To k y o S t e e l M a n u f a c t u r i n g C o . , L t d .

Technology of Hot Rolled Mild Steel Sheets & Steel Strips(Formability, Fatigue property and Spot weldability of SPHC Steel)

Steel Sheets
Hot Rolled Coils
2022.06.01

Contents
1.

Introduction ・・・・・・・・・・・・・・・・・・・

3

2.

Characteristics of manufacturing process ・・・・・・・

5

3.

Data of quality ・・・・・・・・・・・・・・・・・・

6

3.1. Chemical composition and mechanical property ・・・

6

3.2. Press formability (CCV, LHER, Erichsen, and LDR)・・・・

7

3.3. Press formability ( FLD ) ・・・・・・・・・・・・・・ 11
3.4. Fatigue property ・・・・・・・・・・・・・・・・・ 13
3.5. Spot weldability

・・・・・・・・・・・・・・・・・ 14

3.5.1.

Range of suitable welding current ・・・・・・・・ 14

3.5.2.

Evaluation of joint strength ・・・・・・・・・・・ 16

Hot Rolled Mild Steel Sheets & Steel Strips
2022.06.01

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Introduction

Tokyo Steels Views to Global Warming

Introduction❶ Introduction
Source: Home Page, Tokyo Steel Manufacturing Co., Ltd.

In 1997, the Kyoto Protocol became the world s ﬁrst international agreement on the issue,
producing commitments by principally European countries and Japan to reduce their CO 2
emissions in 2012 by about 5% compared with 1990. Further discussions have been
continued at the summits and international conferences, trying to determine additional andstricter targets, and to fashion a system in which all nations can participate.
Taking action against global warming is the responsibility of current generations. We must act
now to reduce CO2 emissions and develop the alternatives for fossil fuels to preserve theEarth's environment.
In Japan, the CO2 emissions of the steel industry account for a little over 14% of the total(FY2008), the highest proportion among all the industries. Since steel is essential for thesociety to achieve industrial development, there is a clear need to ﬁnd a way to reduce CO2
emissions in manufacturing steel.
There is a big diﬀerence in CO2 volume between two methods being used to manufacture
steel; making one ton of steel through a blast furnace method using iron ore and coal as its
main feeds emits two tons of CO2 compared with less than 0.5 tons by an electric furnace
method which is making steel through recycling of steel scrap. For manufacturing exactly thesame type of steel, the CO2 emissions from an electric furnace mill are one fourth of those bya blast furnace mill.
In 1995, we brought the Utsunomiya works on stream, establishing basically almost the same
product lineup and capacity that Tokyo Steel has today. During the 15 years since FY1995,
we have got about a 440-thousand-ton yearly average reduction in CO2 emissions over the
15 years through replacing a supply of steel products which had been produced by the blast
furnace mills. Therefore, we consider that Tokyo Steel has actually achieved a reduction in
CO2 emissions equivalent to 35% of its FY1990 CO2 emissions, which is evidently a huge
reduction compared With the 5% target set for Japan as a whole under the Kyoto Protocol.
When we consider a substantial reduction of CO2 emissions, recycling of steel scrap should
be further promoted in Japan.
The Okayama Plant of Tokyo Steel started the production of hot-rolled mild steel strips from electric
furnace steel by introducing the leading-edge DC electric furnace-hot strip mill in October 1991.
We also introduced the continuous pickling line in 1995, cold rolling mill and surface treatment line
in 1997 and leveller/shear line in 2004 to address the current manufacture of hot-rolled mild steel
sheets and strips, pickled steel sheets and strips, hot-dip galvanized steel strips. By studying anddeveloping the technology to eﬀectively utilize the tramp elements (traveling elements) such as Cu
which increase in volume as the number of recycling count grows while utilizing the accumulated
operation know-how, we provide high-quality and environmentally friendly electric furnace steel
materials that suit the needs in a wide range of ﬁelds including industrial machines, home
appliances and automobiles.
Comparison of the amount of carbon dioxide emissions

Electric furnace
Blast furnace 1）

Comparison of energy consumption

Electric furnace
Blast furnace 2）
Blast furnace 3）

Fig.1 Amount of carbon dioxide emissions and amount of energy consumption under production

