Chain hoist chain strength test: comprehensive analysis and key steps

Chain Hoist chain strength test: comprehensive analysis and key steps
In the fields of industry, construction and logistics, chain hoists are common lifting tools, and their chain strength is directly related to the safety and reliability of the operation. For international wholesale buyers, understanding the specific steps of chain hoist chain strength test will help choose high-quality and safe products. This article will elaborate on the whole process of chain hoist chain strength test, including preliminary preparation, test methods and precautions.

1. Preparation before test
(I) Equipment inspection
Appearance inspection of chain hoist: Carefully check whether the shell of the chain hoist has obvious damage such as cracks and deformation, whether the hook opening exceeds 15% of the original size, whether the chain pitch is elongated by more than 3%, and whether the friction plate thickness wear reaches 10% of the standard value.
Test instrument calibration: Ensure that the tensile testing machine, force sensor, displacement sensor and other test instruments used have been calibrated and are within the effective calibration cycle to ensure the accuracy and reliability of the test data.
Installation of test equipment: Install the hand chain hoist correctly on the test equipment, such as connecting the hand chain wheel of the hand chain hoist to the non-contact torque meter through a matching ring-shaped closed chain and a measuring hand chain wheel to ensure that the connection is firm and reliable.
(II) Test plan formulation
Determine the test standard: According to relevant industry standards and specifications, such as JB/T 7334-2016 "Hand Chain Hoist", clarify the load requirements, test methods and qualification standards of the test.
Set test parameters: According to the rated lifting capacity of the hand chain hoist and specific test requirements, set the load level, loading rate, number of tests and other parameters of the test.
(III) Personnel and safety preparation
Confirmation of personnel qualifications: Personnel participating in the test should have corresponding professional knowledge and operating skills, and be familiar with the operating procedures and safety precautions of the test equipment.
Safety protection measures: Set warning signs in the test area and equip operators with necessary personal protective equipment, such as safety helmets, protective gloves, goggles, etc., to ensure the safety of personnel during the test.

2. Chain strength test method of hand chain hoist
(I) Static load test
No-load test: In the case of no load, reciprocate the forward rod and the reverse rod three times to observe the working condition of the hand chain hoist mechanism to ensure that there is no jamming.
Rated load test: Hang the hand chain hoist on the bracket, gradually increase the load to the rated lifting weight, make the lower hook rise and fall once, check the meshing of the lifting chain and the lifting sprocket, the cruise ship, the hand chain and the hand chain wheel, and the operation of the gear pair, and require no abnormality.
Overload test: Increase the load to 1.25 times the rated lifting weight, keep it for 10 minutes, observe whether the chain and hook are deformed or cracked, and focus on the meshing accuracy of the gear set and the self-locking performance of the brake.
(II) Dynamic fatigue test
Loading and operation: Install the hand chain hoist on the hand chain hoist tensile test machine, load it according to the set test load, and drive it manually or by other similar manual mechanical methods to make the hand chain hoist lift and lower at a certain speed. Generally, the linear speed of the hand chain is about 20m/min.
Cyclic operation: Simulate the actual operation scene, use the rated load to perform multiple cyclic lifting and lowering operations, such as continuous lifting and lowering 1500 times, each lifting, stopping, lowering, and stopping is a cycle, and record the wear rate of the transmission parts. If the chain elongation exceeds 3% during the test, it is determined that the equipment has the risk of material fatigue failure.
(III) Environmental adaptability test
Salt spray test: Place the hand chain hoist in a salt spray chamber, set the parameters such as salt spray concentration, temperature and humidity, and continuously expose it for 72 hours, and then test the corrosion resistance of the outer shell and internal parts, paying special attention to the sealing of welding points and joints.
High temperature and high humidity test: put the equipment into a high temperature and high humidity box, run it under the set high temperature and high humidity conditions for a period of time, and observe the performance changes of the hand chain hoist, such as the lubrication of the chain, the reliability of the brake, etc.
(IV) Other tests
Hook test: on the material testing machine, gradually load to 2 times the rated load through the center of the hook cavity, stay for 1 minute and then unload the load, check the deformation of the hook mouth, which shall not exceed 0.25%; continue to load to 4 times the rated load, the hook should be able to support reliably for 1 minute.
Reliability test: under the rated load, continuously reciprocate the forward rod and the reverse rod to make the cumulative round trip stroke of the wire rope not less than 120m, which can be divided into four times, but the cumulative stroke of the wire rope each time is 30m, and the interval time between each time shall not exceed 1h. The wire rope is not allowed to be replaced during the test, and there shall be no abnormality in the various parts of the hand chain hoist.

3. Recording and analysis of test data
(I) Data recording
Real-time recording: During the test, the data acquisition system is used to record key parameters such as tension, displacement, time, etc. in real time to ensure the accuracy and completeness of the data.
Result recording: Record the results of each test, including detailed information such as load size, loading time, deformation of the chain and hook, and performance of the brake.
(II) Data analysis
Strength analysis: According to the test data, evaluate the strength performance of the hand chain hoist chain under different load conditions to determine whether it meets the design requirements and relevant standards.
Fatigue life analysis: Through the data of dynamic fatigue test, analyze the fatigue life of the chain and predict its reliability in long-term use.
Environmental adaptability analysis: Combined with the results of environmental adaptability test, evaluate the corrosion resistance and performance stability of the hand chain hoist chain under different environmental conditions.

4. Inspection and maintenance after testing
(I) Equipment inspection
Appearance inspection: Check the appearance of the hand chain hoist again to see if there is obvious damage or deformation, especially the chain, hook and key connection parts.
Functional inspection: Operate the hand chain hoist under no-load and light-load conditions to check whether its lifting, lowering and braking functions are normal.
(II) Maintenance
Cleaning and lubrication: Clean and lubricate moving parts such as chains and gears to reduce wear and extend the service life of the equipment.
Parts replacement: If damaged or severely worn parts such as chains and friction plates are found during the test, they should be replaced in time.

5. Summary
The chain hoist chain strength test is an important part to ensure its safety and reliability. Through a strict testing process, the performance of the chain hoist chain can be fully evaluated. From preparation before the test to maintenance after the test, every step needs to be taken seriously to ensure the accuracy and reliability of the test results. For international wholesale buyers, choosing hand chain hoist products that have been strictly tested and have reliable quality is the key to ensuring operational safety and reducing operational risks. I hope that this article's introduction to the chain hoist chain strength test can provide you with valuable information to help you better understand and choose hand chain hoist products.