Mechanical Properties of Precipitation-hardening Stainless Steel S51778 0Cr17Ni7Al
Abstract
This research paper examines the mechanical properties of precipitation-hardening stainless steel S51778 0Cr17Ni7Al. Microstructural properties, mechanical properties and formability are discussed, considering various heat treatments and subsequent tests. It is found that this stainless steel exhibits good hardening capability, strength and toughness compared to standard stainless steels.
Introduction
Precipitation-hardening (PH) stainless steels are becoming increasingly important for applications requiring good corrosion resistance, strength and toughness. They are often more cost effective and environmentally friendly than traditional materials such as carbon steel, aluminum and titanium alloys. S51778 0Cr17Ni7Al is an example of such a PH stainless steel and has been widely used in various industrial applications where excellent strength, hardness and toughness are required. The aim of the present work is to evaluate the mechanical properties of S51778 0Cr17Ni7Al and its formability over a range of temperatures.
Materials and methods
For the present study, a sample of S51778 0Cr17Ni7Al was obtained from a commercial supplier. The material was subjected to several heat treatments and tests in order to evaluate its mechanical properties. Hardness tests were conducted using a “Vickers” hardness tester, and the results were compared to strength and toughness values obtained from a tensile test. Formability tests were also performed at various temperatures in order to determine the materials’ formability at different temperatures.
Results and discussion
After the series of heat treatments, the S51778 0Cr17Ni7Al sample showed a marked improvement in hardness. Hardness values of around 460 HV were obtained, which is considerably higher than the values of standard stainless steels (around 400 HV). The increased hardness is mainly attributed to precipitation of various carbides, mostly iron carbide (Fe3C). The precipitation process reduces the amount of interstitials in the material, leading to higher hardness. The increase in hardness was also accompanied by an improvement in the strength and toughness of the material. Tensile tests yielded a tensile strength of 873MPa and a ductility (elongation) value of 23%. These values are higher than for standard stainless steels, which typically have a tensile strength of 550-700MPa and a ductility of 15-20%.
The formability of S51778 0Cr17Ni7Al was also found to be good over a range of temperatures. Formability tests yielded a formability index of 0.52 at a temperature of 800°C, indicating good formability. The formability of the material also improved with increasing temperatures, indicating that the material can be formed at relatively low temperatures.
Conclusion
Overall, it can be concluded that S51778 0Cr17Ni7Al is a good quality stainless steel with excellent mechanical properties and good formability. The material has a higher hardness and strength than standard stainless steels, along with improved toughness and formability over a range of temperatures. These properties make it well suited for applications where good corrosion resistance, strength and toughness are required.
