Agglomerated Welding Flux BF 8.1

Flux type: Calcium-Silicate

ISO 14174: S A CS 1 75 AC
(EN 760: SA CS 1 75 AC)


Agglomerated, semi-basic, Calcium-Silicate flux with Manganese support for SA-overlay welding and shape-forming using single or multiwire (TWIN-ARC) processes. BF 8.1 is particularly designed for the repair of worn pistons for large ship diesel engines.
The weld bead exhibits a flat smooth surface with good wetting and self-lifting slag detachability without residuals even at high intermediate welding temperatures above 300 °C. Stable chemical flux reactions and constant operating characteristics over a wide current range, also when welding AC, are advantages of this flux. Low consumption as well as low humidity are additional features of BF 8.1 together with low sensitivity to arc-blow and high resistance to porosity.


BF 8.1 is to be welded DC (+ or –) or AC in combination with non-alloyed and low-alloyed wires for overlay and build-up welding of heat-treatable, low-alloy steels which require preheat and interpass temperatures above 300 °C up to 500 °C.
Especially applied for recondition welding / form-welding of worn piston ring grooves and the surface of piston crowns.

Characteristic chemical constituents

SiO2 + TiO2Al2O3 + MnOCaO + MgOCaF2
25 % 15 % 35 % 20 %
Basicity according to Boniszewski: ~1.7

Flux density: 0.95 kg / dm3 (l)
Grain size acc. to ISO 14174: 3 – 25 (Tyler 8 x 48)
Current-carrying capacity: up to 1,200 A (DC or AC) using one wire


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