Process specifications for plasma surfacing

Plasma cladding (PTA) process specifications

Plasma cladding (PTA) is a high-performance surface strengthening technology. To ensure welding quality, strict process specifications must be followed, including welding parameters, equipment settings, material selection, process flow, etc.

1. Main process parameters

1.1 Power supply and welding parameters

parameter	Typical range	illustrate
Current (A)	30-300 A	Influence of penetration and thickness of cladding layer
Voltage (V)	10-40V	Affects the stability of the molten pool
Surfacing speed (mm/min)	50-400 mm/min	Affects layer thickness and weld quality
Powder feeding rate (g/min)	5-50g/min	Influence of alloy composition and layer thickness
Plasma gas flow rate (L/min)	1-10 L/min	Mainly affects arc stability
Shielding gas flow rate (L/min)	5-20 L/min	Protect the molten pool from oxidation
Injection gas flow rate (L/min)	1-5 L/min	Affects powder feeding efficiency
Thickness of cladding layer (mm)	0.2-5 mm	Determined by process requirements

2. PTA cladding process

2.1 Substrate pretreatment

Clean the workpiece surface (remove oil, oxide layer, rust)
Sandblasting or turning (to improve surface roughness and enhance bonding strength)
Preheat (if necessary) , usually 150-400°C to prevent cracking

2.2 Surfacing parameter setting

Select appropriate current, voltage, powder feeding rate, gas flow rate
Adjust the nozzle-workpiece distance (usually 3-10mm)

2.3 Surfacing process control

Ensure arc stability to prevent overheating or lack of fusion
Even powder feeding to avoid uneven composition of cladding layer
Control layer thickness to avoid cracks caused by excessive thickness

2.4 Post-processing

Slow cooling (to avoid cracks caused by thermal stress)
Heat treatment (if necessary) to improve the stability of the weld cladding layer
Mechanical processing (such as grinding, turning) to improve dimensional accuracy

3. Applicable materials and common alloys

Substrate Type	Commonly used cladding alloys	Application Features
Carbon Steel	Iron-based, nickel-based, cobalt-based alloys	Improve wear resistance and corrosion resistance
Stainless steel	Cobalt-based, nickel-based	Enhanced high temperature resistance and corrosion resistance
Tool Steel	Tungsten carbide, iron-based alloy	Improve wear resistance
cast iron	Nickel-based, cobalt-based	Enhance toughness and crack resistance

4. Key points for PTA cladding quality control

Control welding temperature to prevent crack formation
Ensure uniform powder feeding to avoid component segregation
Adjust gas flow to ensure arc stability
Optimize weld overlap to ensure metallurgical bonding between layers
Perform subsequent heat treatment to reduce residual stress

Reasonable setting of PTA cladding process specifications can effectively improve the wear resistance, corrosion resistance and high temperature resistance of parts, and is widely used in mining, petroleum, steel, engineering machinery and other industries.