Technical Data

Enamel Chalkboard
Enamel Whiteboard
Enamel Steel Sheet for InteriorRiver Enamel(Dual Coat Enamel)

August 2015

Introduction

Porcelain enamel is made by fusing glass glaze on a metal base through the process ofbaking at high temperatures. It has been widely used around the world for accessories,
such as shippouyaki cloisonné enamels, kitchen products, and other items since longago.
Porcelain enamel is smooth and hard, and resistant to scratches, chemicals, color
fading, and stains. It can also withstand long, heavy use while maintaining a high levelof performance. River Enamel from JFE Metal Products Corporation takes advantageof these features and is used as a surface material for chalkboards, whiteboards, andprojection screens in schools, public facilities, and offices.
River Enamel is also incombustible and resistant to heat. For these reasons, it is used as
an interior material for items such as kitchen panels and toilet booths.
River Enamel is the best porcelain enamel steel sheet in the world, and is produced
under the strict quality control measures based on the enameling technologies JFE
Metal Products Corporation has developed over more than 40 years.

Table of Contents 1.

Manufacturing Process and Processing Techniques of River Enamel …… ₁
1-1. Manufacturing process ………………………………………………………… ₁
1-2. Processing techniques …………………………………………………………… ₁
1-2-1. Steel sheet for porcelain
enamel ……………………………………………… ₁……………………………………………………………
1-2-2. Glaze ……………………………………………………………………………
……………………………………………………………………… ₁
1-2-3. Application………………………………………………………………………
of glaze …………………………………………………………… ₁
1-2-4. Baking ……………………………………………………………………………
……………………………………………………………………… ₁*Cross-section structure of River
Enamel ……………………………… ₁……………………………………………
*Cross-section structure of aluminum coatedsteel porcelain enamel … ₁………………………………
*Cross-section structure……………………………………………………
of prepanted steel sheet ……………………… ₁
1-2-5. Inspections ………………………………………………………………………
……………………………………………………………………… ₁

2.

Product Specifications of River… …Enamel…………
……………………………………
……………………………… ₁
2-1. Classification ………………………………………………………………………
by application …………………………………………………… ₁

3.

Comparison Table of Markerboard Specifications
andPerformance………………
……
… … … … ………
… ₂① River Enamel ………………………………………………………………………
…………………………………………………………… ₂
Company A …………………………………… ₂② Steel porcelain enamel from……………………………………………………
from Company B ……………… ₂③ Aluminum coated steel porcelain enamel……………………………………………
C (steel white) ……………………… ₂④ Prepanted steel sheet from Company……………………………………………
D (steel white) ……………………… ₂⑤ Prepanted steel sheet from Company……………………………………………
⑥ Photos showing visibility of markerboards……………………………………………
…………………………………… ₂⑦ Features of the River Enamel Markerboard………………………………………
…………………………………… ₂

4.

Comparison Table of Chalkboard Specifications
andPerformance………………
……
… … … ……………
…… ₃① River Enamel ………………………………………………………………………
…………………………………………………………… ₃
A ……………………………………… ₃② Steel porcelain enamel from Company……………………………………………………
③ Aluminum coated steel porcelain enamel from Company B …………………
……………… ₃(steel green) ………………………… ₃④ Prepanted steel sheet from Company C…………………………………………
(steel green) ………………………… ₃⑤ Prepanted steel sheet from Company D…………………………………………
contrast …………………………… ₃⑥ Photos showing chalk adhesiveness and…………………………………………
⑦ Features of the River Enamel Chalkboard………………………………………
…………………………………… ₃

5.

Markerboard maintenance ……………………………………………………
… … … … … … … … …… … … ₄

6.

Chalkboard maintenance ………………………………………………………
… … … … … … … … …… … … ₅

1. Manufacturing Process and Processing Techniques of River Enamel
1-1. Manufacturing process
River Enamel is produced in the fully automated line, as shown in Figure 1.
The steel for eusmeling is pre-processed in a nickel treatment tank before it enters the ground-coat booth, where a roll coater evenly
applies ground coat glaze to the material. The material is then baked at high temperatures in the ground-coat baking furnace, after which
it proceeds to the cover-coat booth. Just as in the ground coating process, here a roll coater or a spraying device applies a finishing glaze,
which is selected according to the intended use of the product. The material is then baked in the cover-coat baking furnace.
Grid embedded products are printed with patterns by a transfer printing machine before they are baked in a transfer printing furnace.
Then, after being subjected to strict checks by surface examination cameras and inspectors, River Enamel is cut and processed into coils
or sheets which become products.

