N-coated Tool Research Articles

Investigation of the Properties of Multilayer Nanostructured Coating Based on the (Ti,Y,Al)N System with High Content of Yttrium

The studies are focused on the properties of the multilayer composite coating based on the (Ti,Y,Al)N system with high content of yttrium (about 40 at.%) of yttrium (Y). The hardness and elastic modulus were defined, and the resistance to fracture was studied during the scratch testing. Two cubic solid solutions (fcc phases), including c-(Ti,Y,Al)N and c-(Y,Ti,Al)N, are formed in the coating. The investigation of the wear resistance of the (Ti,Y,Al)N-coated tools during the turning of steel in comparison with the wear resistance of the tools with the based on the (Ti,Cr,Al)N system coating and the uncoated tools found a noticeable increase (by 250%–270%) in rake wear resistance. Active oxidation processes are observed in the (Ti,Y,Al)N coating during wear. It can be assumed that yttrium oxide is predominantly formed with a possible insignificant formation of titanium and aluminum oxides. At the same time, complete oxidation of c-(Y,Ti,Al)N nanolayers is not observed. Some hypotheses explaining the rather high performance of a coating with a high yttrium content are considered.

Influence of Cutting Speed during the Turning of Inconel 718 on Oxidation Wear Pattern on the Zr-ZrN-(Zr,Mo,Al)N Composite Nanostructured Coating

The properties and oxidation wear patterns in the composite nanostructured coating of Zr-ZrN-(Zr,Mo,Al)N were studied during the turning of Inconel 718 alloy at the cutting speeds of vc = 125 and 200 m/min. The hardness of the coating, its elastic modulus, and critical fracture load during the scratch testing were determined. The study focused on the tribological properties of the Zr-ZrN-(Zr,Mo,Al)N coating at temperatures of 400–900 °C paired with an insert made of Inconel 718, which exhibited a certain advantage over the reference coatings of Zr-ZrN and Ti-TiN-(Ti,Cr,Al)N of similar thickness. The coating of Zr-ZrN-(Zr,Mo,Al)N provided for the longest tool life at the cutting speed of vc = 125 m/min (the tool life was four times longer in comparison with that of the uncoated tool and 15% longer in comparison with that of the Ti-TiN-(Ti,Cr,Al)N-coated tool) and at the cutting speed of vc = 200 m/min (the tool life was 2.5 times longer in comparison with that of the uncoated tool and 75% longer in comparison with that of the Ti-TiN-(Ti,Cr,Al)N-coated tool). While at the cutting speed of vc = 125 m/min, the surface coating layers exhibit only partial oxidation of the external layers (to a depth not exceeding 250 nm), with mostly preserved cubic nitride phases, and then the cutting speed of vc = 200 m/min leads to almost complete oxidation (to the depth of at least 500 nm), however, with a partially preserved nanolayered structure of the coating.

Influence of tribological properties of Zr-ZrN-(Zr,Cr,Al)N and Zr-ZrN-(Zr,Mo,Al)N multilayer nanostructured coatings on the cutting properties of coated tools during dry turning of Inconel 718 alloy

The article studies the tribological properties of multicomponent nanostructured coatings of Zr-ZrN-(Zr,Cr,Al)N and Zr-ZrN-(Zr,Mo,Al)N, as well as the wear resistance and fracture behaviour of cutting tools with the mentioned coatings during the turning of Inconel 718 alloy. The Ti–TiN-(Ti,Cr,Al)N coating was also considered as a reference coating. While the Ti–TiN-(Ti,Cr,Al)N coating is characterized by high hardness, it also demonstrated high coefficients of friction (COF) at temperatures of 600 °C and above (i.e., at temperatures in the cutting zone). The Zr-ZrN-(Zr,Mo,Al)N coating has a balanced combination of high hardness and low COF at cutting zone temperatures. As a result, the Zr-ZrN-(Zr,Mo,Al)N-coated tool demonstrated wear resistance 2.4 times higher than that of the Ti–TiN-(Ti,Cr,Al)N-coated tool. During the process of cutting, zirconium (Zr) and chromium (Cr) oxides are formed in the Zr-ZrN-(Zr,Cr,Al)N coating, and the formation of zirconium and molybdenum (Mo) oxides is detected in the Zr-ZrN-(Zr,Mo,Al)N coating, which can have a positive effect on cutting conditions. Under the cutting conditions, the oxidizing action caused an almost complete transformation of a nitride coating structure into an oxide structure, while the nanolayer structure was partially preserved.

