Metal Service Center Specializing In Aircraft Quality 4130. Stocking Steel, Aluminum, Stainless Steel & Brass In: Bars, Sheets & Tubing. Alloy-Tubing In 4130, 4140 & 4340. Sheets/Plates In 4130 Condition A & N. 4130 Round In Condition 4. ISO 9000: 2000 Certified