Study on Surface Integrity of an Ultra-High Strength Alloy in HSC Process

2006 ◽  
Vol 532-533 ◽  
pp. 241-244
Author(s):  
Zhen Hai Long ◽  
Xi Bin Wang ◽  
Wen Xiang Zhao

Aiming to study the surface integrity of an ultra-high strength alloy in high speed milling process, 2K factorial design experiments were conducted to explore the effects of cutting parameters, such as cutting velocity, feed rate and depth of cut, on microstructure, microhardness and residual stress in the sub-surface layer. The following conclusions could be drawn from this paper within the range of cutting conditions: The cutting parameters could significantly influence the microstructure and microhardness in the surface and sub-surface layers, and the original fine martensite of the surface and sub-surface layer might be transformed into the over-tempered martensite, under-tempered martensite, secondary troostite, and tempered sorbite; Compressive residual stress distributions with different maximum stress values in the sub-surface layer of machined surfaces could emerge in high speed cutting process; the properly arranged cutting condition could achieve ideal surface characteristics and surface integrity.

2013 ◽  
Vol 658 ◽  
pp. 188-193
Author(s):  
Kun Qiu ◽  
Zhen Hai Long

In order to improve the surface quality of ultra high strength low alloy steel work-pieces produced by high-speed face milling process, 23-1 factorial design experiment was con-ducted and the residual stress profiles within the surface and subsurface layer of work-pieces were measured. Corresponding empirical models for the residual stress profile were presented and the effects of cutting parameters (cutting velocity, feed per tooth, depth of cut) on characteristics of the residual stress profile were studied. Results show that: with the range of cutting parameters tested, the compressive residual stress profile would be induced below the work-pieces’ surfaces machined by high speed face milling process. Feed per tooth has the critical influence on the characteristics of the compressive stress profile, and the mechanism of residual stress generation will be different when feed per tooth changes in high speed machining process. To obtain higher compressive stress and deeper compressive stress profile depth, larger feed rate and depth of cut are required.


2006 ◽  
Vol 532-533 ◽  
pp. 349-352
Author(s):  
Wen Xiang Zhao ◽  
Si Qin Pang ◽  
Zhen Hai Long ◽  
Xi Bin Wang

35CrMnSiA, is a kind of important engineering materials that used widely in modern manufacturing fields. The machinability of 35CrMnSiA Steel with hardness of HRc40±2 in high speed turning process was studied in this paper. It is concluded that, when high speed turning of this ultra-high strength alloy steel, the chief wear mode of ceramics is the crater on rake faces; the interaction of depth of cut and feed rate is one of statistic significant effects on cutting force; the interaction of cutting velocity of cut and feed rate is one of statistic significant effects on surface roughness Ra; besides, the empirical formula of average cutting temperature, cutting forces, surface roughness Ra, was established.


2006 ◽  
Vol 524-525 ◽  
pp. 569-574 ◽  
Author(s):  
Guenael Germain ◽  
Franck Morel ◽  
Jean Lu Lebrun ◽  
Anne Morel ◽  
Bertrand Huneau

The use of Laser Assisted Machining (LAM) can improve different aspects of the machinability of high strength materials. A study was undertaken to determine the optimum cutting parameters and to quantify their influence on fatigue strength according to the type of microstructure created. Two different materials were studied: a bearing steel (100Cr6 / AISI 52100) and an aeronautical titanium alloy (Ti6Al4V). In the bearing steel a significant increase of the fatigue resistance was observed due to the transformation of the surface layer into martensite. For the titanium alloy, a slight reduction in the fatigue strength was found as in this case the microstructure and residual stress state of the surface layer was less beneficial. The surface roughness has also been measured and no significant variation has been observed for different laser powers in each material.


2014 ◽  
Vol 543-547 ◽  
pp. 3759-3763
Author(s):  
Lin Lin Wang ◽  
Li Jiao ◽  
Zhi Wen Luo ◽  
Liang Jun Wei

In order to investigate the impact of cutting parameters on surface integrity when high-speed turning 58SiMn without cutting fluid, three-factor three-level orthogonal experiments and single factor experiments based on cutting speed and feed rate are employed, and an empirical model is established. The results of analysis of variance (ANOVA) revealed that feed rate is the dominant factor affecting the surface roughness. With the increase of cutting speed and feed rate, residual tensile stress on the surface becomes larger. Along the depth, micro hardness first decreases and then increases.


