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D1.8 Seismic Supplement Welding Manual
www.lincolnelectric.com
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From a practical perspective, it is expected that most contractors doing D1.8 work will use the same filler
metals for both Demand Critical welds and other welds that are part of the seismic force resisting system.
The effort required to segregate the different filler metals for different joints, and the potential consequences
of inadvertently using the wrong filler metal to make a Demand Critical weld, suggest that it is prudent to use
the same materials (i.e., those qualified for Demand Critical welds) throughout a project.
Filler Metals – All D1.8 Welds
Certificates of conformance for Lincoln Electric’s D1.8 products can be obtained at
http://www.mylincolnelectric.com/LEExtranet/MyLincolnCerts/site/awsd.aspx. Charpy V-Notch (CVN)
properties and diffusible hydrogen levels for each product are contained in these certificates.
For all work done under D1.8, filler metals are required to meet a minimum Charpy V-Notch requirement
of 20 ft•lbf at 0°F, as measured in a standard AWS A5 filler metal classification test. Higher values for the
CVN energy (i.e., >20 ft•lbf) are acceptable, as are test results involving lower testing temperatures
(i.e., lower than 0°F). See D1.8, clause 6.3.1 and Table 6.1.
Most filler metals are required to be capable of depositing weld metal with a maximum diffusible hydrogen
content of 16 mL per 100 grams of deposited weld metal, meeting the requirement for H16. Lower diffusible
hydrogen levels are acceptable (for example, H8, H4, or H2). Exemptions from the requirement include SMAW
electrodes with low hydrogen coatings which may be accepted based on meeting AWS A5.1 or A5.5 electrode
specification for coating moisture content. Solid electrodes for GMAW and EGW are exempted from any
hydrogen measurement. See D1.8, clause 6.3.2.
When FCAW-S filler metals are combined with filler metals deposited by other processes, the combination of
the two must be checked to ensure that the minimum required Charpy V-Notch toughness can be obtained.
Annex B of D1.8 prescribes the required tests. Such testing is not required when FCAW-S is intermixed with
other FCAW-S. Alternatives to Annex B testing are also permitted by D1.8. See D1.8, clause 6.3.4 and
Annex B. Annex B of this manual contains intermix data on Lincoln Electric products.
Filler Metals – Demand Critical Welds
In addition to meeting the requirements above, filler metals used for making Demand Critical welds are required
to meet even more stringent requirements. Included are tests to evaluate the weld metal mechanical properties at
high and low heat input levels, as well as a variety of means by which lot-to-lot consistency of filler metals is ensured.
The actual mechanical properties (tensile, elongation and CVN toughness) of deposited weld metal are
dependent on a variety of factors, including the cooling rate experienced during the welding cycle. As cooling
rates are increased, the yield and tensile strength of the weld deposit typically increases, but the elongation
usually decreases. Conversely, slower cooling rates result in lower strength deposits with greater elongation.
Charpy V-notch toughness values are typically optimal at an intermediate cooling rate, and significant
changes in cooling rate (both increases and decreases) will often result in lower CVN values.