Direction of flow▼

Surface examination
camera▼Figure 1
Overview of theRiver Enamel
manufacturing line

Nickeltreatment
Steel coil

GC booth

Shearing

CC boothGC baking furnace

CC baking furnace

Approx. 800°C

Approx. 800°C

Transfer
printing

Visual inspection

3rd baking
furnace

For grid embedded baking

GC: Ground coating (of the bottom layer of porcelain enamel)
CC: Cover coating (for finishing the porcelain enamel)River Enamel coil or sheet

1-2. Processing techniques
1-2-1. Steel sheet for porcelain enamel
The steel sheet used for River Enamel is a special cold-rolled steel sheet for porcelain enamel (manufactured by JFE Steel Corp.). It
contains far less carbon than decarburized steel sheets for porcelain enamel, a JIS-standard SPP material. For this reason, it is free of
deformities or enamel defects even when it is baked at high temperatures exceeding 800°C.
1-2-2. Glaze
The ground-coat glaze contains a small amount of oxidized metal to facilitate chemical reactions between the glaze and steel sheet,and enhance the adhesion between them.
In regards to the cover-coat glaze, a titanium glaze-based pigment is added to white glaze (white, ivory, or gray) while a transparent
glaze-based pigment is added to a dark-color glaze.
We uniquely blend and control the glaze on our own based on its intended application. This approach enables us to control the qualityof our products.
1-2-3. Application of glaze
We use a computer-controlled roll coater or an automatic spraying device to apply the glaze, thereby ensuring a uniform coating
thickness and creating a smooth surface. In this way, we manufacture products best suited for their intended use.
1-2-4. Baking
River Enamel is made through a double coating process in which the material is ground-coated, baked, cover-coated, and baked again.
The double coating process ensures a thick enamel coating, excellent resistance to rust, and superior durability.
In addition, the inner walls of the baking furnaces are made of ceramic fibers and adopt the radiant tube heating system, providing
excellent thermal efficiency and uniform temperature distribution.

《Cross-section structure》
Figure 2

Top porcelain enamel layer

Top porcelain enamel layer

Bottom porcelain enamel layer

Base coat

Aluminum coat layer

Nickel layer
Ultra-low carbon
cold-rolled steel sheet

PrimerCold-rolled steel sheet

Nickel layer

Zinc-prepanted steel sheet

Aluminum coat layer

Coat layer on the back surface

Bottom porcelain enamel layer

River Enamel from
JFE Metal Products Corporation

Aluminum coated steel porcelain
enamel from another company

Prepanted steel sheet

from another company

River Enamel is dual coat enamel with two surface porcelain enamel layers.
1-2-5. Inspections
Product inspections of River Enamel include a surface inspection by surface examination cameras installed on the manufacturing
line and a subsequent visual inspection by skilled inspectors. In addition, adhesion checks, color tone and gloss level measurements,
and appearance and shape measurements, such as measuring the warpage, are carried out off the manufacturing line at intervals of
specified number of lots. The results of these checks and measurements are recorded.

2. Product Specifications of River Enamel
2-1. Classification by application
Figure 3.
Classification
by application

For markerboard/
chalkboard

River Enamel

Markerboard

Plain

Chalkboard

Grid pattern embedded

Screen board

Board for screen only
(Mica screen)

Kitchen panel
For interiorarchitecture

Toilet boothPartition board

Board for markerboard and screen(455SM)
Board for chalkboard and screen(VIVAE)❶3. Comparison Table of Markerboard Specifications and Performance
JIS S 6052

Item

1

Standard value

G3133、EN10209 : 60 〜180μm
G3314 : 50 〜 100μm

ISO 2178

110μm

110μm

60μm

30μm

30μm

R 4301－

ISO 2178

30μm

50μm

0μm

8μm

8μm

△ E ≦ 1.5

△ E ≦ 1.5

－

－

－

74％

53％

63％

－

－

G 3133 (steel porcelain

enamel product)
G 3314 (aluminum coatedsteel porcelain enamel product)t ≧ 0.3mm

4 from standard ( △ E)

K 5600-4-6－

Gloss level (Gs 20)

Z 874190% or lower

5

0.3〜0.48mm
ISO7724-3

ISO 2813
ISO 7668

Z 8741－6 Visibility－－

7 Mohs hardness－－

EN 101

K5600-5-9－

Decrease of mass during
a wear resistance test
(Wear ring CS-17/ 1kg)
(1,000 revolutions)

R 4301－

Solvent resistance test:
Alcohol, acetone,
10 toluene, xylene, andpetroleum benzine－－

11 Surface roughness

B 0601Rz ≦ 14μm

Gloss level (Gs 45)

8 Wear resistance（Taper type wear resistance test）

9 Impact resistance（Pistol type impact resistance test）

There must not be any rust.

