Pressure-resistant structural materials are the foundation for supporting the descent and ascent of marine equipment. Titanium alloys, with their characteristics of lightweight, high strength, and corrosion resistance, have become the preferred materials for pressure-resistant structures in deep-sea manned equipment and show promising prospects for application. This article briefly describes the development history and research progress of typical deep-sea manned equipment such as submarines, submersibles, deep-sea workstations, and underwater laboratories, as well as their pressure-resistant structural materials. The current state of domestic titanium industry development and the research foundation in the titanium alloy material system for marine engineering, titanium alloy pressure-resistant structure manufacturing technology, and design and testing research is introduced. In combination with the technical characteristics of large deep-sea equipment titanium alloy structures, the article analyzes the key scientific and technological issues and application demands for titanium alloys used in pressure-resistant structures, providing a reference for the future development of titanium alloys for pressure-resistant structures in deep-sea manned equipment.

Upholding the green and low-carbon development of the maritime industry is not only imperative for the control of the global climate change, but also promotes the industrial transformation and upgrading. Since the United Nation launched the action on Climate Change, the international maritime community has been seeking a fundamental solution to the greenhouse gas (GHG) emission reduction through the combination of technology, operation and market. With the continuous enriching of the topics on the marine pollution prevention, the application of new technologies driven by the legislation is promoting the gradually developed “green solutions” for whole-ship solutions. The rapid changes in product concepts and methods are also increasingly affecting the whole process of the ship design, manufacturing and operation, extending to the supply chain management in the perspective of the full life cycle of carbon footprint. The current study aims to analyze and summarize the key points of GHG emission reduction in maritime legislation, industry technological innovation, important hot issues and several major factors affecting the future development of the industry in the past decade. Focusing on the key issue of alternative marine fuel transition, the directions, key points and strategies of the industry to adapt to green and low-carbon are proposed from the perspective of industrial competition and technological development.