... less than 3.1 4.Test:Ultrasonic test Steel grade (the products exported mostly): Chinese standardAmerican ... Quality.10.Marking: Heat No. will be cold stamped and Steel grade, diameter (mm), length (mm), and ... steel (including carbon steel, structural alloy steel, dies steel bearing steel, roll steel, and stainless steel), and electroslag steel (mainly includes bearing steel, roll steel, rapid tool steel ...