Arc spray wire- An efficient and economic spraying material
Electric arc wire spraying is extremely portable for on-site coatings and uses atomized air and electricity to melt pure metal wires and metallic alloy. It is commonly used in piston rings, welded tube seams, boiler walls, capacitors, varistors and big infrastructures.
The electric arc wire spray process involves two metallic wires of the same composition as the coating feedstock. The two wires are fed into the arc gun at controlled and matched speeds after charging those wires electrically with opposing polarity. The opposing charges on the wires produce enough heat that can continuously melt the tips of the wires when the wires are brought together at the contact point. The molten material is atomized and accelerated onto the work piece surface to form the coating using the compressed air.
There are numerous applications of arc spray wire such as
- Bridge decks
- Boiler walls
- Transport pipes
- Welded tube seams
- Piston rings
- Other large infrastructures
There are various features of arc spray wire which make it useful such as
- High spray rates
- Superior portability for on-site coatings
- No need for any gases or process water except compressed air
There are various types of arc spray wires such as thermal spray wires or known as metallizing wire. Thermal spray wires are used for bond coats and repair. Bond coats which are applied using electric arc wire spray are cleaner and are easily machined as compared to their powder-sprayed counterparts. Thermal spray wire is widely known for machine element repair usually on low-alloy steel, carbon steel and stainless steel substrates. Arc thermal spraying process achieves the greatest productivity and this arc spray process involves two wires which are melted using an electric arc. The wires are melted continuously using the high temperature of arc (5000-6000 degree C). The molten wire tips are atomized and propelled towards the substrate at speed more than 100 meters per second using the compressed air or gas. The compressed gas is then used to atomize and propel the molten material onto the work piece to form a coating. Thus this arc spray coatings have excellent coating properties with low porosity and high bond strengths due to the combination of high particle velocity and high temperature.
Arc spraying creates high noise and huge amounts of fume and is a cold thermal spraying process in which the temperature of the substrate is below 150 degrees C. The work piece is not subjected to any metallurgical distortion or changes due to low temperature. There are many advantages of this arc spraying process such as
- It has lowest running costs and highest spray rates
- No flammable gases used
- Two different wires can be used during spraying to create new appropriate coatings
- Cold spray process
- Coatings are economic as no need of kerosene, oxygen or a combustible gas
- Safe process
The arc spray process is used for creating anti-corrosion coatings and this process is also used for spraying work on big components. Material to be sprayed must be conductive to electricity and few of the commonly used materials are cored wires or metallic material. Arc spray process is an excellent tool for spraying a large number of parts or extensive areas due to its efficiency, low running cost and high spray rate.