Failure of boot fitting from cracking and stress corrosio

Schoen, F. G.

English

NASA Technical Reports Server

. . * .  
s 
? 
SPACE DIVISION LAUNCH SYSTEMS BRANCH 
https://ntrs.nasa.gov/search.jsp?R=19680017188 2020-03-12T10:48:07+00:00Z
THE 
DOCUMENT NO. T5-6539- 
VOLUME - OF - 
TITLE 
CONTRACT NO. US8 - 5608 MODEL NO. 
,/‘ 
ISSUE NO. ISSUED TO 
3 - I L - 438 PREPAREDBY 
W. W. Davis 
APPROVED BY 
APPROVEDBY 
APPROVEDBY 
REV. SYM.,-, 
J-401-10-3 REV. 1/64 
Boeing 
E. L. Clark 
R. C. Deviney 
H. B. Farner 
R. A. Morehouse 
P. E. Oster 
F. G. Schoen 
E. D. Tuseth 
HU!’Z!W@ 
NASA 
F. MeDaniel 
F . Uptgrafft 
-
NO. TS-6539- 104 
ii PAGE 
DISTRIBUTION 
5- 7996 LS-92 
5- 7321 LT- 7 1 
5-7996 LS-92 
5-7351 LT-46 
5-7354 LT-49 
fit7996 LS-81 
5-7350 LT-26 
RY.?&VE-VNR 
R-P&VE-ME 
Scientific and Techn-cal Information Facili-y 
Marshall Space Flight Center 
Huntsville, Alabama (Attn: MS-1P) 
Scientific and Technical Information Facility 
P. 0. Box 33 
College Park, Maryland 20740 
Army Miasile Comnand 
Redstone Arsenal, Alabama 35812 
B. W. Barnett AMSMI-RBP 
REV. SYM. - 
1 4 O w 6 2 I  ORIO. 4 l I 8  
- 
REV. 
SYM. - 
CHANGERECORD 
REVISED I ADDED DELETED REVISED 
REV. SYM.,-, 
5-406-35-10 ORIO. 1 '64  
REV. 
SYM. - DESCRIPTION 
RE VIS IONS 
DATE 
REV. SYM.- 
S-4W-38-11 ORIO. 1/64 
APPROVED 
ABSTRACT 
Servoactuator boot f i t t i n g s ,  PIN 60B21146 -1 and -2, fa i led  by cracking 
on the S-IC-502 vehicle e t  KSC. Subsequent analysis revealed tha t  the 
par t s  had not been shimued on assembly and resu l tan t  high in s t a l l a t ion  
s t r e s ses  induced s t r e s s  corrosion cracking i n  the sa l ine  atmosphere a t  
the Space Center, It a lso  developed t h a t  an E.O. against  the assembly 
drawing required shimming an a l l  vehicles except the 502. 
ges t s  that t h i s  t y p e  of f a i l u r e  would be peculiar t o  t h i s  s tage.  
un i t s ,  same p a r t  numbers as  above, were procured and ins ta l led  with 
proper shimming t o  eldslinate in s t a l l a t ion  s t resses  and a l so  reduce the 
poss ib i l i ty  of stress corrosion. 
This sug- 
New 
KEY WORDS 
Boot F i t t i ngs  
Cracking 
Servoactuator 
S-IC-502 
St ress  Corrosion 
1 .o 
2 .o 
3 .o 
4.0  
5.0 
6 .O 
I*- 
? 
REV. SYM. *-, 
D is t r ib u t ion 
Change Record 
BevL s ions 
Abstract 
Table of Contents 
List of Figures 
Objective 
Background 
Conclusions 
Recommendations 
Re fer e nc es 
Page Number 
ii 
iii 
iv 
V 
vi 
v i i  
1 
1 
1 
1 
2 
2 
Figure Number 
1 .  
2 .  
3 .  
4. 
5 .  
6 .  
7 .  
L i s t  of Figures 
Drawing Number 60B21146 Servo 
Actuator Boot P i t t i g g  
Part Number 6OB21146-1 Crack 
Indications 
Part Number 60B21146-2 Crack 
Indications 
Forging Grain Directions 
Fracture Faces of One Crack 
Cross Section Through Fracture 
Longitudinal Section of Fracture 
Page Number 
3 
4 
5 
9 
1 .o 
of f a i l u r e s  i 
2 .o 
s and another 
3 .O resul ted  from 
a l l o y .  The com- 
n e ~ c ~ s ~  of the stress 
bination of  these sust 
posure caused stress c 
4.0 
5 .o 
Q. SY 
5 .O Procedure and R e s u l t s  (Continued) 
Figure 5 shows the f rac ture  faces of one crack taken from the  
60B21146-1 par t  and i s  again typical  of a l l  o ther  cracks ex- 
amined i n  both -1 and -2 pa r t s .  The faces exhibi t  an 
Figure 6 is a micrograph of a cross sec t ion  taken 
of t h i s  f r ac tu re .  Note the  branching nature of the 
lower photograph an enlargement of the indicated 
top photograph. ure 7 is a micrograph taken of 
a longitudinal sect ion.  Tho the  intergranular  paths of the 
cracking found i n  t h i s  inves t i on  were not a s  dramatic o r  
c l a s s i c a l  as i n  other cases, s u f f i c i e n t  evidence was provided 
t o  a t t r i b u t e  the f a i lu re s  t o  stress corrosion cracking. 
6 .O Reference 
a .  
b.  
c .  60B21145 
d .  60B21146 
T e s t  Progress R e p o r t ,  T5-6739 Vol. V I I ;  Section 115 
Quality Laboratory T e s t  Report LSR0513 
EV. SYM. 
4 0 ~ b ~ ~ 9  ORIQ. 4/@b 
a 
3 
I - ¶- 
.I ...L 0 “ 4  
$I 
m 
m 
I Y 
1 
50EI ; >;O. - 5-6539-104 
'* . '\, 
i 
REV. SYM. ~ 
S-406-65-20 ORIG. 4/65 

Long Traverse 
Longitudinal 
Keller's Etch 50X 
Figure 4 Forging Grain Directions 
REV. SYM. ---,,. 
S-406-65-20 ORIG. 4/65 
REV. SYM. - 
5-406-61-29 ORIG. 4/65 
Figure 5 Fracture Faces of One Crack 
Keller's Etch 'i 5 OX 
500 X 
Figure 6 Cross Section Through Fracture 
REV. SYM. - 
5-406-6s-29 OR1 G. 4/65 
i 
REV. SYM. - 
S-406-66-29 ORIG. 4/65 


Failure analysis of actuator boot fittings

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server