Page 136 - Quick Guide to Welding and Weld Inspection by S.E. Hughes, Clifford Matthews

A Quick Guide to Welding and Weld Inspection

Welding of Steels
This is the welder qualification standard used within
Europe for fusion welding steels in accordance with
European standards.
. EN ISO 9606: Approval Testing of Welders – Fusion
Welding
This is the welder qualification standard used within
Europe for fusion welding of materials other than steels in
accordance with European standards. EN ISO 9606 is
divided into Parts 2 to 5 covering aluminium, copper,
nickel, titanium, zirconium and their respective alloys.
There is no Part 1 because agreement could not be reached
for EN 287-1 to be replaced by it.
Figure 8.3 shows the suggested welder qualification form
for ASME IX while Fig. 8.4 shows the welder qualification
form for EN 287-1. An interesting point to note is that the
ASME IX qualification lasts indefinitely as long as the welder
is involved in the use of the specified process and the
manufacturer signs his qualification history to this effect
every six months. This is different to the EN287-1 qualifica-
tion, which also requires signing every six months but
normally only lasts for two years (although it can in some
circumstances be extended for a further two years).

Essential variables
Essential variables are those that will affect the mechanical or
metallurgical properties of a weldment. If they are changed
outside their qualified range a new procedure has to be
qualified. The essential variables will be determined by the
code that is being used so you do not need to guess what they
are. It is also worth bearing in mind that what is an essential
variable in one code may very well not be an essential
variable in another code so it is important to read the code
requirements closely.
The essential variables are recorded in the PQR and it is
from these values that the range (or extent) of approval will

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