JP2001079683A - Method for objectively evaluating welding execution by utilizing heat input temperature by welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of the welding quality, and to certify the appropriate quality realized under an appropriate condition of execution to a third party by combining the data on the welding output side with the heat data measured at a plurality of positions on the welding input side, and objectively evaluating the combined data by the comparative analysis of the theoretical values and actual values. SOLUTION: A groove 5 is welded in the advancing direction 2 using a backing 1. The data on the welding output side (a welding machine side) is measured at appropriate time intervals over the whole time during the welding work, and the heat data on the welding input side (a base metal side) is measured by a plurality of heat sensors A and B to understand the speed, the position, etc., other than the temperature at the same time. The data is combined with each other, and compared with the theoretical and actual values for analysis to objectively evaluate the combined data by the numerical values in the summary sheets, graphs, etc. The welding output condition can be corrected on the real time basis making use of the data. The input, comparative analysis, summation, graphing and evaluation of the data are achieved by making use of computers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to quality control of an electric welded portion of a welded structure of a metal such as steel used for construction, bridges, shipbuilding, civil engineering, machinery, equipment, etc., for heat management required parts.

[0002]

2. Description of the Related Art The quality control of an electric welded portion of a metal is carried out according to the following items, although there are some differences in implementation details depending on the type and material of the metal. 1. Base material side shape of welded part such as groove 1. Welding output side welding output conditions 3. Temperature management between passes 4. Inspection after welding is completed

[0003]

[Problems to be Solved by the Invention]

1. In the case of electric welding, when the welding work is completed, the construction state is unknown from the outside, and the construction report is handwritten, and there is insufficient objective back data during construction. In manual welding, the welding operator is a human being, so the welding manager verifies the welding work by verbal or document, and if necessary, confirms the welding work by saying ``How the operator determines the shape of the welded part It is a repetition of the instruction to protect the welding conditions and the temperature between passes. Although the welding method is instructed and instructed to the welding operator by the welding manager, the welding operation depends on the skill of the welding operator, and the data during the welding is an individual report and the record is from the viewpoint of objectivity. There are many problems.

2. Computer-controlled automatic welding has sufficient recordability on the welding output side and can be said to have sufficient objectivity, but when considering the shape and accuracy of the welded part, it is not possible to follow it and it can be detected even if a defect in welding quality occurs. Often not. Therefore, it is necessary to have a function of determining whether the welding work has been properly completed or a defect has occurred.

3. Until recently, welding has been required to have no work speed and no internal or external defects.
It was pointed out that the thermal history of welding has a great influence on the overall performance of the weld metal and the base metal on the welded side. Speaking of heat management, it was only preheating and postheating, but further heat input management (The amount of heat input per unit welding length) and the temperature control between passes (base metal temperature when welding starts) have come to be performed. This is possible if the welding heat input state is monitored from the base metal side, but one thermal sensor can measure only the temperature above and below a specific position. Only this information is appropriate from the base metal side. Various data including the position on the input side are available for automatic welding, in which it is not possible to determine whether or not various welding operations have been performed, but manual welding is limited to simple electrical data such as input voltage and current. Generally speaking, when it comes to heat input measurement, no other than data on the input side has been tried, but is it possible to evaluate its appropriateness from the heat history on the side of the heat-treated base metal?

4. It is required that the manufacturing procedures for manufacturing products should be properly performed and that the products manufactured as a result should be of proper quality in writing.
Welded workpieces are no exception to this rule, but even computer-controlled automatic welding only records on the welding output side, and even if the manufacturing procedure is proved to be proper, it is not a document that proves proper quality. However, welding has also been properly constructed, and it has become necessary to objectively prove in writing that the quality is proper.

[0008]

[Purpose of solving problems]

All the time during the welding operation is measured at appropriate time intervals on the welding output side data, and at the same time the input side (base material side) thermal data, which has not been attempted in the past, is grasped for the speed and position other than temperature. In order to do so, measure at multiple positions, combine these and compare and analyze with theoretical values and practical values (experience values and range in which defects do not occur), express them numerically such as a spreadsheet or graph, numerically indicate the appropriateness of welding construction The objective is to objectively evaluate and improve the reliability of the welding quality, and to prove to a third party that the quality is the proper quality created by proper construction. Input of these data, comparative analysis, tabulation, graphing, and evaluation are performed using an electronic computer.