5.5

5.5

2.5

2.5

44.7mg113.2mg（There were parts where the （The base materialbase material was also worn.） was also worn.）

＞ 90N

＞ 90N

Dip 20℃、300hr

No change

No change

No change

No change

No change

ISO 4287

Indentation depth:
3 mm

R4301

5.5

＞ 90N

There must be no remaining marker traces or unevenness
in erased areas when the markerboard is viewed from a
distance of one meter.

(Sodium chloride test)

83％
Photograph＞ 90N

S 605215 Corrosion resistance97％
Photograph＞ 90N

13 Marker erasability－

108％
Photograph

2.0mg

S 6052

K 5600-5-2

100％
Photograph

2.0mg

12 Marker adhesion(Cupping test)

100％
Photograph

1.3mg

There must be no unevenness in the lines when themarkerboard is viewed from a distance of one meter. Thelines must look clear when the markerboard is viewed
from a distance of eight meters.

14 Enamel adhesion

Company D(Prepanted
steel sheet)

R 4301

Coat thickness
2 (back surface layer)

Color difference

Company A
Company C
Company B
JFE(Steel porcelain (Aluminum coated steel (Prepanted steel(River Enamel)
porcelain enamel)enamel)sheet)

Standard No.

Coat thickness(surface layer)

3 Steel thickness

Reference standard
and others

1.2μm

1.3μm

1.2μm

0.9μm

1.1μm

Excellent

Excellent

Excellent

Excellent

Excellent

Excellent

Excellent

Excellent

Excellent

Excellent

No cracking/peeling
was observed.

No cracking/peeling
was observed.

No cracking/peeling
was observed.

No rustNo rustNo rustNo cracking/peeling Both cracking andwas observed.
peeling were observed.

No rustNo rustNote: Values with no indicated range are typical values, not guaranteed values.
Note: Values from tests we conducted on our own.

◆ Visibility of Markerboard(Surface reflection and distortion)《River Enamel from JFE》

《Steel porcelain enamel
from Company A 》《Aluminum coated steel porcelain
enamel from Company B》《Prepanted steel sheet
from Company C》《Prepanted steel sheet
from Company D》

The JFE River Enamel Markerboard has an extremely smooth enamel surface, making it easy to write and erase text. The text written
on the markerboard is also very easy to see. In addition, it is highly resistant to rust, wear, impact, scratches, and color fading.

◆ Features of River Enamel Markerboard❷

Ease of writing/visibility

The markerboard has a smooth surface, making it easy to writesmoothly with a marker pen. It also ensures sharp contrast between
written letters, resulting in even higher legibility.

Resistance tosolvents

The surface is able to withstand long-term use due to theblending of glaze which is highly resistant to chemicals. The
surface will not exhibit any changes, even when it is exposed tosolvents such as toluene and alcohol.

Erasability

The smooth surface allows for marker ink to be erased easily with adedicated eraser.

Durability

The hard coating film of the enamel, which is formed through thevitrification of the glaze at high temperatures, is highly resistant towear, impact, and scratches.
Mohs hardness: 5.5

Easy to clean

The markerboard can be cleaned properly with the dedicated eraser.
Refer to the maintenance instructions on the separate sheet when
it becomes dirty. (Usually, the board becomes sufficiently clean by
wiping it with wet dust cloth and then with dry cloth.)Surface roughness

The smooth surface is created by blending the glaze and special
glaze coating techniques. This results in higher performance in bothease of writing and erasability.

Resistance to rust(corrosion)

River Enamel has a thick coat and is free of rust, thanks to the dual
layer structure of the ground coat and cover coat.

Incombustibility

Incombustibility accreditation number: NM-2744

4. Comparison Table of Chalkboard Specifications and Performance
JIS S 6007

Item

1

JFE
(River Enamel)Company A(Steel porcelain
enamel)Company B(Aluminum coated steel
porcelain enamel)Company C(Prepanted steel
sheet)

Company D(Prepanted steel
sheet)

Standard No.

Standard value

R4301

－

ISO 2178

100μm

120μm

50μm

25μm

20μm

R4301

－

ISO 2178

30μm

50μm

0μm

8μm

8μm

Coat thickness(surface layer)

Coat thickness
2 (back surface layer)

G 3133 (steel porcelain enamel

3 Steel thickness

Reference standard andothersproduct)t ≧ 0.3mm

G 3314 (aluminum coated steel

0.3 〜 0.48mm

porcelain enamel product)

Color difference

4 from standard ( △ E)

K 5600-4-6－

ISO7724-3△ E ≦ 1.5

△ E ≦ 1.5－－－

5 Gloss level (Gs 75)

Z 8741≦ 18%

ISO 2813 ISO 7668

16％

19％

19％

5%

11%

adhesiveness6 Chalk
and contrast－－

PhotographPhotographPhotographPhotographPhotograph

7 Mohs hardness－－

EN 101

3.5

3.5

3.5

2.5

2.5

K5600-5-9－

Decrease of mass during
a wear resistance test
(Wear ring CS-17/ 1 kg)(1,000 revolutions)

R 4301－－－Rz ≦ 19μm

8 Wear resistance（Taper type wear resistance test）

9 Impact resistance10（Pistol type impact resistance test）

Solvent resistance test:
Alcohol, acetone,
toluene, xylene, andpetroleum benzine

11 Surface roughness

B 0601

7.2mg

6.7mg

8.0mg

（There were parts where thebase material was also worn.）

37.2mg

＞ 90N

＞ 90N

＞ 90N

＞ 90N

＞ 90N

Dip 20℃、300hr

No change

No change

No change

No change

No change

ISO 4287

13.4μm

14.2μm13.2μm

14.7μm

11.1μmExcellent

Excellent

Excellent

Excellent

Excellent

12 Chalk adhesion

S 6007

There must be no unevenness in the lines when the
chalkboard is viewed from a distance of one meter. Thelines must look clear when the chalkboard is viewed from a
distance of eight meters.

13 Chalk erasability

S 6007

There must be no remaining chalk traces or unevenness inerased areas when the chalkboard is viewed from a distanceof one meter.

14 Enamel adhesion

K 5600-5-2

－

R4301

There must not be
any rust.

（Cupping test）

15 Corrosion resistance（Sodium chloride test）

40.1mgIndentation depth: 3 mmExcellent

Excellent

Excellent

Excellent

Excellent

No cracking/peeling
was observed.

Both cracking andpeeling were observed.

No cracking/peeling
was observed.

No cracking/peeling
was observed.

No cracking/peeling
was observed.

No rustNo rustNo rustNo rustNo rustNote: Values with no indicated range are typical values, not guaranteed values.
Note: Values are from tests we conducted on our own.

◆ Chalk adhesiveness and contrast《River Enamel from JFE》

《Steel porcelain enamel
from Company A 》《Aluminum coated steel porcelain
enamel from Company B》《Prepanted steel sheet
from Company C》《Prepanted steel sheet
from Company D》

The JFE River Enamel Chalkboard has an extremely fine-textured enamel surface, making it easy to write and erase text. The text
written on the chalkboard is also very easy to see. The surface is very hard and boasts superior durability.

◆ Features of River Enamel Chalkboard
Ease of writing/visibility

The chalkboard has a smooth, fine-textured surface, making it easy
to write smoothly. It also ensures greater visibility because written
letters do not appear faint.

Chalkadhesiveness andcontrast

The surface is smooth and fine-textured due to the glaze blending
and special glaze coating techniques. This results in superior chalkadhesiveness. It also ensures that written letters never appear faint,
and provides for sharp contrast.

Erasability

The smooth, fine-textured surface allows for written letters to beerased easily with a dedicated chalk eraser.
(Be sure to keep the chalk eraser clean.)Durability

The hard coating film of the enamel, which is formed throughvitrification of the glaze at high temperatures, is highly resistant towear, impact, and scratches.

Easy to clean

The chalkboard can be sufficiently cleaned with a dedicated eraser.
Refer to the maintenance instructions on the separate sheet when it
becomes dirty. (Be sure to keep the chalk eraser clean.)

Surface roughness

The smooth, fine-textured surface is created by blending theglaze and special glaze coating techniques. This results in higher
performance in both ease of writing and erasability.

