17-4PH stainless steel is a precipitation hardening stainless steel known for its unique properties and wide range of applications. It follows AISI and ASTM standards, model number is 17-4PH (also known as SUS630), and UNS number is S17400. This material originates from the United States and is equivalent to the Chinese brand 0Cr17Ni4Cu4Nb.

17-4PH is widely used in various engineering fields due to its excellent properties. Its main components are carbon, manganese, silicon, chromium, nickel, phosphorus, sulfur, copper and trace amounts of Nb+Ta. These elements are precisely proportioned to give 17-4PH unique mechanical properties and process characteristics. This stainless steel is mainly used to manufacture shafts and steam turbine components, exhibiting its high strength and excellent corrosion resistance.

One of the performance features of 17-4PH is the ease of adjusting its strength level, which is achieved primarily by varying the heat treatment process. Its strengthening methods mainly include martensite transformation and aging treatment to form a precipitation hardening phase. This gives 17-4PH excellent attenuation properties, resistance to corrosion fatigue, and resistance to water droplets.

In terms of mechanical properties, 17-4PH exhibits excellent performance. After aging treatment at different temperatures, its tensile strength, conditional yield strength, elongation, area shrinkage, hardness and other indicators can meet different engineering needs. In addition, its density is moderate at 7.80g/cm³, making it easy to process and apply.

Heat treatment specifications are critical to the performance of 17-4PH. It includes two main steps: solution treatment and aging treatment. Solution treatment is usually carried out at 1020~1060℃, followed by rapid cooling. Aging treatment is carried out at 480°C, 550°C, 580°C or 620°C according to different needs. These processing steps ensure the stability of the internal structure of the material and the optimization of its properties.

In terms of metallographic structure, the structure of 17-4PH is characterized by precipitation hardening. This structure gives it excellent mechanical properties and corrosion resistance, making it suitable for various harsh environments and usage scenarios.

To sum up, 17-4PH stainless steel has become an indispensable material in the engineering field with its unique composition, excellent performance and flexible heat treatment process.