The Effect of Build Up Edge Formation on the Machining Characteristics in Austempered Ferritic Ductile Iron

Author(s):  
Şakir Yazman ◽  
Ahmet Akdemir ◽  
Mesut Uyaner ◽  
Barış Bakırcıoğlu

In this study, chip formation mechanism during the machining of austempered ferritic DI and the effect of the emerging chip morphology on such machining properties as surface roughness and cutting forces has been scrutinized. After austenitizing at 900 °C for 90 min, DI specimens were austempered in a salt bath at 380 °C for 90 min. Chip roots were produced by using a quick stop device during the machining of austempered specimens in different cutting speeds. The metallographies of these specimens were performed and chip morphologies were examined. The fact that the cutting speed increased led to a decrease in built-up edge formation. Depending on this fact, it was detected that the change in built-up edge thickness substantially affected the surface roughness and cutting forces. It was also detected that during the machining, with the effect of cutting forces and stress, spheroidal graphites were broken off in the chip and lost their sphericity and so that the chip became fragile and unstable and grafites here displayed a lubricant feature.

Author(s):  
Abdullah Altin

In this research, we had studied the sensitivity for machining of cobalt-based superalloy Haynes 188 with ceramic cutting tool. The investigation had focused on the effects of the cutting speed, on the cutting forces, and on the surface roughness based on Taguchi’s experimental design. The effects of machining parameters were determined using Taguchi’s L27 orthogonal array. The signal-to-noise ratio was calculated for the average of surface roughness and the cutting forces, and the smaller were used to determine the optimal cutting conditions. The analysis of variance and the signal-to-noise ratio had effects on the parameters on both surface roughness and cutting. Three different types of cutting tools had been used in the experiment, namely KYON 4300, KYS 25, and KYS 30. The cutting force of Fz was considered to be the main cutting force. Depending on the material which had been used as cutting tool, the Fz had the lowest cutting speed and the lowest surface roughness with the KYS25 ceramic tool. The cutting force and the surface roughness of KYON 4300 cutting tool had shown better performance than other cutting tools. The flank wear and notch were found to be more effective in the experiments. The long chips were removed at low and medium cutting speeds, while the sawdust with one edge and narrow pitch at high cutting speeds was obtained.


Author(s):  
Ahmet Akdemir ◽  
Şakir Yazman ◽  
Hacı Saglam ◽  
Mesut Uyaner

Ductile iron can acquire enhanced thermal and mechanical properties from austempering heat treatment. The present study aims to identify the function of different cutting parameters affecting machinability and to quantify its effects. Turning was performed to test machinability according to the ISO3685-1993 (E) standard. After austenitizing at 900 °C for 90 min, austempered ductile iron (ADI) specimens were quenched in a salt bath at 380 °C for 90 min. The cutting force signals along three directions were measured in real time, whereas flank wear and surface roughness were measured offline. For the cutting parameters, the cutting speed and depth of cut were varied, but the feed rate was kept constant. In the flank wear tests, machining length was corresponded to tool life. In addition, in order to find out the effect of cutting parameters on surface roughness (Ra), tangential force (Ft), and flank wear (VB) during turning, response surface methodology (RSM) was utilized by using experimental data. The effect of the depth of cut on the surface roughness was negligible but considerable in the cutting forces. The increased cutting speed produced a positive effect on surface roughness. It is found that the cutting speed was the dominant factor on the surface roughness, tangential force, and flank wear.


Author(s):  
Çağın Bolat ◽  
Berkay Ergene ◽  
Uçan Karakılınç ◽  
Ali Gökşenli

On the road to real applications, although there are lots of efforts focusing on mechanical and physical features in the literature, their machining abilities were examined in a very limited manner. In this study, machining properties of pumice reinforced AA7075 syntactic foams manufactured via the newly offered sandwich infiltration technique were investigated by performing face turning. Physical and microstructural (optical and SEM works) analyses were conducted on fabricated foams to carry out sample characterization. All machining forces were measured for different cutting speeds (25, 50, and 100 m/min) and feed rates (0.05, 0.10, and 0.15 mm/rev). After the turning operation, areal surface roughness values were measured using a 3D surface profilometer and material removal rate (MRR) values were calculated. Besides, chip mixtures including pumice and metal fragments were collected to probe chip morphology in detail. The results showed that machining forces were affected by the operation parameters differently, and the lowest surface roughness was detected at the cutting speed of 100 m/min and 0.05 mm/rev feed rate. Furthermore, the shape of the metal chips changed from long/continuous characteristic to saw-tooth morphology depending on increasing cutting speed levels while pumice particles exhibited breakaway tendency as the feed rates went up.


