JPH02127987A - Quality control method for friction welded zone - Google Patents

Abstract

PURPOSE:To facilitate discrimination of mixing of foreign material and to eliminate the need to inspect a succeeding process by obtaining the approaching quantity speed from an approaching quantity detected during friction welding and the measured welding time and comparing a value corrected by welding pressure with a reference value to control it. CONSTITUTION:The approaching quantity speed V=U3/T3 is calculated from the approaching quantity U3 and the friction time T3. It is then corrected by using a calculating expression by the approaching quantity speed V and the frictional pressure P1 to obtain a control value. The reference value X3 calculated by the calculating expression from the approaching quantity speed V and the frictional pressure P1 is then inputted and this reference value X3 is compared with the control valve X to discriminate the difference between both values. When this difference is out of the predetermined control range, it is then decided that the foreign material is mixed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a quality control method for a welded part formed by friction welding, and particularly to a quality control method for a friction welded part suitable for determining the presence of foreign materials. .

[Conventional technology]

In friction welding, in which a pair of welded parts are butted together and rotated under pressure, the quality of the friction weld is controlled as described in "Friction Welding", page 129, by the Friction Welding Study Group, published by Corona Publishing. 6 In other words, the monitoring items in the friction approach method, which is the method adopted inside the shell and which sets the friction heat generation period by the friction approach distance without using a timer, are mainly the material There are four items: length detection, product length detection, friction pressure detection, and upset pressure detection, and sometimes friction time detection is also added.

Figure 3 shows a cycle diagram for friction welding.

In the figure, P on the vertical axis is the pressing force, P□ is the friction pressure, and P2 is the upset pressure. Further, N is the rotational speed of the chuck side spindle, U is the offset amount, UL is the friction offset amount, and U2 is the upset offset amount. Further, the horizontal axis indicates time, T indicates friction time, and T2 indicates upset time.

by the way,! ! During friction welding, workpieces of the same shape but of different materials may get mixed in due to operator error, but conventionally there was no means to monitor this mixing of different materials.

When foreign materials are mixed in, the amount of friction in a given time varies depending on the high-temperature strength of the materials, and the friction time changes in order to obtain a constant amount of material. Therefore, by measuring this friction time, contamination of foreign materials can be detected.

This method will be explained with reference to FIG.

FIG. 4 is a diagram showing the relationship between friction pressure P and friction time T when the workpiece having the shape shown in FIG. 5 is friction welded.

The workpieces shown in FIG. 5 are a sleeve 2 attached to a chuck 1 of a welding machine and a tube 4 fixed to a clamp 3 side.The sleeve 2 is rotated and pressed against the tube 4 to perform friction welding. Also, the material of the tube 4 is S.
Using two types, TKM20 and STKM13, the friction pressure P
FIG. 4 is a graph showing the results of measuring the relationship between □ and friction time T.

In FIG. 4, A shows the case where STKM20 tube 4 is used, and B shows the case where STKM13 tube 4 is used.

The total variation in the material lengths of the sleeve 2 and tube 4 was set to ±0.4 mm. This variation in material length causes variation in the range surrounded by two lines in the figure. The friction pressure P that is normally used at this time is approximately 4 kg/mm2, and in actual work it is controlled at approximately 4.0±0.5 kg/field 2, so the friction time T□ is STKM20.
In STKM13, the range indicated by "A" in the figure is "A".
The range indicated by "mouth" is the range in which a predetermined offset margin can be obtained.

Therefore, if tube 13 whose material is STKM13 gets mixed in while welding tube 4 whose material is STKM20,
Contamination with foreign materials is determined only when the range ``C'' is monitored, where ``1 mouth'' and ``1 mouth'' do not overlap. In addition, this range “ha”
varies depending on other factors, such as variations in the pressure contact surface, and often becomes an even narrower range.

[Problem to be solved by the invention]

As mentioned above, when foreign materials are mixed in due to operator error, it cannot be determined from the appearance of the workpiece, so inspection in the post-process is important and requires a large amount of man-hours. For this reason, it has been desired to detect the presence of foreign materials in the friction welding process, but conventionally there has been no monitoring method that can detect this. Furthermore, the monitoring of the friction time T-work is not intended to detect the mixing of foreign materials; in actual work, the friction time T-work varies widely due to variations in material length, fluctuations in friction pressure, and variations in the pressure welding surface.

Therefore, depending on the friction time T1, there is a problem in that it is not possible to reliably determine the presence of foreign materials.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a quality control method for friction welds that can reliably determine the occurrence of abnormalities such as foreign material contamination during friction welding.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a quality control method for a friction weld formed by friction welding in which a pair of welded members are abutted against each other and joined by rotation under pressure. The pressure is detected and the welding time is measured, the offset speed calculated from the offset margin and the welding time is corrected by the pressurizing force to obtain a control value, and the control value is compared with a reference value to evaluate the quality. It is characterized by management.

