The Core of Quenching Furnace Process: Precise Temperature Control and Rapid Lifting & Lowering

Quenching furnaces are professional equipment for high-temperature heat treatment of metal workpieces. Its core workflow can be simply described: metal workpieces such as steel are placed inside the furnace and heated to a specified temperature ranging from several hundred to over one thousand degrees Celsius to alter the internal microstructure of the metal. Afterwards, a hydraulic system controls the lifting basket for rapid cooling (immersed in oil, water or air). This rapid cooling process constitutes the essence of quenching technology, and its speed and stability directly determine the phase transformation effect of the metallographic structure inside workpieces.

After quenching, metal properties achieve substantial improvement. Workpieces that are originally soft and prone to deformation gain greatly enhanced hardness, strength and wear resistance, making them suitable for diverse complicated and harsh working conditions. Quenching furnaces are widely adopted in manufacturing automotive gears, bearings, molds and key aerospace components.

Pain Points of Hydraulically Driven Lifting Systems for Quenching Furnaces: Asynchronous Motion, Uncontrollable Speed and Severe Impact

In practical operation, quenching furnaces are generally equipped with lifting basket systems. Metal parts are loaded on the basket, and the hydraulic lifting mechanism controls the timing and speed for the basket to move into and out of the furnace and cooling medium. The precision of this process directly determines the final quality of metal components. Traditional hydraulically driven lifting systems for quenching furnaces are confronted with tough challenges in field operation:

1. Asynchronous Movement of Dual Cylinders When two hydraulic cylinders work together to lift the basket, insufficient synchronization of the quenching furnace hydraulic system will cause basket tilting. As demonstrated in a customer case, the error between dual cylinders reached 20 mm within a 1000 mm stroke, resulting in obvious basket inclination. This undermines process stability and may damage costly workpieces, which represents a major operational pain point of quenching furnaces. Such asynchronous motion usually stems from differences in hydraulic circuit characteristics, uneven load distribution or inaccurate control feedback. Long-term operation will accelerate wear of sealing components and raise leakage risks.

2. Uncontrollable Speed The quenching process requires repeatable and accurate speed profiles when the basket enters the cooling medium. Excessively high speed may cause uneven cooling of workpieces, triggering internal stress and even cracking. If the speed is too low, undesired pearlite transformation may occur and lead to insufficient hardness. Traditional systems rely on manual valve adjustment or simple open-loop control, which cannot cope with fluctuations in oil temperature and load. Consequently, poor consistency exists among batches accompanied by volatile product quality.

3. Severe Impact During Stoppage Poor buffering performance of the hydraulic system generates strong mechanical impact when the basket stops at the stroke limit. Such impact not only creates harsh noise but also transfers vibration to precision workpieces, which may induce microcracks on treated high-hardness components. Meanwhile, continuous impact forces inflict damage on hydraulic cylinders, bearings and rail structures, driving up equipment failure rates and maintenance costs.

The key to resolving the three major pain points of quenching furnace hydraulic systems lies in real-time, high-precision displacement measurement and closed-loop control of hydraulic cylinders — exactly where high-precision magnetostrictive displacement sensors deliver outstanding performance.