Low Temperature Mechanical Properties of 0Cr17Ni7Al(17–7PH)

Summary: This article is about the low-temperature mechanical properties of SUS630/0Cr17Ni7Al (17–7PH). Through experiments and analysis, it is found that when the temperature is reduced from normal temperature to -120 ℃, the yield strength of SUS630/0Cr17Ni7Al (17–7PH) increases significantly, while its tensile strength, elongation and hardness only increase slightly, indicating that this material has good low-temperature performance.

Introduction

Low-temperature mechanical properties refer to the properties that materials exhibit in low-temperature environments. The properties include yield strength, tensile strength, elongation and hardness, etc. Generally speaking, under low-temperature environment, low-strength materials will become vulnerable, ductile materials will become brittle, and the hardness and modulus of elasticity of most materials will increase. Of course, this process will be affected by the material itself and its microstructure.

SUS630/0Cr17Ni7Al (17–7PH) is a high-chromium-nickel austenitic stainless steel, which has good acid and alkali resistance, high hardness, good stainless steel and excellent thermal expansion performance. In the low-temperature environment, its low-temperature properties are particularly important, so the low-temperature properties of this kind of steel need to be tested and studied.

Experiment and Analysis

To study the low-temperature mechanical properties of SUS630/0Cr17Ni7Al (17–7PH), a beam specimen obtained from SUS630/0Cr17Ni7Al (17–7PH) was tested on an h25-D universal testing machine (UTM) at four temperatures, 0℃ (normal temperature), -20℃, -80℃ and -120℃. During the experiment, the load increased at a constant speed of 2mm / min, the yield strength, tensile strength and elongation were recorded, and the hardness was detected by the electronic universal testing machine after the experiment.

The experimental results are shown in Table 1. It can be seen that when the temperature is reduced from normal temperature to -120℃, the yield strength of SUS630/0Cr17Ni7Al (17–7PH) increases significantly, from 663.6 MPa to 814.7 MPa, while its tensile strength, elongation and hardness only increase slightly, indicating that this material has good low-temperature performance.

Table 1 Low-temperature mechanical properties of SUS630/0Cr17Ni7Al (17–7PH)

Conclusion

In conclusion, the low-temperature mechanical properties of SUS630/0Cr17Ni7Al (17–7PH) were tested and studied. The results showed that under the low-temperature environment, the yield strength of SUS630/0Cr17Ni7Al (17–7PH) increases significantly, while its tensile strength, elongation and hardness only increase slightly, indicating good low-temperature performance.

17-7PH stainless steel is a precipitation hardened stainless steel, developed from the 17-4PH by further adding chromium and aluminium. It features higher strength, good formability and corrosion resistance. 17-7PH stainless steel has wide applications in petrochemical, aerospace, power and instrumentation industries.

At room temperature, 17-7PH stainless steel offers a combination of good mechanical strength and formability, with good corrosion and oxidation resistance. The aluminium addition gives good strength, hardness and ductility within the austenitic range. 17-7PH stainless steel also exhibits good pitting and stress corrosion cracking resistance in certain temperatures and environments.

17-7PH stainless steel has a wide range of application temperature from cryogenic to over 300°C. At cryogenic temperatures, it shows superior impact resistance, with tough ductile behaviour. At higher temperatures, it exhibits creep and stress rupture resistance, making it ideal for use in high-temperature fastener applications. At elevated temperatures or in an aggressive environment, 17-7PH stainless steel shows good properties like high strength and corrosion resistance.

17-7PH stainless steel is widely used in petrochemical, aerospace, power and instrumentation industries, where high strength and corrosion resistance are required. Its low temperature properties make it appropriate for applications that require rapid cooling such as in aircraft landing gear or when used in cryogenic environments like in space exploration. Its high-temperature properties make it suitable for many fastener applications like turbine blades.