Agglomerated Welding Flux BF 6.4

Flux type: Aluminate-Basic

ISO 14174: S A AB 1 66 AC H5 *)
(EN 760: SA AB 1 66 AC H5)


A semi-basic flux suitable for high speed welding with single and multi-wire (up to 5 wires) submerged-arc processes. BF 6.4 is designed for pipe-welding and vessels of small diameter (>300 mm) and is especially recommended for spiral pipe fabrication employing the two-run technique. Weld bead performance and slag release are excellent providing flat welds with low reinforcement and flat weld interfaces free from undercut. The flux shows a high resistance to abrasion and a low consumption rate with good flux feeding properties in the transport and recovery system. As a result of low hydrogen levels (max. 5 ml/100g), oxigen levels of about 350 ppm and low nitrogen levels (max. 70 ppm) in the weld deposits, uniform mechanical properties with low temperature toughness are obtained. Due to achievable low hardness levels (max. 240 HV) the weld deposits made with the flux BF 6.4 are also resistant to sour gas environment.


Low-alloy structural steels up to 500 N/mm2, boiler steels and especially pipe steel qualities acc. to EN 10208-2 / API-5L/5LX/5LS up to X 80 with special low-alloy filler materials such as S1Mo1.2 or TiB-grades.

Characteristic chemical constituents

SiO2 + TiO2Al2O3 + MnOCaO + MgOCaF2
25 % 35 % 20 % 17 %
Basicity according to Boniszewski: ~1.4

Metallurgical behaviour acc. to DIN EN 760

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 DIN EN 760: 2 – 16 (Tyler 10 x 65)
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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