Deep cryogenic treatment of carbide tool and its cutting performances in hard milling of AISI H13 steel

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Procedia CIRP 00 (2017) Procedia CIRP 000–000 71 (2018) 35–40

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4th CSI) 4thCIRP CIRPConference Conferenceon onSurface SurfaceIntegrity Integrity(CIRP (CSI 2018)

CIRP Design Conference,tool Mayand 2018,its Nantes, Franceperformances in Deep cryogenic 28th treatment of carbide cutting hard milling of AISI H13 steel A new methodology to analyze the functional and physical architecture of a,b a,b a,b, Binxun Li , Tao Zhang , Song Zhang family * existing products for an assembly oriented product identification a a School of Mechanical Engineering,Shandong University,Jinan 250061,China Key Laboratory of High-efficiency and Clean Mechancial Manufacture (Shandong University),Minisry of Education,China

bb Key

Paul Stief *, Jean-Yves Dantan, Alain Etienne, Ali Siadat

* Corresponding author. Tel.: 86-531-88392746. E-mail address: [email protected] École Nationale Supérieure d’Arts et Métiers, Arts et Métiers ParisTech, LCFC EA 4495, 4 Rue Augustin Fresnel, Metz 57078, France

* Corresponding author. Tel.: +33 3 87 37 54 30; E-mail address: [email protected]

Abstract

Microstructure and mechanical properties of cutting tool have significant effect on tool wear, especially in hard machining process. As an Abstract effective non-destructive modification technology, cryogenic treatment is widely used for carbide tools in order to change its microstructure and phase constituent which reflects the change of hardness, wear resistance and plasticity in macroscale. In this paper, an orthogonal In today’s business environment, the trend towards more product variety and customization is unbroken. Due to this development, the need of experiment was designedproduction to investigate the effect of deep cryogenic treatment parameters (cryogenic temperature, rate, soaking time, agile and reconfigurable systems emerged to cope with various products and product families. To designcooling and optimize production

systems as well temperature) as to chooseon themicrostructure optimal product product analysis methodstool arewith needed. Indeed, most the known methods aim to and tempering andmatches, mechanical properties of carbide Ti (N, C)-Al coatings as well as its cutting 2 2O3 3of analyze a product one milling product of family the physical level.the Different product families, however, mayobserved differ largely in terms the number and performances in or hard AISIonH13 steel. First, microstructure of carbide tool was by means ofofscanning electric nature of components. This fact impedes an efficient comparison and choice of appropriate product family combinations for the production microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The experimental results show that WC grains were system. A new methodology is proposed to analyze existing products in view of their functional and physical architecture. The aim is to cluster refined and large amounts of dispersive carbidefamilies was precipitate out. Secondly, the variation of hardness Vickers tester these products in new assembly oriented product for the optimization of existing assembly lines andwas the measured creation ofthrough future reconfigurable and the surface microhardness was improved evidently after cryogenic treatment. Range analysis was employed and the analysis results reveal assembly systems. Based on Datum Flow Chain, the physical structure of the products is analyzed. Functional subassemblies are identified, and that temperature has the most significant influence on hardness followed by cooling rate, holding time and tempering temperature. a functional analysis is performed. Moreover, a hybrid functional and physical architecture graph (HyFPAG) is the output whichFinally, depictshard the similarity between product familiesout by and providing design support to indicate both, production system planners and product designers. An illustrative milling experiments were carried the experimental results that the flank wear VB decreased under same material removal example of a tool nail-clipper is used tois explain the proposed methodology. An industrial case study on two product families steeringproperties columns of volume and wear resistance strengthened. The research can provide an instruction for improving mechanical andofphysical of thyssenkrupp Presta France is then carried out to give a first industrial evaluation of the proposed approach. cutting tools to increase tool life. © 2017 The Authors. Published by Elsevier B.V. © Authors. Published Elsevier B.V. © 2018 2018 The Theunder Authors. Published by by Elsevier Ltd. committee This is an open articleDesign under the CC BY-NC-ND Peer-review responsibility of the scientific of theaccess 28th CIRP Conference 2018. license Peer-review under responsibility of the scientific committee of the 4th CIRP Conference on Surface Integrity (CSI 2018). (https://creativecommons.org/licenses/by-nc-nd/4.0/) Selection Assembly; and peer-review under responsibility of the scientific committee of the 4th CIRP Conference on Surface Integrity (CSI 2018). Keywords: Design method; Family identification Keywords: deep cryogenic treatment; microstructure; hard milling; cutting performance

