the stud in FIG. 4B, and reference numeral indicates the position of the distal end of the stud in FIG.

FIG. 1E is a diagram showing the time course of the output terminal voltage Vd from the start of welding to the end of welding.
In FIG. 9 (E), time ts0 is the time of the start of short-circuiting at the time of normal welding (hereinafter, referred to as direct welding) other than penetration welding of the upper plate, and time ts1 is the short-circuiting at the time of penetration welding at the time of upper plate penetration welding. This is the start time, which is the time for the tip of the stud to move by the thickness Dp and the gap Dc of the steel plate, which is later than the time ts0.

Further, the time ts2 is the time when the tip of the stud comes into contact with the steel frame at the time of the upper plate penetration welding and starts pushing, and a gap (clearance) is formed between the steel frame Wa and the steel plate Wb.
The delay time from time ts0 to time ts2 varies because Dc is indefinite. If this push start time is delayed,
As shown in FIG. 3 described above, the heat input by the arc is included in the press-in short-circuit period Ts, so that the heat input in the press-in short-circuit period Ts becomes excessive.

Since the gap Dc is indefinite, as shown in FIG. 3B, the arc length Da is Dup + (Dp +
Dc), and (Dp + Dc) as compared with direct welding.
And the variation occurs. Further, in the case of the upper plate penetration welding, the pushing distance De from the surface of the steel frame whose tip of the stud is pushed into the steel frame Wa is Dd− (Dp + Dc) as shown in FIG. Not only does it decrease by (Dp + Dc), but also the indentation distance De from the steel frame surface fluctuates due to this variation in Dc.

To secure welding quality, it is important to obtain required heat input. The heat input of stud welding is defined as the time integral value of the welding voltage value and welding current value during arc generation by pulling up the stud from the workpiece, and the welding voltage value during short-circuit current conduction by pushing the stud into the workpiece. It is the sum of the welding current value and the time integral value.

If the welding conditions are not appropriate and the required heat input cannot be obtained, for example, if the welding current is larger than the appropriate value, if the pulling distance is short, or if the welding posture is poor, the arc will be increased. During this time, the molten surface of the stud contacts the molten pool of the material to be welded, causing a short circuit. If this short-circuit occurs frequently, the arc does not continue sufficiently, resulting in insufficient heat input, making it impossible to push in the required pushing distance during pushing, resulting in poor welding.

Even if the short circuit does not occur during the arc generation and the heat input during the arc generation is appropriate, the studs are not removed due to the above-mentioned penetration of the upper plate and the catch when the welding gun is pushed in. A predetermined time after issuing a command to push the material into the workpiece (hereinafter referred to as a short-circuit voltage detection start time)
When short-circuiting occurs later than t91, as described above, the heat input during the indentation short-circuit period Ts becomes excessive and the molten metal Wm
Is excessively large, resulting in a shortage of excess and a decrease in welding strength.

FIG. 1 and FIG. 2 are shown in Japanese Patent Application No.
-316180 is the same as the diagram described in the subject of the "Main current switching stud welding method" of the prior art 1 described in the prior art 1, but this prior art 1 is intended to solve the problem of the prior art by using the main arc period Ta. In the latter half of the process, the main arc current value Ia is increased.

As shown in FIG. 3, the “method of controlling heat input during the indentation period of stud welding” of the prior application 2 described in Japanese Patent Application No. 9-187403 of the present applicant, as shown in FIG. After the arc is generated by pulling up the stud, the stud is pushed into the workpiece and the welding voltage average value V2c is detected during short-circuit current conduction when the short circuit is conducted, and the welding voltage average value V2c is detected.
Is a method of comparing a value corresponding to the above with a predetermined value, and using the comparison result for display, alarm, quality judgment, heat input control, and the like.

FIG. 3 is an explanatory view of the prior art 2.
FIG. 7A is an output current waveform diagram showing a waveform of the output current Io when a short circuit occurs after a predetermined time t21 after a command to push the stud into the work piece is received, and FIG. FIG. 6 is an output terminal voltage waveform diagram showing a waveform of the output terminal voltage Vd at that time.

