Agglomerated Welding Flux BF 4

Flux type: Aluminate-Basic

ISO 14174: S A AB 1 76 AC H5 *)
(EN 760: SA AB 1 76 AC H5)


Versatile flux for joint welding and surfacing with wire or strip electrodes. BF 4 is suitable for high speed welding of butt and fillet welds with single and multi wire processes. Smooth weld bead appearance with flat weld interfaces free from undercut, self de-slagging without any slag residuals, high current carrying capacity and low flux consumption (wire/flux ratio 1 : 0.9) are other special features of BF 4. Uniform mechanical property performance and low diffusible hydrogen levels make BF 4 flux suitable for most of the SAW processes with its wide range of applications.


Joint welding of non-alloy and low alloy structural steels such as S 355 J2 G3 (St 52-3N) acc. to EN 10025, boiler steels such as P265GH (H II) and 16Mo3 / A335 Gr. P1, as well as fine-grain structural steels with yield strength up to 420 MPa (t < 50 mm) in combination with compatible wires such as S2 or S2Mo. Surfacing with special hard facing wires and strips, including metal powder-cored wires (MPCW).

Characteristic chemical constituents

SiO2 + TiO2Al2O3 + MnOCaO + MgOCaF2
30 % 30 % 25 % 12 %
Basicity according to Boniszewski: ~1,1

Metallurgical behaviour acc. to ISO 14174 type of current DC

Pick-up Silicon
Pick-up Silicon
Pick-up/Burn-out Manganese
Pick-up/Burn-out Manganese

Flux density: 0.95 kg / dm3 (l)
Grain size acc. to ISO 14174: 2 - 20 (Tyler 8 x 65), 4 – 30 (Tyler 6 x 35)
Current-carrying capacity: up to 1,000 A (DC or AC) using one wire

*) Diffusible hydrogen content H5: determined in deposited metal acc. to the method described in ISO 3690
Type of current DC; redrying conditions 200 ± 50°C


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