NETUREN
Induction Tempered Wire
Tempered Spring Steel Wire
１ Introduction
Neturen Co., Ltd. was founded in 1940 and has been
engaged in the induction heating business ever since.
NETUREN Induction Tempered Wire, which is
suitable for cold formed coil spring, is also utilized our
own developed induction heating method.
Our induction tempered wire has been highly
evaluated by many customers in the world for its
excellent quality.
In abroad, NETUREN Induction Tempered Wire has
been manufactured at our joint venture company in
China and USA with the same production method and
quality control as we are applying.
Ako plant in Hyogo, Japan
2
What is NETUREN Induction Tempered Wire?
Normally NETUREN Induction Tempered Wire is
categorized as Oil Tempered Wire for its mechanical
properties, however, our advanced and unique
production system uses electric power instead of gas
as energy source for heating and water instead of oil
for quenching.
3
Principle of Induction Heat Treatment
Induction heat treatment is, as you can see in Fig. 1,
one of heat treatment method assembled, under
accurate control, with Induction Heating Process and
Rapid Cooling System which can cool wire material
uniformly besides rapidly.
As a matter of fact, this system not only materializes
excellent properties of material but
also enables us to heat material so
rapidly up to target temperature in
accordance with its application
without touching anything.
Induction Heat Treatment is quite
effective to non-pollution system
suitable for the age of saving
resources and energy.
High frequency current
Working coil
Steel
Fig. 1 Schematic illustration of induction heating
−1−
4
Manufacturing Process
Material
NETUREN Induction Tempered Wire is manufactured
and shipped according to the process shown in Fig. 2.
Through this process like descaling, drawing,
quenching and tempering the wire is heat-treated to
provide the required mechanical properties and is
continuously inspected by eddy current flaw detector.
Descaling
reception
Drawing
Induction quenching
Induction tempering
Eddy
current
inspection
Winding
Inspection
Packing
Shipment
Fig. 2 Manufacturing process
Heat treatment process
Finished products in coil before packing
−2−
5
Features
From the wire rods to finished products, it is manufactured under perfect quality control by latest facilities and
supreme technology, with automatic induction heating system developed by ourselves.
NETUREN Induction Tempered Wire by excellent manufacturing system has following features:
１．Because of rapid and short time induction heat treatment for austenitization,
● Fine grain structure can be gained.
● Decarburization and oxidation of grain boundary on surface hardly occurs.
２．Because of interaction of fine quenched structure and short time induction tempering,
● High strength and toughness can be obtained at the same time.
３．By using the precise control system for heating and cooling, and the quenching and the tempering
temperature are controlled for each wire one by one,
● Adjustable requested strength according to customer's requirement.
● Uniform strength for entire length of wire can be obtained.
● There is less variation of strength within a series of products manufactured based on the same
specification.
４．For forming of coil spring,
● Reducible the deviation for spring dimension.
● Possible to form smaller D/d springs even using higher strength of wire.
● Fatigue and sag resistances remain high level.
● Cost reduction will be possible by weight saving due to high applied stress.
Raw material
Finished product
Fig. 3 Microstructure
®
φσβ
Fig. 4 Coiling test results
−3−
6
■
Standard specifications
Chemical composition
Wire rod of SAE9254 mainly and other similar grade added special elements are used as raw material.
The chemical composition of SAE9254 is as show in Table 1.
Table 1 Chemical composition (%)
Material
C
Si
Mn
SAE9254
0.51−0.59
1.20−1.60
0.60−0.80
0.035 or less 0.040 or less
0.60−0.80
0.51−0.59
1.20−1.60
0.50−0.90
0.035 or less 0.035 or less
0.55−0.90
（For reference）
JIS G 3560-1994
SWOSC-B
■
P
S
Cr
Diameter range
Diameter range is 6.0mm to 17mm.
Please ask us for smaller diameters than 6.0mm
■ Tolerance and Out of roundness
Tolerance and Out of roundness are as shown in Table 2.
Table 2 Tolerance and Out of roundness (mm)
Diameter
Tolerance
Out of roundness
±0.05
0.05 or less
6.0 to 17.0
■ Mechanical properties
Standard mechanical properties are as shown in Table 3.
Table 3 Mechanical properties
Grade symbol
Tensile strength (N/mm2)
Reduction of area (%)
SWI-180
1,750−1,850
Min. 35
SWI-190
1,850−1,950
Min. 35
SWI-200
1,950−2,050
Min. 35
Other tensile strength range than above standard is applicable.
7
Instructions for safety use
1．For handling and storage
Pay strong attention not to have flaws, scratches, abrasions, scrapes, bruises and other wounds on wire.
Pay strong attention to prevent the wire from moisture such as rain, high humidity or chemical materials not to
occur the rust or corrosion on wire.
Pay strong attention to keep away from the electric or cutting spark.