When this technique is further embodied, an arc is generated by pulling up a stud as a reference from a material to be welded, and then short-circuited by a predetermined time t21 after a command to push the stud into the material to be welded. The average welding voltage V2a and the average welding current I2a are detected during the short-circuit current conduction, and the pushing voltage is set based on the average welding voltage V2a. Then, the stud to be determined is pulled up from the workpiece. After the arc is generated, the stud is pushed into the material to be welded, and the same welding current average I
The welding voltage average value V2c when the current of 2a is applied is detected, and the welding voltage average value V2c is determined as the indentation voltage value to be determined, and the indentation voltage value V2c to be determined is compared with the indentation voltage value V2a to be a reference. Used for display, alarm, quality judgment, heat input control, etc.

Accordingly, the prior application 2 is a method in which a stud to be determined is determined after the end of welding and is used for display, warning, quality determination or heat input control of the next welding. If the heat input is excessive at that time, the welding result of the stud to be determined is bad. The present invention solves this problem.

[0051]

The first method of the present invention is as follows.
The stud welding for interrupting the indentation short-circuit current at the time t9n when the integrated short-circuit period heat input Qta9n calculated from the indentation short-circuit voltage average value Vs (Δt) at each detection interval reaches a preset standard heat input Qst9s for the entire short-circuit period. This is a method for controlling the cumulative input press-down.

In the second method of the present invention, the integrated short-circuit period voltage value Vta9n is set to a predetermined standard heat input Q over the entire short-circuit period.
Short circuit voltage standard value Vst9s for the entire detection period calculated from st9s
This is a method of controlling the cumulative heat input and press-in of stud welding in which the inrush short-circuit current is interrupted at time t9n when the pressure reaches the threshold.

In the third method of the present invention, the integrated short-circuit heat input Q calculated from the short-circuit voltage average value Vs9n over the entire detection period is used.
ta9n is the standard heat input Qst9s for the entire short-circuit period set in advance.
This is a method of controlling the cumulative heat input and press-in of stud welding in which the inrush short-circuit current is interrupted at time t9n when the pressure reaches the threshold.

According to a fourth method of the present invention, in the first method of the present invention, the short-circuit voltage detection start time t91 is set before the start of welding.
The standard heat input Qst9s for the entire short-circuit period when the indentation short-circuit is started beforehand is set in advance, and the indentation short-circuit voltage average value Vs (Δt) for each detection interval is measured from the short-circuit voltage detection start time t91. Heat input average value ΔQst for each detection interval, which is the product of the indentation short-circuit voltage average value Vs (Δt) for each detection interval and the indentation short-circuit current average value Is for the detection period
The integrated heat input Qta9n of the short-circuit period is calculated, and the accumulated heat input Qta9n of the short-circuit period reaches the standard heat input Qst9s of the entire short-circuit period. This is a push-in control method.

According to a fifth method of the present invention, in the second method of the present invention, the short-circuit voltage detection start time t91 is set before the start of welding.
The standard heat input Qst9s for the entire short-circuit period when the indentation short-circuit is started beforehand is set in advance, and the indentation short-circuit voltage average value Vs (Δt) for each detection interval is measured from the short-circuit voltage detection start time t91. The average value of the indentation short-circuit voltage Vs (Δt) for each detection interval is integrated and the integrated short-circuit period voltage value Vt
a9n is calculated, and the short-circuit period integrated voltage value Vta9n reaches the short-circuit voltage standard value Vst9s for the entire detection period obtained by dividing the standard heat input Qst9s for the entire short-circuit period by the indentation short-circuit current average Is for the detection period. This is a method for controlling the integrated heat input and press-in of stud welding that interrupts the press-in short-circuit current at t9n.

