Analysis of Failure Modes and Causes of Filter Press Shafts

I. Introduction

As a key equipment for solid-liquid separation in industrial production, the stable operation of the filter press plays a crucial role in production efficiency and product quality. Shaft components, as the core transmission parts of the filter press, are subjected to complex mechanical stress, friction, wear, corrosion, and other multiple factors during long-term high-load operation, making them highly susceptible to failures such as wear and deformation. Once a filter press shaft fails, it not only causes equipment downtime and production interruptions but may also result in significant economic losses. Traditional repair methods often have many limitations when dealing with filter press shaft failures, such as the tendency of welding repairs to cause thermal stress concentration leading to shaft deformation or even fracture, and the limited thickness and insufficient bonding strength of electroplated coatings making them prone to peeling.

Laser cladding technology, as an advanced surface repair and strengthening technique, has been widely applied in the field of filter press shaft repair in recent years. This technology uses a high-energy laser beam as a heat source to rapidly melt and solidify specific alloy powders or ceramic powders and other cladding materials with the shaft substrate surface, forming a high-performance cladding layer metallurgically bonded to the substrate. This effectively restores the dimensional accuracy of the shaft and significantly enhances its wear resistance, corrosion resistance, and fatigue resistance, providing a new solution for the efficient and reliable repair of filter press shafts.

II. Analysis of Failure Modes and Causes of Filter Press Shafts

1. Wear

<1>Abrasive Wear

During the filtration process, solid particles in the suspension flow with the liquid and continuously scour the shaft surface. These hard particles act like tiny abrasives, continuously cutting and scraping the shaft surface under high-speed rotation, gradually causing wear of the shaft surface material. This phenomenon is particularly severe when filtering materials containing high-hardness, large-particle impurities.

<2>Adhesive Wear

When the shaft and mating parts such as bearings are in relative motion, microscopic irregularities on the contact surfaces lead to localized pressure concentration, causing plastic deformation of the metal at the contact points. This results in mutual attraction of metal atoms between the two surfaces and adhesion. As the shaft continues to rotate, the adhesion points are sheared and destroyed, transferring material from one surface to the other, forming adhesive wear. Poor lubrication conditions can exacerbate adhesive wear, severely affecting the surface quality and dimensional accuracy of the shaft.

2. Corrosion

<1>Chemical Corrosion

The materials processed by the filter press are often corrosive, such as acidic or alkaline solutions. These corrosive media react chemically with the metal on the shaft surface, gradually dissolving the metal atoms and causing corrosion of the shaft surface. For example, in industries such as chemical and metallurgical processing, where the filter press handles materials containing large amounts of acidic or alkaline components, the shaft is prone to chemical corrosion.

<2>Electrochemical Corrosion

Since the shaft is typically made of metal materials, in humid working environments, a thin film of electrolyte solution forms on the shaft surface, creating numerous tiny galvanic cells with different phases or impurities inside the metal. Under the action of these galvanic cells, the metal acts as an anode and undergoes oxidation, gradually corroding and producing defects such as rust spots and pitting, which reduce the shaft's strength and service life.

3. Fatigue Fracture

During long-term operation, the filter press shaft is subjected to alternating loads, such as periodic torque and bending forces. Under the repeated action of alternating stress, stress concentration occurs at microscopic defects on the shaft surface or inside (such as machining marks, pores, etc.). Over time, fatigue cracks gradually form in the stress concentration areas. As the cracks continue to expand, when they reach the shaft's critical load-bearing capacity, the shaft suddenly fractures, causing serious production accidents.

Conclusion

Laser cladding technology, with its unique advantages, shows broad application prospects in the field of filter press shaft repair. Through in-depth analysis of the failure modes and causes of filter press shafts, and by adopting scientific and reasonable laser cladding repair processes, defects such as wear and corrosion can be efficiently and accurately repaired, significantly improving the surface performance and service life of the shaft, and providing strong support for the stable operation of the filter press. With the continuous development and improvement of laser technology, as well as ongoing research into cladding materials and processes, laser cladding repair technology for filter press shafts will continue to innovate and optimize, playing an increasingly important role in industrial production and helping enterprises achieve efficient, green, and sustainable development.