Agglomerated Welding Flux BF 5.1

Flux type: Aluminate-Basic

ISO 14174: S A AB 1 67 AC H5 *)
(EN 760: SA AB 1 67 AC H5)


A neutral, semi-basic agglomerated flux of the aluminate basic type suitable for joint welding of low-alloy structural steels, fine-grained steels and pipe steel qualities. Designed for DC and AC welding
BF 5.1 is suitable for the two-run or multi-layer technique using single or multi-wire processes. The flux shows constant metallurgical characteristics (low Silicon and Manganese pick-up). In combination with appropriate wires, such as Mo-, Ni- or NiMo-alloyed types, uniform mechanical properties with low temperature toughness are achieved. Slag–detachability, even in narrow–groove welds of thick-walled sections, or at high preheating temperature (> 250°C), together with finely rippled weld bead performance and smooth tie–ins, even when fillet welding using high currents, are additional features of the flux.
BF 5.1 is formulated to achieve very low diffusible hydrogen levels (< 4 ml/100 g weld deposit).The chemical com position of the flux, respectively its alloy vector, has been designed for achieving large amount of acicular ferrite with typical standard wires.


SA-welding of low-alloy structural steels (Y.S. up to 420 MPa), boiler and vessel materials, high-strength ship steels such as EH36; fine-grain structural steels up to Y.S. 460 MPa and pipe steel qualities up to X70 grade (ISO 3183 / API-5L).

Characteristic chemical constituents

SiO2 + TiO2Al2O3 + MnOCaO + MgOCaF2
20 % 30 % 30 % 15 %
Basicity according to Boniszewski: ~1,7

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: 1.1 kg / dm3 (l)
Grain size acc. to ISO 14174: 3 – 20 (Tyler 8 x 48)
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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