Common Fault Analysis and Improvement Suggestions for Stainless Steel Leverage Crane

Stainless steel lever cranes, as light and small lifting equipment, are widely used in the fields of industry, construction, and logistics. Their core components (such as chains, gears, and brakes) are mostly made of stainless steel, which has the characteristics of corrosion resistance and high strength. However, in practical use, malfunctions may still occur due to improper operation, insufficient maintenance, or material defects. The following analyzes common faults from three dimensions: mechanical structure, electrical system, and operating standards, and proposes targeted improvement suggestions.

1、 Common fault types and cause analysis

Mechanical structural failure

Chain breakage

Reason: Overloading caused the chain to stretch due to overloading; The chain has been worn for a long time and has not been replaced in a timely manner; Fatigue of stainless steel material (such as the decrease in toughness of 304 stainless steel in high temperature or corrosive environments).

Case: A factory used a stainless steel lever crane to lift 5 tons of goods (rated load of 3 tons), but the chain broke due to overload, causing the goods to fall.

Gear wear or jamming

Reason: Insufficient lubrication leads to dry friction of gears; Insufficient hardness of stainless steel gears (if martensitic stainless steel is not used); Foreign objects enter the gearbox.

Case: Sand particles were mixed into the gearbox of a crane at a construction site, resulting in increased gear wear and decreased transmission efficiency.

The brakes failed.

Reason: Brake pads are worn and not replaced; Fatigue failure of brake spring; The surface of stainless steel brake is oxidized (such as 2205 duplex stainless steel, which is prone to precipitate brittle phases at high temperatures of 600-1000 ℃).

Case: The brake of a crane in a logistics warehouse was corroded by oxidation, causing the goods to slide during the lifting process.

Electrical system malfunction (for electric type)

Motor overload or burnout

Reason: Unstable voltage leads to abnormal current; Motor winding short circuit; Poor heat dissipation of stainless steel motor casing.

Control panel malfunction

Reason: Sensor malfunction (such as damaged limit sensor); Short circuit or poor contact in the circuit.

Operation specification malfunction

Cable stayed and suspended

Consequence: Causing uneven force on one side of the chain, accelerating wear and even breakage.

Suddenly uninstalling

Consequence: The brake instantly bears impact loads, which can easily cause brake failure.

2、 Improvement suggestions and preventive measures

Mechanical structure optimization

Material upgrade:

Chain: Choose high-strength stainless steel (such as 316L) and conduct regular magnetic particle inspection for cracks.

Gear: Made of martensitic stainless steel (such as 440C) and surface quenched to improve hardness.

Brake: Choose corrosion-resistant stainless steel (such as 2205 duplex stainless steel) to avoid use in high-temperature environments.

Lubrication maintenance:

Gearbox: Replace high-temperature resistant grease (such as lithium based grease) every 3 months.

Chain: Apply stainless steel specific lubricating oil (such as WD-40) every week.

Brake maintenance:

Check the thickness of the brake pads every six months and replace them if it is less than 2mm; Clean the brake wheels and apply rust inhibitor.

Electrical system protection

Motor protection:

Install overload protection devices (such as thermal relays) that automatically cut off power when the current exceeds 120% of the rated value.

Install heat sinks on the motor casing to ensure that the working environment temperature is ≤ 60 ℃.

Line inspection:

Use a multimeter to check the resistance of the circuit every month and eliminate the risk of short circuit; Apply conductive paste to the wiring terminals to prevent oxidation.

Operation specification training

Load management:

Overloading is strictly prohibited. Before lifting, check the weight of the goods against the rated load.

To avoid prolonged full load operation, the motor should not work continuously for more than 30 minutes.

Operation skills:

During lifting, maintain vertical lifting and prohibit diagonal pulling and lifting;

Slowly release the load during unloading to avoid sudden impact on the brake.

Regular drills:

Organize emergency drills every quarter to simulate scenarios such as chain breakage and brake failure, and improve the emergency response capabilities of operators.

Intelligent upgrade

Install monitoring system:

Real time monitoring of parameters such as load, motor temperature, vibration frequency, etc., and automatic alarm in case of abnormal data.

For example, a certain enterprise detected abnormal vibration in the gearbox three days in advance by installing vibration sensors, avoiding a major accident.

Remote monitoring platform:

Centralize the management of multiple cranes, record operational data, and generate maintenance reports.

3、 Typical Case Analysis

Case 1: Chain breakage accident

Problem: The crane chain of a certain factory broke due to overload, causing the goods to fall and damage the equipment.

improvement:

Replace with 316L stainless steel chain and install load limiter;

Provide overload hazard training for operators;

Implement a monthly chain inspection system.

Effect: No similar accidents have occurred again, and the service life of the equipment has been extended by 2 times.

Case 2: Brake Failure

Problem: The brake of a crane in a logistics warehouse malfunctioned due to oxidation and corrosion, causing the goods to slide down.

improvement:

Replace with 2205 duplex stainless steel brake and optimize heat dissipation design;

Add a brake dust cover to reduce the entry of foreign objects;

Perform braking performance testing every six months.

Effect: The braking distance is reduced by 40%, and the safety is significantly improved.

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