POSTED ON 3/5/2020 – As a pioneer in Friction Stir Welding (FSW), Mazak MegaStir specializes in finding ways to remove challenging materials from the impossible-to-join list, creating defect-free joints with greater strength than conventional welds. Within the Mazak HYBRID Multi-Tasking family of machine tools, FSW technology often holds the key to breakthroughs in production for aerospace, electronics, energy production and shipbuilding. For manufacturers in the oil and gas industry in particular, recent tests show that FSW can offer excellent results in several welding applications, especially those involving tough X80 steel.
American Petroleum Institute (API) approves X80 steel for oil and gas applications and classifies it through API Specification 5L. Many companies produce this alloy, which offers a minimum yield strength of 80 kpsi (555 MPa). This leading property of pipeline steel defines the amount of tensile stress that elongates the metal by 0.5%, and refers to the relationship between stress applied to the metal and the strain that results from the stress.
Because X80 is a high grade of low-carbon pipeline steel, it can be difficult to weld. Mazak MegaStir conducted a Friction Stir Welding test of X80 steel with an alloy chemistry incorporating 0.18% carbon, 1.80% manganese, 0.03% phosphorus and 0.018% sulfur. The test used a 12″-square specimen of flat X80 plate sectioned in half along the rolling direction. Sanding removed oxidation and scale, and degreasing used a methanol solvent. Because no previous data existed to determine mechanical properties and welding forces, Mazak MegaStir used conservative process parameters.