Tool wear of AlCrW-based-coatings on cemented carbide tools prepared by arc ion plating in dry cutting of alloy steel AISI 5120H

To improve both the critical scratch load and micro-hardness of (Al, Cr) N coating film, (Al, Cr, W)-based coating film was developed. In this study, to clarify the tool wear of the (Al,Cr,W)-based coated tool in the cutting of alloy steel AISI 5120H, the wear progress and wear mechanism of the coating film in the cutting of alloy steel AISI 5120H using six types of (Al,Cr,W)-based coated tools were investigated. The cutting conditions were a cutting speed of 5.00 m/s, feed rate of 0.25 mm/rev and cutting depth of 0.1 mm. The following results were obtained: 1) The wear progress of the (Al64,Cr28,W8)N-coated tool was slower than that of the (Al60,Cr25,W15)N-coated tool. 2) When a (Al64,Cr28,W8)-target was used to deposit a cemented carbide with a bias voltage of -150 V, the wear progress of the (Al64,Cr28,W8)N coated tool was slightly slower than that of the (Al64,Cr28,W8)(C,N)- or the (Al64,Cr28,W8)C-coated tool. 3) The wear progress of the (Al64,Cr28,W8)N coated tool with a bias voltage of -80 V was the slowest.

Tool Wear of Titanium/Tungsten/Silicon/Aluminum- Based-Coated Solid Carbide Thread Milling Cutters in Thread Tapping of Chromium-Molybdenum Steel

resistance. A titanium/tungsten-based coating film, namely (Ti,W) N coating film, has been developed. A (Ti,W,Si)N coating film, which is a titanium/tungsten/silicon-based coating film, has also been developed. Furthermore, titanium/tungsten/ silicon/aluminum-based coating films, namely (Ti,W,Si,Al) N, (Ti,W,Si,Al)C, and (Ti,W,Si,Al)(C,N) coating films, have been developed. And, compared with commercial (Ti,Al)N, the tool wear width of the (Ti,W)N/(Ti,W,Si,Al)N-coated tool was smaller than that of the (Ti,Al)N-coated tool. However, it is not clear whether these coating films are effective tool materials for helical milling with a thread milling cutter. In this study, chromium-molybdenum steel was helical milled with two physical vapor deposition (PVD)-coated cemented carbide thread milling cutters in order to clarify effective tool materials for tapping chromium-molybdenum steel. The coating films used were (Ti,Al)N and (Ti,W)N/(Ti,W,Si,Al)N coating

Performance of PVD (Zr,Ti)N-coated cemented carbide inserts in cutting processes

(Zr,Ti)N coatings with two different gradient structures were deposited on YT15-cemented carbide inserts by multi arc ion plating. Microstructure and properties of these coatings were examined. Dry cutting tests of these coated inserts against 40Cr hardened steel are carried out. This paper presented a detailed analysis of the cutting performance and wear mechanism of these coated inserts. The critical load of EGC shows a little increase compared with TGC because of the thermal expansion coefficient gradient. Compared with YT15 tool, (Zr,Ti)N-coated tools lead to a high quality and good consistency of machined surface during the whole machining process; the cutting temperature will also decrease, but the cutting force change a little. The abrasive wear and boundary wear are the main mode of flank wear, and crater wear and adhesive wear are the main rake wear modes during the machining of 40Cr hardened steel. The (Zr,Ti)N coatings effectively improve the wear resistance of the tools especially the crater wear. The thermal expansion coefficient gradient structure of EGC will reduce the thermal damage of the coating, and its multi-layer structure will mitigate and block the initiation and propagation of microcracks.

Tool Wear of Diamond-Like Carbon-Coated High-Speed Steel with a Cr-Based Interlayer in Cutting of Aluminum Alloys

In cutting aluminum alloy 6061, continuous chips have a negative influence on the machining operation. Usually, Pb is added in order to break continuous chips. However, from the standpoint of environmental protection, it is necessary to improve chip breakability without adding Pb. One effective measure to improve chip breakability is by adding Si to aluminum alloy 6061. However, the influence of Si content on tool wear has not been fully examined. In this study, in order to clarify the influence of a diamond-like carbon (DLC) coating layer with a Cr-based interlayer, namely (Al,Cr)N, on cutting performance, aluminum alloys having different Si contents were turned. The substrate of the tool material was high-speed steel (1.4%C). The tool wear and the surface roughness were experimentally investigated. The following results were obtained: (1) In cutting two kinds of Al-Si alloys, namely the Al-2%Si alloy and Al-4%Si alloy, the progress of wear of the DLC/(Al,Cr)N-coated tool was slower than that of the DLC-coated tool. Therefore, the (Al,Cr)N interlayer was effective for decreasing the tool wear of the DLC-coated tool. (2) The wear progress of the two kinds of DLC-coated tools in cutting of Al-4%Si alloy was faster than that in cutting of Al-2%Si alloy. (3) In cutting of Al-2%Si alloy with the (Al,Cr)N/DLC-coated tool, the surface roughness was almost constant in the range of a cutting distance from 0.1 km to 9.5 km.