Introduction 1.1.Introduction Due to the outstanding mechanical and domain physicalof Due fast development in the properties of cemented carbide, trend e.g., high strength and communication and an ongoing of digitization and hardness, corrosion resistanceenterprises at high temperature well as digitalization, manufacturing are facingasimportant low coefficient of thermal expansion, it has already been challenges in today’s market environments: a continuing widely applied many industrial fields and employed tendency towardsinreduction of product development times as and cutting tool material [1]. The cementedthere carbide with shortened product lifecycles. In addition, is antool increasing specific of coatings has already beenat utilized as time cutting in demand customization, being the same in tool a global hard machining CVD tool coating on competition with process. competitors all and overPVD the world. This trend, cemented carbide have been introduced onemacro after another which is inducing the development from to micro which could high lot temperature and markets, results improve in diminished sizes due strength to augmenting oxidation resistant during machining [2,3]. For coating Ti product varieties (high-volume to low-volume production) [1]. Al22O excellent chemical (N,cope C)-Al 3,this To with augmenting as well as to stability be able to 22O3, 33 possessesvariety and superior hot hardness while potentials Ti (N, C) serves bond identify possible optimization in theasexisting production system, it is important to have a precise knowledge

which range is theand most popular used tool coating [4]. of coat the product characteristics manufactured and/or However, cutting toolsIninevitably subjects to more severe assembled in this system. this context, the main challenge in thermal, and mechanical hard modelling analysis isand nowtribology not only conditions to cope within single millinga process than conventional cutting process. This products, limited product range or existing product families, tobe theable acceleration tool wear even suddentorupture butleads also to to analyzeof and to compare products define ofproduct the cutting tool during hard millingthat process which has a new families. It can be observed classical existing detrimental on surface integrityofasclients well as increase product familieseffect are regrouped in function or features. the costassembly of production. Therefore, the demanding of ways to However, oriented product families are hardly to find. improve the tool life level, is needed. As differ known to all, the On the product family products mainly in two introduction of new materials the employment of main characteristics: (i) tool the number of and components and (ii) the various surface (e.g. coating have been widely researched. type of components mechanical, electrical, electronical). However, deep cryogenicconsidering treatment asmainly a material Classical methodologies singleprocessing products has been introduced and relatively or technology solitary, already existing product families analyze few the researches haveonbeen proposed to (components perform a comprehensive product structure a physical level level) which investigation on it.regarding an efficient definition and causes difficulties comparison of different product families. Addressing this

2212-8271 © 2018 The Authors. Published by Elsevier B.V. 2212-8271 ©under 2018responsibility The Authors. Published Elsevier of Ltd. is an Conference open accessonarticle the (CSI CC BY-NC-ND license Peer-review of the scientificbycommittee theThis 4th CIRP Surfaceunder Integrity 2018). (https://creativecommons.org/licenses/by-nc-nd/4.0/) 2212-8271 © 2017 The Authors. Published by Elsevier B.V. Selection and peer-review under responsibility of the scientific committee of the 4th CIRP Conference on Surface Integrity (CSI 2018). Peer-review under responsibility of the scientific committee of the 28th CIRP Design Conference 2018. 10.1016/j.procir.2018.05.019

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Binxun Li et al. / Procedia CIRP 71 (2018) 35–40 Binxun Li et al / Procedia CIRP 00 (2018) 000–000

