LESSON VII ©
COPYRIGHT 2000 THE ESAB GROUP, INC. 7.11.0.3
Since these are considered single pass
electrodes, the AWS Specification does not
require an all-weld metal tensile test because single pass welds would be highly
diluted with the
base metal. Instead, the specification only requires a transverse tension
test. This is
a 1/4" thick by 1-1/2" wide bar of a minimum 72,000 psi tensile strength material.
It is welded
with a single pass on each side of a square butt joint. The welds are ground
flush with the
bar, and the specimen is pulled until failure in a tensile testing machine. A
speci- men that
breaks in the base plate is considered satisfactory to meet the 72,000 psi mini-
mum. 7.11.0.4
There are no requirements in AWS A5.20-79
for weld metal chemical composi- tion
for the E70T-2 types, since a single pass weld would be highly diluted from the
base plate. We
publish the carbon, manganese and silicon content of the undiluted welding
metal for information purposes to indicate
the relative amount of the deoxidizers in each electrode.
All of the E70T-2 types require CO2
shielding gas and have no AWS impact requirements.
7.11.1
DUAL
SHIELD 110
- This electrode contains the highest amount of deoxidizers
in the group and is for use on carbon
steel plate, that is heavily scaled or rusted. Bead
shape is flat to convex, and the thin
slag is easily removed. Meets the 72,000 psi minimum
tensile strength requirements for this
classification. A.
Undiluted
Weld Metal
Analysis (For
Information Only)
Carbon 0.07%
Manganese 2.30%
Silicon 1.50%
7.11.2
DUAL
SHIELD SP
- This electrode contains a lesser amount of deoxidizers
than Dual
Shield 110 and is for use on carbon steel plate, that has a considerable
amount of mill scale
and rust. The bead contour is very good, and the slag is almost self-removing.
Meets the AWS minimum tensile strength
of 72,000 psi. A.
Undiluted
Weld Metal
Analysis (For
Information Only)
Carbon 0.06%
Manganese 1.70%
Silicon 1.25%