According to a sixth method of the present invention, in the third method of the present invention, the short-circuit voltage detection start time t91 is set before the start of welding.
The standard heat input Qst9s for the entire short-circuit period when the indentation short-circuit is started beforehand is set in advance, and the indentation short-circuit voltage average value Vs (Δt) for each detection interval is measured from the short-circuit voltage detection start time t91. The average value of the indentation short-circuit voltage Vs (Δt) for each detection interval is integrated and the integrated short-circuit period voltage value Vt
a9n is calculated, and the short-circuiting period integrated voltage value Vta9n is divided by the number of detections n to obtain an average short-circuiting voltage Vs9n for the entire detection period =
Vta9n / n is calculated, and the integrated short-circuit heat input Qta9n of the product of the average short-circuit voltage Vs9n during the entire detection period, the average short-circuit current Is during the detection period, and the short-circuit detection period Tsd is calculated. This is a heat input cumulative push-in control method for stud welding in which the short-circuit current is interrupted at time t9n when the cumulative heat input Qta9n during the period reaches the standard heat input Qst9s of the entire short-circuit period.

According to a seventh method of the present invention, the average value of the indentation short-circuit current Is during the detection period of the fourth or the sixth method of the present invention is determined.
The following is a method for controlling the integrated heat input and press-in of stud welding, which is a short-circuit current set value set in a welding power supply device having a constant current output characteristic.

The eighth method of the present invention is directed to an indentation short-circuit current average value Is during the detection period of the fourth or sixth method of the present invention.
The following is a method of controlling the integrated heat input and press-in of stud welding, which is a measured short-circuit current output from the welding power supply device having a constant current output characteristic measured after the short-circuit voltage detection start time t91.

According to a ninth method of the present invention, the average value of the indentation short-circuit current Is during the detection period of the fourth or sixth method of the present invention is obtained.
Is the indentation short-circuit current average Is for each detection interval calculated for each detection interval Δt from the short-circuit voltage detection start time t91.
This is a stud welding heat input integrated push-in control method which is a value calculated by integrating (Δt) from the number of detections from 1 to n.

[0070]

BEST MODE FOR CARRYING OUT THE INVENTION Even when a short circuit does not occur during arc generation and heat input during arc generation is appropriate, a command to push a stud into a material to be welded and then a short circuit voltage detection start point When short-circuiting occurs later than t91, the heat input becomes excessive. Therefore, the method of the present invention is a push-in period heat input control method for controlling the heat input so as not to be excessive.

In the first method of the present invention, as shown in FIG. 4 to be described later, before the welding is started, the standard heat input Qst9s for the entire short-circuit period when the indentation short-circuit is started by the short-circuit voltage detection start time t91 is started. Set in advance.

Next, for example, as shown in FIG. 1, when the gap Dc becomes larger than the value assumed in advance and the pushing period becomes longer, the short-circuit voltage detection start time t
From 91, the average value of the inrush short-circuit voltage Vs for each detection interval
(Δt) is measured, and the average of the heat input amount ΔQst for each detection interval, which is the product of the average of the indentation short-circuit voltage Vs (Δt) for each detection interval and the average of the indentation short-circuit current Is during the detection period, is short-circuited. This is a heat input integrated press-in control method for stud welding in which the integrated heat input Qta9n for the period is calculated, and the integrated heat input Qta9n for the short-circuit period reaches the standard heat input Qst9s for the entire short-circuit period at time t9n to cut off the short-circuit current. .

[0100]

FIG. 4 (A) shows a short-circuit voltage detection start time t91 after a command for pushing a stud to be a reference into a workpiece is issued.
FIG. 7B is an explanatory diagram for calculating the average value of the inrush short-circuit heat input standard value setting period Tss in the indentation short-circuit heat input standard value setting period Tss when the short-circuiting is performed until the short circuit is completed. FIG. 11 is an explanatory diagram for calculating an average value Vs (Δt) of the indentation short-circuit voltage for each detection interval Δt.

