Effects of silicon addition and process conditions upon α-phase sintering, sinter hardening, and mechanical properties of Fe-1.5Mo powder

Youseffi, Mansour; Wright, Christopher S.; Jeyacheya, F.M.

doi:10.1179/003258902225001524

Cited by 12 publications

(25 citation statements)

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“…5C Hanejko et al [16] 1260 7.09 1 1240 sintered and tempered Fe-1.5Mo-3Si-1. 2C Youseffi et al [17] 1250 7.55 0.33 764 sintered and tempered Fe-0.85Mo-6Ni-0. 4C Gething et al [11] 1288 7.50 -943 as-sintered *Estimated from those of 7.05 and 7.30 g Á cm 3 compacts.…”

Section: Ductilitymentioning

confidence: 99%

“…As shown in Table IV, these properties are much better than those of the as-sintered or sinter-hardened highstrength PM steels, as reported in recent literature or in the MPIF standards. [1,2,11,[14][15][16][17] Moreover, the 1323 MPa obtained without quenching heat treatment or accelerated cooling is equivalent to the best tensile strength of the quenched and tempered materials registered in the MPIF standards, i.e., FLN2-4405-190HT. [1] These results showed that the Cr addition is very effective in improving the mechanical properties of Ni-containing materials.…”

Section: Strength and Hardnessmentioning

confidence: 99%

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Improved homogenization of Ni in sintered steels through the use of Cr-containing prealloyed powders

Hwang

2006

Metall Mater Trans A

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The homogenization of Ni in powder metal (PM) steel compacts is usually difficult even after high-temperature sintering at 1250°C. An earlier study by the authors demonstrated that this problem can be alleviated through the addition of 0.5 wt pct Cr in the form of stainless steel powders. To further improve the microstructure and mechanical properties of Ni-containing PM steels and to understand the mechanisms, an attempt was made in this study using the Fe-3Cr-0.5Mo prealloyed powder as the base material. The results showed that the distribution of the Ni additives was significantly improved. As a result, the tensile strength of the Fe-3Cr-0.5Mo-4Ni-0.5C compact sintered at 1250°C reached 1323 MPa. The elongation was higher than 1 pct. These sinter-hardened properties, which were attained using a slow furnace cooling rate, were comparable to those of the sinterhardened alloys reported in the literature using accelerated cooling and were equivalent to those of the best quenched-and-tempered alloys registered in the Metal Powder Industries Federation (MPIF) standards. These improvements were attributed to the positive effect of Cr addition on alloy homogenization due to the reduction of the repelling effect between Ni and C, as was demonstrated through the thermodynamic analysis using the Thermo-Calc program.

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Section: Ductilitymentioning

confidence: 99%

Section: Strength and Hardnessmentioning

confidence: 99%

Improved homogenization of Ni in sintered steels through the use of Cr-containing prealloyed powders

Hwang

2006

Metall Mater Trans A

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“…9 The mechanical properties of UTS of 630 MPa and ETF of y2% found for the sintered hardened material in this study are not as good as those (UTS of 750 MPa and ETF of 2?5%) obtained for Fe-1?5Mo-3Si-1?2C material sintered to 98?8% (7?55 g cm 23 ) relative density. 5 Still, considering the lower relative sintered density (95%) reached in this study for the Fe-2C-2Si material, the mechanical properties are quite satisfactory for hardness levels of ,400 HV. Noteworthy is that even higher hardness levels of y600 HV are achievable for the quenched and tempered alloy.…”

Section: Discussionmentioning

confidence: 78%

Optimising grey iron powder compacts

et al. 2009

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The grey iron microstructure Fe-2C-2Si powder based compact is tailored by different kinds of in situ and post sintering processing. This has been achieved by combining thermodynamic and kinetics modelling of microstructure development with sintering and controlled heat treatment experiments of tensile test specimens die compacted at 600 MPa. Applying optimised sintering conditions led to a grey iron like microstructure with 95% relative sintered density. Sinter hardening the compacts led to 500 MPa in yield strength and 600 MPa in ultimate tensile strength in combination with ductile fracture. Quenched and tempered condition showed the same strength values, but combined with brittle fracture due to martensitic structure. Pore rounding and partial pore filling by graphite were obtained by austenising isothermal hold during the cooling of the sintering cycle.

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“…It was seen that the density of the specimens decreased with increasing Si content. It is known that the addition of Si to iron powder has a shrinkage effect [3] and also reduces the sintered density due to low specific gravity and pressing capability of Si.…”

Section: Resultsmentioning

confidence: 99%

“…Solid solution hardening effect of silicon in the ferrite is higher than the other alloying elements. Youseffi et al [3] noted, however, that silicon has a higher oxygen affinity than copper, nickel and molybdenum.…”

Section: Introductionmentioning

confidence: 95%

Effect of Silicon Content on Wear Behavior of Heat Treated Powder Metallurgy Steels

Tekeli¹,

Güral

2013

High Temperature Materials and Processes

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Three different steel compositions with 1, 3 and 5 mass% Si were prepared using atomized iron (ASC.100.29) and 0.35 mass% natural graphite powders. The mixed powders were cold pressed at 700 MPa and sintered at 1200°C for 30 min under pure Ar gas atmosphere. Some of the sintered specimens was quenched from 850°C and then tempered at 100°C for 1 h. The other sintered specimens were annealed at intercritical heat treatment temperature of 750 o C for 10 min and rapidly water-quenched. The experimental results showed that in as-sintered specimens inhomogeneously dispersed typical pearlitic structure in the ferrite matrix formed and its amount decreased with increasing Si content. In intercritically annealed specimens, the microstructure obtained was a mixture of partially transformed martensite and ferrite C pearlite. In quenched plus tempered specimens, beside tempered martensite, ferritic structure formed and its amount increased with increasing Si content. The wear tests were carried out under dry sliding conditions using a pin-on-disk type machine at constant load, speed and sliding distance. It was seen that, in all specimens, the friction coefficient and the wear rate both increased with increasing Si content. The increase of these values was less in the heat treated specimen than the assintered specimen.

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Effects of silicon addition and process conditions upon α-phase sintering, sinter hardening, and mechanical properties of Fe-1.5Mo powder

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Cited by 12 publications

References 1 publication

Improved homogenization of Ni in sintered steels through the use of Cr-containing prealloyed powders

Improved homogenization of Ni in sintered steels through the use of Cr-containing prealloyed powders

Optimising grey iron powder compacts

Effect of Silicon Content on Wear Behavior of Heat Treated Powder Metallurgy Steels

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