[0010]

[Procedures for solving problems]

In the explanation of the procedure, the welding procedure is adopted as an example of gas shield arc manual welding, and the procedure is as follows. Procedure 1 Input of fixed element information a Date and time, operator name b Work site name, base metal material, welding shape, welding material and bar diameter, shield gas, etc. c Welding procedure (sequence, construction method, etc.) Step 2 Welding output side Measurement of variable element information a Welding output conditions (current, voltage, welding material feed rate, etc.) b Shield gas pressure and flow rate, etc. Procedure 3 Multiple thermal sensors placed near the welding line on the input side (base metal side) Measurement of thermal information from the procedure Procedure 4 Data comparison analysis, tabulation, graphing, evaluation

[0012]

[Examination of input etc. to computer for each procedure]

Procedure 1 Input of fixed element information A method of inputting, recording, and utilizing a basic element of a welding site is a well-established technique. Procedure 2 Measurement of variable element information on the welding output side The method of outputting as electric signal data and converting, inputting, recording and utilizing it as electronic data is an established technology. Procedure 3 Measurement of thermal information from multiple heat sensors arranged near the welding line on the input side (base metal side) Since this measurement data is electrical signal data, it is converted to electronic data, input, recorded and utilized. The method is an established technology. Procedure 4 Data comparative analysis, tabulation, graphing, evaluation It is natural to create back data for comparative analysis, but since this field is the best field of the computer, it is a program software for this. It's not difficult to make.

[0014]

[Effect of placing multiple heat sensors near the welding state on the welding output side and the welding line on the input side (base metal side) and recording heat continuously at the same time]

In order to clarify the welding history, variable element information on the welding output side is continuously measured at appropriate time intervals from the start to the end of welding, and at the same time, one side of the welding line on the input side (base metal side) surface is measured. Alternatively, a plurality of heat sensors are arranged on both sides at a predetermined position near the welding line, and the heat data input by welding is continuously measured at appropriate time intervals from the start to the end of welding. (Depending on the application/purpose, the surface to be placed is the front surface, the back surface,
Either side may be used. ) The following description will be given with reference to FIG. 1. The heat sensors are arranged at two positions on one side of the surface of the welding line, and welding is performed in the direction of the arrow.

1. Measurement of stable welding speed The welding speed is displayed as the average speed from the start to the end of welding, but the section L1 is actually the welding start end section and the section L3.
Since it is the welding end part, there is each processing work and it cannot be said that the welding speed is stable. Since the L2 section is welded at a stable speed even by manual welding, the measurement error is small. The distance between the sections L2 where the welding speed is stable is the peak temperature measured by the thermal sensors A and B. The stable welding speed is obtained by dividing by the time. Therefore, a stable welding speed can be measured by arranging a plurality of heat sensors.

2. Specifying the end processing time zone of the start end terminal If the time zone other than the end processing work is welded at a stable welding speed, the end processing time of L1 = L1-L2 / stable welding speed
Will be If the end processing time of L1 can be calculated and the current/voltage fluctuation time zone on the welding output side of the end processing part can be specified and it becomes clear in the summary table or graph, the work method of this part where the failure rate is high Improvement and standardization also become easy.

3. Confirmation of proper welding work and influence on post-welding inspection Metal has the property of heat diffusion as well as heat conduction. In the welding shown in FIG. 2 and FIG. 3, the peak temperature and the conduction time, which are sensed differently depending on the distance and the heat concentrated portion, are different. The data to be sensed may have some errors or deviations due to the heat effect of the immediately preceding welding, but if compared with the data of the same shape groove cross section properly welded by a predetermined procedure, the welding target position, sequence, operation It can be inferred whether the stick method, penetration depth, etc. are appropriate. With multiple heat sensors, the direction of welding can be easily determined. For example, if a temperature difference occurs at the peak temperature of heat sensors A and B even under appropriate welding output conditions at a stable welding speed, it is possible to aim at welding. It is inferred that a defect has occurred, which serves as data for improving the welding work after that, and is a large index for selecting inspection targets after welding, which leads to rationalization of inspection after welding.

