CORROSION JOINTS
IN
A. A.
RESISTANCE ACID
N. N.
AND
Kuzyukov, Kuzyukova,
OF
BRASS
ALKALINE
WELDED
MEDIA
UDC 669.35' 5:620.178.311.868
N. P. Pilyugina, and V. I. Romaniv
We c a r r i e d out investigations of the c o r r o s i o n r e s i s t a n c e of b r a s s e s L63 and LO62-1 and their welded joints in solutions of 50%0 sulfuric, 85% phosphoric, and 30% acetic acids at 80~ with aeration and without aeration of the m e d i u m , in an 8% solution of sodium hydroxide at 95~ with aeration of the m e d i u m , and in a 170 solution of sodium chloride with 0.3%0 sulfuric acid at 50~ without aeration. Six identical specimens w e r e each tested for 100-500 h. Specimens with thicknesses of 3 and 6 m m w e r e m a d e by manual a r g o n - a r c welding with Br. KMts3-1, MNZhKT-5, and Br. O T s - 4 - 3 welding w i r e s with d i a m e t e r s of 2-3 m m and e l e c trodes with d i a m e t e r s of 3 and 4 m m , r e s p e c t i v e l y , in the following r e g i m e s : currents of 160-200 and 250280 A, r e s p e c t i v e l y , a r c voltages of 14-16 and 15-16 V, r e s p e c t i v e l y , and argon flow rates of 6-8 and 8-10 liters/rain, r e s p e c t i v e l y . The c o r r o s i o n rate was evaluated a c c o r d i n g to the weight loss. Since specific types of c o r r o s i o n are c h a r a c t e r i s t i c of b r a s s e s and their welded joints, the nature and depth of c o r r o s i o n of the base metal and the metal of the h e a t - a f f e c t e d zone and weld were also investigated metallographically. The r e s u l t s of the tests indicate that the specimens of the b r a s s e s and their welded joints made f e r e n t welding m a t e r i a l s had s a t i s f a c t o r y c o r r o s i o n r e s i s t a n c e in the investigated acid media without and in alkaline media with aeration (four and five points on a 10-point scale of c o r r o s i o n resistance). tion of the m e d i u m , especially sulfuric and acetic acids, exerted a significant effect on the c o r r o s i o n During aeration of these media, the c o r r o s i o n rate i n c r e a s e d by an o r d e r .
with difaeration Aerarate.
As s h o w n by the results of the m e t a l l o g r a p h i c investigations given in Table 1, the tested b r a s s e s and their welded joints underwent component-selective c o r r o s i o n and zinc removal in acid media. The m o s t intense zinc r e m o v a l f r o m the metal was o b s e r v e d in the heat-affected zone. The built-up metal underwent s t r u c t u r e - s e l e c t i v e c o r r o s i o n in the/~-phase. In a 1% sodium chloride solution with 0.370 sulfuric acid, the tested s p e c i m e n s underwent general c o r r o s i o n , and zinc r e m o v a l was p r a c t i c a l l y not observed.
TABLE
I:,2 metal
1 Corrosion depth, mm, of the Medium
50% suffudc acid solution
L63
85% phosphoric acid solution 30% acetic acid solution
8% sodium hydroxide solution 50% sulfuricacid solution 85% phosphoric acid solution
L062-1 30% acetic acid solution 8% sodium hydroxide solution
weld metal
Depth of zinc removal, m___mfrom the]
heat-affeeted zone base metal metal
0,02--0,03 0,05--0,07 0,01--0,02 0,05--0,10 -0,02--0,04
-0,03--0,05 0,05--0,10 0,01--0,02 0,04--0,06
0,03--0,06
0,03--0,08
0,03--0,05
0,02--0,04
0,05--0,07 O,05--OflO 0,02--0,03 0,02--0,03 0,01 0,0'2--0,04
0,01--0,08 0,06--0,10 0,03--0,05 0,02--0,03
0,03--0,05 0.03--0,05 0,05--0,06 0,02--0,03 0,02--0,04 0,04--0,06
o,o2-o,os
o,o2-o,o~
0,02~0,04
0,01 0,06
-0,08--0,05 0,01--0,02 -
-
0,04--0,08
weld metal
heat-affected zone base metal
0,12--0,1'4
0,12--0,21
0,12~0,16
-O,IS--O,18 0,05--0,07 --
0,08--0,10 O,I0--0,18 0,08--0,10 0,08--0,14
0,04--0,07 0,08--0, I0 0,04--0,06 0,04--0,08
0,08--0,21
0,08--0,10 0,08--0,10 0,10--0,12 0,08 0,~ 0,03--0,04
0,04--0,08 0,04--0,06 0,10--0,12 0,08--0,10 0,04--0,08 0,08--0,18
0,04--0,06
0,08
I
o,o2-o,~
1. The st~cir~ens were weld~ed with ~, K_Mp.3-1 wir~, 2..~ae,test tipaefor nttmezator gives-me aata of tests wxmout aeration ozme memum; me oenormnator,
specir~ens ~a$ 500 t~. 3. The wm-aeration • doz me memurn. e
T r a n s l a t e d f r o m Khimicheskoe i Neftyanoe Mashinostroenie, No. 8, pp. 24-25, August, 1979.
0 0 0 9 - 2 3 5 5 / 7 9 / 0 7 0 8 - 0 6 1 5 $ 07.50
9 1980 P l e n u m P u b l i s h i n g C o r p o r a t i o n
615
