Böhler Union S 3 NiMo 1 EF3 Ni-Mo Submerged Arc Wire

Ni-Mo SAW wire for unalloyed and low-alloyed fine-grained steels

Böhler Union S 3 NiMo 1 is a copper-coated wire for submerged arc welding of unalloyed and low-alloyed fine-grain steel grades. It is classified AWS A5.23 / SFA-5.23 EF3 and EN ISO 26304-A S3Ni1Mo. The nickel at about 0.95 % and molybdenum at about 0.55 % raise the strength and low-temperature toughness of the weld metal over a C-Mn wire, which is the reason this grade is specified for heavy-wall pressure vessels, offshore structures, spherical tanks and other fabrication in high-strength steels where impact tests are required.

Technical specifications

Using the wire correctly

The Böhler data sheet does not list recommended fluxes or all-weld-metal values for this wire, and its mechanical results depend entirely on the flux used. Basic fluxes such as UV 418 TT are generally preferred where toughness is critical, but the actual selection must be proved on a procedure qualification, so confirm the flux and its test results before ordering. Where the steel is plain structural grade, is the simpler wire. For a heat-resistant steel, use a Cr-Mo wire such as

Union S 2 CrMo.

Storage and wire handling

Copper-coated SAW wire protects itself from rust only while it stays dry and clean. Keep spools and coils in their original packing until use, store them off the floor in a dry room, and do not leave an opened spool on the machine overnight in humid conditions. Surface rust and dust shorten contact tip life, disturb feeding and add hydrogen to the weld. Before ordering, confirm the diameter, spool or coil type and the certificate level (for example EN 10204 type 3.1) that your project requires.

Documents and quotation

The Böhler Welding data sheet for Union S 3 NiMo 1 (US edition, 03/2021) is attached. See the SAW Wire category for more. For a quotation, send diameter, packaging, quantity, flux and certificate requirements.