2011 International Conference on Advanced Materials Engineering
IPCSIT vol.15 (2011) © (2011) IACSIT Press, Singapore
An Investigation of Adhesion Wear Behavior of Tool Steel on
Blanking Die
Komgrit Lawanwong 1+, Natthasak Pornputsiri and Ghit Luangsopapun 2
1
Department of Tool&Die engineering, Faculty of Industrial and Technology, Rajamangala University of
Technology Rattanakosin, Wang Klai Kang Wong Campus Prachubkirikhan 77110, THAILAND.
2
Thailand Institute of Scientific and Technological Research, Pathum Thani 12120, THAILAND.
Abstract. This research work aims to exploration wear phenomenon on punch for blanking stainless steel.
Three punch materials: JIS SKD11, SKH 51 and SKS 3 were studied. Those punches were hardened to fixed
hardness 59 HRC. Stainless steel JIS SUS 430 having the same thickness of 2 mm were employed as
workpiece material for the experiments. Clearance between punch and die of blanking tool was five percent
of workpiece thickness. The strip was blanked into circular shapes of 25 mm. in diameter. Direct
measurement of wear on blanking punch was carried out using optical microscope. Each punch was used for
blanking 2,000 stroke/conditions. It was found that SKH 51 had shown lower wear than SK D 11 and SKS 3
respectively. The higher tungsten, molybdenum and vanadium content of SKH 51 increase the amount of
carbide compound caused hard and durable of cutting edge. Beside, punch SKD 11 had shown highest
adhesive because high chromium content has compatibility of elements. The compatibility of metal element
caused of high adhesion, friction and wear rate. Punch material SKS 3 had shown high wear rate because of
low chemical composition. Moreover punch SKS 3 had shown highest corrosion on cutting edge.
Keywords: Adhesion wear, Blanking die, Stainless steel, Tool steel, Blanking Punch
1. Introduction
One of important process in the metal forming is the blanking process. Blanking and piercing operations
are widely used to cut sheet metal or plates by a shearing process between punch and die for mass production
of precision engineering components. The quality of the parts, evaluated by the profile of the shaped surface
depends on many factors such as tool design; punch material properties, stamping conditions and especially
tool wear [1]. Tool wear in blanking process is very important in case of cutting high production. Hence the
studies on tool wear have been able recently because the wear mechanism and contact conditions such as
punch material conditions, surface roughness and generation of wear particles can not be explained. Many
experimental researches have been done to investigate the wear phenomenon under the relatively simple tests
[2–8] but the researches have been related to experimental observation of wear profiles on blanking tool
could not explain wear phenomenon according to the increase of the number of pieces.
Furthemore, the high precision of the parts, smooth sheared edges and high tool life, many research have
been conducted. Takaishi [9] measured the wear contour on die and punch in the shearing process of
stainless steel sheets according to various clearances between die and punch. Choy and Balendra [10]
analyzed the wear phenomenon with describing the wear punch profile as the changes of radius around
punch edge. Aoki [11] observed wear profiles on punch during sheet metal shearing process. Tronel and
Chenot [12] predicted tool wear in hot forging process by the finite element method. In this paper focuses
wear behaviors of the punch using three kinds punches materials are investigated. In addition, the behaviors
of adhesive wear on blanking punch investigate by SEM and EDS analysis.
+
Corresponding Author Tel.: + 66 32 618570 fax: +66 32 618500.
E-mail address: Komgrit.law@Kmutt.ac.th., Natthasak_idt@Hotmail.com, Ghit@Tistr.mail.go.th
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2. Experimental Procedure
The Stainless steel SUS 430 [JIS] is employed in the experiments. The chemical property of workpiece
material was shown in table 1. Sheet strip of workpiece material thickness is 2 mm and 30 mm in width. A
mechanical property of workpiece material was shown in table 2. The workpiece strip is shown in Fig. 1. The
chemical properties of punch materials were illustrated in table 3. The blanking tool was designed to blank
circular part of 25 mm diameter. The punch cutting edge insert and die button were made from JIS SKD11,
SKH 51 and SKS 3 steel fixed hardened to 60 HRC [Fig.2]. The cutting edge was designed as an insert to the
punch shank as shown in Fig. 3 in order to be easily removed [Fig.3]. Tool clearance employed in this
experiment was 5% of sheet thickness [0.1 mm]. The photograph of blanking tool and die set is shown in Fig.
4. Air feeder installed with die set was used in the experiment. Experiments were carried out using a 60 tons
mechanical press [Fig.5]. Blanking operations were performed without lubricant.
∅ 25 mm
Fig. 1: Workpiece strip
Fig. 2: Blanking punch
Fig. 4: Blanking die set with feeder
Fig. 3: Shank of punch
Fig. 5: Mechanical press 60 tons
In general, the degree of wear is higher for blanking punch than die. Therefore only blanking punch
cutting edge is measured to quantity wear. The flank wear length and face wear length [Fig.6.] were
measured under Optical microscope with program Axivo Version 5. Moreover, adhesive wear on blanking
were observed by Scanning Electron Microscopy [SEM] and Energy Dispersive Spectrometry [EDS]
analysis. Wear measurement have been made after 100, 200, 300, 500, 800, 1,000 and 2,000 strokes.
Table 1: Chemical compositions of workpiece material.(%)
C
Si
Cr
Fe
0.16
0.66
16.89
82.30
Table 2: Mechanical properties of workpiece material.
