Скачать или смотреть WOW Episode 24: When Weld Cracking is GOOD

Everyone knows that cracks are bad except when they aren't. The hardfacing industry has a euphemism for this controlled cracking; we refer to it as weld checking. This week we showcase a chromium carbide (CrC) weld overlay used to protect slurry pipelines in the Canadian oil sands. CrC is both wear-resistant and extremely hard. It is also brittle. As the weld cools and contracts, cracks form. The goal is many small cracks that don't propagate into the base pipe. This "checking" relieves stress and prevents larger cracks which are unacceptable.

You may recognize the system as one of our Tripulse GTAW hot wire two-layer pipe cladders. But this one is configured for GMAW overlay using two D/F Machine Specialties, Inc. heavy-duty water-cooled torches. Thanks to Steve Moerke, his torches stayed cool to the touch even while welding at 400 amps!

Thanks to Douglas Steyer, we shot the arc on video with a Xiris Automation Inc. weld monitoring camera.

Sometimes no single material has all the properties you need. For example, weld overlay allows you to combine the toughness of inexpensive steel with the abrasion resistance of chromium carbide and greatly extend the life of a slurry pipeline.

This is the first episode featuring our new configuration. Negotiating the theme music was complex enough to justify its own blog, Which we will post soon.