Research on the Structure and Wear Properties of Grind-Hardened 42CrMo

2012 ◽  
Vol 619 ◽  
pp. 561-566 ◽  
Author(s):  
Lian Yong Zhang ◽  
Fang Hong Sun ◽  
Yan Hua Jiang

grind-hardening test was performed on 42CrMo steel in the paper. Microstructure of the hardened layer was observed and the wear-resistance of hardened specimens was done too. The results showed that microstructure of the fully hardened layer was mainly composed by lath martensite; microhardness of the hardened layer was above 700HV and the abrasive wear and the adhesive wear properties of hardened layer were 2~9 times than that of the base.

2012 ◽  
Vol 619 ◽  
pp. 567-571 ◽  
Author(s):  
Ke Ming Liu ◽  
Lian Yong Zhang ◽  
Zhuang Ma ◽  
Bo Liu

In order to improve the strength and wear-resistance of agricultural diesel engine crankshaft, the grinding-hardening experiment of crankshaft material 42CrMo steel was carried out on MM7132 surface grinder. Microstructure of the specimens was observed with SSX-550 scanning electron microscope (SEM) and the abrasion experiment was carried out on ML -100 abrasive wear testing machine. The results showed that the maximum mircrohardness of 42CrMo steel after grind hardening was 850HV and the maximum depth of grind hardening layer was 1.25mm. The hardened layer was fully occupied by lath martensite; a little of martensite and much tempered sorbite appeared in the transitional region. The wear-resistance of the specimens after grind hardening was improved by three times.


Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2443
Author(s):  
Jingjing Li ◽  
Jiang Ju ◽  
Weiwei Chang ◽  
Chao Yang ◽  
Jun Wang

In this study, a high aluminum and chromium Fe-B-C coating was prepared using laser cladding on 2Cr13 steel substrate. The microstructure, microhardness, and wear resistance of the high aluminum and chromium Fe-B-C coating were investigated. The results show that this dense coating possesses good metallurgical bond with the substrate. The microstructure is mainly composed of α-(Fe, Cr, Al) lath martensite, orthorhombic M2B boride, orthogonal M3C2, and orthorhombic M7C3 carbides. The microhardness of the coating can reach 620 HV which is 3.3-times higher than that (190 HV) of the substrate. The coating shows a lower friction coefficient of 0.75 than that of the substrate (1.08). The wear rates of the substrate and the coating are 0.295 mg/min and 0.103 mg/min, respectively, indicating the coating exhibits excellent wear resistance. The wear mechanism transforms severe adhesive wear and abrasive wear of the substrate to slight abrasive wear of the coating. The results can provide technical support to improve the properties of the Fe-based laser cladded coating.


2011 ◽  
Vol 189-193 ◽  
pp. 969-973 ◽  
Author(s):  
Zhuang Ma ◽  
Ke Ming Liu ◽  
Lian Yong Zhang

Grind-hardening test were performed on MM7132 surface grinder with corundum grinder wheel in the mesh of 60#. The result shows that the structure of grind-hardened layer is composed with lath martensite and small mixed martensite; the depths of grind-harden layer is largest when the grind depth is 0.3mm, while the depths of grind-harden layer decreased when the grind depth is 0.2mm, 0.4mm, 0.5mm,respectively. The range of microhardness of grind-harden layer is from 754 to 853. The depths of grind-harden layer along the direction of working appeared ladderly.


2020 ◽  
Vol 993 ◽  
pp. 836-843
Author(s):  
Ke Guo ◽  
Zhi Qiang Zhang ◽  
Zhong Zheng Pei ◽  
Jie Xu ◽  
Yi Fan Feng

Here we developed a hot-pressed molded resin-based brake pad material reinforced by a nano sodium titanate whisker in comparison with nano potassium titanate whisker. The effect of the whiskers on the tribology behavior was investigated. Though nano sodium titanate whisker reinforced brake material showed higher porosity (+12.29% averagely) and lower hardness (-25.8% averagely) caused by the impurities, it exhibited improved ability in stabilizing the friction coefficient and enhancing 25.5%, 31.1%, 25.9% higher wear resistance, when the volume contents of whisker are 7.5%, 15% and 22.5%, respectively, compared to the nano potassium titanate whisker reinforced brake material. The wear mechanisms of the nano sodium titanate whisker reinforced brake materials were determined as embedded debris, delaminated crater, moderate layers transfer, uniform furrows, primary plateaus and secondary plateaus in similar size, indicating a main wear form of abrasive wear instead of adhesive wear.


Author(s):  
Mete Han Boztepe ◽  
Melih Bayramoglu

Boronizing is one of the thermochemical surface treatment processes which is extensively used to obtain excellent mechanical properties such as high strength, very high hardness, good toughness and fracture toughness. In this study, AISI 1050 steel specimens have been subjected to pack boronizing process by using Ekabor 2 powder within the stainless steel seal container. The experiments were carried out at temperatures of 800 °C, 850 °C and 900 °C for 3, 6 and 9 hours to investigate the effect of these parameters on the wear resistance of boronized specimens. Pin-on-Disk wear testing is used to characterize wear properties of boronized specimens. Wear tests were performed at dry conditions under constant load of 30 N by using 220 mesh size Al2O3 abrasive paper. Different rotating speeds of the pin-on disk were selected as 300, 600, 900, 1200, 1500 revolutions for each of the test specimens. After the abrasive tests, weight losses of the specimens were measured to determine the abrasive wear resistance of boronized specimens. The results were also compared with unboronized and conventional hardened AISI 1050 steel specimens respectively.


