Ship type military equipment includes destroyers, cruisers, battlecruisers and battleships. Its structure is analyzed and divided into ship platform system and ship power system.
1. Ship platform system
The ship platform system includes keel, deck, shell plate, inner bottom, partition wall and bow post. Keel is an important longitudinal component from stem to stern post. The keel material on small ships is forged steel or iron, and the keel on large ships is made of steel plate. Deck, shell plate, inner bottom and partition wall are all steel plate weldments. The bow post is forged on larger ships. On smaller ships, the upper part is forged and the lower part is cast.
2. Ship power system
Ship power system includes nuclear energy, conventional energy and engine device, as well as auxiliary equipment, equipment, transmission shafting and control and monitoring system required to ensure the normal operation of engine device. In the ship power system, only the engine device involves the demand of steel castings. The common engine devices are gas turbine, diesel engine and steam turbine.
Gas turbine has the characteristics of high power, fast starting speed and low noise. The disadvantage is high cost. It is the first choice of ship power system in the future. “Aviation modified gas turbine” is the mainstream direction of current research and development. Its main manufacturers are general electric company and Pratt Whitney group company (Pratt Whitney for short). The models produced by general electric company mainly need weldments and iron castings, and the models produced by Pratt Whitney company need steel castings. In China, AVIC Chengdu Engine Co., Ltd. is producing Pratt & Whitney models, but Pratt & Whitney made it clear that these aviation modified gas turbines can only be used for civil use, not for military industry.
Diesel engine has the characteristics of good economy, low fuel consumption and simple and sensitive operation. Most of the castings used in the shell are cast iron, and there is no demand for steel castings.
| Products | Texture of material | Casting quality | Demand | Market value | Procurement source |
| Steam turbine shell for submarine | ZG12Cr22Ni12 | 266 kg / piece | On average, China builds one submarine every year. There are 8 engines on a submarine. Each engine needs two shells, and a total of 16 shells are used. | 169 172 yuan / ton | It is mainly purchased from Shenyang Foundry Research Institute, and a small part of it is purchased from China First Heavy Machinery Group Corporation, not from other enterprises. |
| Marine anti wave valve | ZG230-450 | 600 kg / piece | About 10 pieces per year | 180000 yuan / ton | The 703 Research Institute of CSIC has designated an enterprise specializing in the production of marine anti wave valves in China |
| Turbine housing | Chromium molybdenum steel | 1 ~ 2 T / set | The annual demand is about 7-8 sets | No outsourcing | Except for non-ferrous metal products such as cast copper pumps and valves, others are produced in internal military foundry. |
Steam turbine, China has realized the localization of large steam turbine for a long time, and domestic ships have a great demand for steam turbine. Through the three major domestic steam turbine manufacturers, including Dongfang Steam Turbine Co., Ltd., Harbin Steam Turbine Plant Co., Ltd. and Shanghai steam turbine plant of Shanghai Electric Power Station Equipment Co., Ltd., we investigated the demand for steel castings of steam turbines in the military industry, as shown in the table.