Nitric acid

These corrosion data are mainly based on results of general corrosion laboratory tests, carried out with pure chemicals and water solutions nearly saturated with air (the corrosion rate can be quite different if the solution is free from oxygen).

All concentrations are given in weight-% and the solvent is water if nothing else is shown. The corrosion data apply to annealed materials with normal microstructure and clean surfaces, throughout.

Nitric acid, HNO₃
Conc. %	0.5	1	1	1	5	5	5	5	5	10	10	10	10	20	20	20
Temp. °C	250	20	50	100 =BP	20	50	100 =BP	150	290	20	50	101 =BP	145	20	50	103 =BP
Grade or type of alloy:
Carbon steel		2	2	2	2	2	2	2	2	2	2	2	2	2	2	2
13 Cr		0	1	2	0	1	2	2	2	0	1	2	2	0	1	2
Alleima® 1802		0	0	0	0	0	0	2	2	0	0	0	2	0	0	0
Alleima® 3R12	0	0	0	0	0	0	0	1	2	0	0	0	2	0	0	0
Alleima® 3R60	0	0	0	0	0	0	0	1	2	0	0	0	2	0	0	0
18Cr13Ni3Mo ¹⁾		0	0	0	0	0	0	1	2	0	0	0	2	0	0	0
17Cr14Ni4Mo ²⁾		0	0	0	0	0	0	1	2	0	0	0	2	0	0	0
Alleima® 2RK65 ('904L')	0	0	0	0	0	0	0	1	2	0	0	0	2	0	0	0
Sanicro® 28		0	0	0	0	0	0			0	0	0		0
254 SMO		0	0	0	0	0	0			0	0	0
654 SMO		0	0	0	0	0	0			0	0	0
SAF™ 2304		0	0	0	0	0	0			0	0	0
SAF™ 2205		0	0	0	0	0	0			0	0	0
SAF™ 2507		0	0	0	0	0	0			0	0	0
Titanium (CP Ti)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

¹⁾ ASTM 317L, e.g. Alleima® 3R64
²⁾ EN 1.4439, e.g. Alleima® 3R68

Nitric acid, HNO₃
Conc. %	20	30	30	30	30	50	50	50	50	50	60	60	60	60	65	65
Temp. °C	120	20	70	106 =BP	120	20	70	90	110	117 =BP	20	60	100	121 =BP	20	60
Grade or type of alloy:
Carbon steel	2	2	2	2	2	2	2	2	2	2	2	2	2	2	2	2
13 Cr	2	0	1	2	2	0	1	1ig	2	2	0	1	2	2	0	1
Alleima® 1802	2	0	0	1	2	0	0	1ig	1ig	2	0	0	1ig	2	0	0
Alleima® 3R12	1	0	0	0	1	0	0	0ig	1ig	1ig	0	0	1ig	1ig	0	0
Alleima® 3R60	1	0	0	0	1	0	0	0ig	1ig	1ig	0	0	1ig	1ig	0	0
18Cr13Ni3Mo ¹⁾	1	0	0	0	1	0	0	0ig	1ig	1ig	0	0	1ig	1ig	0	0
17Cr14Ni4Mo ²⁾	1	0	0	0	1	0	0	0ig	1ig	1ig	0	0	1ig	1ig	0	0
Alleima® 2RK65 ('904L')	1	0	0	0	1	0	0	0ig	0ig	1ig	0	0	0ig	1ig	0	0
Sanicro® 28		0	0	0		0	0	0ND	0ND	0ND					0	0
254 SMO										1ig					0	0
654 SMO
SAF™ 2304										0ig					0	0
SAF™ 2205		0	0	0		0	0	0ND	0ND	0ND					0	0
SAF™ 2507		0	0	0		0	0	0ND	0ND	0ND					0	0
Titanium (CP Ti)	1	0	0	1	1	0	0	1	1	1	0	0	1	0	0	0
SAF™ 2906										0
SAF™ 2707 HD										0
SAF™ 3207 HD

¹⁾ ASTM 317L, e.g. Alleima® 3R64
²⁾ EN 1.4439, e.g. Alleima® 3R68

Nitric acid, HNO₃
Conc. %	65	65	65	65	80	80	80	80	90	90	90	94	97	99	99	99
Temp. °C	70	90	121 =BP	175	20	50	80	106 =BP	20	80	94 =BP	30	25	25	40	84 =BP
Grade or type of alloy:
Carbon steel	2	2	2		2	2	2	2	2	2	2	2	2	2	2	2
13 Cr	1	1ig	2		0	1	2	2	0	2	2	2	2	2	2	2
Alleima® 1802	0	1ig	2		0	0	1ig	2	0	2	2	0	0	1	2	2
Alleima® 3R12	0	1ig	1ig		0	0	1ig	2	0	2	2	0	0	1	2	2
Alleima® 3R60	0	1ig	1ig		0	0	1ig	1ig	0	2	2	0	0	1	2	2
18Cr13Ni3Mo ¹⁾	0	1ig	1ig		0	0	1ig	1ig	0	2	2	0		1	2	2
17Cr14Ni4Mo ²⁾	0	1ig	1ig		0	0	1ig	1ig	0	2	2	0	1	1	2	2
Alleima® 2RK65 ('904L')	0	0ig	1ig		0	0	1ig	1ig	0	1ig	2	0		1	2	2
Sanicro® 28	0	0ig	0ig
254 SMO	0	0ig	1ig
654 SMO			1ig
SAF™ 2304	0	0ig	1ig				1			1
SAF™ 2205	0	0ig	1ig
SAF™ 2507	0	0ND	1ig
Titanium (CP Ti)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1
SAF™ 2906			0
SAF™ 2707 HD			0
SAF™ 3207 HD			0

¹⁾ ASTM 317L, e.g. Alleima® 3R64
²⁾ EN 1.4439, e.g. Alleima® 3R68

Nitric acid, HNO₃
Temp. °C	25	40
Grade or type of alloy:
Carbon steel
13 Cr
Alleima® 1802
Alleima® 3R12	0	1
Alleima® 3R60	1	1
18Cr13Ni3Mo ¹⁾
17Cr14Ni4Mo ²⁾
Alleima® 2RK65 ('904L')
Sanicro® 28
254 SMO
654 SMO
SAF™ 2304
SAF™ 2205
SAF™ 2507
Titanium (CP Ti)	2	2

¹⁾ ASTM 317L, e.g. Alleima® 3R64
²⁾ EN 1.4439, e.g. Alleima® 3R68

Symbol clarification

These corrosion tables use a number of symbols, having the following meanings:

Symbol	Description
0	Corrosion rate less than 0.1 mm/year. The material is corrosion proof.
1	Corrosion rate 0.1—1.0 mm/year. The material is not corrosion proof, but useful in certain cases.
2	Corrosion rate over 1.0 mm/year. Serious corrosion. The material is not usable.
p, P	Risk (severe risk) of pitting and crevice corrosion.
c, C	Risk (Severe risk) of crevice corrosion. Used when there is a risk of localised corrosion only if crevices are present. Under more severe conditions, when there is also a risk of pitting corrosion, the symbols p or P are used instead.
s, S	Risk (Severe risk) of stress corrosion cracking.
ig	Risk of intergranular corrosion.
BP	Boiling solution.
ND	No data. (Used only where there are no actual data to estimate the risk of localised corrosion instead of p or s).

Disclaimer: Laboratory tests are not strictly comparable with actual service conditions. Accordingly, Alleima makes no warranties, express or implied, and accept no liability, compensatory or consequential, for the performance of different materials in individual applications that may be based on the information provided in this publication.