As shown in FIG. 10A, at the time t0 at which the auxiliary arc current is supplied, the auxiliary arc current Ip is supplied by pressing the welding start / end switch 13 shown in FIG. An auxiliary arc is generated by lifting the workpiece W from the workpiece. At time t2 when the main arc current starts to flow, the auxiliary arc current Ip is switched to the main arc current Ia. At the end of the main arc period or the start short-circuit period t9, a push-in command signal is output to start pushing. The normal short circuit start time delay from the output of the pushing command signal to the contact of the molten tip of the stud S with the molten metal Wm of the workpiece W is ΔT91.

The welding current detection circuit IC shown in FIG.
The welding voltage detection circuit VC detects the short-circuit voltage instantaneous value V (t) at each time t during the indentation short-circuit heat input standard value setting period Tss from the short-circuit voltage detection start time t91 to the short-circuit voltage detection end time t9s. Then, the average value Vs (Δt) of the indentation short-circuit voltage at each detection interval when no short-circuit occurs is calculated. Similarly, the short-circuit current instantaneous value I (t) at each time t is detected, and the indentation short-circuit current average value Is (Δt) is calculated for each detection interval when the indentation short-circuit starts by the short-circuit voltage detection start time t91. I do.

[Explanation of Equations 1 to 3] In FIG. 4, during the indentation short-circuit heat input standard value setting period Tss, the indentation short-circuit current average value Is for the entire detection period or the indentation short-circuit current average value Is ( Δt) and the indentation short-circuit voltage average value Vs (Δt) for each detection interval Δt are calculated, and the heat input amount average value ΔQst for each detection interval is calculated by Equation 1.

[0108]

(Equation 1)

The average heat input amount ΔQst for each detection interval is integrated from the short circuit voltage detection start time t91 to the short circuit voltage detection end time t9s according to Expression 2, and the standard heat input Q for the entire detection period is calculated.
Calculate st.

[0112]

(Equation 2)

The standard heat input Qst for the entire detection period from the first detection interval Δt at the short-circuit voltage detection start time t91 to the s-th detection interval Δt at the short-circuit voltage detection end time t9s is given by Expression 3. It may be calculated.

[0122]

(Equation 3)

[Explanation of FIG. 5] FIG. 5A shows the indentation short-circuit detection period Tsd when a short-circuit is detected after the command to push the stud to be determined into the material to be welded is later than the short-circuit voltage detection start time t91. FIG. 8B is an explanatory diagram for calculating the indentation short-circuit current average Is, and FIG. 9B is an explanatory diagram for calculating the indentation short-circuit voltage average value Vs (Δt) for each detection interval Δt of the indentation short-circuit detection period Tsd at that time. is there. Δ in the figure
T93 is a short-circuit start time delay in an abnormal time from when the pushing command signal is output to when the molten tip of the stud S comes into contact with the molten metal Wm of the workpiece W.

When a power supply device of a substantially constant current control type using a semiconductor switching element such as a thyristor is used as the welding power supply device 1 of FIG. 6 described later, the push-in short-circuit period start time t9 to the push-in short-circuit current end time t10. During this period, a constant current in which the welding current value Io is controlled to be substantially constant flows.

At the end of the main arc period t9, a pushing command signal is output to start pushing, and the molten tip of the stud S is set to the molten metal of the work W to be welded. At the moment of contact with Wm, FIG.
As shown in FIG. This steep increase in current is in a range that can be ignored compared to the average value of the indentation short-circuit current Is. Therefore, the welding current value Io during the indentation short-circuit period Ts is a substantially constant value.
As shown in Equation (5), the integrated heat input Qta may be calculated by measuring the average value Is of the indentation short-circuit current during the detection period.

[Explanation of Equations 4 to 7] The average value of the indentation short-circuit voltage Vs (Δt) at each detection interval and the average value of the indentation short-circuit current Is during the detection period are measured.
Short-circuit voltage detection start time t91 to short-circuit voltage detection end time t
The integrated heat input Qta up to 9n is calculated.

