Microstructure and Mechanical Properties of Spray Deposited W9Mo3Cr4V High Speed Steel

2011 ◽  
Vol 391-392 ◽  
pp. 714-718
Author(s):  
Rui Zhou ◽  
Jian Fei Sun ◽  
Ying Jun Yang

Microstructure and mechanical properties of W9Mo3Cr4V high speed steel fabricated by spray deposition have been studied. Spray deposited W9Mo3Cr4V high speed steel has a typical equiaxed structure which is finer and more homogeneous with a grain size of 20-30 micrometer compared with conventional casted counterparts. There are pores in the matrix of the deposited steel, which involve gas porosity, filling porosity and solidification shrinkage. As-deposited high speed steel is mainly composed of martensite, austenite and carbides which comprise MC carbide and M6C carbide. Mechanical properties show that the hardness and bending strength of the as-deposited steel are higher than that of the conventionally casted ones. However, impact toughness of the high speed steel is lower than that of the conventionally casted steel, which can be attributed to the existence of porosities and M6C carbides which reduce the impact toughness of high speed steels.

2007 ◽  
Vol 336-338 ◽  
pp. 2605-2608 ◽  
Author(s):  
Yan Pei Song ◽  
Xie Min Mao ◽  
Qi Ming Dong ◽  
Liu Ding Tang ◽  
Zhi Ying Ouyang ◽  
...  

Two kinds of thick-walled rings, consisted of WCP/Fe-C gradient composites layers containing about 54 and 70 vol.% of WCP and Fe-C alloy core, were cast by centrifugal casting method. The microstructure, mechanical properties and wear resistance of the gradient composites were investigated. Meanwhile the results were compared with those made of the high speed steel. It was found that WCP in the two kind of gradient composites layers were even well distributed, WCP/Fe-C composites layer of 23-28mm was obtained, the transition layer between the composites layer and matrix alloy core was perfect. The tensile strengths of the two gradient composites layers achieved 345MPa, 460MPa and the impact toughness were 4.6J/cm2, 6.2J/cm2 respectively. Moreover the hardness of the composites layers attained HRA81 and HRA 78. The result of the comparison among the gradient composites layers and that made of the high speed steel showed that the wear resistance of the gradient composites layers containing about 50 and 70 vol.% of WCP was more than 20 times higher than that of the high speed steel under loads of 100N and 200N and sliding velocity of 60 m/s. Finally, the wear-mechanism was discussed.


2014 ◽  
Vol 788 ◽  
pp. 329-333
Author(s):  
Rui Zhou ◽  
Xiao Gang Diao ◽  
Jun Chen ◽  
Xiao Nan Du ◽  
Guo Ding Yuan ◽  
...  

Effects of sintering temperatures on the microstructure and mechanical performance of SPS M3:2 high speed steel prepared by spark plasma sintering was studied. High speed steel sintering curve of continuous heating from ambient temperature to 1200°C was estimated to analyze the sintering processes and sintering temperature range. The sintering temperature within this range was divided into groups to investigate hardness, relative density and microstructure of M3:2 high-speed steel. Strip and quadrate carbides were observed inside the equiaxed grains. SPS sintering temperature at 900°C can lead to nearly full densification with grain size smaller than 20μm. The hardness and bending strength are higher than that of the conventionally powder metallurgy fabricated ones sintered at 1270°C. However, fracture toughness of the high speed steel is lower than that of the conventional powder metallurgy steels. This can be attributed to the shape and distribution of M6C carbides which reduce the impact toughness of high speed steels.


2019 ◽  
Vol 38 (2019) ◽  
pp. 404-410 ◽  
Author(s):  
Weijuan Li ◽  
Haijian Xu ◽  
Xiaochun Sha ◽  
Jingsong Meng ◽  
Zhaodong Wang

AbstractIn this study, oxide dispersion strengthened (ODS) ferritic steels with nominal composition of Fe–14Cr–2W–0.35Y2O3 (14Cr non Zr-ODS) and Fe–14Cr–2W–0.3Zr–0.35Y2O3 (14Cr–Zr-ODS) were fabricated by mechanical alloying (MA) and hot isostatic pressing (HIP) technique to explore the impact of Zr addition on the microstructure and mechanical properties of 14Cr-ODS steels. Microstructure characterization revealed that Zr addition led to the formation of finer oxides, which was identified as Y4Zr3O12, with denser dispersion in the matrix. The ultimate tensile strength (UTS) of the non Zr-ODS steel is about 1201 MPa, but UTS of the Zr-ODS steel increases to1372 MPa, indicating the enhancement of mechanical properties by Zr addition.


Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 978 ◽  
Author(s):  
Pengfei Wang ◽  
Zhaodong Li ◽  
Guobiao Lin ◽  
Shitong Zhou ◽  
Caifu Yang ◽  
...  

