Effect of Soaking Time on Evolution of Microstructure and Hardness during Annealing of EN-47 Spring Steel

The study presents the results of the examination on the effect of soaking time on the Microstructure, Grain shape and hardness properties of annealed EN-47 Spring Steel. The EN-47 Spring Steel samples were heated at 860 °C for soaking times of 60, 120, 240, 480 minutes. Optical Microscopy and Rockwell Hardness were carried out to determine the morphology, grain shape and hardness of the material with increasing soaking time. EN-47 Spring Steel samples showed up a decreased value in hardness with the extent of soaking time. Pearlite colonies expand with the increase in soaking time. The linear relationship between the soaking time and other factors were also observed. Keywords: EN-47, Annealing, Microstructure, Rockwell Hardness.

Influence of Microstructure on Pass through Flux of High Purity Ni

Pass through flux (PTF) is an essential parameter for the magnetron sputtering process of ferromagnetic materials. In the present investigation the influence of deformation, recrystallized microstructure and thickness on PTF of Ni was examined by the analysis of microstructure and hardness of high purity Ni. The experimental results showed that PTF of rolled Ni increased significantly comparing to the annealing microstructure that is related to the dislocation and stress of microstructure. With the recrystallization and grain growth of deformed samples, PTF decreased to be about 30%. PTF was also associated with the thickness of material. It increased by 6% when the thickness of 0.5mm decreased. This research is useful to guide and improve the design, development and preparation of magnetic sputtering materials.

Effect of Hydrogen as a Temporary Alloying Element on the Microstructure and Mechanical Properties of Ti-6Al-4V Titanium Alloy

The α + β dual-phase titanium alloy, Ti-6Al-4V, was thermohydrogen processed with 0.1, 0.3 and 0.5 wt% hydrogen. Hydrogen was removed from the hydrogenated titanium alloy by vacuum annealing. Microstructure and mechanical properties of the hydrogenated and dehydrogenated titanium alloy were investigated. Effect of hydrogen as a temporary alloying element on the microstructure and mechanical properties of Ti-6Al-4V titanium alloy was systematically discussed. It was found that hydrogen stabled the β phase and leaded to the formation of α martensite as well as δ hydride in the hydrogenated titanium alloy. Mechanical properties of hydrogenated titanium alloy deteriorated with increasing hydrogenation content. The α martensite and δ hydride decomposed during the dehydrogenation and the dehydrogenated titanium alloy only consisted of α and β phases. The mechanical properties of hydrogenated titanium alloy with different hydrogen content were recovered and were tend to be consistent after dehydrogenation.

Microstructures and Precipitates in High Purified Fe- 17 wt% Cr Alloy Steels

In the present paper, the influences of rolling temperatures on microstructure and precipitate in high purified Fe- 17 wt% Cr alloy steels were investigated by conventional process and low temperature rolling process. The hot rolled bands were annealed, cold rolled and annealed in the same processes. By means of optical microscopy observations, transmission electron microscopy analyses and thermodynamic calculations, the microstructural evolutions were studied and compared. It was shown that low temperature rolling process resulted in the refined rolling and annealing microstructure; Low temperature rolling process could form more fine TiC precipitates than in the conventional process due to the occurrence of strain-induced precipitation. These results have been confirmed by the thermodynamic calculations.

Influence of Rare Earth on Microstructure of 20MnCrNi2Mo Wear-Resistant Cast Steel

The original austenite grain size, the inclusions and the isothermal annealing microstructure of 20MnCrNi2Mo wear-resistant cast steel without and with Rare Earth were observed by metallographic microscope and QUANTA-400 environmental scanning electronic microscope. The effect mechanism of Rare Earth in 20MnCrNi2Mo wear-resistant cast steel was investigated. The results show that adding Rare Earth in 20MnCrNi2Mo wear-resistant cast steel can refine the original austenite grains. Meanwhile, it can reduce the inclusions size and change the inclusions shape from irregular to nearly spherical. In addition, the Rare Earth in 20MnCrNi2Mo wear-resistant cast steel can increase the amount of ferrite, reduce that of pearlite in the isothermal annealing microstructure and refine the microstructure of pearlite.

Effect of Cold-Rolling Reduction on Recrystallized Annealing Microstructure and Texture of Titanium Stabilized Interstitial Free Steel

Cold rolling and salt bath annealing simulation were conducted to study the evolution of microstructure and textures of a commercially produced Titanium stabilized interstitial free steel by means of optical microscopy and X-ray texture measurement. The results show that all of the as cold-rolled specimens are completely recrystallized after annealing. As the cold-rolling reduction increases, the recystallized ferrite grains are refined, The intensities of the stable {114} and {223} components remain strong after recrystallization. The orientation intensity of the {111} and {111} also increases accordingly. As the cold-rolling reduction increases to 90%, the intensity of {111} tend to be higher than that of {111}.

Study on Effects of Pretreatment on Carbide of a Medium-Alloy High Carbon Steel

The effect of pre-treatment on carbide transformation and morphology of a medium-alloy high carbon steel (0.86C, 0.84Cr, 1.85W, 0.95Mo, 0.31V) with multi-elements was investigated in this paper. The results show that there are multiple types of carbides (M3C、M23C6、M7C3、M6C、MC) in the annealed steel. The morphology of carbide in the annealing microstructure largely relate to the process before annealing. Carbides with disperse spherical and short rod-like distribution exist in the ferritic matrix when the steels are annealed at 820−860°C. The spherical carbides in the ferritic matrix can be obtained by isothermal annealing at 680−720°C after heating at 800°C. The morphology of carbides with different pretreatment process relate to carbide transformation, which can be described by calculating based on phase equilibrium thermodynamic.