Page 140 - Welder - TT - Bengali

CHART 2 (BS 639 : 1976 equivalent to ISO 2560)
COVERING 4 ELECTRODE
EFFICIENCY
A Acid (iron oxide) 5
AR Acid (rutile)
B Basic % recovery
STRENGTH 2 C Cellulosic to nearest
O Oxidising 10% (> 110)
Electrode Tensile Minimum yield R Rutile (medium coated)
designation strength stress. N/mm 2 RR Rutile (heavy coated) (H) 8
N/mm 2 S Other types Indicates
hydrogen
E43 430.550 330
E51 510.650 360 controlled
(> 15mg/100g)
Example (b) E 51 33 B 160 2 0 (H)

1 2 3 4 5 6 7 8
PROCESS
1

Covered WELDING POSITION 6
MMA 1 All positions
electrode 2 All positions except vertical down
3 Flat and, for fi llet welds, horizontal vertical
4 Flat
5 Flat, vertical down and, fl at fi llet welds, horizontal
vertical
6 Any position or combination of positions not clas-
sifi ed above.

ELONGATION 3

First Minimum Temperature for
Digit elongation, % impact value of

E43 E51 28J, °C CURRENT / VOLTAGE 7
0 Not specifi ed Not specifi ed Code Direct current Alternating current
1 20 18 +20
2 22 18 0 Recommended Minimum open
3 24 20 -20 electrode circuit voltage,
4 24 20 -30 polarity V.
5 24 20 -40
Polarity as
recommended Not suitable
by manu- for use on A C
IMPACT 3 0 facturer

Second Minimum Impact properties 1 + or - 50
Digit elongation, % Impact value, J Tempera- 2 - 50
3 + 50
E43 E51 E43 E51 ture °C
4 + or - 70
0 Not specifi ed Not specifi ed 5 - 70
1 22 22 47 47 +20 6 + 70
2 22 22 47 47 0
3 22 22 47 47 -20 7 + or - 90
4 Not 18 Not 41 -30 8 - 90
6 relevant 18 relevant 47 -50 9 + 90

118 CG&M : ওেয় ার (NSQF - সংেশািধত 2022) - অনুশীলেনর জন স িক ত এ ারসাইজ 1.3.48