4. Prediction of position of welding failure part In welding failure, the output state of electricity, gas, welding material supply, etc. on the welding output side is often in an unstable state, but it is difficult to identify the occurrence position from the input side. Since it is possible to calculate the specific position of welding by arranging multiple heat sensors, the defective position can be specified with high accuracy by combining the variable element information on the welding input side and the heat sensor information on the heat input side.

5. Confirmation of proper construction of welds and prevention of defects Even if the information on the welding output side is clear by computer-controlled welding, there are subtle assembly errors in the groove (cross-section) of the weld and heat shrinkage of the welded part due to welding heat. Since it is not possible to confirm whether the work has been performed after absorbing the influence, the inspection for confirming the welding quality is carried out in the same way as in the case of manual welding. Therefore,
If it can be confirmed from the input side (base material side) that proper welding work has been performed, the inspection method can be simplified. Further, even if a defect occurs in the welding process, a time difference occurs due to heat conduction, but the position is known in real time, so that it is possible to perform work interruption repairs and welding output condition changes at that point. This is due to the fact that there is no real-time information, such as repairs based on the results of inspections after completion of welding as in the past, or the occurrence of defective welding sites that result from improper welding work. It is also possible to prevent it.

6. Comprehensive evaluation of welds Welding inspections are divided into non-destructive inspections and destructive inspections, and non-destructive inspections are performed by sampling after welding or by 100% inspection. The welding site construction information can be expressed as highly reliable objective numerical information by using the welding output data and the data from the heat sensor on the input side, so a confirmation test and an abnormal numerical value to confirm the reliability of this numerical value. It is only the examination of the part that shows. This has a large economic effect because the welding internal inspection of the nondestructive inspection is simplified. Weld visual inspection
After welding is completed, the presence or absence of defects on the appearance is checked visually or by using a measuring instrument.In this field as well, the technical field of numerically evaluating the surface irregularities using a computer can be used for welding appearance inspection. Since it came, if this is used together, comprehensive evaluation based on the numerical value of the welded part becomes possible.

7. Welding history (base material shape, welding output side, input side, non-destructive inspection, destructive inspection, etc.) measurement data is compared with theoretical values and empirical values on a computer. b The generated document is highly reliable as data. c It is possible to prove to the third party that the work was properly constructed. d Based on the generated document, it is possible to guarantee that the welding quality is proper, and also to guarantee financially.

[Brief description of drawings]

FIG. 1 is a plan view of a case where two heat sensors are arranged at a predetermined position near a welding line of a portion to be welded.

FIG. 2 is a cross-sectional view of a case where a heat sensor is arranged at one side of a welding line at a welding portion and the heat sensor is welded to the heat sensor side.

FIG. 3 is a cross-sectional view of a case where a heat sensor is arranged at one side of a welding line at a welding site and the other side of the heat sensor is welded.

[Explanation of symbols]

1 backing plate 2 welding direction 3 thermal sensor 3 welded part 5. Groove face

Claims (4)

[Claims] 1. The data obtained by arranging a plurality of heat sensors on the input side of the welding target (base metal side) and the data on the welding heat output side (welding machine side) are combined and analyzed in comparison with theoretical values and practical values. Use numerical values such as a spreadsheet and graphs, objectively evaluate the appropriateness of the welding construction numerically, and use a method to prove to a third party that the quality is proper under the proper construction conditions and these data Method for correcting welding output conditions in real time 2. A method for comprehensively evaluating welding by combining the method described in the preceding paragraph and data such as nondestructive melting inspection and destructive inspection after welding. 3. An act of guaranteeing that the welding quality is proper or monetarily guaranteeing it based on the document generated in claim 1 or claim 2. 4. The act of certifying that the welding technique of the welding operator is appropriate based on the document generated in claim 1 or 2.