What is non-quenched and tempered steel

Non-quenched and tempered steel is based on medium carbon manganese steel with addition of vanadium, titanium, and niobium microalloying elements, so that it can be dissolved in austenite during heating. The solid solubility decreases with cooling, and the microalloying elements vanadium, titanium, and niobium will be precipitated in the first precipitated ferrite and pearlite in the form of fine carbides and nitrides. These precipitates maintain an eutectoid relationship with the parent phase to strengthen the steel.

The mechanical properties of non-quenched and tempered steel in the hot-rolled, forged or normalized state can be close to or reach the level of mechanical properties of the general quenched and tempered state. Therefore, the quenched and tempered process can be omitted in the application, which shortens the production cycle. It saves energy again. The mechanical properties of non-quenched and tempered steel depend on the strengthening of the matrix microstructure and precipitated phases.

Non-quenched and tempered steel is divided into non-quenched and tempered steel for hot forging, non-quenched and tempered steel for direct cutting, cold-work strengthened non-quenched and tempered steel and high toughness non-quenched and tempered steel. Non-quenched and tempered steel for hot forging is used for hot forgings, such as crankshafts, connecting rods, etc. The steel grades are F45V, F35MnVN, F40MnV; non-quenched and tempered steel for direct cutting is directly processed into parts; cold-worked strengthened non-quenched and tempered steel is used for standards parts, such as bolts and nuts; high-toughness non-quenched and tempered steel is used for parts that require higher toughness, the main grades are YF35V, YF40V, YF45V, YF35MnV, YF45MnV, etc.