Steels used for high-speed train wheels require a combination of high strength, toughness, and wear resistance. In 0.54% C-0.9% Si wheel steel, the addition of 0.075 or 0.12 wt % V can refine grains and increase the ferrite content and toughness, although the influence on the microstructure and toughness is complex and poorly understood. We investigated the effect of 0.03, 0.12, and 0.23 wt % V on the microstructure and mechanical properties of medium-carbon steels (0.54% C-0.9% Si) for train wheels. As the V content increased, the precipitation strengthening increased, whereas the grain refinement initially increased, and then it remained unchanged. The increase in strength and hardness was mainly due to V(C,N) precipitation strengthening. Increasing the V content to 0.12 wt % refined the austenite grain size and pearlite block size, and increased the density of high-angle ferrite boundaries and ferrite volume fraction. The grain refinement improved the impact toughness. However, the impact toughness then reduced as the V content was increased to 0.23 wt %, because grain refinement did not further increase, whereas precipitation strengthening and ferrite hardening occurred.


2021 ◽  
Vol 1016 ◽  
pp. 1739-1746
Author(s):  
Yan Mei Li ◽  
Shu Zhan Zhang ◽  
Zai Wei Jiang ◽  
Sheng Yu ◽  
Qi Bin Ye ◽  
...  

The effect of tempering time on the microstructure and mechanical properties of SA738 Gr.B nuclear power steel was studied using SEM, TEM and thermodynamic software, and its precipitation and microstructure evolution during tempering were clarified. The results showed that SA738 Gr.B nuclear power steel has better comprehensive mechanical properties after tempering at 650 °C for 1h. With the extension of the tempering time, M3C transformed into M23C6 with increasing size, which affected the yield strength and impact energy. When the tempering time is 8h ~ 10h, due to the transformation of M3C to M23C6, the composition of matrix around the carbide changed, causing the temperature of Ac1 dropped, forming twin-martensite which deteriorated the impact toughness of the steel.


2016 ◽  
Vol 51 (11) ◽  
pp. 1653-1664 ◽  
Author(s):  
Mohd Shahneel Saharudin ◽  
Rasheed Atif ◽  
Islam Shyha ◽  
Fawad Inam

The degradation of mechanical properties in halloysite nanoclay–polyester nanocomposites was studied after an exposure of 24 h in diluted methanol system by clamping test specimens across steel templates. The glass transition temperature ( Tg) and storage modulus increased steadily with the increase of halloysite nanoclays before and after diluted methanol exposure. The addition of nano-fillers was found to reduce liquid uptake by 0.6% in case of 1 wt% reinforcement compared to monolithic polyester. The mechanical properties of polyester-based nanocomposites were found to decrease as a result of diluted methanol absorption. After diluted methanol exposure, the maximum microhardness, tensile, flexural and impact toughness values were observed at 1 wt% of halloysite nanoclay. The microhardness increased from 203 to 294 HV (45% increase). The Young’s modulus increased from 0.49 to 0.83 GPa (70% increase) and the tensile strength increased from 23 to 27 MPa (17.4% increase). The impact toughness increased from 0.19 to 0.54 kJ/m2 in diluted methanol system (184% increase). Surprisingly, the fracture toughness of all types of nanocomposites was found to increase after exposing to diluted methanol due to plasticization effect. Scanning electron microscope images of the fractured surfaces of tensile specimens revealed that the methanol increased the ductility of the matrix and reduced the mechanical properties of the nanocomposites.


2014 ◽  
Vol 983 ◽  
pp. 94-98 ◽  
Author(s):  
Li Jun Wang ◽  
Jian Hui Qiu ◽  
Eiichi Sakai

The melting mixing was applied in the preparation of Multiwalled carbon nanotubes/Polycarbonate (MWCNTs/PC) nanocomposites. MWCNTs/PC nanocomposites with different MWCNTs contents were prepared under different injection conditions. The mechanical property of nanocomposites was comparatively investigated. The results demonstrated that: the tensile property of the nanocomposites was slightly improved by MWCNTs content increasing; but as the MWCNTs contents went on to increase to 10wt%, the tensile strength and bending strength were obviously decreased about 35% and 47%, respectively, but the impact strength and hardness were increased. The center hardness of MWCNTs/PC nanocomposites was greater than the surface hardness. Besides, the changes on the mechanical properties of the nanocomposites were studies by changing the injection conditions. By Scanning Electron Microscopy (SEM) observation, the microstructure and morphology of nanocomposites were analyzed, revealing that the center of the nanocomposite distributed more MWNTs, and the injection conditions would affect the MWNTs’ dispersion in the matrix and the interfacial interaction between MWCNTs and PC.


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