The culprit behind your metal sheet pans popping and warping in the oven is fairly obvious: it's the heat. However, considering just how heat and metal interact will lead you to better baking ...
Heat oil in a 10-inch cast-iron skillet over a medium-high, tilting pan to coat the bottom. Arrange potato wedges and sausage slices in skillet in a single layer, and sprinkle with 1/4 teaspoon salt.