Papers in JOURNAL OF THE JAPAN SOCIETY FOR TECHNOLOGY OF PLASTICITY
(Vol.39 No.446 March 1998)
Influence of Temperature on Mechanical Properties of
Steel-Plastic Laminates
Formability of Steel Sheets under Chill Working Condition 2
Tetsuro OHWUE, Matsuo USUDA and Takeo NAKAGAWA
(Received on March 18, 1997)
Mechanical properties of steel-plastic laminates are investigated using the uniaxial tensile test in the
temperature range from - 30 Cels. to 100 Cels.. As a result, the tensile strength (TS) of steel-plastic laminates can
be estimated from the TS of the skin steel and the core resin, multiplied by the corresponding thickness ratio.
However the elongation (El) of the steel-plastic laminates cannot be estimated from the El of the skin steel and
that of the core resin. Under chill working conditions between - 30 Cels. to O Cels., if the El of the core resin is
larger than the El of the skin steel, breakage of the skin steel begins before that of the core resin. In contrast,
if the relation between these elongations is reversed for steel-plastic laminates with a brittle core resin, such as
polyamide (nylon 6), breakage of the core resin starts before that of the skin steel.
Key words : uniaxial tensile test, composite materials, steel-plastic laminates, temperature dependence, chill
working condition, tensile strength, elongation
Optimum Design of Outer Tools
Using the Spline Rolling Simulation Model
Spline Rolling of Deep Drawn Cups 3
Ryoichi MATSUNAGA, Tatsuo Ozaki, Teruie TAKEMASU
Ryuzo KAMASHITA, Hidehiko TSUKAMOTO and Akihiro TANAKA
(Received on April 11, 1997)
In a previous paper, a numerical simulation model used to form a loop spline was proposed to obtain information
concerning the optimum shape for an outer tool. The new optimum outer tool was designed using this model. However
this simplified stretch-bend deformation model cannot simulate realistic deformation behavior in the spline rolling
process. In this work, improved numerical simulations using the Finite-Element Method program available are performed
on the spline rolling method, in which the outer tool and the workpiece are conjugated in a complex generating motion.
The deformation of the workpiece and the tooth profile of the spline, obtained analytically by the new simulation model,
agree with the experimental results than those by the previous model. New optimum outer tools are currently being
designed using the new model.
Key words : rotary forming form rolling, sheet metal forming, stretch forming, new forming process, spline,
automatic transmission, simulation, optimum tool profile, Finite-Element Method
Finite-Element Analysis of Metal Flow in Bearing Section during
Extrusion Process of Rectangular and Angle Sections
Combination of Three-Dimensional FE Simulation and Extrusion Die Design -1-
Manabu KIUCHI, Jun YANAGIMOTO and Victor MENDOZA
(Received on April 16, 1997)
This paper presents a rigid-plastic FEM code and describes its application to metal flow simulation during
extrusion aiming to gain a deeper knowledge and information to eliminate geometrical defects of products.
The effects of some variables such as function coefficient, aspect ratio of extrudate's cross section, bearing land
length and position of die opening on metal flow are studied. Results on the average extrusion pressure and
metal flow characteristics in terms of velocity distribution profiles in the bearing section and streamlines are
presented. From these results, it is possible to predict geometric defects of products and find out the method
to reduce them by modification of the die geometry, i.e., bearing length and position of die opening. The
extrusion simulation of rectangular and angle sections is conducted to illustrate the applicability of the
developed code.
Key words : extrusion, die design, flat-faced die, bearing land, simulation, FEM
Finite-Element Analysis of Metal Flow in Bearing Section during
Extrusion Process of "L", "C" and "T" Sections
Combination of Three-Dimensional FE Simulation and Extrusion Die Design -2-
Manabu KIUCHI, Jun YANAGIMOTO and Victor MENDOZA
(Received on April 16, 1997)
Conventionally, various metal sections are extruded using flat-faced dies. This results in metal
flow-related defects such as bending, twisting, tearing and thinning. As a result, time consuming
and expensive post-extrusion operations are needed to obtain acceptable dimensional quality of the product.
This paper describes the application of a newly developed rigid-plastic FEM code to the extrusion of sections
and shows the results of metal flow simulation. The results are used for predicting the geometric defects and
reducing them through modification of the bearing land and the position of die opening. This procedure is
applied to the extrusion of "L", "C" and "T" sections, and the influence on the metal flow of some variables
like friction coefficient, aspect ratio of product's cross section, bearing land length and the position of
die opening is studied. The results are presented making emphasis on the study of the axial velocity
distribution in the bearing land.
