Super silicon welding rod for cast iron

10 January, 2011

Weldability-SIF’s full-fusion rod provides high-strength weld metal

Sif Super Silicon No9 is a welding rod in the Sifbronze range for oxy-acetylene welding of cast iron from Weldability-SIF, suppliers of MIG, TIG, MMA, spot and oxy/fuel welding and plasma cutting machines, torches, accessories, consumables and personal protective equipment.

The rod is designed for full-fusion welding providing an easily machined high-strength weld metal. It has a good colour match with the same structure as grey cast iron.

The rod, which is square in section, is available in 4.0mm, 6.0mm and 10.0mm diameter 1m rods in 1kg and 5kg packets. It is suitable for welding and joining of castings found in general manufacturing, agricultural and construction industries. It can be used to build up and repair worn, cracked, broken or damaged areas as well as for surfacing of new castings. It is particularly suitable for welding cast iron to high alloy steel or cast iron to manganese steel plates. This rod can also be used for TIG welding provided the surface area to be welded has been ground and angled to a fine point.

The weld metal composition of the rod includes 3.3% carbon, 3.0% silicon and 0.7% manganese. It has a melting point of 1,250°C and some pre-heating of the casting may be required as well as a slow cooling rate being preferable. This can be done by wrapping the casting or covering it in sand. Other mechanical properties include an ultimate tensile strength of 200 N/mm2 and a relative hardness of 180.

In most cases, welders will choose a MMA (manual metal arc) welding set and attempt the repair of cast iron using pure nickel or nickel-iron electrodes. This is an expensive and difficult method requiring considerable pre-heating and strict control of the post-weld cooling, owing to the metallurgical difference between the rod and the parent material. Sif Super Silicon No9 is used in the oxy/acetylene process and is much more compatible with the parent material, making it easier to get fast, reliable results and good colour match. As Sif Super Silicon No9 contains no nickel, its use delivers savings over the use of MMA electrodes.

For the best results it is recommended that a Sifbronze cast iron flux is used when welding with the rod.

Weldability-SIF, Peters House, Orbital Centre, Icknield Way, Letchworth, Hertfordshire SG6 1ET; tel: (01462) 482200.