PAGE

References:
1) Makoto Nishino: Theoretical evaluation of CO 2 emission by integrated steelmakers , Ferrum, Vol.3, No.1
(1998),p.23
2) Environmental Aﬀairs Group, the Japan Iron and Steel Federation: Eﬀorts against environmental problems in steel
manufacture industry, Tekkokai (1992), p.24
3) Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry and the Japan Iron andSteel Federation: Energy evaluation study for use of steel products seen from LCA viewpoint3

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Introduction
Introductionin Japan
2.3（CO2 ton/steel ton）※1

0.003（CO2 ton/steel ton）※2

blast furnace0.53（CO2 ton/steel ton）※1

electric furnaceFe0.003（CO2 ton/steel ton）※2

overseasfrom Brazil
0.37（CO2 ton/steel ton）※3
from Australia
0.11（CO2 ton/steel ton）※3

iron ore

References:※1 Makoto Nishino: Theoretical evaluation of CO 2 emission by integrated steelmakers , Ferrum, Vol.3, No.1
(1998), p.23.
※2 In case of 50km land transportation after Ministry of Economy, Trade and Industry and Ministry of Land,
Infrastructure, Transport and Tourism: A guideline for a calculation method on CO2 emissions in transport sector(http://www.enecho.meti.go.jp/policy/images/060518pamph.pdf)(2010), p.6.
※3 Ship & Ocean Foundation: A report on research concerning the reduction of CO2 emission from vessels August
2000 (assuming that the iron content of iron ore is 60%, Japanese version p.92).

Fig.2 Amount of CO2 emissions per one ton of steel (products) accompanying recycles of steel

PAGE

4

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Characteristics of manufacturing process

Hot rolled mild steel sheets and steel strips by Tokyo Steel are produced by using:1) A large direct current electric furnace with eccentric bottom tapping (EBT)・ Steel scrap is melted homogenously and eﬃciently by optimized arrangement of electrodes.
・ Low inclusion and low nitrogen content of steel are obtained by EBTWhile minimizing the mixture of impurities such as inclusion by EBT, we reduce the mixture ofnitrogen to manufacture clean liquid steel.
2) Steel reﬁning at ladle furnace・ Homogeneity of chemical compositions is obtained by stirring Ar-bubbling.
・ Quality of continuously cast slab is stabilized by temperature control.
3) Continuous casting・ Reduction in inclusion and improvement of internal quality of slab is obtained by complete
insulating from the air.
4) Hot strip mill・ Improvement in surface quality by ultrahigh-pressure water descaling
We set up the descalers at the entrance and the exit side of a rougher mill and also at theentrance side of a ﬁnishing tandem mill. They remove the scales generated on the rollingmaterial surface.
・ Improvement of the precision of thickness of steel sheets by a coil box
We wind steel plates before entering a ﬁnishing mill and equalize the temperature all over thematerials in order to reduce the disturbance due to temperature diﬀerence and improve thesheet thickness precision.
・ Microstructural optimization of steels by TMCP ( Thermo-Mechanical Control Process )We can obtain the required microstructures and mechanical properties by controlling thecooling patterns over a run-out table.
As described above, we can apply the most suitable conditions to production by using various high advanced
steel making facilities and hot strip mill. And we can manufacture high quality steel products with excellent
mechanical property, formability, and weldability.

Characteristics of manufacturing process❷ Characteristics of manufacturing process

DC furnace steel making plantelectric furnace

ladle furnace

continuous casting machineﬁnishing tandem mill

pickling line

skin-passcold roll mill(reverse cold roll mill)（welding）
welderheating furnace

winding device

leveller shear line

rougher millhot coilcut sheetoiler

surface treatment line
annealing furnaceacid bathslabpickled coil(oiling)(welding)

welderRapid cooling equipment

alloying furnace

STF

degasserzinc-coated coil（anti-corrosive）
chromating coater

shipping

zinc potskin-pass

Process drawing ( Flowchart )

PAGE

Fig.3

tension leveller5Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

This document introduces the characteristics of SPHC steel including the formability, fatigue property andspot weldability.

