Shougang Jingtang aims to further expand the energy-oriented steel market. Recently, its new product, LPG carrier high-strength steel P690QL1, was put into mass production and successfully supplied to China Merchants Jinling Shipyard Dingheng Co., Ltd.

Jingtang has further broadened its supply range of high-grade quenched and tempered products, and broken through the limits in low temperature resistance, product thickness and strength. Liquefied Petroleum Gas (LPG) is a by-product of oil exploitation and refining, and natural gas processing. As the core equipment of large full-pressure LPG carriers, LPG storage tanks bear dynamic load which imposes high technical requirements, making them difficult to manufacture. Because LPG ships sail on the sea throughout the year, the requirements for the safe service of their steel plates are particularly strict. LPG marine steel needs to meet service conditions under high pressure and ultra-low temperature, which is a great test of the stability of a steel mill’s manufacturing processes. China Merchants Jinling Shipyard Dingheng Co., Ltd. is the world's leading LPG carrier manufacturer, and Shougang and Shipyard Dingheng have a long-term and stable friendly cooperative relationship. In the course of their long-term cooperation, the shipbuilding enterprise has delivered many ships with excellent performance using Shougang’s medium steel plates. Relying on the advantages of the Shougang Group, the Shougang Medium and Heavy Plate Team made full use of the online office conference system to overcome the impact of the epidemic, actively promoted communication with customers and adopted the "Cloud Conference" and "Cloud Signing" methods which contributed to the smooth implementation of the project.

As a new type of ship, the LPG carrier of this project possesses deeply optimized hull lines and layout, and meets the latest specification requirements, with its performance reaching the world-leading level in every aspect. Compared with traditional full-pressure LPG carriers, this ship has such advantages as low oil consumption and green environmental protection. The required product is European standard quenched and tempered high-strength steel, and the lower limit of its tensile strength is 770 MPa. It is required to have low-temperature impact properties above 80 joules at -40°C and excellent welding performance, making its technical difficulty is very high.

The project has a tight timeline and heavy workload. The Jingtang Medium and Heavy Plate Team and the relevant personnel of the shipbuilding enterprise have made great efforts from the initial technical and commercial communication to the later contract execution and delivery. In order to ensure the smooth delivery of the first contract, Zhang Xuefeng of the Medium and Heavy Plate Division cooperated with Zhang Yuefei of the Manufacturing Department to carefully study the technical conditions of the products. According to the processing, welding and use characteristics of LPG marine storage tanks, they discussed the composition design and welding process with Wang Fenghui, the welder from the Technical Center, and fully analyzed the historical data. Based on the thickness and class intervals of the orders, they refined the composition design and heat treatment quenching and tempering process, and carried out thoroughly detailed process tests, in order to ensure that the products were qualified on the first attempt and achieve a new breakthrough in the performance of LPG marine high-strength steel for medium and heavy plate products. A total of 1,659 tons were delivered this time, which is the first time that Jingtang has delivered more than 1,000 tons in bulk supply.

The production of LPG marine high-strength steel has created the conditions for Jingtang to further strengthen its deep strategic cooperation with China Me