Covered Electrodes For Cast Iron

 Cast Iron Welding Consumables Introduction-Covered Electrodes

 

1.Welding Consumables Selection and Recommendation:

Specification of Cast Iron welding according to AWS A5.15: It consists of OFW, GMAW, FCAW, and SMAW, the four categories welding. The following relevant classification and features.

 

category

規格類號

Characteristics

Bare Rod

(OFW)

RCI

Use for gray cast iron welding

RCI-A

Fewer content of Ni and Mo alloys, better liquidity and faster wire melting speed.

RCI-B

Use as nodular cast iron welding for high strength gray cast iron, malleable cast iron, and nodular cast iron.

Electrode or Wire


(SMAW)

ENi-CI

The content of Ni of weldmetal at 90~95% is general for gray cast iron, iron-based or non-iron based workpieces. If considers the weld strength and toughness, it recommends ENiFe-CI grade welding consumables, besides, the malleable cast iron or nodular cast iron is for processing consideration.

ENi-CI-A

Flux design involves Al for molten iron fluidity and slag coverage improvement but the weld toughness effect.

ENiFe-CI

The content of Ni of weldmetal at 50% is general for the most cast iron workpieces and steel iron materials on dissimilar materials welding, especial better for large or high strength on cast iron welding.

ENiFe-CI-A

Additional content of Al in flux compared to ENiFe-CI for molten iron fluidity and slag coverage improvement but the weld toughness effect.

ENiFeMn-CI

The content of Mn of the weldmetal about 12% is to improve molten iron fluidity, cracking resistance, strength and toughness. Use as hardfacing welding application better for ENiFe-CI.

ENiCu-A

Similar to ENiFe-CI、ENiFe-CI-AENiFeMn-CI applications, use as coating welding.

ENiCu-B

SMAW

ESt

Specialized in cast iron welding design for carbon steel electrodes, difference to AWS A5.1 the materials the weld difficult to cut and process. It uses smaller current to weld for the weld cracking prevent.

FCAW

ENiFeT3-CI

It is generally designed for self-shield flux-cored wire, the content of Mn about 3~5% to improve the weld cracking resistance, strength and toughness as same as ENiFe-Ci on application. 

GMAW

ERNi-CI

Content of Ni at 99% for coating welding.

ERNiFeMn-CI

Suitable for high strength of nodular cast iron welding.

 

 

 

4.Welding Operation Points

(1)Storage Management


Refer to the storage management of carbon steel consumables.

 

(2)Welding Precaution


①Cleaning the dirty, solvent, foreign materials or oil attached the surface of the workpiece by heating with gas at 400℃ upwards prior to welding for the condition of the weld blowholes.

 

Preheat temperature of cast iron welding is classifying high-temp. (by heating) and low-temp. (by cooling). It estimates the cracking situation by welding consumables matchup dependent on the materials and workpiece thickness.

 

③Non-preheat or low temp. preheat in Nodular welding, it generally recommends ENiFe-CI grads for lower incidence of cracking.

 

④The groove opening angle of casting workpiece recommends in 70~90°, and the root recommends to be processed into an arc (R) to increase the penetration of the bottom weld.

 

⑤To avoid using carbon rod for back shoveling or removal that would cause the situation of the weld cracking by the excessive carbon deposit.

 

⑥Lower welding current is to avoid excessive hardening at heat affected zone (HAZ) for cracking matter.

 

⑦The length of each weld is limited to 50 mm under straight welding direction nor weaving welding in order to avoid excessive heat impact at HAZ.

 

⑧When weld a small gap of a bowl-shape workpiece, the welding direction is to be handled in the way of the vortex-like upward. The long weld welding should be in the ways of symmetrical welding and skip welding that distributes the stress evenly for welding arrangement in order for cracking matter.

 

⑨When cast iron welds with a dissimilar material, it firstly does coating and then joint welding. The area or width of the coating must be great than the joint weld in order to avoid the welding toe cracking nearby.

View:

SN-55

鑄鐵SMAW銲接
AWS A5.15 ENiFe-CI
JIS Z3252 DFCNiFe
EN --
GB T10044 EZNiFe-1

SN-99

鑄鐵SMAW銲接
AWS A5.15 ENi-CI
JIS Z3252 DFCNi
EN --
GB T10044 EZNi-1