Study on the Double-Fined Treatment and Superplasticity of GCr15 Die Steels

2013 ◽  
Vol 662 ◽  
pp. 356-361
Author(s):  
Xing Hai Liu ◽  
Feng Juan Wu ◽  
Hui Bin Wu ◽  
Ji Quan Sun ◽  
Xue Ping Ren

Heat treatment has a signifieant impact on the performance of the GCr15 die steel. Using scanning electron microscopy, optical microscopy, hardness tester and tensile testing machine analyses the influence of double-fined treatment on microstructure and mechanical properties of GCr15 steels. The results show that the double-fined treatment can make the carbids which haven’t insoluted fine to 320nm and the grains fine to No. 10. The dislocated martensite become more after double-fined treatment; at the same time, there are more sheet-retained austernite in lathy martensite and around sheet martensite; broken-orifice changes from definitely cleavage brittleness fracture to definitely cleavage tenacity fracture. By double-fined treatment, die steel can be given the neeessary strength and toughness, and the life can be substantially increased. The superplasticity of GCr15 die steel was improved by double-fined treatment. The optimal temperature range of the elongation is: 680~780°C. Anti-oxidants can improve the elongation of GCr15 steels.

2014 ◽  
Vol 590 ◽  
pp. 181-186
Author(s):  
Xiao Song Li ◽  
An Hui Cai ◽  
Ji Jie Zeng

Using optical microscope, electronic tensile testing machine, scanning electron microscopy methods, such as detailed treatment of the B hypoeutectic Al-Si alloy microstructure, mechanical properties and fracture morphology were studied. The results showed that after treatment by the B refinement, α-Al dendrite phase was refined, resulting in mechanical properties of Al-Si alloy significantly improved. Which, B content 0.036wt.%, the alloy the best, the σb, δ, respectively, than the non-thinning increased 67.8% and 15.2%. From the fracture surface, the fracture morphology of the specimen showed a quasi-cleavage fracture. Which, B content 0.036wt.% at the time of fracture is more deep dimples, and a good plastic toughness.


Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 825 ◽  
Author(s):  
Sheng Hong ◽  
Yuping Wu ◽  
Bo Wang ◽  
Jinran Lin

The main objective of this study was to develop an efficient coating to increase the wear resistance of cold work die steel at different temperatures. The microstructures of high-velocity oxygen-fuel (HVOF)-sprayed WC-CoCr coatings were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of temperature on the tribological properties of the coatings and the reference Cr12MoV cold work die steel were both investigated by SEM, environmental scanning electron microscopy (ESEM), X-ray diffraction (XRD), and a pin-on-disk high-temperature tribometer. The coating exhibited a significantly lower wear rate and superior resistance against sliding wear as compared to the die steel at each test temperature, whereas no major differences in terms of the variation tendency of the friction coefficient as a function of temperature were observed in both the coatings and the die steels. These can be attributed to the presence of nanocrystalline grains and the fcc-Co phase in the coating. Moreover, the wear mechanisms of the coatings and the die steels were compared and discussed. The coating presented herein provided a competitive approach to improve the sliding wear performance of cold work die steel.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 568
Author(s):  
Xinwei She ◽  
Xianquan Jiang ◽  
Bao Qi ◽  
Kang Chen

The effect of Er on microstructure and mechanical properties of the 5052 aluminum alloy with a big width-to-thickness ratio was investigated by a metallurgical microscope, scanning electron microscope and tensile testing machine. The results showed that the precipitates were slightly refined after Er addition and Al3Fe was transformed into Al6Fe and AlEr with/without a small amount of Fe or Si. The effect of Er on grain refinement was related to its content. When Er content was lower or higher than 0.4%, the grain would coarsen. Homogenization could refine the grain by controlling Er content and distribution in the Al matrix. Long time homogenization at high temperature would significantly reduce the strength of the 5052 aluminum alloy and 5052 aluminum alloys with low Er content, but help to improve the plasticity of those with high Er content. The ultimate tensile strength, yield strength and elongation of the as-cast 5052 aluminum alloy were 197 MPa, 117 MPa and 22.5% respectively. The strength was the highest, when Er content was 0.4 wt. % and the elongation was the best at 0.1 wt. % Er content.