Influence of Concentration of Sulfurous and Phospherous EP Additives in Cutting Oil in Hobbing with MQL System

In this paper, the influence of concentration of sulfurous and phosphorous EP additives added on flank wear, crater wear of TiN- and (Al, Ti) N-coated tools, and finished surface roughness were investigated with minimal quantity lubrication (MQL) system in hobbing. Experiments were conducted by simulating hobbing by fly tool cutting on a milling machine. The results helped clarify the following points; (1) In the cases of polysulfide and sulfurized fatty oil, the flank wear decreased in the concentration of additive of 1.0 % (by weight), which showed a optimum concentration. In the case of tricresyl phosphate (TCP), the flank wear decreased with an increase in the concentration. Sulfurized fatty oil showed better wear reduction effect than any other additives. (2) When increasing in the concentration of the additives used in the tests, the crater wear becomes large, which was suggested to be caused by corrosion of additives. (3) Finished surface roughness obtained with EP additives tested is smaller than that obtained with no additive oil. (4) From the viewpoints of flank wear, crater wear and finished surface roughness, sulfurized fatty oil, of which the concentration is 1.0 %, is suitable for MQL system using (Al, Ti) N-coated tool in hobbing.

Influence of Kinds of Cemented Carbide Hob Materials in Hobbing with MQL System

This paper investigates the influence of kinds of cemented carbide hob materials coated with fully TiN and (Ti, Al)N coatings, in hobbing with minimal quantity lubrication (MQL) system compared with dry cutting in cutting performance, in terms of flank wear (tool life), crater wear and finished surface roughness. Experiments were carried out by simulating hobbing by fly tool cutting on a milling machine. The results obtained are summarized as follows. (1) When changing the kinds of hob materials, P10, P20 and P30, as a substrate, the P30 hob material showed a longest tool life, even if the kinds of coating films were changed. The tool life obtained with the Fully (Ti, Al)N-coated tools is longer than that obtained with TiN-coated tools. The flank wear reduction effect by MQL system, which prolongs the tool life compared with the dry cutting, was recognized. (2) Although the reduction effect was recognized in the crater wear, the thermal cracks occur on the rake face of both fully TiN-and (Ti, Al)N-coated P30 tools. (3) The MQL system decreases the surface roughness with all of the cemented carbide hob materials and the coating films tested. (4) From the viewpoints of the tool life, the crater wear and the surface roughness, the use of MQL system for the fully (Ti, Al)N-coated P30 tool is effective.

B17 ホブ切り用水溶性切削油剤に関する基礎的研究 : pHの影響(OS-6 切削加工(3))

This paper presents the influence of pH of water-soluble cutting fluids with and without synthetic lubricating additive for hobbing; Fluid A and Fluid B, on the flank wear, using TiN- and (Al,Ti)N-coated tools. Experiments were conducted by simulating hobbingby fly tool cutting on a milling machine. The following result was clarified: When using both Fluid A and Fluid B, the flank wear decreases with decreasing pH, in which the FluidAhavingpH 8.0 and the Fluid B having pH 9.0 showed the smallest flank wear width with both TiN- and (Al,Ti)N-coated tools.

B16 切りくずの切削過程におけるホブ摩耗の分配 : 舞いツールによる基礎実験(OS-6 切削加工(3))

In this paper, after developing a method to divide the cutting length of a chip into four equal parts, investigation were carried out on the distribution ratio of hob wear when cutting each of the parts. Experiments were conducted by simulating hobbing by fly tool cutting on a milling machine. The results obtained are summarized as follows. (1)In the cases of dry cutting and MQL system when using TiN-coated tool, the distribution ratio of bob wear is largest at the end part of cutting chip, but in the case of flood, it is standardized at each part of cutting chip. (2) When using (Al,Ti)N-coated tool, the distribution ratio of hob wear obtained with dry cutting and MQL system is greatest at the beginning part of cutting chip, but that obtained with flood is standardized at each part of cutting chip.

311 極微量切削油供給によるボブ切りの基礎的研究 : ドライ切削との切削性能の比較(OS 材料加工・精密加工(その1))

This paper compares the cutting performance of minimal quantity lubrication (MQL) system with dry cutting in terms of flank wear, crater wear and finished surface roughness when using various kinds of cutting tools. Experiments were conducted by simulating hobbing by fly tool cutting on a milling machine. The results obtained are summarized as follows. (1) When using an uncoated tool, TiN- and (Al, Ti) N-coated tools without coating on the rake face, and fully TiN- and (Al, Ti) N-coated tools, MQL decreases the flank wear, crater wear and finished surface roughness compared with the wear and the roughness by dry cutting, particularly at the high cutting speed of 159 m/min. The reason suggested is the lubricating properties improved even with an extremely small quantity of cutting oil, which reduces the occurrence of deposited metal on the cutting edge. (2) With both the fully TiN- and (Al, Ti) N-coated tools, the MQL system showed better cutting performance in terms of reduced tool wear and reduced finished surface roughness compared with that by dry cutting; in particular, the fully (Al, Ti) N-coated tool is suitable for an MQL system in hobbing.