[0144]

(Equation 4)

The average value V of the indentation short-circuit voltage at each detection interval
s (Δt) and average short-circuit current Is during the detection period
And the integrated heat input amount Qta from the first detection interval Δt at the short-circuit voltage detection start time t91 to the n-th detection interval Δt at the short-circuit voltage detection end time t9n may be calculated by Equation 5. .

[0152]

(Equation 5)

The average value V of the indentation short-circuit voltage at each detection interval
s (Δt) and average short-circuit current I for each detection interval
s (Δt) is measured to calculate the integrated heat input Qta from the detection interval Δt at the short-circuit voltage detection start time t91 to the detection interval Δt at the short-circuit voltage detection end time t9n using Equation 6. Is also good.

[0162]

(Equation 6)

Average indentation short-circuit voltage V for each detection interval
s (Δt) and average short-circuit current I for each detection interval
s (Δt) is measured, and the integrated heat input Qta from the first detection interval Δt at the short-circuit voltage detection start time t91 to the n-th detection interval Δt at the short-circuit voltage detection end time t9n is calculated by Equation 7. May be.

[0172]

(Equation 7)

[Explanation of Expression 8] When the output characteristics of the welding power supply device are substantially constant current characteristics, the welding current value Io during each welding is obtained.
Is a constant value, only the indentation short-circuit voltage average value Vs (Δt) for each detection interval is integrated from the number of detections of 1 to n, and the short-circuiting period integrated voltage value Vta9n is calculated by Expression 8.

[0182]

(Equation 8)

In FIG. 4 described above, the short-circuit voltage standard value Vst9s in the entire detection period of the push-in short-circuit heat input standard value setting period Tss when the push-in short-circuit starts by the short-circuit voltage detection start time t91 is denoted by the symbol in FIG. G1, G2, G3
And G4. Similarly, in FIG. 5 described above, the indentation short-circuit detection period Tsd when the indentation short-circuit is started later than the short-circuit voltage detection start time t91.
In the figure, the integrated voltage value Vta9n
The integrated value is surrounded by 1, H2, H3, H4, H5, and H6.

In the method using the above equation 8, the integrated short-circuit period voltage value Vta9n of the press-in short-circuit detection period Tsd in FIG.
When the short-circuit heat standard value setting period Tss in FIG. 5 reaches the short-circuit voltage standard value Vst9s in the entire detection period, the inrush short-circuit current is cut off.

Using Equations 1 to 8, the integrated short-circuit period heat input Qta9n or the integrated short-circuit voltage Vta9n is calculated as
The method of interrupting the short-circuit current when the standard heat input amount or the short-circuit voltage standard value Vst9s for the entire short-circuit period has been set has been described in the section of "Means for Solving the Problems", and will not be described.

[Explanation of FIG. 6] FIG. 6 is a block diagram of a stud welding apparatus for implementing the press-in period heat input control method of the present invention. In FIG. 6, the welding power source 1 outputs the welding power of the welding current value Io at the output terminal voltage value Vd with the commercial power of the three-phase AC power source A as input, the welding gun GN, and the welding control device 3. The welding gun GN includes a servo motor 24 for moving the stud S and a movement amount detection circuit M such as a potentiometer for detecting the movement amount of the stud S.
C, a contact member GN2 and the like.

The welding power supply device 1 detects the welding current value Io supplied to the welding gun GN and outputs a welding current detection signal Ic, and the output terminal voltage value Vd of the welding power supply device 1. It is formed of a welding voltage detection circuit VC that detects and outputs a welding voltage detection signal Vc, and a welding current adjustment circuit 15 that is a semiconductor switching element such as a thyristor that controls the welding current value Io according to the current command signal.

