A 100Cr6 (AISI E52100) steel in the hardness range of 180 to 750 HV10 was machined. Quick stop tests were carried out at various hardness values to observe the different chip formation mechanisms. A limit was found between the shearing and cracking chip formation. Experiments on the selected steel at 750 HV10 were carried out at various cutting speeds and feed rates. The “saw tooth chips” obtained were examined geometrically and metallurgically on longitudinal midsections. A relationship has been established between the chip geometry and the cutting conditions. A theoretical study of the chip shape was made, in particular its thickness. The friction stick slip velocities, and the segment apparition frequency were calculated. Each stage of the chip formation could be observed on each micrograph of Q.S.T, especially the crack initiation. A discussion on the apparition of the thin white layers is also proposed. [S1087-1357(00)01502-1]

Issue Section:
Technical Papers
Keywords:
steel manufacture, cutting, machining, metallurgy, hardness, cracks
Topics:
Cutting, Fracture (Materials), Steel, Vickers hardness testing, Die cutting, Shearing (Deformation)
1.
Komanduri
,
R.
, and
Brown
,
R. H.
,
1981
, “
The Mechanics of Chip Segmentation in Machining
,”
ASME J. Eng. Ind.
,
103
, No.
1
, pp.
33
–
51
.
2.
Shaw
,
M. C.
, and
Vyas
,
A.
,
1998
, “
The Mechanisms of Chip Formation With Hard Turning Steel
,”
Ann. CIRP
,
47/1
, pp.
77
–
82
.
3.
Shaw, M. C., 1967, “Assessment of Machinability,” Machinability, 11, ISI Special Report 94, The Iron and Steel Institute, London.
4.
Lemaire
,
J. C.
, and
Backoffen
,
W. A.
,
1972
, “
Adiabatic Instability in the Orthogonal Cutting of Steel
,”
Metall. Trans.
,
3
, pp.
477
–
481
.
5.
Berktold, A., 1992, Drehrau¨men Geha¨rteter Stahlwerkstoffe, Doctoral Thesis, RWTH Aachen, published in VDI-Verlag.
6.
Ko¨nig
,
W.
,
Berktold
,
A.
, and
Koch
,
F.
,
1993
, “
Turning Versus Grinding—A Comparison of Surface Integrity Aspects and Attainable Accuracies
,”
Ann. CIRP
,
42
/
1
, pp.
39
–
43
.
7.
Nakayama, K., 1974, “The Formation of Saw-Toothed Chip in Metal Cutting,” Proc. of Int. Conf. on Production Engineering, Tokyo, Part 1, pp. 572–577.
8.
El-Wardany, T. I., and Elbestawi, M. A., 1998, “Phenomenological Analysis of Material Side Flow in Hard Turning: Causes, Modeling and Elimination,” Proc. of the CIRP Int. Workshop on Modeling of Machining Operations, Atlanta, Georgia, USA pp. 141–150.
9.
Davies
,
A.
,
Burns
,
T. J.
, and
Evans
,
C. J.
,
1997
, “
On the Dynamics of Chip Formation in Machining Hard Metals
,”
Ann. CIRP
,
46
/
1
, pp.
25
–
30
.
10.
Komanduri
,
R.
et al.,
1982
, “
On the Catastrophic Shear Instability in High Speed Machining of an A15J4340 Steel
,”
ASME J. Eng. Ind.
,
104
, pp.
121
–
131
.
11.
Matsumoto
,
Y.
,
Barasm
,
M. M.
, and
Liu
,
C.
,
1987
, “
Cutting Mechanism During Machining of Hardened Steel
,”
Mater. Sci. Technol.
,
3
, pp.
299
–
305
.
12.
Walker, T. J., and Shaw, M. C., 1969, “On Deformation at Large Strains,” Proc. of the 10th Int. M.T.D.R. Conference, London, p. 241.
13.
Arnold
,
R. N.
,
1946
, “
The Mechanism of Tool Vibration in Cutting Steel
,”
Proc. Inst. Mech. Eng., London
,
154
, p.
261
261
.
14.
Ueda
,
N.
, and
Matsuo
,
T.
,
1982
, “
An Analysis of Saw-Toothed Chip Formation
,”
Ann. CIRP
,
31
, No.
1
, pp.
81
–
84
.
Copyright © 2000
 by ASME
You do not currently have access to this content.