Sheet Metal Forming

364 / Sheet Metal Forming—Processes and Applications
twinning-induced plasticity (TWIP) steels, 107
at elevated temperature, 113
strain rate, 112
twist compression test (TCT), 119, 330–331(F)
two-dimensional (2-D) simulations, 26, 27
two-point incremental forming (TPIF), 274(F), 276, 277, 
283
U
U-bend tests, 119
U-channel drawing of dual-phase steels, 120–121(F)
U-channels, 120, 121
warm forming, 128–129
U-die bending
punch force/punch displacement curve, 35(F)
with/without pressure pad, 35(F)
ultimate tensile strength (UTS), 108
ultra-high-speed (UHS) blanking
adiabatic phenomenon, 12
advantages of, 12
applications, 12
punching operations, 12
ultra-high-speed (UHS) blanking presses, 12
ultrahigh-strength steels (UHSS), 133, 143
Ultralight Steel Auto Body Programme, 112
unclamping, 281(F), 282
University of Dortmund (IUL), 162, 169
University of Stuttgart (IFU), 165, 166
USIBOR 1500P, 154
V
Vanadis 6, 333
vanadium carbide (VC), 328
Vancron 40, 333
V-die bending
bottoming, 34(F)
coining, 34(F)
FEA analysis, 26–27(F,T), 28(F)
finite-element analysis (FEA), 26–27(F,T)
overview, 28(F), 34
punch force/punch displacement curve, 35(F)
vibrations
acoustic emission sensors, 307
cushion systems, 125
horizontal, 10
press, 124
punch, 8
reducing, 10
vertical, 10
Vickers hardness, 320, 321(F)
Vickers hardness number (HV), 320
viscous pressure bulge test (VBT), 27(F), 53, 58(T), 59,
65
viscous pressure forming, 158, 160(F)
Voestalpine, 154
Volkswagen Passat, 153
von Mises yield criterion, 22, 142, 184
W
wall curl, 126
warm forming, 96(F)
AHSS, 128–129
aluminum alloys (
see
aluminum alloys, warm forming)
applications, 96, 98
die heating techniques, 93–94
heating system for round cup tooling, 94(F)
heating systems for industrial stamping tooling,
94(F)
open warm forming tooling, 96(F)
tooling in which dies and punch are heated, 95(F)
view/dimensions of the round tool, 95(F)
heat transfer, 92
heating methods, 91
isothermal warm forming, 90–91
lubrication, 92
magnesium alloys (
see
magnesium alloys, warm 
forming)
magnesium sheets, minimum bending radii, 93(T)
mechanics of deformation, 91–92(F)
nonisothermal warm forming, 90–91
drawability, 92(F)
LDR, 92(F)
polytetrafluoroethylene film, 92, 93(F)
press selection, 94–96
servo motor drive system, 97(F)
slide motion of the servo press, 98(F)
tool design, hydraulic press, 96(F)
tool design, mechanical press, 97(F)
process design, 92–93
springback, AHSS, 128–129
as a system, 90
tool design, 92–93
warm sheet hydroforming
challenges/issues in process simulation
data required as input, 172(T)
heat-transfer, 173
interface friction coefficient, 173
interface heat-transfer coefficients, 173
overview, 172
sheet material flow-stress data, 172–173
overview, 170–171
warm SHF-D, 171–172(F)
warm SHF-P, 171, 172(F)
warp, 41, 42(F)
wear. 
See also
plating and coating
AHSS, 113, 118
Archard wear equation, 318
cast iron dies, 319
cast steels, 319
die inserts, 199
die wear, 125, 153, 296, 320
feeding inserts, 197
inserts, 319
lubrication, 215
overentry of the punch, 8
press cushion, 124

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