Zhuojin Pipe Fitting Co., LtdMechanical Properties Comparison of TIG and CO2 Laser Welds in 08Al Steel
Literature Overview
This study, published in Applied Laser (2015, Vol. 35, No. 5, pp. 569–573) by Jiang Shichun, Liu Jia, Shi Yan, Zhang Hong, and Zhang Zhimin from Changchun University of Science and Technology, compares the mechanical properties of TIG (Tungsten Inert Gas) welding and CO2 laser welding joints in 2 mm thick 08Al steel plates. The research employs tensile testing, bend testing, and microhardness measurements to characterize the weld joints. The study provides valuable comparative data for engineers selecting between conventional arc welding and laser welding processes for thin-gauge aluminum-killed low-carbon steel applications.
Material Background
08Al steel is a low-carbon aluminum-killed steel with the following typical composition and properties:
| Property | Typical Value |
|---|---|
| C | 0.05–0.08% |
| Si | 0.17–0.37% |
| Mn | 0.30–0.60% |
| Al | 0.020–0.050% |
| S | ≤0.035% |
| P | ≤0.035% |
| Density (g/cm³) | 7.85 |
| Thermal Conductivity (W/m·K) | 50–55 |
| CTE (×10⁻⁶/K) | 11–12 |
| UTS (Base Metal) | 280–320 MPa |
| Yield Strength (Base Metal) | 180–220 MPa |
| Elongation (Base Metal) | 25–30% |
08Al steel is widely used in applications requiring good formability, weldability, and moderate strength, including structural components, pressure vessels, and piping systems. The aluminum deoxidation provides clean, non-inclusion-prone steel with good surface quality.
Welding Process Parameters
TIG Welding Parameters
| Parameter | Value |
|---|---|
| Shielding Gas | Argon (100%) or Argon + 5% Helium |
| Filler Wire | ER70S-6 or ER65-6 (matching low-carbon steel) |
| Current | 80–120 A |
| Voltage | 12–16 V |
| Travel Speed | 30–50 mm/min |
| Heat Input | 0.5–0.8 kJ/mm |
| Arc Length | 2–3 mm |
| Nozzle Diameter | 8–10 mm |
CO2 Laser Welding Parameters
| Parameter | Value |
|---|---|
| Laser Power | 2.0–3.0 kW |
| Focal Spot Diameter | 0.2–0.5 mm |
| Travel Speed | 1500–3000 mm/min |
| Heat Input | 0.3–0.6 kJ/mm |
| Shielding Gas | Argon or CO2 (depending on equipment) |
| Focus Position | On surface or slightly below |
| Pulse Mode | Continuous or pulsed |
The significant difference in heat input between TIG welding (0.5–0.8 kJ/mm) and CO2 laser welding (0.3–0.6 kJ/mm) is a key factor influencing the mechanical properties of the weld joints.
Mechanical Properties Results
Tensile Properties
| Property | TIG Weld |
|---|