Marmon/Keystone, The Pipe, Tubing and Bar People With over a century of expertise in the metals industry, our intense focus is on solving our customers' pain points using unique methodologies. We have the inventory of products and services you need Marmon/Keystone is a leading distributor of specialty pipe, tubing, and bar. Carbon steel, stainless steel, aluminum, alloy tubular, chrome-plated, stainless and nitro-carburized.