The welding control device 3 has an arithmetic processing circuit CPU
And the “welding current value I output from the arithmetic processing circuit CPU.
D / A conversion circuit 6 for converting a “digital signal corresponding to o” to an analog signal, and a current command output circuit 5 for controlling the welding current value Io according to the converted “analog signal corresponding to the welding current value Io”. And an A / D conversion circuit 7 for supplying the detected welding current detection signal Ic to the arithmetic processing circuit CPU.
The detected welding voltage detection signal Vc into an arithmetic processing circuit CP.
A / D conversion circuit 8 for supplying to U, and arithmetic processing circuit CPU
A D / A conversion circuit 21 for converting a digital signal corresponding to the movement amount M of the predetermined stud output from the D / A converter into an analog signal, and a servo module in accordance with the analog signal corresponding to the converted movement amount M of the stud. Motor drive circuit 26 for driving motor 24, A / D conversion circuit 20 for supplying detected movement amount detection signal Mc to arithmetic processing circuit CPU, and storage for storing preset conditions, welding result data, and the like. Circuit 11
And a display circuit such as a digital panel for displaying preset conditions and welding results or a display circuit or an alarm circuit 12 (hereinafter, referred to as a display circuit 12) including an alarm circuit for notifying an operator of an abnormality.

Hereinafter, the operation of the stud welding apparatus of the embodiment shown in FIG. 6 will be described. As shown in FIG. 4, before the start of welding, the standard heat input Qst9s for the entire short-circuit period when the indentation short-circuit starts by the short-circuit voltage detection start time t91 is set in advance.

The tip of the stud held by the welding gun GN is pressed to a position where it comes into contact with the workpiece W, and the welding gun GN is pressed.
When the welding start / end switch 13 provided in the
The stud S at the contact position is pulled up by a preset pulling distance L1, and at the same time, supplies the auxiliary arc current Ip.

Next, when the arc is generated by raising the stud, the auxiliary arc current Ip is set after a preset time.
To the main arc current Ia. Auxiliary arc current Ip
Alternatively, when a predetermined time has elapsed after the required welding current value has been reached from the start of energization of the main arc current Ia, the stud S is pushed toward the workpiece W. On the way, the stud S is short-circuited to the workpiece W, and a press-in short-circuit current Is flows for the press-in short-circuit period Ts. The following operations have been described in the sections of Expressions 1 to 8 and “Means for Solving the Problem”, and thus description thereof will be omitted.

[1000]

Even if the short circuit does not occur during the arc generation and the heat input during the arc generation is appropriate, after the command to push the stud into the work piece is received, the short circuit voltage detection start time t91 When short-circuiting occurs too late, the heat input becomes excessive, but in the present invention, the short-circuit period integrated heat input Qta9n calculated from the indentation short-circuit voltage average value Vs (Δt) for each detection interval is:
Since the push-in short-circuit current is cut off at time t9n when the standard heat input Qst9s of the entire short-circuit period is set in advance, the heat input is not excessive and welding defects do not occur.

[Brief description of the drawings]

FIG. 1 is a diagram showing a positional relationship between a steel plate and a steel plate in a case where a steel plate is wavy and a gap (clearance) is generated between the steel plate and the steel plate when the steel plate is disposed on the steel plate.

FIG. 2 is a steel plate / stud positional relationship diagram showing a positional relationship between a steel plate and a stud tip when there is a gap between a steel frame and a steel plate.

FIG. 3 is an explanatory view of the prior art 2; FIG. 3 (A) shows an output when a short circuit occurs after a predetermined time t21 after a command for pushing a stud into a workpiece is issued; FIG. 4B is an output current waveform diagram showing a waveform of a current Io, and FIG.
FIG. 6 is an output terminal voltage waveform diagram showing a waveform of the output terminal voltage Vd at that time.

FIG. 4 (A) is a diagram illustrating a standard indentation short-circuit heat input value setting period T when a short-circuit is detected before a short-circuit voltage detection start time t91 after a command for pushing a stud to be a reference into a workpiece to be welded;
FIG. 8B is a diagram illustrating the calculation of the average short-circuit current Is of the ss, and FIG. 6B illustrates the average short-circuit voltage Vs (Δt) at each detection interval Δt of the standard short-circuit heat input standard value setting period Tss. It is explanatory drawing which calculates.