2009 ◽  
Vol 407-408 ◽  
pp. 577-581
Author(s):  
Shi Chao Xiu ◽  
Zhi Jie Geng ◽  
Guang Qi Cai

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.


2014 ◽  
Vol 989-994 ◽  
pp. 3331-3334
Author(s):  
Tao Zhang ◽  
Guo He Li ◽  
L. Han

High speed milling is a newly developed advanced manufacturing technology. Surface integrity is an important object of machined parts. Surface roughness is mostly used to evaluate to the surface integrity. A theoretical surface roughness model for high face milling was established. The influence of cutting parameters on the surface roughness is analyzed. The surface roughness decreases when the cutter radius increases, total number of tooth and rotation angular speed, while it increases with the feeding velocity. The high speed face milling can get a smooth surface and it can replace the grinding with higher efficiency.


2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Mohd Shahfizal Ruslan ◽  
Kamal Othman ◽  
Jaharah A.Ghani ◽  
Mohd Shahir Kassim ◽  
Che Hassan Che Haron

Magnesium alloy is a material with a high strength to weight ratio and is suitable for various applications such as in automotive, aerospace, electronics, industrial, biomedical and sports. Most end products require a mirror-like finish, therefore, this paper will present how a mirror-like finishing can be achieved using a high speed face milling that is equivalent to the manual polishing process. The high speed cutting regime for magnesium alloy was studied at the range of 900-1400 m/min, and the feed rate for finishing at 0.03-0.09 mm/tooth. The surface roughness found for this range of cutting parameters were between 0.061-0.133 µm, which is less than the 0.5µm that can be obtained by manual polishing. Furthermore, from the S/N ratio plots, the optimum cutting condition for the surface roughness can be achieved at a cutting speed of 1100 m/min, feed rate 0.03 mm/tooth, axial depth of cut of 0.20 mm and radial depth of cut of 10 mm. From the experimental result the lowest surface roughness of 0.061µm was obtained at 900 m/min with the same conditions for other cutting parameters. This study revealed that by milling AZ91D at a high speed cutting, it is possible to eliminate the polishing process to achieve a mirror-like finishing.


2014 ◽  
Vol 541-542 ◽  
pp. 785-791 ◽  
Author(s):  
Joon Young Koo ◽  
Pyeong Ho Kim ◽  
Moon Ho Cho ◽  
Hyuk Kim ◽  
Jeong Kyu Oh ◽  
...  

This paper presents finite element method (FEM) and experimental analysis on high-speed milling for thin-wall machining of Al7075-T651. Changes in cutting forces, temperature, and chip morphology according to cutting conditions are analyzed using FEM. Results of machining experiments are analyzed in terms of cutting forces and surface integrity such as surface roughness and surface condition. Variables of cutting conditions are feed per tooth, spindle speed, and axial depth of cut. Cutting conditions to improve surface integrity were investigated by analysis on cutting forces and surface roughness, and machined surface condition.


2006 ◽  
Vol 315-316 ◽  
pp. 140-144 ◽  
Author(s):  
Su Yu Wang ◽  
Xing Ai ◽  
Jun Zhao ◽  
Z.J. Lv

An orthogonal cutting model was presented to simulate high-speed machining (HSM) process based on metal cutting theory and finite element method (FEM). The residual stresses in the machined surface layer were obtained with various cutting speeds using finite element simulation. The variations of residual stresses in the cutting direction and beneath the workpiece surface were studied. It is shown that the thermal load produced at higher cutting speed is the primary factor affecting the residual stress in the machined surface layer.


2018 ◽  
Vol 157 ◽  
pp. 05010
Author(s):  
Jozef Holubjak ◽  
Jozef Pilc ◽  
Tatiana Czanova ◽  
Pavol Martikan ◽  
Dusan Mital ◽  
...  

This article deals with impact of cutting conditions when hard turning of shaped-complex surfaces which are concentration origin of cracks especially in the area of notches. These areas significantly reduce the lifetime and functionality of surface by degradation of surface integrity where are the significant number of destruction cracks. Actual experiments are focused on detection of impact of each individual cutting condition on the generation of residual stress and its impact in each surface and subsurface layer of material. Results and evaluations explain what way is necessary to design and apply cutting conditions when hard turning of shaped-complex surfaces.


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