Yield Strength
2
289 N/mm
Tensile Strength
2
545 N/mm
26
Elongation
Hardness
27 %
142 HV
Table 3: Chemical compositions of punch materials (%)
C
Si
Fe
W
SKD 11
0.95
0.32
82.30
0.70
SKH 51
0.80
0.40
76.79
0.72
91.35
SKS 3
Blanking direction
0.95
Mn
Ni
Cr
Mo
V
0.49
0.25
10.33
0.72
0.3
11.25
0.25
0.35
4.38
5.10
1.88
0.7
1.10
0.25
6.72
-
0.20
Flank wear length
Material
Face wear position
Flank wear position
Face wear length
Fig. 6: Measurement on punch cutting edge
3. Results and Discussions
3.1. Influence of Particle Adhesion to Tool Wears
In the blanking experiments the level of face wear length is lower than flank wear length because punch
side slides back and forth against workpiece material during the blanking operation. Where as there is no
sliding action between punch face and workpiece material.
The results of flank wear length and face wear length of blanking punch with number of workpiece are
shown in Fig.7 and 8, respectively. From Fig. 7 and 8 the wear length on punch has been investigated up to
2,000 strokes. It was found that the flank wear length quickly increases at the beginning of experiments up to
500 strokes. After 1,000 strokes, wear length becomes to stable. In Fig. 11, face wear length quickly
increases at the beginning of experiment up to 500 strokes. After 500 strokes, wear length becomes to stable.
1.4
1.2
Flank wear length (mm)
Blanking direction
1
0.8
0.6
Flank wear
SKD 11
0.4
SKH 51
0.2
SKS 3
0
0
500
1000
1500
2000
2500
Number of workpiece
Fig. 7: The relationship of flank wears with number of parts.
It was found that the flank and face wear length of punch material SKH 51 had shown lower wear rate
than SKD 11 and SKS 3 respectively. The higher tungsten, molybdenum and vanadium content of SKH 51
increase the amount of carbide compound caused hard and durable of cutting edge. The flank and face wear
length of punch material JIS; SKS 3 is larger than punch material JIS; SKD 11 and SKH 51, respectively.
Since punch material SKS 3 has low molybdenum and chromium composition that show low wear resistance.
On the other hand punch material JIS; SKD 11 and JIS; SKH 51 had shown nearly wear resistance trend.
Moreover JIS; SKD 11 had shown adhesion of workpiece to blanking punch more than punch material JIS;
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SKH 51. Further more,it was found that punch material JIS; SKD 11 high chromium similar workpiece [SUS
430] has compatibility of element.
s
Face wear length (mm)
0.5
0.4
Blanking direction
0.3
0.2
Flank wear
SKD 11
SKH 51
0.1
SKS 3
0
0
500
1000
1500
2000
2500
Number of workpiece
Fig. 8: The relationship of face wears with number of parts.
Adhesion phenomenal of workpiece material with cutting had shown Fig.9-11. Adhesion of workpiece
on punch SKD 11 is large than punch SKH 51 and SKS 3. It was found that compatibility between
workpiece material [high chromium content] and punch material [SKD 11 high chromium content] caused of
adhesion on the surface. The compatibility of metal element caused of high adhesion, friction and wear rate.
Adhesion of workpiece to blanking punch make sure the result of adhesion by EDS had shown in Fig.9.
Blanking direction
Blanking direction
Adhesion of workpiece
Cr
100 Strokes
SKD 11
Fig. 9: SEM image at 100X and EDS analysis of the adhesion on cutting edge of SKD 11.
Blanking direction
Blanking direction
Cr
SKH 51
100 Strokes
Fig. 10: SEM image at 100X and EDS analysis of the adhesion on cutting edge of SKH 51.
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Blanking direction
Blanking direction
SKS 3
100 Strokes
Cr
Fig. 11: SEM image at 100X and EDS analysis of the adhesion on cutting edge of SKS 3
The results of SEM and EDS analysis from the experiments after 2000 strokes had shown in Fig.11Fig.13. It was found that Fig.11-13 SEM image of surface cutting punch does not show adhesion of
workpieces because junction of adhesion separated occurs at the interface. High pickup of workpiece on
punch surface caused of high adhesion and high wear rate. EDS analysis had shown insignificant amount of
adhesion on cutting edge. Furthermore, in the case of SKS 3 [Fig.11] had shown EDS analysis confirmed
that there the high corrosion around surface.
Blanking direction
Blanking direction
SKD 11
2000 Strokes
Cr
Fig. 12: SEM image at 100X and EDS analysis of the adhesion on cutting edge of SKD 11.
Blanking direction
Blanking direction
SKH 51
2000 Strokes
Cr
Fig. 13: SEM image at 100X and EDS analysis of the adhesion on cutting edge of SKH 51.
Blanking direction
Blanking direction
Corrosion
Cl
SKS 3
2000 Strokes
Fig. 14: SEM image at 100X and EDS analysis of the adhesion on cutting edge of SKD 3
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4. Summary
The aim of the study was explorations of adhesion wear on blanking die. Tool steel of higher tungsten,
molybdenum and vanadium content had shown high wear resistance and durable of cutting edge. Moreover,
punch high chromium content had shown compatibility of metal elements cased of high adhesion, friction
and wear rate. Punch material SKS 3 had shown high wear rate and high corrosion because low chemical
composition content.
5. Acknowledgements
The authors would like to give our attitude to Department of Tools and Material King Mongkut’s
University of Technology Thonburi (Thailand) for supporting the die equipment and Office of the Higher
Education Commission for funding of the research.
6. References
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