PRO 7018 Vacuum Pack, SFA/AWS A5.1: E7018 – Prowelder Brand

No Re-Baking, No Holding Ovens, No Quivers.
MMA electrodes in a Vacuum Pack can be used straight
from the package without the need to re-bake them and
store them temporarily in holding ovens and quivers. Upon
opening, fresh and dry electrodes are guaranteed when the
vacuum is maintained. Many of the un-alloyed and low
alloyed electrodes have H4 or H5 classification which
means the requirement of maximum 4.0 or 5.0 ml diffusible
hydrogen/100g weld metal is met. Diffusible hydrogen
classes are not applicable for stainless and high alloyed
electrodes. A low hydrogen class value is beneficial
because it reduces the risk of hydrogen cracking and
permits lower preheating and interpass temperatures to be
applied during welding. This leads to decreased energy
consumption and thereby lower costs for a work site. For
very critical applications and severe environments, a safe
practice is to use heating quivers in order to prevent
moisture pick up at the welding site. Depending on welding
environment, the type of coating and hygroscopic
properties, the application and welding positions, a redrying
operation may be required at a higher frequency to
ensure that all requirements are met. For austenitic
stainless steel and nickel base electrodes, the main danger
is too damp electrodes causing start porosity. If the safe
exposure times are followed this issue can be prevented.
The ferritic and ferritic martensitic grades can suffer from
hydrogen cracking if too damp electrodes are used.