May.20,2026
The crankshaft is an important component of the engine. It bears the force from the connecting rod, converts it into torque, and outputs the torque to drive other accessories on the engine. The crankshaft is subjected to the centrifugal force of rotating mass, periodically changing gas inertia force and reciprocating inertia force, resulting in bending and torsional loads. Therefore, the crankshaft must have sufficient strength and rigidity, with wear-resistant journal surfaces, stable operation and good balance.
Medium-frequency induction quenching of crankshaft Medium-frequency induction quenching adopts a computer-monitored closed-loop medium-frequency induction heating device, featuring high efficiency, stable quality and controllable operation.
Soft nitriding of crankshaft For mass-produced crankshafts, a computer-controlled nitrogen-based gas soft nitriding production line will be adopted to improve product quality. The line consists of a front cleaning machine (cleaning and drying), preheating furnace, soft nitriding furnace, cooling oil tank, rear cleaning machine (cleaning and drying), control system, and gas generation and distribution system.
Surface strengthening technologies of crankshaft Fillet rolling strengthening will be widely used for ductile iron crankshafts. In addition, composite processes such as fillet rolling strengthening plus journal surface quenching will be widely applied. For forged steel crankshafts, journal plus fillet quenching will be more commonly used.
Smelting Obtaining high-temperature, low-sulfur pure molten iron is the key to producing high-quality ductile iron. Domestic production mainly uses cupolas without pre-desulfurization; meanwhile, high-purity pig iron is scarce and coke quality is poor. The process is: melt iron in a cupola, perform external desulfurization, then heat and adjust composition in an induction furnace. Vacuum direct-reading spectrometers are widely used to detect molten iron composition.
Molding Air impact molding is obviously superior to clay sand molding, producing high-precision crankshaft castings with no springback deformation, which is especially important for multi-throw crankshafts. Some domestic manufacturers have introduced air impact molding from Germany, Italy, Spain, etc., but very few have introduced complete production lines.
Electroslag melting and casting The application of electroslag remelting in crankshaft production makes the performance of cast crankshafts comparable to forged ones. It features short R&D cycle, high metal utilization, simple equipment and excellent product performance.