2015 ◽  
Vol 1095 ◽  
pp. 135-139
Author(s):  
Wei Xi Shi ◽  
Cheng Wu Du ◽  
Gui Mao Li ◽  
Zhi Ming Liu

The morphology of eutectic and primary silicon phases was analyzed by OM and SEM. OM and SEM results show that pure Nd can significantly refine both eutectic and primary silicon of hypereutectic Al-20%Si alloy. Morphology of primary silicon is transformed from star-shaped and irregular morphology to fine polyhedral and grain size of primary silicon is refined from 80~120 μm to 20~50 μm. Friction and wear resistance tests show that friction coefficient of Al-20%Si alloy reduces after Nd modification. Wear resistance of Al-20%Si alloy after modification is significantly improved as compared to the initial sample. The dominant wear mechanism for 0.3% Nd modified alloy is abrasive wear, adhesive wear and oxidative wear mechanism, but wear mechanism for unmodified alloy is abrasive wear and adhesive wear mechanism.


2016 ◽  
Vol 368 ◽  
pp. 55-58 ◽  
Author(s):  
Šárka Houdková ◽  
Eva Smazalová

The influence of high temperature exposure on the mechanical and wear properties of selected HVOF sprayed CrC and No/Co – based alloy coatings were tested. Comparison of as-sprayed and 600°C/116 h annealed coatings’ microhardness, cohesive strength, abrasive and adhesive wear resistance showed that the Co-based Stellite 6 coating’s wear properties were deteriorated by heat exlosure despite of the increase of its hardness and cohesive strength. The heat exposure was found to be beneficial for both mechanical and wear properties of NiCrBSi self-fluxing coating. On the contrary, mechanical properties of Cr3C2-NiCr coating slightly decreased, while its wear resistance slightly increased as a result of high temperature exposure.


2021 ◽  
Vol 57 (1) ◽  
pp. 97-104
Author(s):  
D.-B. Wei ◽  
X. Zhou ◽  
F.-K. Li ◽  
M.-F. Li ◽  
S.-Q. Li ◽  
...  

To improve the wear resistance of ?-TiAl alloy, Ta alloy layer was prepared on surface by double glow plasma surface alloying technique. The tribology behavior of Ta alloy layer against Si3N4 at 25?, 350? and 500? were comparatively studied. The results showed that Ta alloy layer comprised a deposition layer and a diffusion layer. The deposition layer played a role in protection as a soft film. With the increase of temperature, the wear mechanism of ?-TiAl changed from abrasive wear to coexistence of abrasive wear and oxidation wear. Ta alloy layer?s wear mechanism changed from adhesive wear to coexistence of adhesive wear and oxidation wear. Surface Ta alloying process significantly reduced the wear volume, the specific wear rate and the friction coefficient of ?-TiAl and improved the wear resistance properties of ?-TiAl.


Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 610 ◽  
Author(s):  
Yu-Yang Gao ◽  
Feng Qiu ◽  
Tian-Shu Liu ◽  
Jian-Ge Chu ◽  
Qing-Long Zhao ◽  
...  

The in situ TiC/Al-Cu nanocomposites were fabricated in the Al-Ti-C reaction systems with various carbon sources by the combined method of combustion synthesis, hot pressing, and hot extrusion. The carbon sources used in this paper were the pure C black, hybrid carbon source (50 wt.% C black + 50 wt.% CNTs) and pure CNTs. The average sizes of nano-TiC particles range from 67 nm to 239 nm. The TiC/Al-Cu nanocomposites fabricated by the hybrid carbon source showed more homogenously distributed nano-TiC particles, higher tensile strength and hardness, and better abrasive wear resistance than those of the nanocomposites fabricated by pure C black and pure CNTs. As the nano-TiC particles content increased, the tensile strength, hardness, and the abrasive wear resistance of the nanocomposites increased. The 30 vol.% TiC/Al-Cu nanocomposite fabricated by the hybrid carbon source showed the highest yield strength (531 MPa), tensile strength (656 MPa), hardness (331.2 HV), and the best abrasive wear resistance.


2020 ◽  
Vol 10 (20) ◽  
pp. 7363
Author(s):  
Lei Xu ◽  
Erkuo Yang ◽  
Yasong Wang ◽  
Changyun Li ◽  
Zhiru Chen ◽  
...  

Ultra high-pressure sintering (UHPS) was used to prepare AA6061/SiCp composites with different contents and the effect of sintering temperatures on microstructure and mechanical properties was investigated in this study. The results showed that a uniform distribution of nano-SiC particles (N-SiCp) is obtained by the UHPS method. With the increase in N-SiCp contents, the higher hardness and better wear resistance could be inspected. The interfacial reactions and Al4C3 phase appeared above 550 °C. The relative density of composites first increased and then decreased; with the temperature raising it reached 99.58% at 600 °C. The hardness and wear property showed the same trend with the hardness reaching 52 HRA and wear rate being 1.0 × 10−6 g/m at 600 °C. Besides, the wear mechanism of the composites is mainly composed of abrasive wear and adhesive wear.


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