scholarly journals Surface Integrity and Corrosion Resistance of 42CrMo4 High-Strength Steel Strengthened by Hard Turning

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6995
Author(s):  
Qingzhong Xu ◽  
Yan Liu ◽  
Haiyang Lu ◽  
Jichen Liu ◽  
Gangjun Cai

To improve the surface corrosion resistance of 42CrMo4 high-strength steel used in a marine environment, this article studied the effects of hard turning on the surface integrity and corrosion resistance of 42CrMo4 high-strength steel through the single factor experimental method, namely hard turning, polarization corrosion, electrochemical impedance spectroscopy, potentiodynamic polarization curve, and salt spray tests. The results indicated that the surface integrity was modified by the hard turning, with a surface roughness lower than Ra 0.8 μm, decreased surface microhardness, fine and uniform surface microstructure, and dominant surface residual compressive stress. The hard turning process was feasible to strengthen the surface corrosion resistance of 42CrMo4 high-strength steel. The better corrosion resistance of the surface layer than that of the substrate material can be ascribed to the uniform carbides and compact microstructure. The corrosion resistance varied with cutting speeds as a result of the changed surface microhardness and residual compressive stress, varied with feed rates as a result of the changed surface roughness, and varied with cutting depths as a result of the changed surface residual compressive stress, respectively. The surface integrity with smaller surface roughness and microhardness and bigger surface residual compressive stress was beneficial for corrosion resistance.

2014 ◽  
Vol 670-671 ◽  
pp. 52-55
Author(s):  
Yan Chai ◽  
Wei Feng He ◽  
Guang Yu He ◽  
Yu Qin Li

To solve the crack and fracture problem in blade made of K403 alloy, the samples of K403 are laser shock processed and then the microstructure, microhardness, residual compressive stress and surface roughness of the samples are tested. The test results show that some grains are observed refined in the grain boundary of shock region, the microhardness improves in a depth of 0.8mm from the surface and the surface microhardness improves 16%, a residual compressive stress which is more than 450MPa is developed in a depth of 1mm from the surface, and obvious changes of the surface roughness are not tested.


Author(s):  
Wit Grzesik ◽  
Krzysztof Żak

This paper presents the state of surface integrity produced on hardened-high strength 41Cr4 steel after hard machining and finish ball burnishing. Surfaces machined by sequential machining processes were characterized using 2D and 3D surface roughness parameters. Moreover, detailed functionality of the generated surfaces was performed using a set of 3D functional roughness parameters. Among the characteristics of the surface layer, its microstructure, the distribution of microhardness and the residual stresses were determined. This investigation confirms that ball burnishing allows producing surfaces with lower surface roughness and better service properties than those generated by cubic boron nitride (CBN) finish hard turning operations.


2013 ◽  
Vol 797 ◽  
pp. 657-662
Author(s):  
Feng Jiao ◽  
Xiang Liu ◽  
Chong Yang Zhao ◽  
Xiong Zhang

Surface residual stress has become one of the important indexes measuring surface integrity in hard turning of precision parts. The type of surface residual stress and the influence rules of cutting parameters on surface residual stress in hard turning of GCr15 steel are studied in this paper. Research results show that no matter in common or ultrasonic turning, tangential surface residual compressive stress can be found in machined surface. The effect of cutting speed on the residual compressive stress is the greatest, the effect of feed rate takes the second place and the effect of depth of cut is minimal. The conclusions have provided experimental basis for enhancing the surface integrity of quenched GCr15 steel precision parts.


2017 ◽  
Vol 8 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Kankan Ji ◽  
Xingquan Zhang ◽  
Shubao Yang ◽  
Liping Shi ◽  
Shiyi Wang ◽  
...  

Purpose The purpose of this paper is to evaluate surface integrity of quenched steel 1045 ground drily by the brazed cubic boron nitride (CBN) grinding wheel and the black SiC wheel, respectively. Surface integrity, including surface roughness, sub-surface hardness, residual stresses and surface morphology, was investigated in detail, and the surface quality of samples ground by two grinding wheels was compared. Design/methodology/approach In the present work, surface integrity of quenched steel 1045 machined by the CBN grinding wheel and the SiC wheel was investigated systematically. All the specimens were machined with a single pass in the down-cutting mode of dry condition. Surface morphology of the ground specimen was observed by using OLYMPUS BX51M optical microscopy. Surface roughness of seven points was measured by using a surface roughness tester at a cut-off length of 1.8 mm and the measurement traces were perpendicular to the grinding direction. Sub-surface micro-hardness was measured by using HVS-1000 digital micro-hardness tester after the cross-section surface was polished. The residual stress was tested by using X-350A X-ray stress analyzer. Findings When the cut depth is increased from 0.01 to 0.07 mm, the steel surface machined by the CBN wheel remains clear grinding mark, lower roughness, higher micro-hardness and higher magnitude of compressive stress and fine microstructure, while the surface machined by the SiC grinding wheel becomes worse with increasing of cut depth. The value of micro-hardness decreases, and the surface roughness increases, and the surface compressive stress turns into tensile stress. Some micro-cracks and voids occur when the sample is processed by the SiC grinding wheel with cut depth 0.07 mm. Originality/value In this paper, the specimens of quenched steel 1045 were machined by the CBN grinding wheel and the SiC wheel with various cutting depths. The processing quality resulted from the CBN grinding wheel is better than that resulted from the SiC grinding wheel.


2009 ◽  
Vol 626-627 ◽  
pp. 225-230 ◽  
Author(s):  
Wei Wei Ming ◽  
Ming Chen ◽  
Bin Rong

Titanium alloys are extensively applied in aerospace, automotive, biomedical, and chemical industries owing to their excellent performance combining high strength-to-density ratio, good corrosion resistance, and high strength at elevated temperature. Ti-6.5Al-3.5Mo-1.5Zr-0.3Si (TC11) alloys are used to replace the most common Ti-6Al-4V in some important applications such as some parts in aerospace engine. The purpose of this paper is to evaluate the machinability of TC11 alloys in the finish hard turning conditions. The paper presents the machinability results of TC11 alloys compared with Ti-6Al-4V, and analyzes the variables such as cutting force, surface integrity, and tool wear mechanism in the experiments.


Author(s):  
Ben Wang ◽  
Qi Zhang ◽  
Minghai Wang ◽  
Yaohui Zheng ◽  
Xianjun Kong

Ti alloy has been widely applied in aerospace due to its high strength, good corrosion resistance, and excellent high-temperature performances. The quality and usability of Ti alloy parts are closely related to surface integrity. In this study, a comparative analysis of the milling surface integrity between laser deposition manufacturing and traditional Ti6Al4V samples was conducted. End milling surfaces of additive and traditional Ti6Al4V samples were observed with an orthogonal experiment under different milling parameters from the perspectives of cutting force, surface morphology, surface roughness, subsurface damages, and microhardness. Results demonstrate that the additive Ti6Al4V sample has a slightly higher cutting force and surface roughness relative to traditional Ti6Al4V. This is related to the higher hardness and plasticity of the additive Ti6Al4V sample. There are unmelted powder particle defects on the milling surface of the additive Ti6Al4V sample and serious cracking defects on the subsurface of the additive Ti6Al4V sample. The microhardness of the work hardening layer and base of the additive Ti6Al4V sample is higher than that of traditional Ti6Al4V. Moreover, the additive Ti6Al4V sample presents higher work hardening and a larger depth of the hardening layer. These findings demonstrate that material properties and manufacturing processes can influence surface integrity significantly.


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