[Effect]

According to the above method, the offset speed is determined from the offset detected during friction welding and the measured welding time.

By comparing and managing the value corrected by the pressing force with the basic value, it is possible to determine whether foreign materials are mixed in from the difference in high temperature strength.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the basic configuration of an embodiment of the present invention. Blocks 5 and 6 detect the approach margin U3 and friction pressure P during friction welding, and block 7 measures the friction time T3 at that time.

Next, in block 8, the following calculations are performed using the welding machine control panel 9.

First, from the deviation U and friction time T, the deviation speed V=
Calculate U3 /T3. Note that the computation of the approach margin speed V may be performed not for the entire period T1, but for a certain period after the elapse of the slope period T4 shown in FIG. 3, for example, about 0.5 seconds. Next, correction is made using the calculation formula (1) shown below using the approaching speed V and the friction pressure P to obtain the control value.

However, V: Approaching speed (=us/T3) (an
/sec) b = correction value, pl: @ vapor pressure (kg/mm
2) Multiplier of a: P Next, in block 10, input the reference value: lcs calculated from the predetermined approach speed V and friction pressure P by the above formula (1), and in block 11 This reference value xs is compared with the control value to determine the difference. If this difference is outside a predetermined control range, it is determined that there is foreign material contamination. This determination result is displayed in block 12.

Next, the operation of this embodiment will be explained.

The approach speed V is not affected by the length of the material at all, and the difference occurs due to the difference in high temperature strength. Also, since the approach speed changes depending on the friction pressure P, the control value is determined by dividing it by Pla to ensure accuracy.

Also, the approach speed changes depending on the cleanliness of the joint surface, but this effect is only during the initial slope period T4, so
By adopting the approach speed T□ during the friction period T3, there is no influence from the cleanliness of the joint surfaces.6 Next, a specific example of this embodiment will be explained with reference to FIG. .

A sleeve 2 and a tube 4 as shown in FIG. 5 are used as workpieces, and the sleeve 2 gripped by the chuck 1 has a joint portion having an outer diameter of 60 nm, a plate thickness of 2 m, and is made of S30 material. In addition, the tube 4 fixed to the clamp 3 has the same dimensions as the sleeve 2, with an outer diameter of 60 mm and a plate thickness of 2 m.
The material is STKM20. Further, in the calculation formula (1), a=1. Figure 2 shows the control value when b=-0,83. Mark 0 in the diagram is tube 4
This is the case where the material is STKM20, and the part surrounded by the broken line in the figure shows the control range of control value 0.82±O, OS.

Next, tube 4 of the same size formed of STKM13
If STKM13 is mixed in, the control value will be as indicated by the Δ symbol in the figure.
It is clearly distinguished from the tube 4 of No. 0. This is because the control value changes greatly due to slight differences in high temperature strength.

According to this embodiment, when a foreign material gets mixed in during friction welding, it can be immediately determined, so there is no need for post-process inspection. Furthermore, even if there is no foreign material mixed in, abnormal conditions during friction welding can be monitored.

For example, if the voltage drops due to fluctuations in the factory power supply and the number of rotations of the spindle that rotates the chuck 1 changes, the heat generation state of the friction part changes, the approach speed changes, and the control value goes out of the control range.

Note that the calculation formula (1) for calculating the control value is not limited to this, and any other calculation formula may be used as long as it is corrected by the approach margin speed vti - friction pressure P.

〔Effect of the invention〕

As explained in detail above, according to the present invention, the quality of the friction weld is controlled using the control value obtained by correcting the approach speed during friction welding by the friction pressure, so that the contamination of foreign materials can be prevented. It is now possible to easily distinguish between the two, and post-process inspections are no longer necessary. It is also possible to monitor the occurrence of abnormalities during friction welding.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a graph showing fluctuations in control values based on experimental results of this embodiment, and Fig. 3 is a graph showing changes in spindle rotation speed, friction pressure, and offset over time. FIG. 4 is a graph showing the relationship between friction pressure and friction time for obtaining a predetermined offset margin, and FIG. 5 is a longitudinal sectional view showing the workpiece used in this example. 2... Sleeve, (member to be welded) 4... Tube, (member to be welded) U... Approach allowance, T... Welding time, P... Pressure force. Engineering...Management value. Agent Tetsuro Abe Figure Figure 3 Figure 4

Claims (1)

[Claims] (1) In a quality control method for a friction weld formed by friction welding, in which a pair of welded members are butted against each other and joined by rotation under pressure, the approach margin and pressure force during friction welding are detected, and the welding time is Friction characterized in that a control value is obtained by correcting the deviation speed calculated from the deviation deviation and welding time by the pressurizing force, and the quality is controlled by comparing the control value with a reference value. Quality control method for welded parts.