Attention should be paid to the aspects of fatigue damage of stainless steel lever hoist chain

1、 Causes of fatigue damage

material fatigue

Under long-term repeated loading, stainless steel chains will produce micro cracks and gradually expand, ultimately leading to rupture. This type of fatigue damage is one of the main causes of chain failure.

Usage environment

Damp or corrosive environments can accelerate the fatigue process of the chain. Although stainless steel has good corrosion resistance, long-term use in highly corrosive environments may still reduce the fatigue strength of the chain due to corrosion.

Load situation

Overloading or frequent use near rated load can significantly shorten the fatigue life of the chain. Excessive load can cause stress concentration inside the chain, accelerating the formation and propagation of fatigue cracks.

Maintenance

Lack of regular inspection and maintenance can lead to fatigue damage to the chain not being detected and dealt with in a timely manner. For example, wear, deformation, or insufficient lubrication of the chain may exacerbate the occurrence of fatigue damage.

2、 Testing methods and techniques

Traditional linear ultrasonic testing

This method may underestimate the severity of fatigue cracks due to poor crack direction or small gaps. Therefore, in the detection process, it is necessary to combine other methods for comprehensive judgment.

Nonlinear ultrasonic testing

By measuring the relative nonlinearity coefficient, microscopic damage can be more effectively detected. This method is not affected by the macroscopic crack state and can more accurately evaluate the fatigue damage degree of the chain.

Magnetic particle testing and penetrant testing

Used to inspect cracks on the surface of the chain. These two methods can visually display defects on the surface of the chain, which helps to detect and deal with fatigue damage in a timely manner.

3、 Preventive measures and maintenance standards

Material selection and design

Select high-strength and corrosion-resistant stainless steel materials, and optimize the chain structure design to reduce stress concentration. For example, adopting a reasonable chain pitch and sprocket tooth profile to reduce friction and wear of the chain during operation.

using standards

Strictly adhere to the rated load and avoid overloading. When used in a tilted or horizontal direction, adjust the zipper direction to conform to the sprocket and prevent it from slipping or getting stuck. At the same time, avoid using in strong magnetic fields or high temperature environments to prevent electrical failures or material performance degradation.

Regular inspection and testing

Regularly inspect the chain for signs of wear and fatigue, such as elongation, deformation, or cracks. Use non-linear ultrasonic testing and other techniques for regular inspections to promptly detect and address potential fatigue damage.

Maintenance

Timely replace worn or damaged components such as chains, sprockets, or brakes. Keep the chain clean and lubricated to reduce friction and wear. At the same time, regular comprehensive inspections and maintenance of the equipment are carried out to ensure that it is in good working condition.

4、 Industry standards and case analysis

Industry standards

GB/T 20653-2020 specifies the basic parameters, technical requirements, testing methods, etc. of stainless steel lever hoists. These standards provide us with the basis for equipment selection, use, and maintenance.

case analysis

Understand the common causes and solutions of chain fatigue damage through practical cases. For example, a chemical plant used stainless steel lever hoists for long-term overloading, resulting in chain fatigue and breakage, causing equipment damage and personnel injuries. This case reminds us that we must strictly follow the usage regulations and avoid dangerous behaviors such as overloading.

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment