NAS 303AM (SUS 303,UNS S30300)
NAS Free-machining Stainless SteelNAS 303AM (SUS 303, UNS S30300) is a high free-machining austenitic stainless steel in whichmachinability is improved by adding sulfur to Type 304. Although sulfur is an alloying element that
reduces corrosion resistance, the corrosion resistance of NAS 303AM is close to that of Type 304 in
mildly corrosion atmosphere. Nippon Yakin supplies this product in plate form.

Steel Grade / StandardNASJIS G 4304

ASTM A895

NAS 303AM

SUS 303

UNS S30300

Chemical Composition[wt %]

CSiMnPSNiCrMoSpecification(SUS 303)

0.15

1.00

2.00

0.20

0.15

8.00~
10.00

17.00~
19.00(1)

Specification(UNS S30300)

0.15

1.00

2.00

0.20

0.15

8.00~
10.00

17.00~
19.00(1) Mo must not exceed 0.60%.

Physical Properties
Density[g/cm3]

7.93

Specific heat

[J/kg • °C]

502

Electrical resistivity[μΩ • cm]

72

Thermal conductivity[W/m • K]

25 °C

16.3

Average coefficient of thermal expansion[10-6/°C]

0~100 °C

17.3

Magnetism
Melting range

None
[°C]

1,405~1,454

NAS 303AM (SUS 303, UNS S30300)

Mechanical Properties
Hardness

0.2% proof stress Tensile strength Elongation[N/mm2 ][N/mm2 ]

[%]

[HB]

[HRB]

[HV]

205

520

35187

90200

Specification (SUS 303)
Specification (UNS S30300)
Example

202

Plate

20mmt

287

610

56183

−

−

Plate

50mm

262

576

61

166

−

−t

This material’s machinability is controlled by dispersed sulfides. NAS 303AM

Machinability

has excellent machinability. NAS 303AM’s excellent machinability enables
remarkable extension of tool life, good surface finish, and other advantages
during machining operations.

1. Drill speed test
<Test conditions>Cutting speed

Alloy(1) Test sheet thickness: 3mm(2) Drill diameter: 1.2mm(3) Drill speed: 890rpm[mm/sec]

NAS 303AM

0.67

Type 304

0.30(4) Weight: 2.0kg(5) Water cooling
As the result of the drill speed test, a much higher cutting
speed can be obtained with NAS 303AM in comparison
with that of Type 304. The shapes of the cutting chips areshown in the photograph. As the chips of NAS 303AM are
extremely small and brittle in comparison with those ofType 304. Load of the drill is also smaller in case of NAS303AM.
Type 304

NAS 303AMShape of cutting chips with NAS 303AM and Type 304

2. Drill cutting resistance testFeed<Test conditions>(1) Test sheet thickness: 10mm

Alloy(2) Drill diameter: 5mm

Max. feed

Max. torque Max. thrust load

[mm/rev][N • m][N]

NAS 303AM

93443

0.35 or moreType 304

185704Drill
fractured at
0.08(3) Drill speed: 1500rpm (constant)(4) Drill Feed : 0.05-0.35mm/rev[At 0.05mm/rev](5) Water soluble cutting fluid was used.
(6) Measurement item: Cutting resistance ofdrill (Torque and thrust load)

NAS 303AM (SUS 303, UNS S30300)

Results of cutting resistance test of NAS 303AM and Type 304
Sheet thickness: 10mm, drill speed: 1,500rpm
500

2000
Drill fractured

NAS 303AMNAS 303AM

Type 304

Type 304

400

Max. thrust load [N]•Max. torque [N cm]

1500

300

200

Drill fractured
1000

500
100

0000.1

0.2

0.3

0.4

00.1

Drill feed [mm/rev]

0.2

0.30.4

Drill feed [mm/rev]

In the results of the drill cutting resistance test, at the same feed rate, the maximum torque and the maximum
thrust load of NAS 303AM are both much lower in comparison with those of Type 304, and drilling is also
possible at a far faster drill feed rate than that at which the drill fractured with Type 304. Thus, the productivity ofNAS 303AM in cutting work is greatly improved.

3. Drill life test
<Test conditions>(1) Test sheet thickness: 10mm(2) Drill diameter: 5mm(3) Drill speed: 1500rpm(4) Drill Feed : 0.07mm/rev(5) Water soluble cutting liquid was used.
(6) Measurement item: Number of holes that

The number of holes that can be drilled with one drill
under these test conditions with Type 304 is 1 hole (thedrill fractured while drilling 2nd hole). In contrast, with NAS
303AM, the maximum number of 625 holes are drilled
without drill fracture.
With NAS 303AM, tool life is greatly improved thanks to
the low load on the cutting tool.

can be drilled with one drill (up to max. 625)

NAS 303AM

Type 304

NAS 303AM (SUS 303, UNS S30300)

Corrosion Resistance
1. Salt Spray Test (SST)
Alloy

Test result

NAS 303AM

No rustType 304

No rust<Test conditions> JIS Z 2371,“Methods of salt spray testing”(1) Spraying with 5% NaCl aqueous solution(2) 35 °C(3) 72hr test
In the salt spray test, rust is not observed with NAS 303AM.

2. Pitting potential measurement<Test conditions> JIS G 0577, “Method of pitting
potential measurement for stainless steels”

Alloy

Pitting potential Vc’100[V vs. SCE]

NAS 303AM

0.19(2) 30 °C

Type 304

0.32(3) Test surface: Polished to 600 grit

Type 430

0.08(1) 3.5% NaCl aqueous solution (method B)(4) Measurement of pitting potential Vc’100.
In the pitting potential measurements, the pitting potential of NAS 303AM shows a lower value than Type 304 but
a higher value than Type 430, indicating that NAS 303AM has comparatively high pitting corrosion resistance.

Bending Formability
Weldability
Heat Treatment

NAS 303AM is not suitable for bending forming and similar processing, as its
ductility is lower than that of Type 304 due to its high sulfur content.
NAS 303AM is not recommended for applications requiring welding.
Because NAS 303AM is an austenitec stainless steel, heat treatment isequivalent to that with the standard austenitic stainless steels. The following
heat treatment conditions are normally used :Solution heat treatment: 1,010-1,150°C ; Water cooling

Pickling

A mixed acid of nitric acid and hydrofluoric acid is used in pickling. Pleaseavoid over-pickling. In some cases surface roughening may occur.

For more information, please contact:
Nippon Yakin Kogyo Co., Ltd.
Material Solutions Sales Department
San-Ei Bldg., 5-8, 1-chome Kyobashi, Chuo-ku,
Tokyo 104-8365 Japan
TEL: +81-3-3273-4649

FAX: +81-3-3273-4642

E-Mail: inquiry@nyk.co.jp
URL: http://www.nyk.co.jp/en/

Note regarding the handling of property data:
The technical information contained in this product guide is representativevalues obtained in property tests and other items used to explain theperformance of the product. With the exception of items specifically mentioned
as provisions of a “Standard,” the contents do not represent guaranteed
upper limit or lower limit values. The respective data given on this technicalinformation are typical examples and may be different in some cases from thedata obtained from the actual product. No responsibility shall, therefore, beassumed for damages arising from using the technical information data. This
information is also subject to change in the future without notice. To obtain themost recent information, please contact Nippon Yakin.

2014.4.17