A better solution is to cut the steel at an angle so it meets the sidewalk or ground. Make Your Yard Look More Polished With Garden Edging ...

Sunnydaze Brown Steel Metal Landscaping Edging Border (42-in. long, 5 pieces) Sturdy spikes and a secure, interlocking design make this edging easy to install.

The landscape edging comes in slate gray and brown, in addition to the black that’s shown, and in multiple heights. Each pack comes with five pieces that are 39 inches long and 1.6 millimeters ...

They say 'A thick steel edging either 3/16-inch or 1/4-inch thick that will hold up over time is a nice way to set a permanent bed edge and keep a lawn and planted bed separate.' ...