China Shipbuilding Industry Institute No. 725: Exploring "Evaluation Methods for the Extreme Environmental Fracture Resistance of Ship and Marine Steel"
Release time：2024-08-23click：2
This year is the first year to fully implement the spirit of the 20th National Congress of the Communist Party of China. All units of China Shipbuilding Corporation have thoroughly studied and implemented the spirit of General Secretary Xi Jinping’s series of important instructions and the spirit of the 20th National Congress of the Communist Party of China, always grasped the primary task of high-quality development, and firmly Establish the concept of "calculating wins beforehand, controlling wins during events, and truly winning after events", effectively enhance operation and management capabilities, and regard value creation throughout the process as the central task, and pay close attention to detail and success. To this end, China Shipbuilding WeChat has set up a column on "Establishing the 'Three Wins' Concept and Lean to Create Value" to continuously publish and broadcast the typical practices, innovative results and latest achievements of member units.
To develop the marine economy and build a strong maritime country, the 725th Inspection Center of China State Shipbuilding Corporation resolutely implements the "three-win" concept and focuses on the performance of high-end marine equipment and marine new energy equipment in extreme environments and high-voltage environments. In order to meet the application requirements of strength and large-size materials, we have devoted ourselves to research and developed the "Extreme Environment Fracture Resistance Evaluation Method of Ship and Marine Steel", which plays a very important technical support role in the service reliability of equipment.
Calculate “win” in advance and establish top-level planning and evaluation methods
With the development of the marine economy, large and ultra-large Large-scale equipment is emerging one after another, and the thickness of steel plates has exceeded 300mm. Affected by the smelting process and welding process, the steel plate base metal, welds, heat-affected zones, fusion lines and other locations under different low temperatures have different fracture resistance. It is necessary to conduct a comprehensive evaluation from multiple parameters such as the effectiveness of the crack propagation path, load-displacement curve characteristics, specimen fracture morphology, and CTOD characteristic value determination.
As the "Ship Material Verification Test Center" authorized by China Classification Society, the 725th Testing Center has established a technical research team to do top-level planning of technology, digest and absorb relevant foreign information, Simulating ship and marine engineering service conditions started in early 2021. After more than 2 years, the 300T quasi-static loading equipment was independently developed, combined with the temperature requirements of extreme service environments (low temperature range 0℃ ~ -196℃, LNG liquefied natural gas Steel for ship-borne containers requires a special temperature point -165°C), and a large-size environmental device was designed to break through the technical bottleneck of medium ratio in special low-temperature environments. Through repeated trials and explorations, a system for extreme environment fracture resistance of ship-sea steel was established. This evaluation method provides an assessment basis for the safe operation of ship and marine equipment.
Control everything to "win", and lean management ensures accurate results
The difficulty of this evaluation technology lies in the large size of the sample, the difficulty in accurately positioning the metallographic structure of the steel plate welded joint and the heat-affected zone, the difficulty in achieving accurate sample processing, and the difficulty in prefabricating the qualified fatigue crack length. The technical difficulty is high, and if the crack flatness error exceeds 5%, the test results may be invalid.
To this end, the testing center uses lean management as the starting point to sort out the difficulties in quality control during the test process, and has successively introduced eight lean manufacturing modules to optimize the equipment layout of sample processing and test processes. Developed a series of test tooling and applied for more than ten patents. Through the laboratory management system, various factors affecting the test results are accurately analyzed, and the control of the test process is strengthened to ensure the accuracy of the test results.
Afterwards, the evaluation method was promoted and applied
The service safety of equipment provides data support and has also attracted great attention from major domestic steel mills, ship and offshore platform construction companies, offshore wind turbine generators and their product suppliers, etc.
At present, it has been promoted in more than 70% of domestic ship and offshore equipment construction fields, including the largest offshore wind power project under construction in the country with a single pile foundation structure - Huaneng Cangnan Offshore Wind Power No. 2 Wind Power Project, etc., relevant performance indicators provide a basis for evaluating the service reliability of equipment. On this basis, the 725th Institute continues to expand the coverage radius of the technical line, guides the technical departments of relevant enterprises to improve the smelting process, welding process and heat treatment process of large-size steel plates, increase the anti-fracture performance of the material, and strive to create a market in the field of shipbuilding and marine engineering. The value chain provides technical evaluation basis for building high-quality equipment and extending the safe service life of equipment, achieving "real win".
Original title: Establishing the "Three Wins" Concept to Create Value with Lean | China Shipbuilding Industry Institute No. 725: Exploring the "Evaluation Method for the Extreme Environmental Fracture Resistance of Ship and Marine Steel"
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