Data of quality❸ Data of quality

3.1. Chemical composition and mechanical property
The chemical composition and mechanical properties of the samples are listed in Table 1 and Table 2.
Comparing steel strips or steel sheets with steel plates, they are produced with lower C and Si contents thansteel plates. In addition, when we focus on the metal microstructure, they have uniform crystal grain
diameters in both thickness and width with little inclusions thanks to the steel making, rolling and coolingprocesses (Photo1).
Table1

Chemical composition

chemical composition (mass %)
C

Si

Mn

P

S

Cu

Ni

Cr

Mo

V

N

Ceq

thickness 1.6mm 0.01 0.02 0.14 0.013 0.001 0.23 0.09 0.12 0.03 0.001 0.0037 0.07

Table2Mechanical properties

yield strength tensile strength elongation（N/mm22） （N/mm22）（％）
thickness 1.6mm

284

356

44.2

n-valuer-value

0.227

0.93

0.1mm

Photo1

Optical microstructure

PAGE

6

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

The deformation modes in press forming can be classiﬁed as deep drawing, bulging, stretch-ﬂanging andbending as shown in Fig.4. The relationship as shown in Table 3 is observed between these deformation
modes and the characteristic values of the material.

shrinkstretch

punch
die

inﬂow

die

Data of quality

3.2. Press Formability(CCV, LHER, Erichsen, and LDR)

outﬂow
stretchstretchdeep drawing bulging
stretch-ﬂanging,outﬂowbending

outﬂow

stretchstretchFig.4 Schematic illustration of typical defomation

Table3Characteristic value

n valueｒvalueCharacteristic value and test method

Test method

PointsTensile test

Drawability is improved as the value of work hardening coeﬃcient (n-value) islarger because elongation until localized shrinkage occurs is large. It becomesthe indicator for whether the material excels in bulging/strain uniformity during
pressing. The general value for mild steels in market ranges about 0.15 to0.25.

Tensile test

The ratio value between sheet width strain and sheet thickness strain which isalso called plastic anisotropy or Lankford value, and deep drawability is higher
as this value is larger. The general value for hot rolled sheets and strips inmarket ranges 0.80 to 0.95.

Conical cup value
Conical cup test
( CCV )A test combining deep drawing and bulging deformation (composite formabilitytest).

Limiting hole
Hole expanding
expansion ratio
test(LHER)

One of the stretch-ﬂanging tests to test how easy it is to form with tensile
deformation of the ﬂange edge and inside as the deformation mode.

Erichsen value

The amount of stretching when the center of the sheet is pushed up with apunch with the edges held and the sheet suﬀers fracture is called the Erichsen
value and it is an indicator for evaluating the bulging formability (forming withbiaxial tension deformation).

Erichsen test

Limiting drawing Deep drawability
ratio
test
(LDR)
Bendability

Bend test

A method for deep drawing (shrink-ﬂanging deformation) property testingand it is an indicator for how easy it is to form by drawing into the die hole bypunching force with ﬂange deformation by tension and compression.

A test to evaluate how easy it is to form by bending with approximate planestrain deformation and crack generation is checked after carrying out speciﬁed
radius bending.

PAGE

7

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

Table4

test item

methodConical cup

JIS Z 2243

hole expansion

JFS T 1001(1996)

Erichsen

JIS Z 2247

deep drawing−

Conditions for tests

test piece
27 modellubricantφ78

work speed blank holding force

machining oil

10mm/minnone

no lubricant

20mm/min9.0ton100×100mm

graphite grease

10mm/min1.0tonφ78〜92mm

Daphne SK

25mm/min2.0ton100×100(die inside diameterφ10.4mm)

Data of quality

For press formability test, we have carried out conical cup test, hole expansion test, Erichsen test, and deep
drawing test. Table 4 and Tables 5 to 8 list the conditions for each test and the test results, respectively.
The SPHC steel by Tokyo Steel exhibits the excellent workability including 203% hole expansion ratio and2.20% limiting drawing ratio.

Conical cup test

D0

rp
d0

da

D0

d2

ru

θ
2

crack

rd

rp

outer diameter of cup D0 when cracking
form into a conical cup shape until the bottom breaks

Fig.5 Schematic showing tool and specimen dimensions for the conical cup test

Table5Results of conical cup test

samplemax (mm)min (mm)

CCV (mm)

1

61.15

60.82

60.99

2

61.07

60.82

60.85

3

61.14

61.06

61.10

average (mm)
61.0

PAGE

8

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

Data of quality

Hole expanding test
There are two kinds for the punch: conical and cylindrical types
die

die diameterdie shoulder R

initial holediameterburrhole diameter
after fractured

holding force
thicknesstest piece

punch

Fig.6 Conical type

Table6

Results of hole expansion test
(Comparison with other companies)