Deep cryogenic treatment which referred as a nondestructive modification technology of various materials is putting the cutting tool into an environment for a period of time where the temperature is far below the ambient temperature, generally about -180℃ [5-10]. It was believed that some microstructural changes do occur interior of the cutting tool but do not confined to the surface of the material. Deep cryogenic treatment as a new material process has been adopted and successfully applied for different materials including ferrous metal, magnesium alloy as well as nickel-base alloy. Li et al. [11] investigated the mechanical properties and microstructures of IN718 superalloy subjected to cryogenic treatment. It was found that the grains are refined significantly and the internal stress increases. Barron [12] conducted abrasive wear tests on a wide variety of steels, and found that steels with retained austenite at room temperature exhibit stronger wear resistance after deep cryogenic treatment. Araghchi et al. [13] applied a novel deep cryogenic treatment to relieve residual stresses of aluminium alloy subjected to quenching. As for the cemented carbide tool, several researches have been experimentally confirmed that deep cryogenic treatment can modify microstructures and mechanical properties of cemented carbide cutting tools as well as significantly improve the tool wear resistance and also reduce the friction coefficient. Zhang et al. [14] reported that hardness and bending strength of WC-12Co cemented carbide increases slightly while no significant change in the microstructure and the elemental distribution. Yong and Ding [15] reported that the hardness, compression strength, wear resistance and fatigue resistance were enhanced while the bending strength and toughness are not changed evidently Yong et al. [16] observed cryogenic treated tools exhibit better tool wear resistance than untreated ones through milling operation. Nevertheless, there are still some differences regarding cutting performance in hard milling of AISI H13 steel while using deep cryogenic treatment with different processing parameter. Sreeramareddy et al. [17] found that flank wear of deep cryogenic treated cutting tool was lower than untreated and cutting force during machining AISI 1040 was lower with treated cutting tools. In this study, an orthogonal designed experiment L25(54) was carried out to investigate the effect of deep cryogenic treatment processing parameters (cryogenic temperature, cooling rate, soaking time, and tempering temperature) on microstructure and mechanical property of the cutting tool. Besides, an attempt has been made to investigate any improvement of cutting performance in cryogenically treated cemented carbide cutting tool during hard milling AISI H13 steel.

The cutting tools were firstly put into Cryoprocessor (type SLX-30, Cryopower) for treatment using liquid nitrogen. The details of the experiments and the schematic diagram of deep cryogenic treatment process are shown in Table 1 and Fig.1, respectively. The tempering speed for all experiments was set to 5°C/min and natural cooling to room temperature was employed. Table 1. Orthogonal experiment conditions for deep cryogenic treatment. Factor Temperature (°C)

Cooling rate

1

-70.0

2

-100.0

3 4 5

Level

Soaking time (min)

Tempering temperature (°C)

2.0

60

20.0

3.5

90

60.0

-130.0

5.0

120

100.0

-160.0

6.5

150

140.0

-190.0

8.0

180

180.0

(°C /min)

2.2. Hardness measurement The hardness of deep cryogenic treated cutting tool as well as original cutting tool was measured on a Vickers microhardness test machine. The microhardness was measured with 100g load. To avoid the statistical error, at least three readings were taken to evaluate the average microhardness of the cutting tools. The indentation of microhardness measurement is shown in Fig.2.

Fig.1. Schematic diagram of deep cryogenic treatment process

2.3. Metallurgical observation

2. Experimental works 2.1. Deep cryogenic treatment The raw material adopted in this experiment are WC-Co cemented carbide indexable inserts with coating Ti (N, C)Al2O3 (type XOMX090308TR-M08 F40M, Seco company).

Fig.2. The indentation of microhardness measurement on cutting tool.

