AISI 4140 Steel is a Alloy Structural Steel belong to ASTM A29A29M Steel Grade standard. And AISI 4140 used in Oil and Gas industry and Large Machinery Strutural. What’s more, AISI 4140 Steel 42CrMo4 steel China Supplier and factory Otai Special Steel Supply AISI 4140 steel in Round bar, Plate, Flat bar, Square, Forging Ring and others any shape. And provide cutting, sawing, milled, machining processing.