Resistance to rust(corrosion)

River Enamel has a thick coat and is free of rust, thanks to the dual
layer structure of the ground coat and cover coat.

Incombustibility

Incombustibility accreditation number: NM-2744❸

5. Markerboard maintenanceMarkerboard
A markerboard may become badly stained or the erasability may deteriorate, depending on the use
environment. The possible causes of stains are listed below.
The following section also describes what to do when the markerboard is badly stained or when theerasability has deteriorated.

Causes of noticeable stains① The use of a badly stained eraser will also leave bad stains on the markerboard surface.
② If you erase a letter or word written in marker ink immediately after you write it, the marker ink will
spread over the board because it has not yet dried.
③ If you use a neutral detergent or a dirty dust cloth to clean the surface of the board, the detergent or
water stain on the surface may absorb the dirt from the eraser, making the markerboard dirty.
④ Air discharged from an air conditioner, tar, dirt left by hands, or finger marks may badly stain the board
surface.

Cleaning a badly stained markerboard① Wipe the board surface with a clean, wet dust cloth, and then wipe it with a dry dust cloth to remove all
the residual water.
② If the stain remains after performing the previous step, use a commercially available ethyl alcohol (99.9%)
to clean the board.
Do not use a dirty dust cloth or neutral detergent. Doing so will make the board surface susceptible tostains.
③ Be sure to use a clean eraser. If the eraser is extremely dirty, wash it with water, and then let it dry
thoroughly before using it.
④ A thicker-piled eraser works better.

Causes of deterioration in eraser performance① Letters written with old markers (with faint parts or faded colors) may be hard to erase, even during
normal use, because of an imbalance in the ink components.
② Letters that are left unerased for a long time and those which have been exposed to sunlight or air froman air conditioner may be hard to erase.
③ Letters are hard to erase with an old eraser (with worn or torn fabric) or one with a lot of marker dust onit.
④ Letters written with a marker are extremely difficult to erase if you clean the board surface witha chemical such as acid and alkali or a neutral detergent.

What to do when letters written with markers are hard to erase① Replace the marker with a new one when the letters written are faint or their colors appear faded.
② Replace the eraser with a new one when the fabric is worn or torn. When an eraser is extremely dirty,
clean it by washing it with water, and then let it dry thoroughly before using it.
③ Do not clean the board surface with a chemical such as acid and alkali or a neutral detergent.

Ordinary markerboard maintenance
Wipe the markerboard with a clean, wet dust cloth, and then wipe it with a clean dry cloth.

❹6. Chalkboard maintenance
Chalkboard
Just as with a markerboard, a chalkboard may become badly stained or the erasability may deteriorate,depending on the use environment. The possible causes of stains are listed below.
The following section also describes what to do when the chalkboard is badly stained or when the erasability
has deteriorated.

Causes of noticeable stains and deterioration in erasability① A chalkboard that has been used for a long time may become extremely dirty due to the chalk powder
deposited on the surface or dirt left by hands.
② Cleaning the chalkboard surface with a dirty cloth or neutral detergent may cause stains to remain.
③ The use of a chalk eraser with a large amount of chalk powder on it will make the board surface
extremely dirty.
④ The use of an old chalk eraser with worn or torn fabric will make the board surface extremely dirty.
⑤ Letters written with chalk will be extremely difficult to erase if the board surface is cleaned witha chemical such as acid and alkali.

What to do when the chalkboard is extremely dirty and when the letters are hard to erase① Remove the chalk powder from the eraser with an electric chalk eraser cleaner before each use.
② We recommend replace chalk erasers with new erasers when they become old and worn down, or when
the fabric begins to tear.
③ When a chalkboard has been used for a long time and has become dirty, wipe it with a clean, wet dust
cloth, and then with a clean dry cloth.
④ Do not clean the board surface with a chemical such as acid and alkali.

Ordinary chalkboard maintenance
Clean the board surface with a chalk eraser. Remove chalk powder from the eraser before using it.

❺Technical Data

River Enamel (Dual Coat Enamel)

http://www.jfe-kenzai.co.jp/
Head oﬃce:

11F, Shinagawa Season Terrace, 1-2-70, Konan, Minato-ku Tokyo 〒108-0075, Japan

River Enamel Sales Department：
11F, Shinagawa Season Terrace, 1-2-70, Konan, Minato-ku Tokyo 〒108-0075, Japan
Phone: +81-3-5715-7580 FAX: +81-3-5460-3231

18.07⑷-2POD-SN