Author(s):  
Brian Davis ◽  
David Dabrow ◽  
Licheng Ju ◽  
Anhai Li ◽  
Chengying Xu ◽  
...  

Magnesium (Mg) and its alloys are among the lightest metallic structural materials, making them very attractive for use in the aerospace and automotive industries. Recently, Mg has been used in metal matrix composites (MMCs), demonstrating significant improvements in mechanical performance. However, the machinability of Mg-based MMCs is still largely elusive. In this study, Mg-based MMCs are machined using a wide range of cutting speeds in order to elucidate both the chip morphology and chip formation mechanism. Cutting speed is found to have the most significant influence on both the chip morphology and chip formation mechanism, with the propensity of discontinuous, particle-type chip formation increasing as the cutting speed increases. Saw-tooth chips are found to be the primary chip morphology at low cutting speeds (lower than 0.5 m/s), while discontinuous, particle-type chips prevail at high cutting speeds (higher than 1.0 m/s). Using in situ high speed imaging, the formation of the saw-tooth chip morphology is found to be due to crack initiation at the free surface. However, as the cutting speed (and strain rate) increases, the formation of the discontinuous, particle-type chip morphology is found to be due to crack initiation at the tool tip. In addition, the influences of tool rake angle, particle size, and particle volume fracture are investigated and found to have little effect on the chip morphology and chip formation mechanism.


Author(s):  
K. Aslantas ◽  
İ. Ucun ◽  
K. Gök

The study deals with the machinability properties of austempered ductile iron using cubic boron nitride cutting tools. To emphasize the role of the austempering process, ductile iron specimens were first austenitized in salt bath at 900°C for 60min, after which they were quenched in a salt bath at 250°C and 325°C for 60min. Machining tests were carried out at various cutting speeds under the constant depth of cut and the feed rate. Tool performance was evaluated based on the workpiece surface roughness and flank wear. The influence of the austempering temperature and cutting speed on the chip form was also studied. The results point out that the lower austempering temperature results in the increase in the cutting forces, while better surface roughness is attained.


Author(s):  
Brian Davis ◽  
David Dabrow ◽  
Licheng Ju ◽  
Anhai Li ◽  
Chengying Xu ◽  
...  

Magnesium (Mg) and its alloys are among the lightest metallic structural materials, making them very attractive for use in the aerospace and automotive industries. Recently, Mg has been used in metal matrix composites (MMCs), demonstrating significant improvements in mechanical performance. However, the machinability of Mg-based MMCs is still largely elusive. In this study, Mg-based MMCs are machined using a wide range of cutting speeds in order to elucidate both the chip morphology and chip formation mechanism. Cutting speed is found to have the most significant influence on both the chip morphology and chip formation mechanism, with the propensity of discontinuous, particle-type chip formation increasing as the cutting speed increases. Saw-tooth chips are found to be the primary chip morphology at low cutting speeds (lower than 0.5 m/s), while discontinuous, particle-type chips prevail at high cutting speeds (higher than 1.0 m/s). Using in situ high-speed imaging, the formation of the saw-tooth chip morphology is found to be due to crack initiation at the free surface. However, as the cutting speed (and strain rate) increases, the formation of the discontinuous, particle-type chip morphology is found to be due to crack initiation at the tool tip. In addition, the influences of tool rake angle, particle size, and particle volume fracture are investigated and found to have little effect on the chip morphology and chip formation mechanism.


2014 ◽  
Vol 493 ◽  
pp. 546-551 ◽  
Author(s):  
Safian Sharif ◽  
Habib Safari ◽  
Sudin Izman ◽  
Denni Kurniawan

The surface quality generated when high speed dry end milling (HSDEM) Ti-6Al-4V-ELI titanium alloy with coated and uncoated carbide tools were investigated. Evaluation was conducted using TiAlN+TiN coated and uncoated cemented carbide tools under different high cutting speeds and feed rates conditions. Surface roughness and cutting forces were measured when using new tools. The milled surface quality and corresponding alteration were characterized through electron microscopy. Within the investigated conditions high quality surface finish was obtained on the machined surface. Increasing cutting speed from 200 to 300 m/min during the process improved the surface finished particularly under lower feed rates. In term of generated surface quality, uncoated H25 grade carbide tools out performed coated F40M grade specifically at the higher cutting conditions. The main damages observed after HSDEM on the surface for all machining conditions contain redeposited materials, feed marks, and tool edge marks. Under both tested feed rates the resultant cutting force decreased by increasing the cutting speeds and uncoated carbide tools provide the lower cutting forces compared to coated types.


