Steel structure ultrasonic inspection report common problems and countermeasures

In recent years, the building steel structure has gradually become popular, and has become the mainstream structure of industrial enterprise housing. However, the weld quality of the building steel structure has always been the key factor affecting its quality, so the non-destructive testing of the building steel structure has become the top priority in the testing work.

As one of many non-destructive testing methods, ultrasonic non-destructive testing has a core position in the testing of building steel structure, and the quality of its testing report directly affects the safety grade assessment of building engineering quality.

However, as far as the ultrasonic nondestructive testing report of building steel structure is concerned, there are still many significant problems.

From the perspective of improving the quality of building steel structure inspection report, this paper based on the problem perspective, from the analysis of reasons, to carry on a deeper analysis of the corresponding countermeasures has very important practical significance.

Ultrasonic nondestructive testing has the characteristics of no damage to the structure and fast detection speed, and has obvious advantages in actual operation.

However, due to the existence of various objective factors, there are many problems in the link of the detection report after the completion of the detection work, which are the reaction of the problems in all aspects of the entire detection process.

The author summarizes it on the basis of work experience, mainly including seven aspects. Next, it is explained one by one.

(1) The probe selection is wrong

Ultrasonic detector is composed of many components, of which the probe is a very important component. Different probes are consistent in terms of function, but there are obvious differences in performance, in simple terms, different probes should have different roles, for different steel structure types, need to choose the probe that is suitable to ensure the reliability and authenticity of steel structure ultrasonic test results. However, in the actual operation process, the relevant detection personnel do not realize the importance of this problem, in the selection of the probe, often for the convenience of work, random selection, in the case of not fully considering the applicability, random selection of the probe, resulting in the probe is not applicable, and then affect the actual detection process in the final result. For example, if the probe K value is too small or the chip area is too large, it may not be able to obtain a good defect echo. If this happens, the inspection report of the building steel structure will not be able to guarantee its effectiveness.

(2) The selection of standard specimen and comparison specimen is wrong

In the process of ultrasonic testing, in order to determine whether there are defects in the welding seam of the building steel structure, the authenticity and effectiveness of the results cannot be guaranteed only by relying on naked eye observation. Therefore, it is necessary to compare the standard specimen with the comparison specimen to find the problems, and then determine whether the building steel structure has defects, and then grade the defects according to the relevant standards. This is used to determine the safety level of the building steel structure. However, in the actual situation, there is often confusion between the standard specimen and the contrast specimen in the ultrasonic test report, which directly affects the division of the safety grade of the building steel structure.

(3) Surface coupling compensation error

After the inspection personnel completed the writing of the defects of the relevant steel structure, they did not carry out test analysis on the subsequent surface coupling compensation, and compared it with the standard specimen to determine the compensation value. They only relied on experience to carry out arbitrary compensation, resulting in the surface coupling compensation error.

(4) The state of the flaw detection surface is not accurately filled

When writing test reports, inspectors often hold a cynical attitude and lack a strong sense of responsibility when writing test questions. In the absence of a comprehensive analysis of the status of the flaw surface, they fill in various information, such as the smoothness of the flaw surface, the temperature of the specimen, whether the specimen has been completed for more than 24 hours, and the type of coupling agent. Therefore, the quality of the test report needs to be improved.

(5) The steel type and thickness of the weld base material are not shown on the report

In short, in the test report, it is usually necessary to record the information in detail, so that the inspection personnel can have a reference for follow-up work, the type and thickness of the weld base metal as an important test information, in the test report must have a detailed record, especially according to the current GB/T29712-2013 "Weld non-destructive testing - ultrasonic testing - acceptance grade". Defect length and thickness are important indicators for grading. However, in actual operation, inspectors do not realize this importance, so they neglect to fill in the information related to the weld base metal grade and thickness in the report issued.

(6) The grade evaluation of the inspected weld is relatively vague

After the weld inspection, the grade evaluation, as an important content, is mainly based on the test results, and then compared with the relevant standards to determine the grade. However, in the actual operation, the inspection personnel in the grade assessment, often according to their own experience, or do not refer to the standard for grade assessment, resulting in the inspection of the weld grade assessment errors.

(7) The weld rating is wrong

Just like the above operation, in the actual writing process, the inspection personnel, due to their own weak sense of responsibility, coupled with the lack of personal work experience, caused the weld grade assessment errors, such as the first level of the wrong assessment of the second level, which directly affected the follow-up work.

2.1 Cause analysis of detection report problems

The reason why the above problems appear in the ultrasonic test report of building steel structure is that in actual operation, there are the following three problems.