Key words : extrusion, die design, bearing land, simulation, FEM
Edge-Drop Reduction Effect of Intermediate Roll Shift
Technology Development for Controlling
Strip Edge-Drop in a Cold Tandem Mill 1
Atsushi AIZAWA, Kenji HARA, Kazunari NAKAMOTO,
Masaki OTSUKA, Junya HAYAKAWA and Toshinori MIKI
(Received on May 27, 1997)
A 3-dimensional analysis model based on the slab method for predicting the edge-drop of a strip in a cold
tandem mill in which the thickness deviation was compensated for by the lengthwise deviation of a strip
between stands was developed. From simulations carried out using this model, it was found that the edge-drop
is decreased considerably by the intermediate roll shift and that the edge-drop control characteristics are
considerably different at each stand. The above results were confirmed experimentally in a cold tandem mill
and the calculated edge thickness profiles of cold-rolled strips were in good agreement with the experimental
results. Therefore, it is concluded that edge-drop can be improved effectively by combining the intermediate roll
shifts at multiple stands.
Key words : cold strip rolling, tandem mill, slab method, 3-dimensional analysis, edge-drop, intermediate roll shift
Coil Deformation and Flatness Change under Strip Coiling
Flatness Change of Thin Strip during Coiling Process 2
Shusuke YANAGI Shigeo HATTORI, Yasushi MAEDA,
Haruhiro IBATA, Yuichiro SUGIMOTO and Mamoru SAWADA
(Received on May 27, 1997)
The flatness of a thin strip sometimes changes during the coiling process, causing the flatness of the coil to
deviate from that strictly required by the customer. To prevent this flatness change during the coiling process,
we investigated the coil deformation during the coiling process using a numerical analysis method recently
developed by us . Following that, we conducted an experiment using one of the recoiling lines of our
production plant. From a study based both on the numerical analysis and the experiment, we obtained the
following results. ( I ) The inner radius of the coil is gradually reduced and the inner part of the coil is
gradually deformed into a concave shape during the coiling process due to the coiling tension and the strip
crown. This deformation is the possible cause of a wavy edge at the inner part of the coil. (2) Coiling tension
is concentrated around the lateral center of the strip width. However, the tensile stress imported around the
strip center does not reach the yield stress unless the coiling tension is extremely high. Therefore, it is more
unlikely that the concentration of the coiling tension directly cause the flatness change.
Key words : strip coiling, strip crown, coiling tension, flatness change
Effect of Thermo-Mechanical Treatment on Mechanical
Properties of 2024Al-3Fe-5Ni P/M Alloy
Kenji MATSUKI, Ryouichi KITANO, Mitsugu TOKIZAWA, Tetsuo AIDA
Takamasa YOKOTE, Jun KUSUI and Kazuhiko YOKOE
(Received on June 5 1997)
Rapidly solidified powders of 2024Al-3mass%Fe-5mass%Ni (3F5N) alloy up to 45 micro meters in diameter were cold
isostatically pressed and further extruded at 623K in argon atmosphere. The age hardening behaviour and
tensile properties of the 3F5N extrusions subjected to various thermomechanical treatments (TMT : RA, RSA
and SRA) which included warm rolling (R), solution treatment (S) and ageing (A) at 428K were compared
with those of the specimen after TMT without warm rolling (T6). The values of the ageing peak hardness of
the specimens subjected to TMT with warm rolling were higher than those of the specimens subjected to T6
treatment. The increase in peak hardness is due to the improved precipitation behaviour of the S' phase as well
as work hardening. The tensile tests of the specimens aged to a peak hardness level at 428K reveal that TMT
treatments cause a substantial improvement in the tensile properties. Electron microscopy of TMT materials
revealed that the precipitates of the S' intermediate phase formed on dislocation Iines are finer and more
uniform than those of T6 Such a fine and uniform distribution of the S ' phase is considered to enhance the
age-hardenability of TMT materials
Key words : 2024Al-3Fe-5Ni P/M alloy, thermomechanical treatment, age hardening, mechanical property, S'
phase
Bore-Expand Testing of Aluminum and Copper Alloy Sheets
at High Temperatures
Makoto SUGAMATA, Tatsuya IWATA and Junichi KANEKO
(Received on June 13, 1997)
High temperature formability in the bore-expanding and stretch-flanging of aluminum and copper alloy sheets
has been studied. Formability tests were carried out using experimental apparatus in which a blank sheet, die
and punch were heated uniformly at temperatures between RT and 723K Fully annealed aluminum alloys
(JIS: A1100, A3004, A5052 and A5182) and copper alloys (JIS: C1100, C2200, C2600 and C2801) were used
as test materials The influence of the punch shape on bore-expansion was investigated using a flat, spherical
and cone shaped punches. The limiting bore-expanding ratio (LBER) of aluminum alloy sheets increases with
the testing temperature, whereas that of copper alloy sheets decreases. It is shown that LBER values at
various temperatures correlate to tensile elongation. Although LBER values of tested sheets depend on the
shape of the punch head at room and high temperatures, the relationship between LBER and the testing
temperature is shown to be relatively similar for three kinds of punch heads. Thus, any change of formability
during the stretch-flanging of sheets with rising temperature can be tested using a punch head of any shape.