In order to observing the change of microstructure of the cutting tool, microstructural observation and element analysis were performed in Quanta 250 FEG scanning



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37

electron microscope (SEM) and INCA Energy X-203 MAX-50 energy dispersive spectrum (EDS), respectively. Before observation, the cutting tools were mounted, polished till to without obvious scratches and then etched to reveal its microstructure using mixed solution with 20% potassium ferricyanide and 20% caustic soda in equal proportion for about 20 to 30 seconds. X-ray diffraction (XRD) was used to identify the occurrence of phase transformation. 2.4. Hard milling experiments In order to evaluate cutting performance of the cryogenic treated tools during hard milling process, i.e., the wear behaviour of cutting tools, hard milling experiments were conducted on a CNC vertical machining centre (ACE-V500, DAEWOO) without any coolant in hard milling of AISI H13 steel which are widely used in die and mould industries. The flank wear (VB) of the cutting tool as an indicator has been used to evaluate the wear resistance with same removal volume (9000 mm3) of material AISI H13 steel. The specific cutting condition is listed in Table 2. Dino-Lite microscope was applied to measure the flank wear (VB) of cutting tool after milling experiments.

Fig.3. The detailed machining setup in hard milling operation. Table 2. Machining parameters for hard milling experiments. Cutting speed vc （m/min）

Feed per tooth f z（mm/tooth）

Depth of radial cut ae （mm）

Depth of axial cut ap （mm）

200

0.2

2.5

2.0

Fig.4. Comparison of microstructure of cutting tool (a) original; (b) after deep cryogenic treatment (cryogenic temperature -190°C, cooling rate 8°C /min, soaking time 150 min, tempering temperature 100°C, similarly hereinafter).

3. Results and discussions 3.1. Microstructure changes and EDS analysis In order to investigate the microstructure evolution of the cemented carbide cutting tool and element distribution after deep cryogenic treatment, the etched surface were observed and analysed under SEM and EDS. Figure 4 shows the

comparison of microstructure of cutting tool before and after deep cryogenic treatment. It can be observed that polygonal particles in off-white colour become more refined while its morphology and distribution present no pronounced changes before and after deep cryogenic treatment. In addition, the amount of small particles in black colour increases and has a relatively uniform distribution. For further investigation, EDS analysis was performed to identify the element distribution as shown in

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38

the percentage of Co in phase η is higher than that in WC phase. Generally, the binder phase Co has two types of structures, i.e., α-Co phase with FCC structure and ε-Co phase with HCP structure [15]. The XRD analysis in the following corroborates the occurrence of phase transformation as shown in Fig.7. The amount of decarbonisation phase ε-Co increases slightly as reflected by peak intensity in Fig.7. It can be reasonably inferred that the Co binder phase transforms from α-Co (FCC) to ε-Co (HCP) after deep cryogenic treatment.

Fig.5. The EDS analysis results of the three selected locations are shown in Fig.6. It was indicated that the offwhite particle is WC phase and the black particle is mainly Co binder phase which are surround by WC phase. Moreover, besides the two WC and Co phase, an interphase was appeared which refers to decarbonisation phase η as shown in Fig.5 labelled as number 1. As can be seen from Fig.6, the carbon content in decarbonisation phase η is lower than that in WC phase. Thus, carbide was precipitate out from WC phase after deep cryogenic treatment. In addition,

3.2. Microhardness variation

Fig.5. EDS analysis for different locations after deep cryogenic treatment.

The microhardness values of cutting tools for different deep cryogenic treatment are listed in Table 3. Before deep cryogenic treatment, the microhardness of cutting tool was measured and was approximate to 1537 HV. From Table 3, it can be clearly seen that the microhardness of all cutting tools after deep cryogenic treatment improves with various degree compared with original value. According to analysis of variance in Table 4, cryogenic temperature has the most significance on microhardness followed by cooling rate and soaking time while the tempering temperature is the least. In the present experiment, the optimal cryogenic processing parameters are obtained as follows: cryogenic temperature 190°C, cooling rate 8°C /min, soaking time 90min, and tempering temperature 60°C.

Fig.6. EDS results of chemical compositions.

Fig.7. XRD analysis before and after deep cryogenic treatment.

