Processes and methods used for Wear protection
SMAW(Shielded Metal Arc Welding )
also known as
Manual Metal Arc Welding (MMA ) , or Stick welding
+ plus
Wide range of alloys (electrodes) available.
Low cost of equipment , available in most workshops.
Easy to apply no special skills required :
– minus
Relative high dilution of weld deposit (20-40 % )
2– 3 layers may be required to achieve maximum wear properties
Low Deposition rate ( between 1– 3 kg/ h )
(FCAW) Flux Cored Wire Welding (GMAW ) gas metal arc welding
+ plus
High deposition rates from 2– 11 kg /h
Large range of alloys available to suit most application .
Easy to use.
– minus
Relative high dilution of weld deposit (20-40 % )
2– 3 layers may be required to achieve maximum wear properties
TIG (GTAW) Gas Tungsten Arc welding
+ plus
Low dilution,
Good control of weld deposit
Low dilution (5-15 %)
Ideal for Hard facing of tools & dies
– minus
Low deposition rates
Limited range of alloys available.
High welding skill necessary
Gas (oxy-acetylene) Hard facing (OFW)
+ plus
Excellent control over the deposit shape.
Minimum dilution of weld deposit (0-5 %)
Slow heating and cooling minimizes thermal shock of part
Equipment easily available at low cost
– minus
High heat input necessary
Low deposition rate
Not suitable for very large components
Powder Flame Spraying (Spray& Fuse)
A two step process where the powder is sprayed with a thermal spray gun and thereafter fused to achieve a dense coating
+ plus
Low cost of equipment ,easy to use
Only low dilution with base metal
Exact control over deposit shape and thickness
Wide range of powders available
– minus
High heat input necessary for spray & fuse coating
(PTA) Plasma Transferred Arc surfacing with powders classified as nickel base, cobalt base and iron base
+ plus
Low dilution of weld deposit (5-10 %)
Exact control over deposit thickness and shape,
Complete metallurgical bond between base metal and powder alloy
Automation is possible.
High deposition rate : up to 20 kg/h
– minus
Relative high cost of equipment
Limited mobility
High operator skill necessary
Other Processes used
- HVOF (High –Velocity Oxy –Fuel) spraying)
- WFS (Wire flame spray)
- CGS (Cold gas spray)
- AS (Arc spray )
Processes Used for Wear protection
HVOF (High –Velocity Oxy –Fuel) spraying)
+ plus
Low heat input, therefore workpiece remains relative cool with little change to either workpiece or sprayed material
Exact control over deposit thickness and shape and extremely thin coatings van be produced
Can be automated
Deposition rate from 2-15 kg/h
– minus
High cost of equipment
Limited mobility
Electric Arc Spraying (TWAS) (twin arc wire spraying)
+ plus
High deposition rates (8– 20 kg/h)
Preferred process for corrosion protection
No or only limited dilution of deposit
Can be automated
Good control over deposit thickness & shape
– minus
Relative high cost of the equipment
Limited mobility
Exposure to electric arc and fumes ,
SAW (submerged arc welding)
+ plus
fast deposition
Ideal for large parts such as rollers etc/
Suitable for automatic application
Produces sound and smooth deposits
– minus
Limited range of alloys available
Not suitable for smaller parts
Special equipment necessary
High dilution