Key words : sheet metal forming, stretch-flanging, bore-expanding, aluminum alloy sheet, copper alloy sheet,
high temperature test
Forming Limit and Influence of Clearance
Development of Die Smooth-Necked Can 2
Hideki UTSUNOMIYA and Hisashi NISHIMURA
(Received on June 13, 1997)
The forming limit for each stage in the die smooth-necking of steel and aluminum DI(Drawn & Ironed)
cans with the conventional thickness is investigated experimentally. The effect of clearance thickness
distribution, and internal pressure on the die smooth-neck formability is investigated. The thinning of the wall
thickness to be necked is studied for a steel DI can. I . 20 mm diameter necking for each stage is attempted
and favorable results are obtained. I . 40 mm diameter necking for each stage generates unfavourable results.
The clearance is one of the most important factors for the die smooth-necking. It is found that edge waves
are corrected using the right amount of clearance and in the case of large clearance the edge waves remain and
grow to edge wrinkles in the following necking stage. On the other hand , small clearance readily causes
sinking at the middle of necked area. A wall with uniform thickness in the longitudinal and circumferential
directions is suitable The internal pressure prevents the occurrence of edge wrinkles and sinking. With the
night amount of clearance O . 123 mm thick wall can be necked to I . 20 mm diameter necking without the
occurrence of wrinkles or sinking.
Key words : tube forming, nosing, forming limit, die design, DI can, die smooth-necking
Optimurn Die Design of Sheet Forming by Using
the Finite-Element Method and Discretized Optimization Algorithms
- Application to Multi Design Parameters and
Multi Objective Functions Problem -
Eiji NAKAMACHI, Tadashi HONDA,
Hidetoshi NAKAYASU Tsutao KATAYAMA and Yasunori NAKAMURA
(Received on June 18, 1997)
In this study, an optimum die design system was developed by combining finite element (FE) analysis and
discretized optimization algorithms . This computerized die design system is required in industries to reduce
time consumption and cost. Recently, advanced FE analysis has provided accurate forming-process informa-
tion. However, the synthesis technology to determine the optimum forming-process condition, which includes
optimum die design, is still insufficient. The derivative based optimization scheme cannot be applied to this
kind of forming optimization Therefore discretized optimization algorithms such as "sweepmg simplex" and
simulated annealing methods , are employed. It is demonstrated that this optimum die design system is a
powerful tool which can be used to determine efficiently the optimum conditions.
Key words : multistage forming, die design, FEM, optimization methods, sweeping simplex, simulated
annealing
Optimum Design of Sheet Metal Crystal Texture Based on the
Finite-Element Method and Discretized Optimization Algorithm
Eiji NAKAMACHI and Yoshinori HAMADA
(Received on June 18, 1997)
Recently, the computational simulation technology assisted in the development of the sheet metal fabrication
design and formability test analysis. In this study , the computerized texture design system was newly
developed to determine the ideal crystalline orientation distribution, which means the high formability of sheet
metal. This design system consists of a formability analysis using the dynamic-explicit finite-element code based
on the elastic/crystalline plasticity theory and the discretized optimization code, which employed the "Simplex
Method" and "Hybrid Method" The optimum crystal orientation combination of brass, copper and cube
textures for aluminum alloy sheet metal with high formability was investigated and the performance of the
optimization algorithms was studied.
Key words : FE analysis, optimum design , crystal texture, crystalline plasticity, formability, sheet metal
forming
Effect of Tool Stiffness on the Sheet Bending Process
Hisashi TAKIZAWA and Akitake MAKINOUCHI
(Received on July 2, 1997)
Although V bending with press brakes is widely used in the practical manufacturing process, it is difficult to
accurately predict the bending process due to complicated deformation. FEM analysis has been used as one
of the main methods for accurately predicting bending deformation. However, a large difference has been
observed between the bend angle predicted using FEM analysis and that obtained experimentally. In this paper,
the influence of tool deformation on bending accuracy is investigated by comparing the results from the
experiments and the FEM program AITAS2D analysis while considering the tool deformation. As a result rt
is found that the horizontal and vertical deformation of the punch have obvious influences on the punch stroke,
bend angle and product shape . The present FEM analysis which considers the tool deformation is shown to
be effective for accurate bending analysis.
Key words : bending, press-brake, sheet metal, bending tool, tool stiffness, FEM