Table 3. Microhardness value for different deep cryogenic treatment. Factor Level

Temperature

Cooling rate

Soaking time

HV

Tempering temperature / °C

(kg f/mm2 )

/°C

°C/min

/min

1

-70

2.0

60

20

1575.1

2

-70

3.5

90

60

1592.4

3

-70

5.0

120

100

1624.0

4

-70

6.5

150

140

1607.2

5

-70

8.0

180

180

1655.5

6

-100

2.0

90

100

1637.5

7

-100

3.5

120

140

1602

8

-100

5.0

150

180

1646.4



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9

-100

6.5

180

20

1624.0

10

-100

8.0

60

60

1642.2

11

-130

2.0

120

180

1717.9

12

-130

3.5

150

20

1672.5

13

-130

5.0

180

60

1660.3

14

-130

6.5

60

100

1758.3

15

-130

8.0

90

140

1823.9

16

-160

2.0

150

60

1710.9

17

-160

3.5

180

100

1667.6

18

-160

5.0

60

140

1732.3

19

-160

6.5

90

180

1788.9

20

-160

8.0

120

20

1827.2

21

-190

2.0

180

140

1680.3

22

-190

3.5

60

180

1690.1

23

-190

5.0

90

20

1784.2

24

-190

6.5

120

60

1785.1

25

-190

8.0

150

100

1808.1

Table 4. The analysis of variance for microhardness. Fα

Significance 1 **

Source Cryogenic temperature

Sum of squares 38578.26

DOF 4

Variance 9644.56

F-value 15.1

F0.01(4，8)=7.01

Cooling rate

8616.37

4

2154.09

3.36

F0.05(4，8)=3.84

⊙

Soaking time

6376.37

4

1594.09

2.48

F0.1(4，8)=2.81

△

Tempering temperature

1166.19

4

291.55

0.454

F0.2(4，8)=1.90

3.3. Tool flank wear Figure 8 reports the trend of flank wear for the analysed cases. The comparison of worn surface morphology of flank after hard milling experiments with original and cryogenic treated cutting tool are shown in Fig.9. Observing the results it is clear that the variation trend of flank wear before removal volume 9000 mm3 is relatively stable for both original and deep cryogenic treated cutting tools. After completing hard milling experiments with the same removal volume of material 9000 mm3, the flank wear (VB) of original cutting tool has reached 240.3μm which is quite larger than that cryogenic treated cutting tool with flank wear of 115.8μm. Besides, the tipping of the original cutting tool occurs after finishing hard milling process. As a result, deep cryogenic treated cutting tool has less wear than original one which reveals the improvement of tool wear resistance of cutting tool after deep cryogenic treatment. Since WC particles are of hard and brittle phase, refined WC particles after cryogenic treatment become harder than before which makes cutting tool presents strong wear resistance. In addition, the increase amount of ε-Co phase after cryogenic treatment is also more strength than α-Co phase. Therefore, the combination of two factors render the cutting tool demonstrates strong wear resistance behaviour. As for the binder phase Co, it has the ability to plastically deform to some degree. After deep cryogenic treatment, the amount of Co particles increases which is benefit to the

cutting tool and avoid the occurrence of tipping or sudden of rupture of cutting insert.

Fig.8. Comparison of flank tool wear as function of volume of material removal

1

** Highly significant, ⊙ Significant, △ Influential.

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Binxun Li et al. / Procedia CIRP 71 (2018) 35–40

Fig.9. Comparison of tool flank worn after milling experiments (a) original; (b) cryogenic treated tool.