Even such a small surface defects may cause the breakage of spring or rebase the properties of spring.
* Do not use steel wire rope but use nylon sling for lifting.
* It is recommended to put the wire on rubber sheet or squared timber for storage.
2．For use
1) Rewinding stand must be used for rewinding of wire in coil. It is recommended to use rewinding stand with
low frictional resistance.
2) Be careful with spring back of wire end when cutting the bindings for wire in coil.
3) Do not apply plating to the springs processed from the wire.
4) Low annealing temperature must be done after formed of coil spring within 24 hours.
−4−
〈Reference data〉
Conditions of low temperature annealing
■ Recommended conditions
Following are the recommended conditions for low temperature annealing to be processed after forming of coil spring
using SWI-180 and SWI-200 respectively.
Grade symbol
(Tensile strength)
Heating temperature
SWI-180
(1750∼1850N/mm2)
400℃±10℃
SWI-200
(1950∼2050N/mm2)
380℃±10℃
Holding Time
Holding Time
Heating
temperature
30min. or more
Heating time
Relationship between temperature and tensile strength
SWI−180
SWI−200
1900
2100
Under constant
keeping temp.
in 30min.
1800
Tensile 1700
strength
（N/mm2）1600
Under constant
keeping temp.
in 30min.
2000
1900
Tensile
strength 1800
（N/mm2）1700
1500
1600
1400
as coil 300
325
350
375
400
425
450
475
500
1500
as coil 300
325
350
375
400
425
450
475
500
Heating temperature(℃)
Heating temperature(℃)
Relationship between temperature and residual stress
SWI−180
SWI−200
1000
1200
Spring specification
d=11.5mm
D=115.0mm
Measuring point
Inner side, Axial direction of wire
Under constant keeping time in 30min.
800
Residual 600
stress
（N/mm2） 400
800
Residual
600
stress
（N/mm2） 400
200
0
as coil
Spring specification
d=11.5mm
D=115.0mm
Measuring point
Inner side, Axial direction of wire
Under constant keeping timein 30min.
1000
200
375
350
400
425
0
as coil
450
Heating temperature(℃)
350
375
400
425
450
Heating temperature(℃)
Relationship between holding time of heating and residual stress
SWI−180
SWI−200
1000
1000
Spring specification
d=11.5mm
D=115.0mm
Measuring point
Inner side, Axial direction of wire
Under constant keeping temp. at 400℃
800
Residual 600
stress
（N/mm2） 400
800
Residual
600
stress
（N/mm2）
400
200
0
as coil
Spring specification
d=11.5mm
D=115.0mm
Measuring point
Inner side, Axial direction of wire
Under constant keeping temp. at 375℃
200
30
10
20
30
40
50
0
as coil
60
Keeping Time(min.)
10
20
30
40
Keeping Time(min.)
−5−
50
60
−6−
1,610−1,760
（150）
1,710−1,860
（150）
1,660−1,810
（150）
JIS G 3560
SWOSC−B
1,950−2,050
（100）
1,850−1,950
（100）
1,750−1,850
（100）
NETUREN Induction Tempered Wire
SWI-200
SWI-190
SWI-180
Tensile strength(N/mm2)
0.090 or less
±0.090
・USAGE
suspensions in two- and four-wheel vehicles,
(ITW is not available for valve springs.)
high fatigue resistance and high sag resistance.
shutter,industrial machine and other springs need
emergency brake for large-sized vehicles,
0.060 or less
JIS G 3560
SWOSC−B
0.070 or less
±0.050
NETUREN Induction
Tempered Wire
0.050 or less
NETUREN Induction
Tempered Wire
Roundness(mm)
±0.070
±0.060
JIS G 3560
SWOSC−B
Tolerance(mm)
* Numerical figures in parentheses show the specified range of tensile strength.
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0
16.5
17.0
Dia.
(mm)
Comparison between "SWOSC-B JIS G 3560 " and "NETUREN Induction Tempered Wire
〈Reference data〉
用 途
＞30
＞35
JIS G 3560
SWOSC−B
＞35
NETUREN Induction
Tempered Wire
Reduction of area(%)
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0
16.5
17.0
Dia.
(mm)
NETUREN CO.,LTD.
2-17-1, Higashi-gotanda, Shinagawa-ku, Tokyo 141-8639, Japan Tel : +81-3- 3443- 5444 Fax : +81- 3- 5488-7538
■
Affiliate companies manufacturing NETUREN Induction Tempered Wire;
Shanghai Neturen Co., Ltd.
802 Baiyin road Jiading, Shanghai 201821, China
Tel：+86-21-6916-9803
Fax：+86-21-6916-9503
Tel：+1-513-863-1900
Fax：+1-513-863-1147
Neturen America Corporation
2995 Moser Court, Hamilton, Ohio, USA
No.27333
2013030500S