1、 The importance of ship inspection and casting testing

As a national strategic industry, the product quality of the shipbuilding industry is directly related to navigation safety and marine environmental protection. As an important component of ship structures, the quality inspection of castings is a key link in ensuring the safe operation of ships. Ship inspection of castings mainly includes multiple aspects such as dimensional accuracy, surface quality, internal defects, mechanical properties, etc. Any error in any link may lead to serious consequences. Therefore, understanding and avoiding common errors in the testing process is of great significance for improving the quality of ship inspection castings.

2、 Common types of errors in ship inspection casting testing

1. Human error in operation

Human factors are one of the main sources of detection errors, including:

Insufficient skills or experience of the testing personnel

Improper operation or failure to follow standard procedures

Visual fatigue leads to misjudgment

Subjective bias affects test results

2. Equipment and instrument errors

The accuracy and status of the detection equipment directly affect the detection results:

The instrument is not calibrated regularly or maintained improperly

The equipment accuracy does not meet the testing requirements

Sensor sensitivity decreases

Environmental interference causes equipment abnormalities

3. Detection method error

Improper selection or non-standard execution of detection methods:

Misunderstanding or improper application of testing standards

The sampling location is not representative

Unreasonable detection parameter settings

Improper timing of detection

4. Environmental condition error

The impact of environmental factors on test results:

Fluctuations in material properties caused by changes in temperature and humidity

Vibration and noise interference detection equipment

Lighting conditions affect the visual inspection effect

Electromagnetic interference affects the accuracy of electronic devices

5. Data processing errors

Problems encountered during the recording and analysis of test results:

Data recording errors or omissions

Improper application of calculation formulas

Statistical analysis deviation

Report preparation is not standardized

3、 Methods to avoid detection errors in ship inspection castings

1. Strengthen personnel training and management

Establish a comprehensive qualification certification system for testing personnel to ensure that they possess the necessary professional knowledge and skills

Regularly organize technical training and experience exchange to improve the professional level of testing personnel

Implement a rotation system for testing personnel to avoid fatigue and habitual thinking caused by long-term single work

Establish a quality responsibility system for testing, clarify the responsibilities of each link, and enhance the sense of responsibility of testing personnel

2. Improve equipment management system

Establish strict procurement standards for testing equipment to ensure that equipment accuracy meets testing requirements

Establish equipment ledger, implement regular calibration and maintenance plan

Monitor the status of key detection equipment, promptly detect and eliminate faults

Equip necessary backup equipment to prevent the detection progress from being affected by equipment failure

3. Optimize detection methods and processes

Choose the most suitable testing method and standard based on the type of casting and testing requirements

Develop detailed testing operating procedures and clarify the technical requirements for each step

Implementing multi method joint testing for complex castings to improve testing reliability

Establish a testing process validation system to ensure the effectiveness of testing methods

4. Control and detect environmental conditions

Establish a testing laboratory that meets standards and controls environmental parameters such as temperature and humidity

Take vibration isolation measures for vibration sensitive equipment

Ensure sufficient and uniform lighting in the visual inspection area

Take shielding measures for electromagnetic sensitive equipment

5. Standardize data processing procedures

Adopting an electronic data collection system to reduce human recording errors

Establish a data review mechanism to ensure the accuracy of test results

Use standardized data processing software to avoid calculation errors

Standardize the format of testing reports to ensure complete information and accurate expression

6. Implement full process quality control

Establish a full process inspection system from raw materials to finished products

Set quality control points for key processes

Implement a quality control model that combines first piece inspection and process sampling inspection

Establish a quality traceability system to facilitate problem analysis and improvement

7. Adopting advanced detection technology

Introduce automated detection equipment to reduce the impact of human factors

Advanced non-destructive testing technologies such as digital radiography (DR) and computed tomography (CT) are applied

Using machine vision technology to improve the accuracy and efficiency of surface defect detection

Develop an intelligent data analysis system to assist in the judgment of detection results

8. Establish a continuous improvement mechanism

Regularly analyze and test data to identify systematic errors

Encourage testing personnel to provide improvement suggestions

Track new detection technologies and development trends in the industry

Participate in the formulation and revision of industry standards, and maintain the progressiveness of testing methods

4、 Typical Case Analysis

A shipyard has repeatedly encountered missed inspections in the inspection of large rudder handle castings. After analysis, it was found that the main reason is:

The inspection personnel have insufficient understanding of the key inspection points for complex structural castings

Unreasonable parameter settings for ultrasonic testing

The division of detection areas is not scientific

Improvement measures:

Develop special testing procedures for this type of casting

Optimize ultrasonic testing parameters and validate them through test blocks

Adopting partition detection method to ensure full coverage

Introducing TOFD detection technology as a supplement

After implementation, the defect detection rate of this type of casting increased from 82% to 98%, effectively avoiding quality hazards.

Errors in the process of ship inspection casting testing are inevitable, but they can be controlled within an acceptable range through systematic management and technical measures. The key lies in establishing a scientific quality management system, improving personnel quality, optimizing testing methods, improving equipment management, and continuously tracking and improving. With the continuous development of detection technology, intelligent and automated detection methods will provide new solutions for improving the accuracy of ship inspection casting detection. Shipbuilding enterprises should attach great importance to quality control in testing, laying a solid foundation for building high-quality ships.