Fundamental Research on Hobbing with Minimal Quantity Lubrication of Cutting Oil (Effect of Cutting Speed)

In this paper, we investigate the effect of cutting speed on flank wear, crater wear and finished surface roughness during hobbing using an uncoated tool, and TiN- and (Al, Ti)N- coated tools with a minimal quantity lubrication (MQL) system. The experiments were conducted by simulating hobbing by fly tool cutting on a milling machine. The results helped clarify the following points. (1) With the uncoated tool and the TiN-coated tool, the flank wear increases upon increasing in the cutting speed from 47m/min to 86m/min. Conversely, flank wear decreases at the higher speed of 117m/min. It was impossible to cut at 159m/min owing to the failure of the cutting edge. With the (Al, Ti)N-coated tool, the flank wear showed nearly the same small value, irrespective of cutting speed. (2) The cutting speed also has a large effect on crater wear, particularly for the TiN-and (Al, Ti)N-coated tools. The cutting speed of 117m/min is suitable for decreasing crater wear. (3) The finished surface roughness is small for all the tools used in this test for cutting speeds less than 86m/min, after which it becomes large because of the adhesion of deposited metal at cutting speeds more than 117m/min. When using the TiN- and (Al, Ti)N-coated tools, there is a critical cutting groove length, at which the surface roughness decreases rapidly.

Cutting performance of Ti–Al–Si–N-coated tool by a hybrid-coating system for high-hardened materials

Hard coatings are known to improve the performance of cutting tools in aggressive machining applications, such as high-speed machining. Unfortunately, the development of cutting tool for high-speed machining is not enough in machining of difficult-to-cut material. New superhard Ti–Al–Si–N films, characterized as a nanocomposite nano-sized (Ti,Al,Si)N crystallites embedded in amorphous Si 3N 4 matrix, was successfully synthesized on WC-Co substrates by a hybrid-coating system of arc ion plating (AIP) and sputtering method. The hardness of Ti–Al–Si–N film increased with incorporation of Si, and had the maximum value ∼50 GPa at the Si content of 9 at.%, respectively. In this study, Ti–Al–Si–N coatings were applied to end-mills made of WC-Co material by a hybrid-coating system. The tool performances for the high-hardened material were studied under high-speed cutting conditions. Additionally, the relationship between the machining characteristics and the Si contents were investigated under various high-spindle speeds. It showed the tool life was improved up to 50% at the Si content of 9 at.%.

Basic study of ball end milling on hardened steel

This study deals with ball end milling with a (Al,Ti)N-coated tool on hardened steel. The cutting forces in ball end milling with a helical flute were obtained theoretically and experimentally not only for a flat surface, but also for an inclined work surface. They are agreed with each other. The influence of the cutting conditions on tool life is discussed: it changed from 200 to 1100 m, depending on the cutting conditions. For the cutting conditions of a large inclined angle of the work-piece surface and a large feed rate, a long tool life was obtained. The causes of reduced tool life changed, depending on the cutting conditions.

Applicative characterization of cathodic arc-deposited Ti–B–N coatings

Reactive cathodic arc evaporation of a Ti–B alloy with 3.5 at.% boron was applied to deposit Ti–B–N coatings with a resulting boron content of 1 at.%. The discharge behaviour was characterized. The coatings were investigated by depth-sensing indentation measurements before and after thermal loadings at 700 °C under vacuum and under atmospheric conditions as well as by milling and drilling tests with coated tools. The results were compared to TiN and (Ti,Al)(C,N) reference systems. The Ti–B–N coatings showed an increased thermal stability in comparison to TiN and (Ti,Al)(C,N). In the application tests Ti–B–N-coated tools showed improved performance compared to the (Ti,Al)(C,N)-coated reference tools.

The performance of (Ti,Al)N-coated flowdrills

The oxidation resistance of (Ti,Al)N coatings at elevated temperatures makes them suitable for applications where other coatings fail. Results about the performance of (Ti,Al)N coatings at elevated temperatures have been published for metal cutting operations, but much less is known about the behaviour of (Ti,Al)N-coated tools in contact with molten metals. Uncoated cemented carbide flowdrills were compared with (Ti, Al)N coated flowdrills. Respectively about 5000 holes and over 100 000 holes in austenitic stainless AISI 304 have been produced. The tool wear and the deposition of workpiece material on the tool were examined by means of scanning electron microscopy and energy-dispersive X-ray analysis. In particular, the influence of these deposits on the tool life is discussed.