. . bend stress | fatigue lite | fatigue life ratio 
Material Environment [MPa] (- of cycles) | FLR 
250 620,8 1 
- 300 195,8 : 1 
350 03 1 
250 188,5 0,465 
citric acid + CI’ 300 91,8 0,468 
350 34,0 | 0,843 
. . 250 1 804,0 2,906 
Sodium | hydroxide 300 5973 3.049 
350 | 44,7 1.108 
250 968,3 
: 300 181,6 1 
| 350 2 176 N ZU 
250 273,5 0,282 
citric acid + CI’ 300 121,3 0,667 
350 3 J2T7 0,897 
sodium hydroxide 250 21878 | 2,259 
oF 300 420,7 2,315 
om so Lo sy L128 
Table 1: Results of the fatigue tests (average values) 
Results and discussion 
Fatigue life of 316L type steel was generally higher than 304. Citric acid caused 50% = 
reduction of fatigue life for type 304 steel and about 40% for 316L at a stress 300 MPa. An alkaline A 
solution considerably increased the fatigue life in both cases. 
350 
340 
>—316L air 
330 © 316L citr acid+Cl 
316L citr hydrox +Cl 
320 
5 304 air 
3 310 *— 304 citr acid+Cli 
5 -4— 304 citr hydrox. +C! 
2 300 
E 290 + 
: 280 
270 
260 
250 L _ - = 
10 000 100 1 000 000 10 000 000 
fatigue life [cycles] 
Fig.2: Limit fatigue life range for 304 and 316L type stainless steels in air and corrodants. 
air 
304 
air 
316L 
310