2009 ◽  
Vol 23 (06n07) ◽  
pp. 1796-1802 ◽  
Author(s):  
A. G. JAHARAH ◽  
C. H. CHE HASSAN ◽  
M. J. GHAZALI ◽  
A. B. SULONG ◽  
M. Z. OMAR ◽  
...  

This paper presents the performance of uncoated carbide cutting tool when machining cast iron in dry cutting conditions. Experiments were conducted at various cutting speeds, feed rates, and depths of cut according to Taguchi method design of experiment using a standard orthogonal array L 9(34). The effects of cutting speeds (100-146 m/min), feed rates (0.20-0.35 mm/tooth) and depths of cut (1.0-2.0 mm) on the tool life, surface roughness and cutting forces were evaluated using ANOVA. Results showed that the effects of cutting speed, depth of cut and the feed rate were similar affecting the failure of the carbide cutting tools within the range of tested machining parameters. The contribution of cutting speed, feed rate, and depth of cut in controlling the tool life were 32.12%, 38.56% and 29.32% respectively. Whereas, the cutting speed was the main factor influencing the average surface roughness (Ra) value followed by feed rate. These factors contribute 60.53% and 35.59% respectively to the Ra value. On the other hand, cutting forces generated were greatly influenced by the depth of cut (66.52%) and the feed rate (32.6%). Cutting speed was found insignificant in controlling the generated cutting forces.


2021 ◽  
Vol 16 (2) ◽  
pp. 200
Author(s):  
Rusnaldy Rusnaldy ◽  
Yusuf Umardani ◽  
Diva Tsamara Putra ◽  
Jovian Bernard

<p><em>Austempered ductile iron (ADI) is a difficult material for machining, </em><em>even though ADI is believed to have several advantages such as strength, ductility, high toughness, fatigue resistance, good dynamic wear resistance, has a good strength-to-weight ratio, easy to manufacture  and easy to cast that causes it to be widely used in various applications.  </em><em>This study investigates the effect of milling parameters on surface rougness and chip thickness ratio on milling of ADI. To produce ADI, ductile irons  were first austenitized in furnace at 900<sup>o</sup>C for 1 hour and then they were quenched in salt bath at 375<sup>o</sup>C for 1 hour. The work material was machined with uncoated carbide tool. The tool was 20 mm in diameter. The cutting experiments were carried out in the dry mode. The feed was varied from 0.05 to 0.1 mm/tooth for cutting speed ranging from 15 m/min to 25 mm/min and depth of cut ranging from 0.1 mm to 0.3 mm. The surface roughness was measured using the Mitutoyo SJ-201, surface roughness machine. The chip thickness was measured using software Image J from the photograph produced by digital microscope endoscope. The results show that connected and loose chips were produced. Long and continuous chips were not found in this study. The effects of cutting speeds, feeds and depth of cut on surface roughness and chip thickness ratio  are reported in this paper</em><em></em></p>


2014 ◽  
Vol 68 (4) ◽  
Author(s):  
M. S. Said ◽  
J. A. Ghani ◽  
R. Othman ◽  
M. A. Selamat ◽  
N. N. Wan ◽  
...  

The purpose of this research is to demonstrate surface roughness and chip formation by the machining of Aluminium silicon alloy (AlSic) matrix composite, reinforced with aluminium nitride (AlN), with three types of carbide inserts present. Experiments were conducted at various cutting speeds, feed rates, and depths of cut, according to the Taguchi method, using a standard orthogonal array L9 (34). The effects of cutting speeds, feed rates, depths of cut, and types of tool on surface roughness during the milling operation were evaluated using Taguchi optimization methodology, using the signal-to-noise (S/N) ratio. The surface finish produced is very important in determining whether the quality of the machined part is within specification and permissible tolerance limits. It is understood that chip formation is a fundamental element that influences tool performance. The analysis of chip formation was done using a Sometech SV-35 video microscope. The analysis of results, using the S/N ratio, concluded that a combination of low feed rate, low depth of cut, medium cutting speed, and an uncoated tool, gave a remarkable surface finish. The chips formed from the experiment varied from semi–continuous to discontinuous. 


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