Impact of Cooling Character on Structure and CTE of Invar Alloy with 0.6%C

2017 ◽  
Vol 265 ◽  
pp. 807-810
Author(s):  
A.S. Zhilin ◽  
S.V. Grachev ◽  
S.M. Nikiforova
Keyword(s):  
Thermal Expansion ◽  
Cooling Rate ◽  
Coefficient Of Thermal Expansion ◽  
Invar Alloy ◽  
Cooling Rates ◽  
Volume Percentage ◽  
Invar Alloys

Metallography analysis of invar alloys crystallized with different cooling rates has been carried out. The study has demonstrated that velocity of crystallization has an impact on the dispersity of graphite. The higher velocity of cooling, the more dispersive graphite is. The volume percentage of graphite in alloy, crystallized with high cooling rate, is lower than compared with low cooling rate. Crystallization with low cooling rate leads to the reduction of the amount of carbon into γ-phase. The coefficient of thermal expansion is basically depends on the amount of carbon into γ-phase.

scholarly journals Impact of Cooling Character on Structure and CTE of Cast Invar Alloy Made From Secondary Raw Materials

2017 ◽  
Vol 2 (2) ◽  
pp. 188
Author(s):  
A.S. Zhilin ◽  
S.V. Grachev ◽  
V.R. Ramazanova ◽  
O. V. Maslova
Keyword(s):  
Thermal Expansion ◽  
Cooling Rate ◽  
Coefficient Of Thermal Expansion ◽  
Raw Materials ◽  
Invar Alloy ◽  
Cooling Rates ◽  
Volume Percentage ◽  
Secondary Raw Materials ◽  
Invar Alloys

<p>Metallography analysis of invar alloys made from secondary raw materials and crystallized with different cooling rates has been carried out. The study has demonstrated that velocity of crystallization has an impact on the dispersity of graphite. The higher velocity of cooling, the more dispersive graphite is. The volume percentage of graphite in alloy, crystallized with high cooling rate, is lower than compared with low cooling rate. Crystallization with low cooling rate leads to the reduction of the amount of carbon into g-phase. The coefficient of thermal expansion is basically depends on the amount of carbon into g-phase.</p>

scholarly journals Strengthening of the Fe-Ni Invar Alloy Through Chromium

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1297 ◽  
Author(s):  
Qingshuang Sui ◽  
Jun He ◽  
Xin Zhang ◽  
Zhonghua Sun ◽  
Yunfei Zhang ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Mechanical Strength ◽  
Aging Time ◽  
Power Transmission ◽  
Coefficient Of Thermal Expansion ◽  
High Strength ◽  
Invar Alloy ◽  
Invar Alloys ◽  
Low Thermal Expansion ◽  
Cost Efficient

Invar alloys with both high strength and low thermal expansion are urgently needed in fields such as overhead power transmission, aero-molds, and so on. In this paper, Cr was introduced as a cost-efficient alloying element into the Fe-36Ni binary invar alloy to increase its mechanical strength. Our results confirmed that fine Cr7C3 precipitants, together with some Fe3C, in the invar alloy aged at 425 °C could be obtained with a short aging time. Those precipitants then grew and aggregated at grain or sub-grain boundaries with an increase in aging time. Simultaneously, mechanical strength and coefficient of thermal expansion (CTE) parabolically varied with the increase in aging time. The sample aged at 425 °C for 7 h presented a maximum strength of 644.4 MPa, together with a minimum coefficient of thermal expansion of 3.30 × 10−6 K−1 in the temperature range of 20–100 °C. This optimized result should be primarily attributed to the precipitation of the nanoscaled Cr7C3.

Effect of Mo doping on the microstructure and properties of an Fe36Ni Invar alloy

2020 ◽  
Vol 34 (31) ◽  
pp. 2050297
Author(s):  
Liming Dong ◽  
Zhaopeng Yu ◽  
Xianjun Hu ◽  
Fang Feng
Keyword(s):  
Grain Size ◽  
Thermal Expansion ◽  
Grain Boundaries ◽  
Coefficient Of Thermal Expansion ◽  
Solution Temperature ◽  
Microstructure And Properties ◽  
Invar Alloys ◽  
Average Grain Size ◽  
Mo Content ◽  
Hot Rolled

The effects of doping with different Mo contents on the microstructure and properties of Fe36Ni Invar alloys were investigated. The results show that when 0.9 wt.% Mo and 1.8 wt.% Mo were added to Fe36Ni, the tensile strengths of the hot rolled alloys were 46 and 61 MPa higher than that of the 0 wt.% Mo sample, respectively. With an increase in Mo content from 0.9 to 1.8 wt.%, the solution temperature of the highest hardness after heat treatment increased from 800[Formula: see text]C to 850[Formula: see text]C, respectively. The addition of 0.9 wt.% Mo refined the average grain size from 37 to 15 [Formula: see text]m, and an excessive amount of Mo (1.8 wt.%) did not refine the grains further. After Mo was added, the precipitates on the original grain boundaries changed into nanoprecipitates dispersed in the grain boundaries and inside the grains. Mo was present in the alloy in the form of a carbide and in solid solution, which affected the magnetic lattice effect and increased the thermal expansion coefficient of the alloy. However, upon comparing the samples doped with 0 wt.% Mo, 0.9 wt.% Mo and 1.8 wt.% Mo, it was found that the addition of 0.9 wt.% Mo not only refined the grain size and improved the mechanical properties of the alloy but also led to a low coefficient of thermal expansion (CTE) over the range from 20[Formula: see text]C to 300[Formula: see text]C.

Effect of carbon on the coefficient of thermal expansion of as-cast Fe−30wt.%Ni−12.5wt.%Co−×C invar alloys

2002 ◽  
Vol 8 (3) ◽  
pp. 247-252 ◽  
Author(s):  
Bong-Seo Kim ◽  
Kyung-Jae Yoo ◽  
Byung-Geol Kim ◽  
Hee-Woong Lee
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Invar Alloys

The Effect of the Structure and the Heating and Cooling Rate on the Thermal Expansion of Grey Cast Iron

1984 ◽  
Vol 34 ◽  
Author(s):  
P. A. Sunnerkrantz ◽  
H. Fredriksson
Keyword(s):  
Thermal Expansion ◽  
Cast Iron ◽  
Temperature Dependence ◽  
Carbon Content ◽  
Cooling Rate ◽  
Grey Cast Iron ◽  
Cooling Rates ◽  
Heating And Cooling ◽  
Grey Cast ◽  
Increasing Temperature

ABSTRACTThe thermal expansion of grey cast iron was studied in six different alloys. The expansion was determined at two different heating and cooling rates. It was found that the expansion was influenced by the heating and cooling rates. The thermal expansion was larger than the thermal expansion in steel and the thermal expansion also increased with increasing temperature. The thermal expansion was theoretically analysed. The temperature dependence was accounted for, by considering the fact that the carbon content in austenite and ferrite increases with increasing temperature.

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