New Haven Steel Ball Group of Companies offers Stainless Steel Balls with Martensitic. New Haven Steel Ball Group of Companies is an ISO/TS 16949:2002 and ISO 14001 accredited company. The company manufactures Steel Balls. The Stainless Steel Balls with Martensitic Quality are designed to provide stainless properties with maximum hardness. The Stainless Steel Balls are always used in a hardened condition and in some respects behave similar to tool steels. The Stainless Steel Balls with Martensitic Quality is Ferro-magnetic and makes a fair permanent magnet. As these are hardened balls they are not readily machinable. All balls of this material are passivated.