0Cr17Ni7Al(17–7PH) physical properties

Introduction

17-7PH (S17700) stainless steel is a precipitation-hardened stainless steel that is used for a variety of applications. It has high strength and corrosion resistance, as well as being lightweight. The name 17-7PH is derived from the composition of the material, which is composed of 17% chromium and 7% nickel, with the remainder being iron. It also contains small amounts of aluminum (Al) and phosphorus (P) which are used to increase its strength and improve its corrosion resistance.

Chemical Composition

The chemical composition of 17-7PH stainless steel is as follows:

• 17% chromium

• 7% nickel

• 1.5% aluminum

• 0.5% phosphorus

• 0.2% silicon

• 0.5% manganese

• 0.2% copper

• Balance iron

Physical Properties

17-7PH stainless steel has a number of physical properties that make it suitable for numerous applications. These include:

• High strength – The high chromium and nickel content of this steel provide it with a strength of up to 925 MPa.

• High corrosion resistance – The addition of Al and P to the alloy increases its resistance to corrosion.

• High hardness – The hardness of 17-7PH is usually around 39 HRC.

• Low thermal expansion – Due to its low thermal expansion coefficient, this steel is well-suited to applications where precise measurements and materials resistance to changes in temperature need to be considered.

• Good ductility – Despite its hardness, 17-7PH stainless steel also has good ductility at low temperatures.

• Low cost – Compared to other grades of stainless steel, 17-7PH is a relatively inexpensive material.

Applications

17-7PH stainless steel is used for a variety of applications where high strength, corrosion resistance and low thermal expansion are important. These include:

• Aerospace components – High strength, low thermal expansion and corrosion resistance make 17-7PH suitable for components in the aerospace industry.

• Medical implants – The combination of high strength and corrosion resistance make it suitable for medical implants, such as replacement bones and joints.

• Food and pharmaceutical processing – The high corrosion resistance of 17-7PH make it suitable for equipment used in food and pharmaceutical processing.

• Oil and gas – The corrosion resistance and low thermal expansion of 17-7PH make it suitable for use in oil and gas applications.

• Watchmaking – The combination of low thermal expansion, hardness and corrosion resistance make 17-7PH suitable for use in watch parts and components.

Conclusion

17-7PH is a precipitation-hardened stainless steel that is composed of 17% chromium and 7% nickel. It has a high strength and corrosion resistance and a low thermal expansion coefficient, making it suitable for a variety of applications. Some common applications include aerospace components, medical implants, food and pharmaceutical processing and oil and gas components. The low cost of 17-7PH makes it an attractive option for many industries.

The physical properties of Type 17–7PH are as follows: It is a precipitation hardened stainless steel that is well suited for applications requiring high strength. The alloy is primarily composed of chromium, nickel, and iron and its alloying contents provide a high tensile strength of up to 180 ksi (1.24 GPa) and require a minimal amount of cold working prior to use. In addition to its excellent strength, 17–7PH also offers good corrosion resistance to both aqueous and non-aqueous environments, even when subjected to high temperatures. The high chromium ratio provides increased resistance to oxidation, enabling improved service-life in marine and high-temperature environments.

The mechanical properties of 17–7PH include good ductility and fracture toughness. The alloy is suitable for cold working to increase its strength and wear resistance, as well as its spring properties. This makes it suitable for a range of applications including springs, fasteners and components requiring resistance to a wide range of atmospheres.

The alloy can be heat treated to improve its wear resistance, but its main technique is an answer to age hardening – precipitation hardening. Precipitation hardening involves a quenching operation that leads to the precipitation of different carbides which imparts strength to the alloy. 17–7PH can be hardened through heat treatments at temperatures between 900-1150˚F (482–621˚C).

Overall, 17–7PH is a versatile and highly corrosion-resistant stainless steel suitable for a range of applications where high tensile strength and wear resistance are required. The alloy provides an excellent balance of strength and ductility with good corrosion resistance and fracture toughness, allowing for effective use in a variety of conditions. This makes it an excellent choice for applications in industries such as aerospace, medical, automotive and automotive aftermarket applications.