This work aims at the development of carbon steel AISI 1536 through the microalloying addition of boron. Three grades of this steel with different content of boron up to 0.0055% were melted in 100 kg induction furnace...This work aims at the development of carbon steel AISI 1536 through the microalloying addition of boron. Three grades of this steel with different content of boron up to 0.0055% were melted in 100 kg induction furnace. The pro- duced steels were hardened at 960°C for 30 min., followed by tempering at different temperatures and durations. All hardened steels have martensite phase as illustrated with microstructures and X-ray diffraction. Hardness of all tem- pered steel samples was measured to calculate the activation energies of carbon migration through martensite phase. The results indicated that the activation energies of carbon migration through martensite phase decreases with the in- crease of boron content due to its positive effect on the crystallinity of martensite phase. Also, the results showed that the addition of boron up to 0.0023% can improve the steel properties at the lowest temperature and tempered time.展开更多
This work aims at investigating the influence of titanium addition on behavior of medium carbon steel. Three types of medium carbon steel with different titanium content and one reference steel titanium free were prod...This work aims at investigating the influence of titanium addition on behavior of medium carbon steel. Three types of medium carbon steel with different titanium content and one reference steel titanium free were produced in 100 kg induction furnace. Titanium addition was increased up to 0.230%. The produced steels were forged at start temperature 1150°C. Forging process was finished at temperatures 900°C, 975°C, and 1050°C. Microstructure examination and hardness measurement were carried out for forged steels. Mechanical properties and impact measurements were carried out for quenched tempered steels. Ti addition was found to have significant influence on refinement of grains and increase of ferrite/pearlite ratio. It was also, observed that grain size decreases as finishing temperature of forging process decreases. Both Ti addition and lowering finishing forging temperature have positive effect on hardness. In addition, results indicated that addition of titanium has significant effect on the mechanical properties and toughness.展开更多
Nitriding process of medium carbon ferromanganese was carried out in the solid state, on lab and bench scale at temperature range 1023-1323 K using different nitrogen and hydrogen pressures. The influence of H2/N2 gas...Nitriding process of medium carbon ferromanganese was carried out in the solid state, on lab and bench scale at temperature range 1023-1323 K using different nitrogen and hydrogen pressures. The influence of H2/N2 gas ratio, temperature and time on nitriding process of fine (-2 mm) medium carbon ferromanganese were investigated. Nitrogen content, in weight percent ranging from 2.1 to 9.7 could be obtained. The optimum temperature and time of nitriding process was found to be 1223 K and 21.6 ks respectively. The results showed that nitrogen content is mainly depending on time and temperature of nitriding process. The comparison between results of lab and bench scale, at optimum conditions, showed good coincidence. At optimum conditions;1223 K, 21.6 ks and at 2/8 of H2/N2, nitrogen content of fine medium carbon ferromanganese was 9.5%.展开更多
文摘This work aims at the development of carbon steel AISI 1536 through the microalloying addition of boron. Three grades of this steel with different content of boron up to 0.0055% were melted in 100 kg induction furnace. The pro- duced steels were hardened at 960°C for 30 min., followed by tempering at different temperatures and durations. All hardened steels have martensite phase as illustrated with microstructures and X-ray diffraction. Hardness of all tem- pered steel samples was measured to calculate the activation energies of carbon migration through martensite phase. The results indicated that the activation energies of carbon migration through martensite phase decreases with the in- crease of boron content due to its positive effect on the crystallinity of martensite phase. Also, the results showed that the addition of boron up to 0.0023% can improve the steel properties at the lowest temperature and tempered time.
文摘This work aims at investigating the influence of titanium addition on behavior of medium carbon steel. Three types of medium carbon steel with different titanium content and one reference steel titanium free were produced in 100 kg induction furnace. Titanium addition was increased up to 0.230%. The produced steels were forged at start temperature 1150°C. Forging process was finished at temperatures 900°C, 975°C, and 1050°C. Microstructure examination and hardness measurement were carried out for forged steels. Mechanical properties and impact measurements were carried out for quenched tempered steels. Ti addition was found to have significant influence on refinement of grains and increase of ferrite/pearlite ratio. It was also, observed that grain size decreases as finishing temperature of forging process decreases. Both Ti addition and lowering finishing forging temperature have positive effect on hardness. In addition, results indicated that addition of titanium has significant effect on the mechanical properties and toughness.
文摘Nitriding process of medium carbon ferromanganese was carried out in the solid state, on lab and bench scale at temperature range 1023-1323 K using different nitrogen and hydrogen pressures. The influence of H2/N2 gas ratio, temperature and time on nitriding process of fine (-2 mm) medium carbon ferromanganese were investigated. Nitrogen content, in weight percent ranging from 2.1 to 9.7 could be obtained. The optimum temperature and time of nitriding process was found to be 1223 K and 21.6 ks respectively. The results showed that nitrogen content is mainly depending on time and temperature of nitriding process. The comparison between results of lab and bench scale, at optimum conditions, showed good coincidence. At optimum conditions;1223 K, 21.6 ks and at 2/8 of H2/N2, nitrogen content of fine medium carbon ferromanganese was 9.5%.
