Papers by Keyword: Ferrite Stainless Steel

Abstract: The effect of rare earth element on structure and mechanical properties of the 430 ferrite stainless steel was studied by metallographic examination, scanning electron microscope (SEM), tensile test and impact test. The results show that the proper amount of RE can refine microstructure of 430 ferrite stainless steel. The fracture mode of 430 ferrite stainless steel is typical dimple fracture. 430 ferrite stainless steel containing 0.056% RE can improve its impact toughness and the high temperature strength, and the transverse impact toughness increases 37.2% at 253K respectively comparing with that of 430 ferrite stainless steel without RE. And at 1273K, the high temperature strength increases by 38.3% than that of 430 ferrite stainless steel without RE.

Abstract: A primary study on the resistance to high-temperature-oxidation of 430 ferrite stainless steel and its oxidation process before and after the addition of RE elements was reported. Results show that the oxidation resistance of 430 ferrite stainless steel after adding RE is indeed great. The value of oxidation rate of Sample 1 (without adding RE) is 2.87 times higher than Sample 2, respectively at 1423K after oxidizeing for totally 144h. And the dense and adherent Cr2O3 scale and FeCr2O4 scale are formed and played the protection role to the 430 ferrite stainless steel. In the internal oxidation layer, the pinning effect of silicon dioxide is strengthened by RE.

Abstract: The effects of RE metals on the inclusions and the impact property of 430 ferrite stainless steel were studied by metallographic examination, scanning electron microscope (SEM) and energy spectrum analysis. The results show that the morphologies and sizes of inclusions in 430 ferrite stainless steel are changed, and RE played a very good role of modifying inclusions. The fracture mode of 430 ferrite stainless steel is typical cleavage fracture, but quasi-cleavage and dimple fracture after adding RE into the steel. The transverse impact property of 430 ferrite stainless steel is improved obviously by RE. In comparison with 430 ferrite stainless steel without RE, the transverse impact property of 430 ferrite stainless steel with RE is increased 38.53% at -20°C, respectively.

Abstract: The anodic polarization curves of 430 ferrite stainless steels with various RE contents in 3.5% NaCl neutral solutions have been measured by electrochemical methods. The effect of RE on pitting corrosion resistance of 430 ferrite stainless steels has been studied by the metallographic examination. The results show that sulfide and other irregular inclusions are modified to round or oval-shaped RE2O2S and RES after adding RE to 430 ferrite stainless steesl. RE makes sulfide, and other irregular inclusions change to dispersed round or oval-shaped RE inclusions, effectively inhibits the occurrence of pitting corrosion, thereby enhancing the corrosion resistance of 430 ferrite stainless steels.

Abstract: This paper mainly studies the microstructure and strengthening mechanism of ferritic stainless under laser shock. the mechanical properties and microstructure were observed through the X-ray diffraction and TEM. The results showed that laser induced shock wave peak pressure is higher than the yield strength of stainless steel, the plastic deformation occus under the impact of the role of stress and high strain rate. when the laser power increases, ferritic stainless steel will have an obvious phase transition from the body-centered cubic into hexagonal system.

Abstract: The structural recrystallization mechanisms operating in an Fe – 27%Cr – 9% Ni dual-phase (ferrite-austenite) stainless steel after large strain processing to total strain of 4.4 were investigated in the temperature range of 400-700oC. The severe deformation resulted in the development of an ultrafine grained microstructure consisting of highly elongated grains/subgrains with transverse dimensions of 160 nm and 130 nm in ferrite and austenite, respectively. The annealing mechanism operating in ferrite phase was considered as continuous recrystallization, which involved recovery leading to the development of essentially polygonized microstructure. On the other hand, the mechanism of discontinuous nucleation took place at an early recrystallization stage in austenite phase.

Abstract: A method of Monte Carlo combined with welding experiments was adopted to study the grain size and microstructure in welding heat affected zone of the ferrite stainless steel. Firstly, the kinetic equation of grain growth was established with the experimental data . Then , a simulation procedure based on the kinetic equation was worked out. Agreement between Monte Carlo simulation result and the real experiment results was obtained.