First of all, the professional technical level and comprehensive practical ability of ultrasonic non-destructive testing personnel need to be improved, and the current standards are not fully mastered, resulting in frequent small errors in actual operation, such as fuzzy grade assessment.

Secondly, ultrasonic non-destructive testing personnel lack enough work experience, while personal responsibility and professional quality need to be improved, this state also reflects that the testing personnel do not realize that the issue of the test report needs to bear the corresponding legal responsibility.

Finally, the supervision and management department of testing work has not formed a uniform provision for the ultrasonic non-destructive testing report, and it is not specific in terms of quality requirements.

The existence of the above problems, under the combined effect, led to the above seven problems in the ultrasonic nondestructive testing report, which had an adverse impact on the safety and stability of buildings. Therefore, it is particularly important to discuss the countermeasures of related problems in this paper.

2.2 Analysis of common problems and countermeasures

For the seven problems analyzed above, in order to be effectively solved, the relevant personnel need to analyze the causes of the problems on the basis of clarifying the problems, and then take corresponding measures according to the actual needs.

The author believes that the solution of the above problems mainly starts from the following aspects.

(1) Countermeasures to the problem of incorrect probe selection

After consulting the relevant provisions in GB/T11345-2013 "Ultrasonic Testing Technology, testing Grade and Evaluation of Weld Non-destructive Testing", the inspection personnel choose the appropriate probe in strict accordance with the relevant provisions and combined with the specific needs of the work.

(2) Countermeasures when the selection of standard specimen and comparison specimen is wrong

Relevant inspection personnel need to combine the use of the detected component and the plate thickness, select the standard specimen and the comparison specimen that are suitable for it. Under normal circumstances, the on-site selection of steel structure ultrasonic testing standard specimens and comparison specimens must be strictly implemented with reference to the relevant provisions of GB/T11345 "Weld non-destructive testing - Ultrasonic testing - Technology, testing grade and evaluation".

(3) Countermeasures to the problem of surface coupling compensation error

In view of the varying roughness of the surface of the steel structure, the coupling compensation should be determined according to the measured ultrasonic data.

(4) Countermeasures for the problem of inaccurate filling in the state of the flaw detection surface. The writing of the state of the flaw detection surface is not without requirements, but needs to be strictly filled in with reference to the relevant provisions of GB/T11345 "Non-destructive testing of welds - ultrasonic testing - technology, detection grade and evaluation", that is, smooth and smooth, convenient for the probe to be freely scanned.

(5) The weld base metal grade and thickness do not show the problem countermeasures in the report

The information related to the weld base material grade and thickness is displayed in the inspection member in order to determine the inspection time and to select the appropriate standard, test piece and probe.

(6) Countermeasures to the fuzzy problem of weld grade evaluation

In the ultrasonic non-destructive testing report, the amplitude, length and depth of weld defects need to be clearly recorded, mainly to provide relevant reference data for subsequent weld grade evaluation. Whether the record of the amplitude in the test report is clear, only according to the level of the record amplitude, can determine whether the inspected weld is defective or not, once there is a defect, further operations need to be carried out, that is, defect positioning, and finally the level assessment. If the welding seam of the building steel structure is characterized as a more serious defect after the assessment, it needs to be repaired in time to avoid burying safety hazards for subsequent work, so as to ensure the safety and stability of the building steel structure.

(7) Countermeasures for the problem of wrong weld rating

In the ultrasonic non-destructive testing report of steel structure, the correct rating and judgment of the inspected welds are mainly referred to GB/T29712 "Non-destructive testing of welds - Ultrasonic testing - Acceptance grade" for systematic evaluation.

In addition, in order to avoid the above problems in the ultrasonic non-destructive testing report and effectively improve the quality of the test report, it is necessary to regularly communicate with the test report, communicate and solve the controversial problems among them, and regularly organize relevant personnel for systematic training. In addition, the relevant departments need to develop unified quality standards, and need to strengthen the necessary supervision and management.

In summary, steel structure, as the mainstream form of industrial enterprise housing structure, has obvious advantages in the stability, safety, economy and efficiency of industrial enterprise buildings.

However, once the weld quality of the steel structure is not up to standard, there will be adverse consequences and hidden dangers.

Therefore, the building steel structure ultrasonic nondestructive testing is particularly important.

In view of this, this paper analyzes the common problems and countermeasures in the ultrasonic inspection report of building steel structure, which has very important practical significance to improve the safety and stability of building steel structure.