FIG. 5 (A) is a diagram illustrating an average value of a short-circuit current in a short-circuit detection period Tsd when a short-circuit is detected after a short-circuit voltage detection start time t91 after a command for pressing a stud to be determined into a workpiece is issued; FIG. 4 is an explanatory diagram for calculating Is,
FIG. 11B shows the average indentation short-circuit voltage Vs (Δt) for each detection interval Δt in the indentation short-circuit detection period Tsd at that time.
It is explanatory drawing which calculates.

FIG. 6 is a diagram showing an embodiment of a stud welding apparatus for performing the method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Welding power supply device 3 ... Welding control device 5 ... Current command output circuit 6, 21 ... D / A conversion circuit 7, 8, 20 ... A / D conversion circuit 11 ... Storage circuit 12 ... Display circuit 13 ... Welding start / end switch Reference numeral 15: welding current adjusting circuit 17: secondary cable / welding cable 24: servo motor 26: motor driving circuit 27: condition setting circuit A: three-phase AC power supply CPU: arithmetic processing circuit Da: arc length Dc: The clearance (clearance) (between the steel frame Wa and the steel plate Wb) Dd: the pressing distance from the reference point P / the pressing distance according to the set value Dd0: the actual pressing distance (when the pressing is insufficient) De: from the steel frame surface Indentation distance Dp ... steel plate thickness Dup ... pulling distance GN ... welding gun GN2 ... contact member Ia ... main arc current IC ... welding current detection circuit Ic ... welding current detection signal Io ... Force current / welding current value Ip ... Auxiliary arc current Is ... Push short-circuit current / Push short-circuit current average Is (Δt)… Push short-circuit current average at each detection interval I (t)… Short-circuit current instantaneous value M… Stud Moving amount of the tip MC: Moving amount detection circuit Mc: Moving amount detection signal P: Reference point Qr: Required heat input Qst: Standard heat input Qst9s: Standard heat input for the entire short-circuit period Qta: Integrated heat input Qta9n: Short-circuit period integration Heat input amount ΔQst: Average heat input amount at each detection interval S: Stud t0: Start of auxiliary arc current energization t2: Start of main arc current energization t9: End of main arc period / start of push-in short-circuit period t10: time point at which the short-circuit current is pushed in, t91: short-circuit voltage detection start time point t91 to t9n: detection start time of each detection interval Δt t93: short-circuit voltage detection start time point t91 short-circuited time point t9n Once at the shorted period overall standard heat input Qst9s /
Short-circuit voltage standard value Vst9s during the entire detection period t9s: Short-circuit voltage detection end time Ta: Main arc period Ts: Push-in short-circuit period ts0: Push-in short-circuit start time in direct welding ts1: Upper plate penetration welding S2: Push-in short-circuit detection time period Tsd: Push-in short-circuit detection time period Tss: Push-in short-circuit heat input standard value setting period ΔT91: Short-circuit start time delay in normal operation ΔT93: Short-circuit start time delay in abnormal operation Va: Arc Voltage value / Main arc voltage value before switching VC ... Welding voltage detection circuit Vc ... Welding voltage detection signal Vd ... Output terminal voltage / output terminal voltage value Vs (Δt) ... Average pushing short-circuit voltage at each detection interval Vst9s ... Short-circuit voltage Standard value Vs9n: average short-circuit voltage during the entire detection period V (t): instantaneous short-circuit voltage Vta9n: integrated voltage during the short-circuit period Δt: detection interval W: material to be welded Wa: steel frame b ... steel plate Wm ... molten metal

Claims (9)

