Manufacturer: Nippon Yakin Kogyo Co., Ltd
Model: NAS355N

NAS355N
High Corrosion Resistant Nickel Alloy

NAS355N is a high corrosion resistant nickel alloy, providing corrosion resistance in high-concentration chloride ion or sulfuric acid environments and in extremely severe corrosive environments where both high-concentration chloride ions and sulfuric acid exist. They significantly reduced the nickel content of this alloy compared to conventional high corrosion resistant nickel alloys, achieving a good balance between cost and corrosion resistance performance. Nippon Yakin supplies this product in plate, sheet, and strip form.

Chemical Composition	23Cr-35Ni-7.5Mo-3Cu-0.2N
Product shape	Coil	Sheet	Plate
Workability	The hot and cold workability of NAS355N is basically the same as that of standard austenitic stainless steels such as Type 304, Type 316.However, you must consider that this material has high strength in both cold and hot working processes.
Weldability	Various welding methods are applicable in the same manner as with the standard austenitic stainless steels, including shielded metal arc welding, TIG welding, and plasma welding.You should use Alloy 276 welding consumable.
Heat Treatment	Solution heat treatment is performed at 1030°C~1180°C using water cooling.
Pickling	They use a mixture of nitric acid and hydrofluoric acid in pickling. However, due to the high corrosion resistance of NAS355N, scale is somewhat difficult to remove in comparison with Type 304. Therefore, you should immerse the material in an alkaline solution before pickling, or, if possible, use shot blasting, which is extremely effective.
Applications	Chemical plants, Flue gas desulfurization plants, Heat exchangers, Environment-related equipment.

Grade/Standard

Nippon Yakin Grade	JIS	ASTM	EN
NAS355N	—	—	—

Chemical Composition

	C	Si	Mn	P	S	Ni	Cr	Mo	Cu	N
Specification (NAS355N)	≦0.030	≦1.00	≦1.00	≦0.020	≦0.005	35.00 – 36.00	22.00 – 24.00	7.00 – 8.00	3.00 – 4.00	0.19 – 0.24

Physical Properties

Density [g/cm³]	8.16
Specific heat [J/kg·K]	431
Electrical resistivity [µΩ·cm]	107.4
Thermal conductivity [W/m·K]	9.99
Average coefficient of thermal expansion [10⁻⁶/°C]	30 – 100°C: 13.7 30 – 200°C: 14.2 30 – 300°C: 14.5 30 – 400°C: 14.9
Young’s modulus [MPa]	18.7 × 10⁴
Magnetism	None
Melting range [°C]	1320 – 1366

Mechanical Properties at Room Temperature

Specification	0.2% proof stress [N/mm²]	Tensile strength [N/mm²]	Elongation [%]	Hardness [HV]	Hardness [HBW]	Hardness [HRBW]
Specification (NAS355N)	≥295	≥640	≥35	≥230	≥217	≤96
Example: Cold-rolled sheet 2mm	422	807	49	196	—	91

Pitting Corrosion Resistance

Alloy	ASTM G48 Method A		ASTM G48 Method C
	22°C	50°C	Critical pitting corrosion temperature (CPT) [°C]
NAS335X	○	×	30
NAS64	○	○	55
NAS185N	○	○	70
NAS254N	○	○	80
NAS354N	○	○	103
NAS355N	○	○	100

ASTM G48 Method A (○: No pitting corrosion, ×: Pitting corrosion)
Test solution: 6%FeCl₃
Test temperature: 22°C, 50°C (Recommended temperature in this test)
Test time: 72h

Crevice Corrosion Resistance

Alloy	Critical crevice corrosion temperature (CCT) [°C]
NAS335X	<0
NAS64	30
NAS185N	40
NAS254N	45
NAS354N	50
NAS355N	55

 Test conditions: ASTM G48 Method D
Test solution: 6%FeCl₃ + 1%HCl
Test time: 72h

Stress Corrosion Cracking Resistance

Alloy	45% (155°C)	42% (143°C)	40% (138°C)	38% (134°C)	35% (126°C)	30% (115°C)	25% (110°C)	20% (108°C)
NAS335X	×	×	×	×	○	○	○	○
NAS64	×	×	×	×	○	○	○	○
NAS185N	×	×	×	○	○	○	○	○
NAS254N	×	×	○	○	○	○	○
NAS354N	×	×	×	○	○	○	○	○
NAS355N	×	○	○	○	○	○	○	○

Test conditions: Immersion in boiling MgCl₂ solution
Test time: 300h
They use a U-bend test specimen.
○: No stress corrosion cracking      ×: Stress corrosion cracking

Acid Resistance

Corrosion rate in sulfuric acid at 80°C (mm/y)

Alloy	5%	10%	20%	40%	60%	80%
NAS335X	0.01	0.02	0.31	0.12	0.60	2.15
NAS64	<0.01	0.02	1.07	191.9	1054	60.72
NAS185N	0.04	1.32	2.89	3.20	4.78	—
NAS254N	0.05	1.02	2.11	2.16	7.76	—
NAS354N	0.01	0.03	0.23	0.06	3.02	4.99
NAS355N	<0.01	<0.01	0.31	—	1.12	—

Test time: 24h

Corrosion rate in hydrochloric acid at 80°C (mm/y)

Alloy	0.1%	1%	2%	3%
NAS64	0.01	0.12	12.94	30.51
NAS185N	0.01	0.02	4.20	7.21
NAS254N	0.01	0.02	0.01	9.14
NAS354N	<0.01	0.03	0.02	7.35
NAS355N	—	<0.01	—	3.65

Test time: 24h

Alloy	JIS	UNS No.	Chemical composition
NAS335X	NCF020	N08020	20Cr-33Ni-2.5Mo-3Cu-0.4Nb
NAS64	SUS329J4L	S32506	25Cr-6.5Ni-3.3Mo-0.17N
NAS185N	SUS312L	S31254	20Cr-18Ni-6Mo-0.8Cu-0.2N
NAS354N	NCF354	N08354	23Cr-35Ni-7.5Mo-0.2N
NAS355N	—	—	23Cr-35Ni-5Mo-3Cu-0.2N

Workability

The hot and cold workability of NAS355N is basically the same as that of standard austenitic stainless steels such as Type 304, Type 316, etc. However, you must consider the high strength of this material in both cold and hot working processes.

Weldability

Various welding methods are applicable in the same manner as with standard austenitic stainless steels, including shielded metal arc welding, TIG welding, and plasma welding. Alloy 276 welding consumable should be used.

Heat Treatment

Solution heat treatment is performed at 1030°C~1180°C using water cooling.

Pickling

A mixture of nitric acid and hydrofluoric acid is used in pickling. However, due to the high corrosion resistance of NAS355N, scale is somewhat difficult to remove in comparison with Type 304. Therefore, the material should be immersed in an alkaline solution before pickling, or if possible, shot blasting is extremely effective.

Applications

Chemical plants, Flue gas desulfurization plants, Heat exchangers, Environment-related equipment.