What Is The 4140 Hot Rolled Steel Bar?

 4140 Hot rolled steel bars are products of a bar mill. Depending on the final application, the 4140 bars can be either shipped as hot rolled bars or further processed into cold rolled bars, also known as cold finished steel bars. 

Most common types of hot rolled steel bar is merchant bar quality , Depending on their chemical composition and properties, 4140 Hot rolled steel bars can be used in a wide variety of applications, such as general purpose structural, machinery parts, frames, fixtures, automotive and agricultural implements and equipment, brackets, stakes, hydraulic cylinder filed like cylinder piston rods. As well as many other miscellaneous, non-critical applications that involve mild cold bending, mild hot forming, punching, machining, and/or welding.

Hot rolled steel bars can also be produced as special bar quality steels like CK45 4340 or stainless steel, and also special heat treatment like Q+T and Induction Hardened for more critical applications. Yutong's  bar can have special requirements for minimal steel impurities or tighter chemistry, dimensional, or property tolerances. They are mainly used in the production of fast-moving automotive and aircraft parts that require high-demanding performance.

Hot rolled steel bar begins by heating blooms or billets in a reheat furnace. The temperature of the billet exiting the reheat furnace is dependent on the steel grade being rolled and the design of the rolling mill. However, it must be heated above the material’s recrystallization temperature, due to the extreme amount of reduction done during this process.

Processing parameters, such as reheating temperature, hot rolling specifics of reduction per pass, temperature of each rolling pass, interpass times, strain rates in each pass, total amount of rolling reduction, steel chemistry and final cooling time-temperature profile can all influence the final as rolled steel bar properties.