Servo Valves in Continuous Casting Machines: Applications, Common Faults & Troubleshooting

Continuous casting is a core process in modern steel production. Its control precision directly impacts the quality of steel products and production efficiency. In continuous casting equipment, servo valves act as key actuators in electro-hydraulic control systems. They deliver high-precision motion control for multiple critical components of the caster by accurately regulating flow and pressure in the hydraulic system.

Mold vibration is a make-or-break process in continuous casting. Its performance directly affects billet surface quality and caster productivity. Modern casters mostly use hydraulic servo vibration systems instead of traditional mechanical vibration devices. The main advantage is that servo valve-controlled hydraulic vibration systems allow flexible waveform adjustment and real-time parameter tuning.

In mold vibration systems, servo valves work under high-frequency, long-stroke conditions. This leads to faster wear and increased zero-position leakage, which in turn causes higher zero-position current and jitter at the peak of the vibration curve. Additionally, the harsh high-temperature environment of continuous casting can easily damage position sensor systems—poor cooling leads to malfunctions and erratic signals, challenging the reliable operation of servo valves. In practice, servo valve-controlled hydraulic vibration systems can achieve non-sinusoidal vibration patterns. This type of waveform effectively reduces friction between the billet and mold, enhances lubrication between the billet shell and mold, and ultimately improves billet surface quality.

Dynamic soft reduction technology is one of the core technologies for improving internal billet quality in modern casters. It uses servo valves to precisely control the shrinkage of segment roll gaps, compensating for volume shrinkage during billet solidification. This minimizes internal defects like central porosity and shrinkage cavities. In this application, servo valves need to adjust roll gap openings in real time based on casting speed, steel grade, and cooling parameters—control precision typically needs to reach the micron level.

In horizontal continuous casting, casting speed control places particularly strict demands on servo valve performance. The electro-hydraulic servo drive for billet casting must precisely regulate casting rhythm, speed, and counter-thrust according to the characteristics of horizontal continuous casting processes. This prevents billet shell breakage or tearing due to excessive resistance. Here, servo valves work with tachometers and servo motors to form a complete position-speed closed-loop control system.

The unique challenge of casting speed control lies in handling large inertial loads and hydraulic shocks from high-frequency reversing—while maintaining extremely high speed control precision. Even minor fluctuations can lead to unstable billet quality or production interruptions. Therefore, servo valves in this application must have exceptional resolution and fast response capabilities to ensure smooth, accurate casting.