| 1. |
- Akhtar, Farid
(författare)
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Effect of additive Cu-10Sn alloy on sintering Behavior of elemental powders in composition of 465 stainless steel
- 2007
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X .- 2210-3988. ; 14:4, s. 61-74
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Tidskriftsartikel (refereegranskat)abstract
- The addition of Cu-10Sn alloy for developing the high strength 465 maraging stainless steel from elemental powders was studied. The sintering parameters investigated include the sintering temperature, the sintering time, and the mass percent of Cu-10Sn. For vacuum sintering, effective sintering occurs at temperature between 1250°C and 1300°C. The maximum sintered density was achieved at 1300°C for 60 min with 3% (in mass percent) Cu-10Sn alloy. More than 3% (in mass percent) Cu-10Sn content and temperature above 1300°C caused slumping of the samples. A maximum density of 7.4 g/cm3 was achieved with 3% (in mass percent) Cu-10Sn content at a sintering temperature of 1300°C for 60 min. A maximum ultimate tensile strength (UTS) of 517 MPa was achieved with 3% (in mass percent) Cu-10Sn content. With content higher than 2% (in mass percent) Cu-10Sn, a maximum increase in the density was observed. The fracture morphologies of the sintered samples are also reported.
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| 2. |
- Feng, S., et al.
(författare)
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Formation of In-Situ Dispersion Strengthening Particles in Cast FeCrAl Alloy
- 2010
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X. ; 17:2, s. 74-78
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Tidskriftsartikel (refereegranskat)abstract
- In order to fabricate dispersion strengthened alloys strengthened by submicron-sized or nano-sized stable particles through casting routes, understanding of the formation process of dispersion strengthening particles in metal melt is of significance. Thus, nano NiO and TiO2 particles were selected as reactant to form in-situ dispersion strengthening oxide particles in Fe20Cr5Al alloy. Nano NiO and TiO2 particle powder was separately dispersed into nano Ni powder first. The loose mixed nano powder was added in Fe20Cr5Al alloy melt when pouring the melt into mold. The study shows that nano NiO particles were not as effective as nano TiO2 particles in forming dispersion strengthening Al2O3 particles. The final diameters of dispersion strengthening oxide particles arose from nano TiO2 particles were of submicron. The Brownian collision of particles had caused this coarsening.
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| 3. |
- Gong, Karin Anne Xia, 1965, et al.
(författare)
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Wear Evaluation on Ni3Al/MnS Composite Related to Metallurgical Processes
- 2012
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X. ; 19:7, s. 46-54
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Tidskriftsartikel (refereegranskat)abstract
- Iron alloyed Ni3Al with composition of Ni-18. 8A1-10. 7Fe0. 5Mn-0. 5Ti-0.2B in atom percent (NAC alloy)showed attractive tribological properties under unlubrication condition at room temperature. The alloy was preparedby hot isostatic pressing (HIP) process. The wear properties were associated with its intrinsic deformation mechanism.Unfortunately, the single phase NAC-alloy worked inadequately with its counterpart disk, and also showed apoor machinability. In the present work, NAC-alloy matrix composite with 6% (volume percent) MnS (manganese sulfide)particle addition was studied to improve its wear behaviors and performance on machining. Two metallurgical processes of HIP and vacuum casting were applied to produce the testing materials. Pin-on-disk (POD) measurements were carried outat room temperature. A commercial vermicular graphite cast iron was selected as a reference material. The counterpartdisk was made of a grey cast iron as liner material in ship engines. The contact pressures of 2. 83 MPa and 5. 66 MPawere normally applied in the tests. The investigation indicated that MnS particle addition in the NAC-alloy compositesfunctions as an effective solid lubricant, and improved wear properties and machinability of the materials. Obviously,as-cast NAC-alloy with in-situ formed MnS phase was working more effectively with the counterpart, comparingto the HIPed NAC-alloy composite with MnS particles. At the high contact pressure of 5.66 MPa, the specificwear rate of the as-cast NAC-alloy composite was high. The phenomenon of the negative effect is mostly due to thebrittle second NiAl phase as evidenced in the microstructure analysis.
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| 4. |
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| 5. |
- Vuorinen, Esa, et al.
(författare)
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Wear Characteristics of Surface Hardened Ausferritic Si-Steel
- 2007
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X .- 2210-3988. ; 14:5, supp 1, s. 245-248
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Tidskriftsartikel (refereegranskat)abstract
- High strength steels can be produced by austempering of Si-containing steels. It is possible to achieve high toughness and good wear resistance in these steels. Surface hardening of this group of steels can further increase the surface hardness and wear resistance and in combination with high strength in the bulk, also the fatigue strength. Surface hardening by laser-hardening has been performed on steel 55Si7 after austempering of the steel in order to create a ferritic-austenitic carbide free microstructure. Tempering effects and hardness values have been studied. Optical as well as scanning electron microscopy has been used together with x-ray diffractometry in the characterization of the micro-structural changes. Wear resistance testing of austempered and laser hardened samples respectively of the Si-alloyed steel have been reported and also compared with that of the conventional Cr-alloyed steel. The results of the specific phase transformation from austenite to martensite during wear process will be reported.
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| 6. |
- Yang, Qixing, et al.