Photo2 Test pieces after hole
expansion test
(cylindrical type)limiting hole expansion ratio (%)

average (%)

Our material

210.4 , 206.5 , 192.4

203.1

Blast furnace A corporation

175.9 , 115.0 , 139.2

143.4

Blast furnace B corporation

155.1 , 139.4 , 138.7

144.4

Blast furnace C corporation

152.9 , 124.0 , 161.0

146.0

Erichsen test
magniﬁcation

Photo3

Test piece after Erichsen test

Fig.7 Schematic illustration of erichsen test tool shape
Table7

Results of Erichsen test

height (mm)

1

15.5

2

15.2

3

16.0

average (mm)

15.6

PAGE

sample9Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

Data of quality

Deep drawing test
rolling direction

Rolled steel material
DieDie
earring

fractured
破断サンプル
samplePunch

successfully penetrated sample

Photo4 Test pieces after deep drawing test
(typically deformed samples)

Table8

Fig.8 Schematic illustration of deep drowing test
tool shape

Results of deep drawing test

blank diameter（㎜）○：good, ×：bad

φ78

○

φ80

○

φ82

○

φ84

○

φ86

○

φ88

○

φ90

×

φ92

×

LDR

2.20

PAGE

10

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

While the previous section showed the results of various formability tests, they alone cannot predict the press
formability for real complicated shapes. Therefore, we drew Forming Limit Diagram (FLD) to estimate theforming limit in the actual press working; the FLD is obtained by giving the various forming paths from theequal biaxial strain state path to uniaxial strain state path through tests such as tensile and ﬂuid pressurebulging tests.

Data of quality

3.3. Press formability (FLD)

Next, we explain the FLD more in detail. We measure the major(ε1)and minor (ε2) strains at the necking
part by Scribed Circle Method just before fracture occurs. And we plot these values on the coordinate planeof ε1 and ε2 and draw a FLD by linking those points. The FLD shows how forming limits change by theratio of ε１ to ε2. Generally speaking, the forming limit becomes smaller near the plane strain condition
where ε2/ε1 = 0. FLD is used widely for selecting materials and/or solving forming problems. (FLD isexpressed as the deformation in x and y directions and the working limit for drawing to bulging as shown in
Fig.9.)

Forming Limit Diagram
plane strain tension
unchange in thickness

F

ε

1

0.6

drawing region

stretching region

equal biaxial tension

F
D
E

E

A

B

0.4

ε
1

D

A

B

C

=
2

-ε
0.2

thickness increasing region

ε

2

-0.5

-0.4

-0.3

-0.2

-0.1

Fig.9

0.1

0.2

0.3

0.4

0.5

Explanation of FLD

Table 9 and Fig.10 show the test conditions and the FLD obtained, respectively. The maximum strain andthe minimum strain change by the deformation mode; as shown in Table 10, the former is in the range from
43% to 72% and the latter is in the range from -18% to 60%.

Table9FLD test conditions

test piece(C×L)

lubricantequal biaxial deformation

210×210 mmhydro-static bulging

unequal biaxial deformation (1)200×200 mm

hydro-static bulging

unequal biaxial deformation (2)200×200 mm

hydro-static bulging

plane strain deformation

200×120 mm

no lubricant

uni-axial tensile deformation

200× 35 mmーwork speed

blank holding force
100ton30mm/min

100ton
100ton10〜20mm/min

60ton
−

PAGE

forming mode11

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality○：Good（○…the maximum value）
×：NG（×…the minimum value）●：Forming Limit Diagram

80
70

Data of quality

Ex（％）
90

60
50
40
30
20
10

-50 -40-30 -20

-10

0

10

20

30

40

50

60

70

80

Ey（％）

Fig.10Forming limit diagram

Table10

Results of FLD test

Deformation mode

forming limit
Ex(%)

Ey(%)

equal biaxial deformation

72

60

unequal biaxial deformation (1)5329unequal biaxial deformation (2)4813plane strain deformation

43

2

uni-axial tensile deformation

58

-18

PAGE

12

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

We carried out tensile fatigue test and plane bending fatigue test, of which test pieces are shown in Fig.11.
Table11 shows the test conditions. Table12 and Fig.12 show the test results. The tensile fatigue limit andplane bending fatigue limit were 320 MPa and 170 MPa, respectively.

