X-ray indications in gaseous oxygen line longitudinal weld and effect on properties of tubin

Sands, R. R.

English

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A E R O - S P  A C E  DlVlSl O N  Y 
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'T5-6539-78 
DOCUMENT NO. 
VOLUME -OF,-, 
,+NVESTIGATION OF X-RAY INDICATIONS IN Gox LINE WELD 6 TlTL 
MODEL NO. SAT v/s-Ic CONTRACT NO. 
-5 
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ISSUE NO. M 22 ISSUED. TO 
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NO. T5- 6539- 78 
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BOEING+ 
E. L. Clark 
R. Cooper 
J. Gregerson 
J . Johnson 
W. R. Lanfear 
R. Meek 
R. Nansen 
R. R. Sands (3) 
C. E. Thornburg 
G. Verkaik 
R. L. Weddell 
5- 7996 
5-3355 
5-3272 
2- 5545 
5-3250 
5-3350 
5- 7355 
5- 7996 
5-3490 
5-7355 
5- 3490 
NASA 
F. McDaniel 
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F. Uptagrafft R- P&VE-ME 
Scientific and Technical Information Facility 
Marshall Space Flight Center 
Huntsville, Alabama (Attn: MS-1P) 
Scientific and Technical Information Facility 
P. 0. Box 33 
College Park, Maryland 20740 
LS-92 
LE- 20 
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88- 03 
LN-41 
LC- 20 
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mU#.ZNm 
ABSTRACT 
NO. T5- 6539- 78 
Numerous defect indications were revealed in the 4 1/2" GOX 
x-ray. Bend tests proved that tubes containing these indications were 
brittle in the weld areas. 
inspection point to incipient meltfng of the weld fusion line as the 
cause of the indications. Proper heat treatment controls eliminated the 
problem. 
tube by 
Metallurgical tests and vendor plant 
KEY WORDS 
X-ray Weld indications 
Welding 
Inconel 718 
Incipient Melting 
718 Heating 
TABLE OF CONTENTS 
IIHHZtNm 
Distribution 
Change Record 
Rev i s ion 
Abstract 
Table of Contents 
List of Figures 
NO. T5- 6539- 78 
1.0 OBJECT 
2.0 BACKGROUND 
3.0 CONCLUSIONS 
4.0 RECOMMENDATIONS 
5.0 PROCEDURE AND RESULTS 
6.0 DISCUSSION 
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LIST OF FIGURES 
mmE/M@ REV. SYM. - 
PAGE 
3 
SUBJECT -
X-Ray P o s i t i v e  P r i n t  of Defec ts  
Defect  Area 3 
Higher Magni f ica t ion  of F igu re  # 2 4 
Typica l  Tubing Cross Sec t ion  i n  X-Ray 
NO. T5-6539-78 
PAGE 
v i  
Tes t  Set-Up 5 
T e s t  Rings Before and A f t e r  T e s t i n g  6 
7 X-Ray Posit irve of Reproduced Defec ts  
F r a c t u r e  Face of Ring Cracked i n  Tes t ing  7 
Cross Sec t ion  of Crack i n  Defect  Area 8 
1 .o OBJECT 
To determine the nature of x-ray indications in the GOX line 
longitudinal weld and their effect on the properties of the 
tubing. 
2 .o BACKGROUND 
3 .O 
The 4-1/2" welded Inconel 718 tubing used in the GOX duct system 
of S-IC when x-rayed in the final heat treated condition, 
revealed numerous indications along the edges of the longitudina 
weld, (Figure #I.) 
and solution heat treatment did not show these indications. These 
tubes have been produced in two production lots; (1) those, 
solution treated at the tube vendor's plant at 1750° * 25OF and 
subsequently at Lindberg in Los Angeles at 1950°F (f 25O), have 
not shown these indications when x-rayed at the Michoud assembly 
facility, and (2 those, solution treated at the tube vendor's 
plant at 1950O F 4 25OF only, showed these indications when x-rayed 
at Michoud assembly facility. 
system it was decided to determine the nature and source of these 
indications and their effect on the reliability tubing. 
These welds when x-rayed prior to planishing 
Due to the criticality of the 
CONCLUSIONS 
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1) X-ray indications were due to incipient melting in the weld 
fusion lines. 
2) Incipient melting was caused by heating tubes in excess of 
1950°F f 25. 
3 )  Incipient melting creates a brittle condition in the weld 
fusion line. 
4.0 RECOMMENDATIONS 
1) Heat treatment of welded Inconel # 718 tubes should be 
conducted in a certified furnace at a temperature not exceeding 
1950° * 250. 
5 .O PROCEDURES AND RESULTS 
A section of tubing containing defects was delivered to the MGCP 
Lab accompanied by x-rays of the longitudinal seam welds. "Worst 
areas" were removed and they in turn were x-rayed to accurately 
locate the defects. (Figure nl). Sections were cut exposing the 