4. Conclusions In this study, cemented carbide cutting tools with coating were subjected to deep cryogenic treatment based on orthogonal designed experiments to investigate the influence on its microstructure and mechanical property. After that, hard milling experiments were carried out to evaluate the cutting performances of deep cryogenic treated cutting tools. The main conclusions of this research are the following:  The effect of cryogenic process parameters on microhardness of cutting tool has been investigated through orthogonal designed experiments. The significance of process parameters on microhardness are as follows: cryogenic temperature ＞ cooling rate ＞ soaking time ＞ tempering temperature. The optimal parameters are obtained with cryogenic temperature 190°C, cooling rate 8°C /min, soaking time 90min, and tempering temperature 60°C.  The WC particles become refined and the Co binder phase transforms from α-Co (FCC) to ε-Co (HCP) after deep cryogenic treatment.  The cutting tool after cryogenic treatment presents relatively strong wear resistance in hard milling process. It can be inferred than deep cryogenic treatment can be employed to improve tool life. Acknowledgements This work was supported by the National Natural Science Foundation of China (Grants No. 51575321 and No.51175309), and Taishan Scholars Program of Shandong Province References [1] Zhao SX, Song XY, Zhang JX, Liu XM, Effect of size machining of raw powder particles on propertied of spark plasma sintered ultrafine WC-Co cemented carbides. Acta Metall Sin 2007; 01:107-112. [2] Rebenne HE, Bhat DG. Review of CVD TiN coatings for wearresistant applications: deposition processes, properties and performance *. Sur Coat Tech 1994; 63(1-2):1-13.

[3] Matthews A. Titanium Nitride PVD Coating Technology. Surface Engineering 2014;1(2):93-104. [4] Layyous AA, Freinkel DM, Israel R. Al2O3-coated cemented carbides: optimization of structure, number of layers and type of interlayer. Surf Coat Tech 1992; 56(1):89-95. [5] Yong AYL, Seah KHW, Rahman M. Performance of cryogenically treated tungsten carbide tools in milling operations. Int J Adv Manuf Technol 2007; 32(7-8):638-643. [6] Gisip J, Gazo R, Stewart HA. Effects of cryogenic treatment and refrigerated air on tool wear when machining medium density fiberboard. J Mater Process Technol 2009; 209(11):5117-5122. [7] Rahman M, Yong KH, Seah KHW. Performance evaluation of cryogenically treated tungsten carbide cutting tool inserts. P I Mech Eng B-J Eng 2003; 217(1):29-43. [8] Gill SS, Singh R, Singh H, et al. Wear behavior of cryogenically treated tungsten carbide inserts under dry and wet turning conditions. Int J Mach Tools Manuf. Int J Mach Tools Manuf 2009; 49(3-4):256260. [9] Liu Y, Shao S, Xu CS, et al. Effect of cryogenic treatment on the microstructure and mechanical properties of Mg–1.5Zn–0.15Gd magnesium alloy. Mater Sci Eng A 2013; 588(5):76-81. [10] Wang K, Tan Z, Gu K, et al. Effect of deep cryogenic treatment on structure-property relationship in an ultrahigh strength Mn-Si-Cr bainite/martensite multiphase rail steel. Mater Sci Eng A 2016; 684:559-566. [11] Li J, Zhou J, Xu S, et al. Effects of Cryogenic Treatment on Mechanical Properties and Micro-structures of IN718 Super-alloy. Mater Sci Eng A 2017; 707:612-619. [12] Barron R F. Cryogenic treatment of metals to improve wear resistance. Cryogenics 1982; 22(8):409-413. [13] Araghchi M, Mansouri H, Vafaei R, et al. A novel cryogenic treatment for reduction of residual stresses in 2024 aluminium alloy. Mater Sci Eng A 2017, 689:48-52. [14] Zhang H, Chen L, Sun J,et al. Influence of Deep Cryogenic Treatment on Microstructures and Mechanical Properties of an UltrafineGrained WC-12Co Cemented Carbide. Acta Metall Sin 2014; 27(5):894-900. [15] Yong J, Ding C. Effect of cryogenic treatment on WC–Co cemented carbides. Mater Sci Eng A 2011;528(3):1735-1739. [16] Yong AYL, Seah KHW, Rahman M. Performance of cryogenically treated tungsten carbide tools in milling operations. Int J Adv Manuf Technol 2007; 32(7-8):638-643. [17] Sreeramareddy TV, Sornakumar T, Venkataramareddy M, et al. Turning studies of deep cryogenic treated P-40 Tungsten carbide cutting tool insert – Technical Communication. Mach Sci Technol 2009; 13(2):269-281.