LongTeng EM12K Silicon-Killed Submerged Arc Welding Wire

LongTeng EM12K Wire Summary

LongTeng EM12K appears in the submerged arc section of the LongTeng catalogue as a silicon-killed medium-manganese grade. The conformance line prints the designation EM12K, the reference flux is the sintered type SJ101, and the diameters are 2.5, 3.2, 4.0 and 5.0 mm. The catalogue application text calls for high speed welding and filling welding on steel plate of 420 MPa tensile strength. Its most distinctive printed feature is the impact requirement, which is stated at minus 40 degrees Celsius, colder than the minus 20 degrees given for several neighbouring grades.

Seven Star LLC supplies the wire from Muscat for fabricators and contractors in Oman and across the GCC. This page keeps strictly to what the manufacturer printed and marks all numbers as typical values listed by the manufacturer.

What the K Suffix Means

As general class information, the suffix K in an AWS A5.17 designation marks a silicon-killed wire, one carrying extra silicon (and often manganese) so that the molten pool is deoxidised more effectively. Silicon-killed wires tend to cope better with plate surfaces that carry mill scale or light rust, and they are often chosen where the weld must also pass a toughness test. EM12K combines this feature with the medium-manganese, 0.12 percent nominal carbon base of the EM12 class. The explanation is generic knowledge of the class naming scheme and does not extend the manufacturer’s statements.

Chemistry Note

The chemical analysis row printed under LongTeng EM12K in the catalogue is identical, digit for digit, to the row printed under the plain EM12 entry on the same page. Since a silicon-killed wire would normally be expected to show a different silicon level, Seven Star LLC does not reproduce that row on this page. Please request the test certificate for the lot, which shows the actual analysis, before specifying the wire against a procedure that sets silicon limits.

Mechanical Data Listed by the Manufacturer

• Tensile strength range of 415 to 550 MPa.
• Minimum yield strength of 330 MPa.
• Minimum elongation of 22 percent.
• Minimum impact energy of 27 J at minus 40 degrees Celsius.
• Flux SJ101, a sintered flux, listed as the pairing.
• Diameters 2.5, 3.2, 4.0 and 5.0 mm.

Those figures are how the catalogue describes LongTeng EM12K. They are not a replacement for a procedure qualification record, and real results depend on plate, heat input, interpass temperature and flux condition.

Working With LongTeng EM12K in Submerged Arc Welding

In this process the wire runs through a contact tip into a mound of flux, and the arc burns invisibly beneath it. The flux shields the pool, forms slag and can even add or remove elements, which is why the wire and flux are always considered together. For LongTeng EM12K, the manufacturer points to SJ101. As a matter of general practice, sintered flux is stored in sealed packaging and dried before use, and used flux is recycled only if it is kept clean and free from fines.

Wire size is selected by joint design. Narrow-gap or thinner sections favour 2.5 or 3.2 mm for tighter control, and thick plate with wide grooves favours 4.0 or 5.0 mm for deposition rate. Direct current electrode positive is a common choice for submerged arc work on carbon steel, but the correct polarity, amperage and travel speed come from your welding procedure specification and are not printed in the catalogue for this grade.

Use Cases in the Sultanate and the Gulf

A wire carrying a minus 40 degree impact requirement is considered for steel that will see cold service or will be tested to a low temperature, such as storage vessels, pressure equipment, bridge and crane structures and fabricated frames that are shipped to cooler climates. In Oman most fabrication shops sit around Sohar, Sur and Duqm, where LongTeng EM12K would be one of the options on a quotation for plate in the 420 MPa class.

When a customer asks for an alternative, our team compares the sibling entries in the catalogue and requests the manufacturer’s test certificate for the lot that would be supplied. We never ask a buyer to rely on a catalogue number alone.

Choosing the Right Diameter and Pack

Buyers sometimes treat diameter as a minor detail, yet it sets deposition rate, penetration profile and the number of passes needed to fill a joint. A fabricator who welds long longitudinal seams on rolled shells usually prefers larger wire on heavy coils or drums, because fewer reel changes mean fewer start and stop points, while a shop that welds smaller assemblies may choose 2.5 mm wire on lighter coils. Tell us how the wire will be used and we will relate the catalogue sizes to your machine, so that the order for LongTeng EM12K fits the equipment on your floor.

Specification Table

Typical values listed by the manufacturer for LongTeng EM12K:

Package Reference

The package reference pages of the catalogue show submerged arc coil wire in 25, 50, 100, 250 and 350 kg weights and drums of 150, 250 and 350 kg. These are the manufacturer’s reference packages and not a promise of what is on our shelf. Tell us the size that suits your machine when you ask for a price on LongTeng EM12K.

More From Seven Star LLC

See the ESAB Rebel EMP 285ic welding machine, the Lincoln Electric Power Wave S500 power source and the Lapp OLFLEX Classic 110 flexible control cable, or go back to the submerged arc welding wire category.

Call To Action

For a quotation on LongTeng EM12K, send Seven Star LLC your diameter, quantity, packing preference and the toughness requirement of your project. Download the datasheet extract on this page and ask for the manufacturer’s test certificate with the order.