cross sections of several defects and these were mounted and given 
a metallographic examination. This examination revealed an 
anomaly in the structure of the weld in the area of the weld 
fusion.(Fig. # 2, 33. These anamolies were located in the first 
1/4 to 1/3 of the distance from the inside of the tubing. 
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T5-6539- 78 NO. 
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6 .  
PROCEDURES AND RESULTS (Continued) 
To determine the effect of these anomalies on the integrity of 
the tube, a part was obtained that showed one end free of indica- 
tion and one end heavy with indications. 
sections were removed from each end. (Each set of six representing 
defect containing and defect free material respectively). A bend 
test (across the weld) was performed on these rings. (See Figure 
#4 for test setup) the ring was set in a jig in a standard test 
machine and a penetrator with a 1/4" diameter head was placed 
against the weld center and the ring was compressed. The defect 
free rings were bent until the inside surfaces of the rings touched 
No failure occurred. The rings containing defects were compressed 
1/2" maximum when definite failure ocurred, (See Figure #5). 
Six 1/2" wide ring 
Boeing personnel (Project, M&P, Materiel, Manufacturing Development 
and Quality Control) then visited the tube vendor to observe tube 
production. X-rays were taken after welding, planishing, heat 
treating and sizing. The defects were first reproduced in the 
ends of the tubes that got excessively overheated during induction 
heating, (See Figure V6).  This pointed to incipient melting as 
the cause of the defect. To confirm this condition, tubes were 
processed by the vendor at 1750°F, 1950°F, 2225OF and 24000F. 
X-rays of these test tubes showed clear at 1750°F, minor indication 
at 1950°F (furnace used was improperly controlled and was probaby not 
1950°F in defect areas). 
and extremely heavy defects at 2225OF and tube melting at 23500F and 
2400'F. In order to confirm improper furnace control at 1950OF four 
tubes were sent to Los Angeles to be heat treated in a properly 
certified furnace at 1950OF. X-rays of  these welds showed no 
defects in the four tubes. 
Continuous defects at 2100°F, continuous 
0 DISCUS S ION 
The furnace used to heat treat the tubes at the vendor facility 
is a Tocco induction type with homemade copper coils. The 
temperature control used was an optical pyrometer. The vendor was' 
not sure whether the pyrometer was calibrated once every six 
months, or once per year. The furnace operator measured the 
temperature on a single spot on the tube through the coils. At 
1950°F the pyrometer dot was extremely hard to discern, let 
alone get an accurate color balance. The tubing, having a sliglt 
bow, varied in position relative to the coil. One tube observed 
was run close to the bottom of the coil and this particular area 
was in excess of 1950'F. 
followed by another tube, were obviously overheated. The furnace 
controls were continuously mnu&lly adjusted while the Boeing team 
was observing this operation. 
The ends of the tube if not closely 
REV. SYM. - 
S--406-03-21 ORIO. 4/08 
F i g  e *  # 1 X-Ray Positive Print of Showing 
Defect Indications 
Fig. # 2 Typical Tubing Cross Section in X-Ray 
Defect Area 
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1 oox 2oox 
Fig. # 3 Higher Magnification of F i g u r e  # 2 Area 
5 OX 
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Fig .  # 4 Test Set For Bending of Tube Ring Specimens 
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Fig. # 5 #l Untested Ring 
8 2  
# 3  Typical Defect Free Ring 
Typical Defect Containing Ring with Crack Detail 
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' F i g .  # 6 X - r a y  P o s i t i v e  P r i n t  Showing D e f e c t s  
i n  H o t  Ends of  Tubing  During Product  
Reproduced 
0 I1 
F i g .  # 7 F r a c t u r e  Face  o f  F a i l e d  Ring 6 X  
nr\ t  
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Fig. # 8 Metallographical Crossection of Failed 
Ring - Note Crack P r o p a g a t e s  Through 
Defect Area 
T5-6539-78 
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Investigation of X-ray indications in GOX LINE weld

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