High Strength Weld Metal for Demanding Structural Applications

摘要

Weld metals and methods for welding ferritic steels are provided. The weld metals have high strength and high ductile tearing resistance and are suitable for use in strain based pipelines. The weld metals are comprised of between 0.03 and 0.08 wt % carbon, between 2.0 and 3.5 wt % nickel, not greater than about 2.0 wt % manganese, not greater than about 0.80 wt % molybdenum, not greater than about 0.70 wt % silicon, not greater than about 0.03 wt % aluminum, not greater than 0.02 wt % titanium, not greater than 0.04 wt % zirconium, between 100 and 225 ppm oxygen, not greater than about 100 ppm nitrogen, not greater than about 100 ppm sulfur, not greater than about 100 ppm phosphorus, and the balance essentially iron. The weld metals are applied using a power source with pulsed current waveform control with <5% CO2 and <2% oxygen in the shielding gas.

主权项

1. A weld metal for ferritic steel base metals, comprising:
between 0.03 and 0.08 wt % carbon; between 2.0 and 3.5 wt % nickel; not greater than about 2.0 wt % manganese; not greater than about 0.80 wt % molybdenum; not greater than about 0.70 wt % silicon; not greater than about 0.03 wt % aluminum; not greater than 0.02 wt % titanium; not greater than 0.04 wt % zirconium; between 100 and 225 ppm oxygen; not greater than about 100 ppm nitrogen; not greater than about 100 ppm sulfur; not greater than about 100 ppm phosphorus; and the balance iron, wherein the weld metal comprises an SBD-AFIM microstructure, the weld metal is applied using a pulsed gas metal arc welding process with an advanced pulsed waveform power supply and utilizes a shielding gas comprised of less than 5% CO2 and less than 2% O2, the applied weld metal has a tensile strength of greater than 90 ksi and a SENT R-curve delta value of greater than 0.75.