Neumo Ehrenberg Group Automated ©rbital OTeldin

Clamping System Closed Chamber Weld Head

heat chemical composition

Shielding Gas Atmosphere: ARGON 5) Low ionization potential 5-\ ^ess hea 6) Low thermal conductivity L-/ ferr • Good gap-bridging ability

Shielding Gas Atmosphere: HYDROGEN (2-5% "Very effective reducer)^> Cleaner welds • Increases heat input 2> Increased weld Improves puddle wetting

Butt Welding: Heat-to-Heat variation surface-active elements surface-active elements

Schematic Configoration of Surface Fluid Flow ("Marangoni Effect")

Surface Tension-Driven Fluid Flow Schematic Model © Negative surface tension temperature coefficien ® Positive surface tension temperature coefficient

Sharp pointed electrode Additions of helium and / or hydrogen

Combination of low thermal conductivity and high thermal expantion: • Residual Stresses Distortion of thin sections in lightly restrai Less heat input r More frequent tack welds - Implementing heat sinks Restraining using J & F

Typical Weld Microstructure in Austenitic Stainless Steel Crbide Precipitation Cast Weld Metal ariation in grain size

Temperature ProfiI During Welding Carbides Precipitation

Sensitizing Effect ("Coking") Chromium Carbides

Carbide Precipitation in Stainless Steels

I.D. Bead Meander ("Snaking") Tube Contamination Hardness Changes Island Inclusions (Metallic & Non-Metallic) Excessive Head Purge

• Organic / Hydrocarbon Residues Contamination (Oil, Grease, Paint, Etc.) r Excessive Moisture or Condensation Sources Promoting Porosity in Welds

r Lower cost for machined parts. Inclusion Rating : «■ "Pits", "Stringers", "Pin-Holes" after passivation Resetting of weld parameters. Solidification Temperature Range Increased segregation in weld. Rouoher weld bead surface.

(?. c) Effect of Various Elements OJns^ on Weld Penetration • Sulfur s=> Very strongly increases. •Oxygen s=> Dissolved oxygen -^^B Very strongly increases. m r Aluminums Very strongly decreases by removing dissolved 02 to form r Silicon s=>Max. at approx. 0.50%. PhOSphorOUS No effect in range of