Classification and Designation of Welding Filler Materials
Printable Version
Abstract:
Important Euronorm (EN) standards
for welding filler metals are:
[] EN 12072 standard that covers classification of wire
electrodes, wires and rods for gas shielded metal arc welding, gas tungsten arc
welding, plasma arc welding and submerged arc welding of stainless and heat resisting
steels.
[]
EN 758 standard, which specifies classification of tubular cored electrodes, for
metal arc welding, with or without a gas shield.
[]
EN 499 standard, which covers electrodes and deposited metal in the as-welded
condition for manual metal arc welding.
Standard
EN 12072
The
standard EN12072 specifies requirements for classification of wire electrodes,
wires and rods for gas shielded metal arc welding, gas tungsten arc welding, plasma
arc welding and submerged arc welding of stainless and heat resisting steels.
The classification of the wire electrodes, wires and rods is based on their chemical
composition.
For
stainless steel welding consumables there is no unique relationship between the
product form (wire electrode, wire or rod) and the welding process used (gas shielded
metal arc welding, gas tungsten arc welding, plasma arc welding or submerged arc
welding). For this reason the wire electrodes, wires or rods can be classified
on the basis of any of the above product forms and can be used as appropriate,
for more than on of the above processes.
A
wire electrode, wire or rod is classified in accordance with its chemical composition.
The classification is divided into two parts, as follows:
The
first part gives a symbol indicating the product/process to be identified, as
follows:
G = Gas shielded metal arc welding.
(MIG America where it was invented MAG Europe)
W = Gas tungsten arc welding.
( TIG or GTAW developed in USA )
P = Plasma arc welding.
S = Submerged
arc welding.
The
second part gives a symbol indicating the chemical composition of the wire electrode,
wire or rod. This grade has the symbol 25 20 Mn and is a heat resisting type.
The influence of the shielding gas or flux on the chemical composition of
the all-weld metal is considered. Differences between the chemical composition
of the all-weld metal and the wire electrode, wire or rod can occur.
Proof and tensile strength of the weld metal made by this grade is expected to
conform with the minimum requirements contained in the mechanical properties table.
Elongation and impact properties of the weld metal can deviate from the minimum
values specified for the corresponding parent metal as a result of variations
in the microstructure.
Standard EN 758
This specification specifies the requirements for classification
of tubular cored electrodes (Flux cored again invented in Americain) the as-welded
condition for metal arc welding, with or without a gas shield, of non alloy and
fine grain steels with a minimum yield strength of up to 500 N/mm. One tubular
cored electrode can be tested and classified with different gases.
The
designation contains 6 compulsory and 2 optional parts.
Compulsory
Section:
The
first part, T, is a symbol denoting that it is a tubular cored electrode used
in the metal arc welding process.
The
second part, 50, is a symbol denoting the yield strength, tensile strength and
elongation of the all-weld metal in the as-welded condition.
The
third part is a symbol denoting the temperature at which minimum average impact
energy of 47 J of all-weld metal can be achieved, as follows:
Z = No requirement
A = +20°C
0 = 0°C
2 = -20°C
3 = -30°C
4 = -40°C
5 = -50°C
6 = -60°C
The
fourth part, Z, is a symbol indicating the chemical composition of all-weld metal.
The symbol Z denotes any agreed composition other than those grades already contained
in the specification.
The
fifth part is a symbol indicating the type of tubular cored electrode relative
to its core composition and slag characteristics, as follows:
R = Rutile,
slow freezing slag, single and multiple pass types of weld, requiring a shielding
gas.
P = Rutile, fast freezing slag, single and multiple pass types of weld,
requiring a shielding gas.
B = Basic, single and multiple pass types of weld,
requiring a shielding gas.
M = Metal powder, single and multiple pass types
of weld, requiring a shielding gas.
V = Rutile or basic/fluoride, single pass
type of weld, not requiring a shielding gas.
W = Basic/fluoride, slow freezing
slag, single and multiple pass types of weld, not requiring a shielding gas.
Y = Basic/fluoride, fast freezing slag, single and multiple pass types of weld,
not requiring a shielding gas.
Z = Other types.
The
sixth part is a symbol indicating the type of shielding gas as follows:
M
= mixed gases: (EN 439 - M2 but without helium).
C
= EN 439 - C1, carbon dioxide
N = This symbol
shall be used for tubular cored electrodes without a gas shield.
(From
Ed. The self shielded rubbish was also invented and promted in America thanks
to Lincoln Electric)
Optional
Section (the next two parts have not been included in the designation for this
grade):
The
seventh part gives a symbol for the welding position as follows:
1 = all positions;
2 = all positions, except vertical down;
3 = flat butt weld, flat fillet weld,
horizontal-vertical fillet weld;
4 = flat butt weld, flat fillet weld;
5 = vertical down and positions according to symbol 3.
The
eighth part gives a symbol indicating the hydrogen content of deposited metal
as follows:
Symbol Hydrogen content ml/100 g deposited metal
H5 5 maximum
H10 10 maximum
H15 15 maximum
Standard EN 499
This specification specifies the requirements for classification
of covered electrodes and deposited metal in the as-welded condition for manual
metal arc welding of non alloy and fine grain steels with a minimum yield strength
of up to 500 N/mm in the welded condition.
The designation contains 5 compulsory
and 3 optional parts.
Compulsory
Section: The first part, E, is a symbol denoting that it is a covered electrode
used in the manual metal arc welding process.
The
second part, 38, is a symbol denoting the yield strength, tensile strength and
elongation of the all-weld metal in the as-welded condition.
The
third part is a symbol denoting the temperature at which minimum average impact
energy of 47 J of all-weld metal can be achieved, as follows:
Z = No requirement
A = +20°C
0 = 0°C
2 = -20°C
3 = -30°C
4 = -40°C
5 = -50°C
6 = -60°C
The
fourth part, 1Ni, is a symbol indicating the chemical composition of all-weld
metal.
The
fifth part is a symbol indicating the type of electrode covering as follows:
A = acid covering
C = cellulosic covering
R = rutile covering
RR =
rutile thick covering
RC = rutile-cellulosic covering
RA = rutile-acid
covering
RB = rutile-basic covering
B = basic covering
Optional
Section (the next three parts have not been included in the designation for this
grade):
The
sixth part gives a symbol for the weld metal recovery and type of current as follows:
Symbol % weld metal recovery Type of current
1 less than or equal to 105 a.c.
+ d.c.
2 less than or equal to 105 d.c.
3 over 105 up to and inc.125 a.c.
+ d.c.
4 over 105 up to and inc.125 d.c.
5 over 125 up to and inc.160
a.c. + d.c.
6 over 125 up to and inc.160 d.c.
7 over 160 a.c. + d.c.
8 over 160 d.c.
The
seventh part gives a symbol for welding position as follows:
1 = all positions
2 = all positions, except vertical down
3 = flat butt weld, flat fillet weld,
horizontal vertical fillet weld
4 = flat butt weld, flat fillet weld
5
= vertical down and positions according to symbol 3
The
eighth part gives a symbol indicating the hydrogen content of all-weld metal as
follows:
Symbol Hydrogen content ml/100 g all-weld metal
H5 5 maximum
H10 10 maximum
H15 15 maximum.
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