(författare)
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Briquette Smelting in Electric Arc Furnace to Recycle Wastes from Stainless Steel Production
- 2015
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X .- 2210-3988. ; 22:Suppl. 1, s. 10-16
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Tidskriftsartikel (refereegranskat)abstract
- Wastes from stainless steel production were briquetted together with carbon for smelt-reduction in the electric arc furnace, EAF, to achieve an internal recycling. A laboratory induction furnace was used to simulate the EAF. With a close simulation of the smelting, disintegration of the briquettes heated under load and recovery of metals from briquettes melted together with stainless steel and slag former were investigated. The influences of test conditions on carbon reduction of oxides in the briquettes were also examined. The briquettes endured heating at 1 186 °C under load of 3.5 kg and could be charged to the melt in small quantity without causing serious splashing. For a high metal recovery, it was necessary to charge the briquettes together with slag former. Small local zones of smelt-reduction with high carbon concentration could thus be formed during the charger heating. Silicon content in the metal near to the briquettes should be minimised to achieve a high degree of carbon reduction. Based on results obtained from this study, suggestions were made on smooth operations of smelt-reduction of the briquettes by using EAF or induction furnace with large scales.
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| 7. |
- Yong-an, Min, et al.
(författare)
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Oxidation and Thermal Fatigue Behaviors of Two Type Hot Work Steels During Thermal Cycling
- 2013
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X .- 2210-3988. ; 20:11, s. 90-97
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Tidskriftsartikel (refereegranskat)abstract
- Thermal fatigue test has been carried out on widely used hot work steel 4Cr5MoSiV1 and a low alloyed steel 3Cr3MoV in temperature range of 200 to 700 degrees C. Tempering resistance, as well as high temperature hardness/strength of steel specimens, works as a dominating material parameter on thermal fatigue resistance. During the heating period, high hardness can depress the inelastic deformation. This deformation is the origination of tensile stress, which acts as the driving force of heat checking during the cooling period. The cyclic strain-oxidation interaction can speed up the damage on surface defects, which plays an obvious role in initiation of thermal cracks. On 4Cr5MoSiV1 steel specimens, borders between the matrix and inclusions such as titanium compounds, or lager carbides such as primary carbides, are focused by strain and attacked by oxidation, and are main initiating places of cracks. While on 3Cr3MoV steel specimens, larger strain causes plastic deformation concentrating around grain boundaries. Then the following oxidation accelerates this grain boundary damage and creates cracks.
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| 8. |
- Zandira, Masoud, 1983, et al.
(författare)
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Fracture Characteristics of Austempered Spheroidal Graphite Aluminum Cast Irons
- 2010
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X. ; 17:2, s. 31-35
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Tidskriftsartikel (refereegranskat)abstract
- The fracture characteristics of austempered spheroidal graphite aluminum cast iron had been investigated. The chemical content of the alloy was C3.2, Al2.2, Ni0.8 and Mg0.05 (in mass percent, %). Impact test samples were produced from keel blocks cast in CO2 molding process. The oversized impact samples were austenitized at 850 and 950 degrees C for 2 h followed by austempering at 300 and 400 degrees C for 30, 60, 120 and 180 min. The austempered samples were machined and tested at room temperature. The impact strength values for those samples austempered at 400 degrees C varied between 90 and 110J. Lower bainitic structures showed impact strength values of 22 to 50J. The fractures of the samples were examined using SEM. The results showed that the upper bainitic fracture revealed a honey Comb-like topography, which confirmed the ductile fracture behavior. The lower bainitic fractures of those samples austempered for short times revealed brittle fracture.
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| 9. |
- Zhang, Hui-ning, et al.
(författare)
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Carbothermic Reduction of Zinc and Iron Oxides in Electric Arc Furnace Dust
- 2014
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Ingår i: Journal of Iron and Steel Research International. - 1006-706X .- 2210-3988. ; 21:4, s. 427-432
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Tidskriftsartikel (refereegranskat)abstract
- The reduction of zinc and iron oxides from electric arc furnace dust (EAFD) by carbon was investigated at temperatures between 800 and 1300 °C. The analytic technique employed includes chemical analysis, X-ray fluorescence spectroscopy (XRF), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) equipped with X-ray energy dispersive spectrometry (EDS), and thermodynamic database FactSage 6. 2. It was found that the reduction of zinc and iron oxides depends largely on Boudouad reaction. At 900 °C, zinc exists in tested samples as ZnO, which is reduced in the temperature range of 1000 — 1100 °C. At 1100 °C, 99. 11% of the zinc is evaporated. The metallization ratio of Fe is 79. 19% at 1300 °C, as the content of Fe2+ is still 9. 40%. A higher temperature is thus required for a higher reduction degree of Fe oxides by solid or gaseous carbon
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| 10. |
- Zheng, Weisen, et al.
(författare)
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Thermodynamic modeling of Fe-C-Mn-Si alloys
- 2017
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Ingår i: Journal of Iron and Steel Research International. - : Gangtie Yanjiu Xuebao. - 1006-706X .- 2210-3988. ; 24:2, s. 190-197
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Tidskriftsartikel (refereegranskat)abstract
- The thermodynamic database of the Fe-C-Mn-Si system has been developed in the framework of the CALPHAD approach. The sub-ternary systems have been carefully evaluated and revised based on available experimental data. A satisfactory description of the liquid phase in the Fe-C-Si system has been obtained. The C-Mn-Si system was assessed treating the liquid phase as a substitutional solution. Phase equilibria in the C-Mn-Si system, especially those involving the liquid phase, can he well described. Based on the extrapolation of the experimental data in the quaternary system, the Fe-Mn-Si system has been modified to agree well with experimental data at high temperatures. The comparison between the calculated and measured phase transformation temperatures confirms the reliability of the present quaternary database. Additionally, the solidification process of Fe-0. 16C-1. 5 M n-1. 5 Si ( wt. % Yo) alloy was simulated by using the thermodynamic database developed.
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