Fig.11

Specimen of fotlgue test

Table11

Fatigue test conditions

tensile fatigue test

item
stress ratio

plane bending fatigue test

0.05

-1.0

test frequency

20Hz
1×107 times

maximum number of cycles

Table12Results of fatigue test

tensile fatigue testNo.

plane bending fatigue test

maximum stress number of cycles（MPa）(cycle)note

maximum stress number of cycles（MPa）(cycle)

note

1

200

2,015,000

no failure

170

10,000,000

no failure2240

4,968,000

no failure

180

3,878,300

failure3

300

10,000,000

no failure

190

1,394,800

failure4

320

10,000,000

no failure200

1,145,800

failure5330

3,789,981

failure220

473,200

failure6

340

478,486

failure230

293,600

failure7

350

281,532

failure250

166,700

failure8

370

13,540

failure270

85,000

failure

9

380

9,329

failure

10

390

2,931

failuretensile fatigue test

450

Data of quality

3.4. Fatigue property

plane bending fatigue test

300

400
250

350
300

200

250
200

150

150
1.0E＋03

1.0E＋04

1.0E＋05

1.0E＋06

1.0E＋07

S-N curves

1.0E＋05

1.0E＋06

1.0E＋07

PAGE

Fig.12

1.0E＋0413

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

3.5.1 Range of suitable welding current
The current range, from the minimum current required to give a nugget diameter of 4√t( 5.06 mm in thepresent test) to the current resulting in the onset of expulsion was adopted as the suitable welding current
range. We employed DR-shaped electrode of d=6 mm shown in Fig.13 and carried out spot welding on
the basic conditions in Table13. Table14 lists each condition and its measured nugget diameter.
It is concluded from Table14 and Fig.5 that the minimum limit current is 6.3 kA and the suitable current
range is 2.5 kA (Table 15). Photo.5 shows typical cross sections of the welds.

dface diameter DrR

D type

mark

D

Model

Table13

ｒ

ｄ

ｒ

5
6.5

32

63

5

6.5

16

8

40

80

6

8

20

10

50

100

8

10

25

12.5

32

16

40

20
Electrode shapereference : JIS C 9304(1999)

Base conditions for spot welding

1%Cr-Cu dome type

initial pressure time

29cycles/50Hz

electrode force

270kg

welding time

15cycles/50Hz

holding time

1cycles/50Hz

ﬂow rate of cooling water

top and bottom

Table14R

13electrode

test piece №

DR type10

Fig.13

Data of quality

3.5. Spot weldability

φ16mm

tip (nose) φ6mm(R40)

2.5L/min.

Conditions for spot welding and diameters of nugget

welding current (kA) weld thickness (mm)expulsionnugget diameter (mm)

1

4.6

3.11

none

−

2

4.9

3.10

none

0.99

3

5.2

3.11

none

2.54

4

5.5

3.11

none

3.35

5

5.8

3.09

none

4.24

6

6.1

3.08

none

4.78

7

6.4

3.07

none

−

8

6.7

3.07

none

5.23

9

7.0

3.04

none

−

10

7.3

3.01

none

6.05

11

7.6

3.00

none

−

12

7.9

3.00

none

6.40

13

8.2

2.94

none

−

14

8.5

2.92

none

6.86

15

8.8

2.82

expulsion

−

PAGE

14

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

Data of quality

No.2（4.9ｋA）

No.3（5.2ｋA）

No.4（5.5ｋA）

No.5（5.8ｋA）

No.6（6.1ｋA）

No.8（6.7ｋA）

No.10（7.3ｋA）

No.12（7.9ｋA）

No.14（8.5ｋA）
Photo5

Cross sections of welds (Enclosure line is appointed at suitable welding current range)

PAGE

15

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

Data of quality

10

nugget diameter at cross section (mm)

9
8
7
6

4√t

5

expulsion
8.8kA

4
3

6.3kA

2
1
0
4

5

6

7

8

9

10

11

12

welding current (kA)
Fig.14

Weld growth curve (nugget diameter against welding current)

Table15

Suitable welding current range

the lowest limit current (4√t)

6.3kA

the upper limit current (expulsion)

8.8kA

Suitable current range

2.5kA

3.5.2 Evaluation of joint strength
We carried out the tensile shear strength (TSS) test and the cross tension strength (CTS) test as shown in
Fig.15, where the current 6.3 kA for spot welding was employed by considering the lowest limit current
which would deliver nugget diameter (4√t).

