High Temperature Mechanical Properties of Chromium-Nickel Martensitic Stainless Steel 1Cr17Ni2(AIS1431)

Introduction

In stainless steel series, Martensite Stainless Steel is one of the most widely used and one of the most important classes. H1Cr17Ni2 (AIS1431) Martensite stainless steel is a common and important form of stainless steel, and its application field is quite extensive. High-temperature mechanical properties refer to the ability of materials under high temperature (generally 600~800℃) environment to maintain certain physical, chemical and mechanical properties without structural damage and material properties. The high temperature mechanical properties of stainless steel also have significant influencing factors on the reliability, performance and service life of the product. Therefore, the research and application of its high-temperature mechanical properties have important theoretical and practical significance.

High Temperature Mechanical Properties of 1Cr17Ni2(AIS1431) Martensite Stainless Steel

Tensile properties

Tensile properties are an important index to measure the mechanical properties of materials at room temperature or high temperature，.Research shows that when the temperature of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel is below room temperature, its tensile strength can reach as high as 850~900MPa. When the temperature rises to 600~800℃, the tensile strength of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel will significantly decrease, reaching about 500~700MPa under various loading conditions. At the same time, the total elongation of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel increases with increasing temperature, generally reaching more than 30%.

Impact toughness

Impact toughness is the ability of a material to absorb energy when it is impacted. The impact toughness of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel decreases with increasing temperature, which is different from the effect of tensile properties. When the temperature is below room temperature, the impact toughness of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel is generally between 40~50J, while when the temperature rises to 600~800℃, the impact toughness of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel will reduce to 10~15J.

Structural stability

Structural stability refers to the ability of a material to preserve the structural form without changing its properties. During the high temperature test of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel, it was found that the structure of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel maintained relatively stable under 600~800℃ high temperature environment, but there were some local sorting phenomenon, and the fine grain size was also slightly coarsened, but it maintained its fine structure and did not cause a significant decrease in mechanical properties.

Creep properties

The creep properties of a material refer to the ability of a material to maintain its structural stability and mechanical properties under long-term, continuous and high-intensity load. Tests show that under 600~800℃ high temperature environment, the creep rate of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel increases with increasing load and temperature, but the time-dependent creep rate of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel is moderate, which means that under certain loads, the creep deformation of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel meeting the requirements can be controlled within a certain range.

Fatigue Properties

Fatigue properties refer to the phenomenon that a material produces a certain number of cycles of plastic deformation due to the alternate stress between tension and compression within a given range. Research showed that the fatigue properties of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel were significantly affected by temperature. Under 500~600℃, the fatigue strength and fatigue life of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel are relatively high, in which the fatigue strength and fatigue life can reach 1.2~2.0 times and 10~100 times higher than room temperature, respectively. But when it was further heated to 800℃, the fatigue strength of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel would drop sharply, and the fatigue life would be significantly reduced.

Conclusion

In summary, the high-temperature mechanical properties of H1Cr17Ni2 (AIS1431) Martensite Stainless Steel are entangled with each other, the overall and local performance of which are affected by temperature to varying degrees, and so is the reliability of its engineering application. Comprehensive consideration needs to be taken into these specific effects when selecting the usage environment, especially temperature conditions, for H1Cr17Ni2 (AIS1431) Martensite Stainless Steel. In addition, for H1Cr17Ni2 (AIS1431) Martensite Stainless Steel in engineering applications under high temperature, measures such as controlling the operating temperature, selecting the appropriate stress level, controlling the loading and updating frequently, etc. may be used in order to improve its fatigue and creep properties.

AISI431 martensitic stainless steel is highly resistant to corrosion and oxidation, particularly in mildly reducing environments. It exhibits a unique combination of high strength and toughness that have generated it as an effective material for mechanical applications. AISI431 has better mechanical properties compared to other 400 series martensitic stainless steels and compared to AISI436, it has higher strength and hardness but with slightly lower toughness.

At ambient temperature, AISI431 exhibits higher yield strength of 350-400 MPa, ultimate tensile strength of 760-900 MPa and elongation of 30-50%. At high temperatures, AISI431 still maintains somewhat good strength and hardness but with significantly lower ductility and fracture strength.

At temperature up to 500℃, AISI431 displays high strength and hardness but with dynamic fatigue properties falling off rapidly above 200℃. Beyond this temperature, yield strength and hardness decreases rapidly up to 1060℃ resulting in creep ductility increasing up to 800℃ beyond which also decreases. At 1100~1120℃, impact toughness of AISI431 also reduces significantly, displaying a poor impact resistance.

At high temperature, AISI431 is found to be susceptible to oxidation and sensitization resulting in reduced corrosion resistance and susceptibility to intergranular corrosion. In addition, high temperature carburizing in the presence of carbon can also promote Formation of chromium carbides.- resulting in reduced corrosion resistance at those temperatures.

In conclusion, AISI431 exhibits good high temperature strength and hardness with comparatively good corrosion and oxidation resistance. However, it is still likely to suffer from high temperature oxidation, sensitization and carburization leading to reduced corrosion resistance. Thus it is not suitable for applications which are exposed to high temperature environment or for the applications requiring superior corrosion resistance.