2018 ◽  
Vol 37 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Ma Kun ◽  
Liu Tingting ◽  
Liu Ya ◽  
Su Xuping ◽  
Wang Jianhua

AbstractThe tensile properties of the alloy 2618 and 2618-Ti were tested using a tensile testing machine. The morphologies of the fracture of tensile samples were observed using scanning electron microscopy. The strengthening and toughening mechanisms of alloy 2618-Ti at elevated temperature were systematically investigated based on the analyses of experimental results. The results showed that the tensile strength of alloy 2618-Ti is much higher than that of alloy 2618 at the temperature range of 250 and 300 °C. But the elongation of alloy 2618-Ti is much higher than that of alloy 2618 at the temperature range of 200 and 300 °C. The equal-strength temperature of intragranular and grain boundary of alloy 2618-Ti is about 235 °C. When the temperature is lower than 235 °C, the strengthening of alloy 2618-Ti is ascribed to the strengthening effect of fine grains and dispersed Al3Ti/Al18Mg3Ti2 phase. When the temperature is higher than 235 °C, the strengthening effect of alloy 2618-Ti is mainly attributed to the load transfer of Al3Ti and Al18Mg3Ti2 particles. The toughening of alloy 2618-Ti at elevated temperature is mainly ascribed to the fine grain microstructure, excellent combination between matrix and dispersed Al3Ti/Al18Mg3Ti2 particles as well as the recrystallization of the alloy at elevated temperature.


2020 ◽  
Vol 93 (2) ◽  
pp. 286-296
Author(s):  
N. T. Thuong ◽  
N. P. D. Linh ◽  
C. H. Ha ◽  
P. T. Nghia ◽  
S. Kawahara

ABSTRACT NR/Na+-montmorillonite (NR/Na+-MMT) nanocomposites were prepared through mixing in the latex stage. NR/Na+-MMT nanocomposites with various amounts of Na+-MMT were fabricated using three types of NR latexes: fresh NR (FNR), high ammonia NR, and deproteinized NR latex. The Na+-MMT and NR latexes were characterized by particle size distribution and Fourier transform infrared spectroscopy analyses. The nanocomposite materials were then analyzed by scanning electron microscopy, transmission electron microscopy, and contact angle measurements. The mechanical properties of the resulting products were measured by tensile testing machine. The composite prepared from FNR gave the best tensile strength at 3 phr MMT loading. The outstanding properties are proposed to be due to the contribution of the water-soluble compounds present in FNR that possess similar hydrophilicity to Na+-MMT.


2013 ◽  
Vol 423-426 ◽  
pp. 771-774
Author(s):  
Ning Ma ◽  
Huan Tao Wu ◽  
Fu Xing Ye ◽  
Guo Sheng Zhang

In this work, a scrapped cross shaft which was assembled at the differential of ZL50C loader was analyzed by scanning electron microscopy (SEM) to examine the failure mechanism and was remanufactured by HVOF with ~500μm thickness WC-12Co coatings on it. The microstructure, phase compositions and properties of deposited WC-12Co coatings were investigated through optical microscope (OM), SEM, X-ray diffraction (XRD), microhardness tester and tensile testing machine. The results show that the coatings were very dense, and their porosities were lower than 1%. According to the X-ray Diffraction (XRD) analysis, the phase compositions of the sprayed coatings consisted of WC, Co and W2C. The microhardness of the coating was approximated to 1100 HV0.1and the bonding strength was higher than 63.7 MPa. It can be concluded that WC-12Co coating sprayed by HVOF was suitable for the remanufacturing of shaft parts.


1978 ◽  
Vol 14 (3) ◽  
pp. 269-272 ◽  
Author(s):  
J. F. M. Fennell

SUMMARYThe use of a durometer to assess hardness of onion bulbs is described, and compared with the use of a tensile testing machine. Results from the two tests were closely correlated, and significant varietal differences were detected in bulb hardness by both machines. The durometer is of particular value because of the simplicity and non-destructive nature of the test procedure.


2021 ◽  
Vol 410 ◽  
pp. 617-623
Author(s):  
Elena N. Gryadynova ◽  
Andrey V. Gorin ◽  
Alexey Yu. Rodichev

The article contains the analysis of thermoplastics used in prototyping machine parts. We used several types of experimental samples with different filling percentages. The equipment on which the experimental studies were carried out is shown. During the experiment, a specialized tensile testing machine was used. The experimental samples were installed in the developed centering device. Normal conditions were observed during the tests. The results of an experimental tensile study of PLA-plastic specimens are presented. The typical stress-strain diagram of an experimental sample is described, which describes the dependence of stress on relative deformation. An equation of the linear dependence of the tensile strength on the percentage of filament filling has been compiled, which makes it possible to determine the tensile strength of the product at any percentage of the filling of the plastic filament. The assessment is adequately verified by Fisher's criterion. Recommendations for filament filling in prototyping machine parts are given.


1972 ◽  
Vol 5 (12) ◽  
pp. 1231-1232 ◽  
Author(s):  
C A O Henning ◽  
F W Boswell ◽  
J M Corbett

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