(b)

(a)

(a) tensile shear strength (TSS) test
Fig.15(b) cross tension strength (CTS) test

TSS and CTS tests

PAGE

16

Hot Rolled Mild Steel Sheets & Steel Strips

2022.06.01

Data of quality

Table16

test type test No.

Results of joint performance tests

Data of quality

Tables 16 and 17 show the performance of the weld joints and the average joint strengths, respectively.
Both of TSS and CTS tests show that the fractured modes are of the mother metal plug. And both of thestrengths are higher than those of conventional mild steel sheets, indicating suﬃcient joint strengths.

nugget diameterwelding current weld thickness
joint strength
expulsion
fracture mode
(mm)
(mm)
(kA)
(kN)

TSS (kN)

1

6.3

3.11

none

mother metal plug

11.21

TSS (kN)

2

6.3

3.10

none

mother metal plug

11.09

TSS (kN)

3

6.3

3.11

none

mother metal plug

11.16

TSS (kN)

4

6.3

3.11

none

mother metal plug

11.31

TSS (kN)

5

6.3

3.09

none

mother metal plug

11.21

CTS (kN)

6

6.3

3.08

none

mother metal plug

8.77

CTS (kN)

7

6.3

3.07

none

mother metal plug

8.65

CTS (kN)

8

6.3

3.07

none

mother metal plug

8.60

CTS (kN)

9

6.3

3.04

none

mother metal plug

8.70

CTS (kN)

10

6.3

3.01

none

mother metal plug

8.52

macro

11

6.3

3.00

none

4.36

macro

12

6.3

3.00

none

4.65

Table17nugget diameter(mm)

tensile shearing test(kN)

cross tension test
(kN)

11.20
(σ=0.072)

8.65(σ=0.085)(3.7√t)d1

d2

symmetry plug fractured1

d2

asymmetry plug fracturea)in case of plug fracture
shear-fractured nugget

d1

d2

corona-bondb)in case of interfacial fracture
d1
d3

d2

4.65

Joint strength on averagec)in case of partial plug fracture

PAGE

Fig.16 Fracture pattern

reference : JIS Z 3136(1999)17

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Head oﬃce

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Telephone(81)3-3501-3223 FAX.(81)3-3580-8859 (sales)
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Nittochi Nagoya Bldg, 7F, 2-1-1,Sakae, Naka-ku, Nagoya-shi,
Aichi 460-0008, Japan
Telephone(81)52-203-0855 FAX.(81)52-203-3021
Kyushu branch oﬃce
3-5-1, Minami Futajima, Wakamatsu-ku, Kitakyushu-shi,
Fukuoka 808-0109, Japan (Located at Kyushu Plant)
Telephone(81)93-791-5988 FAX.(81)93-701-3581
Okayama sales oﬃce
4-1-1, Minamise, Kurashiki-shi, Okayama 712-8055, Japan(Located at Okayama Plant)
Telephone(81)86-455-7169 FAX.(81)86-455-3105
Utsunomiya sales oﬃce 11-1, Kiyohara-kogyo-danchi, Utsunomiya-shi, Tochigi 321-3231, Japan(Located at Utsunomiya Plant)
Telephone(81)28-670-6235 FAX.(81)28-670-6238

Tahara Plant

2-1-3, Shirahama, Tahara-shi, Aichi 441-3436, Japan
Telephone(81)531-24-0810 FAX.(81)531-24-0818
Okayama Plant
4-1-1, Minamise, Kurashiki-shi, Okayama 712-8055, Japan
Telephone(81)86-455-7151 FAX.(81)86-455-3105
Kyushu Plant
3-5-1, Minami Futajima, Wakamatsu-ku, Kitakyushu-shi,
Fukuoka 808-0109, Japan
Telephone(81)93-791-2635 FAX.(81)93-791-2639
Utsunomiya Plant
11-1, Kiyohara-kogyo-danchi, Utsunomiya-shi, Tochigi 321-3231, Japan
Telephone(81)28-670-5607 FAX.(81)28-670-5608
Takamatsu Steel Center 5-1-1, Asahi-machi, Takamatsu-shi, Kagawa 760-0065, Japan
Telephone(81)87-822-3111 FAX.(81)87-822-3117

edited 2022 June
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