[Claims] 1. A stud welding method in which an arc is generated by pulling up a stud from a material to be welded, and after the lifting period is completed, the stud is pushed into the material to be welded by a predetermined pressing distance to perform welding. A heat input integrated press-in control method for stud welding in which the short-circuit current is interrupted when the integrated short-term heat input calculated from the voltage average value reaches a preset standard heat input for the entire short-circuit period. 2. A stud welding method in which a stud is pulled up from a material to be welded to generate an arc, and after completion of the raising period, the stud is pushed into the material to be welded by a predetermined pushing distance to perform welding. A heat input integrated press-in control method for stud welding in which a press-in short-circuit current is interrupted when a short-circuit voltage standard value of the entire detection period calculated from a preset standard heat input amount of the entire short circuit period is reached. 3. A stud welding method in which a stud is pulled up from a material to be welded to generate an arc, and after the lifting period is over, the stud is pushed into the material to be welded by a predetermined pushing distance to perform welding. A stud welding integrated heat input press-in control method for interrupting a press-in short-circuit current when the integrated heat input amount during the short circuit period calculated from the average value reaches a predetermined standard heat input amount during the entire short circuit period. 4. A stud welding method in which a stud is pulled up from a material to be welded to generate an arc, and after the lifting period, the stud is pushed into the material to be welded by a predetermined pushing distance to perform welding. The standard heat input for the entire short-circuit period when the indentation short-circuit starts by the time when the voltage detection starts is set in advance, and from the point in time when the short-circuit voltage detection starts, the average indentation short-circuit voltage for each detection interval is measured. The average heat input amount for each detection interval of the product of the average indentation short-circuit voltage value and the average indentation short-circuit current value during the detection period is calculated to calculate the short-circuit period integrated heat input amount, and the short-circuit period integrated heat input amount is A heat input cumulative push-in control method of stud welding for interrupting a push-in short-circuit current when a standard heat input amount of the entire short-circuit period is reached. 5. A stud welding method in which a stud is pulled up from a material to be welded to generate an arc, and after the lifting period, the stud is pushed into the material to be welded by a predetermined pushing distance to perform welding. The standard heat input for the entire short-circuit period when the indentation short-circuit starts by the time when the voltage detection starts is set in advance, and from the point in time when the short-circuit voltage detection starts, the average indentation short-circuit voltage for each detection interval is measured. The average value of the indentation short-circuit voltage is integrated to calculate the short-circuit period integrated voltage value, and the short-circuit period integrated voltage value is obtained by dividing the standard heat input amount of the entire short-circuit period by the average indentation short-circuit current value in the detection period. A heat input integrated push-in control method for stud welding that interrupts the push-in short-circuit current when the short-circuit voltage standard value for the entire period is reached. 6. A stud welding method in which an arc is generated by pulling up a stud from a material to be welded, and after a period of raising is completed, a stud is pushed into the material to be welded by a predetermined pushing distance to perform welding. The standard heat input for the entire short-circuit period when the indentation short-circuit starts by the time when the voltage detection starts is set in advance, and from the point in time when the short-circuit voltage detection starts, the average indentation short-circuit voltage for each detection interval is measured. The average value of the short-circuit voltage is calculated by integrating the average value of the indentation short-circuit voltage for each of them, and the integrated voltage value of the short-circuit period is calculated by dividing the integrated voltage value of the short-circuit period by the number of detections. Calculate the short-circuit period integrated heat input of the product of the short-circuit voltage average value and the indentation short-circuit current average value and the indentation short-circuit detection period during the detection period, and the short-circuit period integrated heat input is A heat input cumulative push-in control method of stud welding for interrupting a push-in short-circuit current when a standard heat input amount of the entire short-circuit period is reached. 7. A method for controlling integrated heat input and press-in of stud welding, wherein the average value of the press-in short-circuit current during the detection period according to claim 4 or 6 is a short-circuit current set value set in the welding power supply device having a constant current output characteristic. . 8. The short-circuit current average value during the detection period according to claim 4 or 6 is a short-circuit current measurement value output from the welding power supply having a constant current output characteristic measured after the start of short-circuit voltage detection. A control method for controlling the cumulative heat input of certain stud welding. 9. The indentation short-circuit current average value during the detection period according to claim 4 or claim 6, wherein:
A stud welding heat input integrated push-in control method, which is a value calculated by integrating the average indentation short-circuit current for each detection interval calculated for each detection interval from the number of times of detection to 1 to n times.