Roller Chain Strength Test

Roller chain strength testing is a critical step in ensuring the durability and reliability of industrial chains. By applying controlled tensile force, this test helps manufacturers detect potential defects that may arise from improper material selection, heat treatment issues, or assembly errors. Conducting such evaluations is essential to maintaining consistent quality and performance in demanding applications.

Strength Testing Method

ISO 606 standardization (Short-pitch transmission precision roller and bush chains, attachments and associated chain sprockets) is one of the most commonly adopted testing standards for the chain strength test. Below are some key points when carrying out the test.

Test Chain Length

The chain to be tested for tensile strength should be at least five pitches in length.

Mounting Method

When testing, the connecting between the specimen and the testing machine, apply a tensile force slowly to the ends of chain by using fixtures which permit free movement on both sides of the chain centerline, in the normal plane of articulation.

Tensile Force Application

During the testing, the tensile force should be increased slowly. The extending speed should not exceed 50.8mm/min. As the tensile force increases, the chain will be elongated at the same time, until the highest tensile force to break the chain. The ultimate tensile strength is the maximum stress that the chain can withstand while being stretched before breaking. This can also be reviewed from force/extension diagram; the highest point on stress curve is the tensile strength of the chain.

Invalid Test Conditions

If the fracture or breakage occurs at the connection between the chain and the grip, the test should be considered invalid.

Destructive Testing Note

The chain strength test is a destructive test, which means that the test is accomplished by forcing the chain to fail under stress factors. Even though there is no visibly crack on the surface, the chain should not be used after testing.

Chain Testing Standard

Except welded steel chain, plastic chain, most of the international standards stipulate the tensile strength of the chain. The main standards are listed below:

1. Roller chain: ISO 606, ASME B29.1, JIS B1801
2. Double pitch roller chain: ISO 1275, ASME B29.100, JIS B 1803
3. Leaf chain: ISO 4347, ASME B29.8, JIS B 1804
4. Motorcycle chain: ISO 10190
5. Stainless steel: Currently, only ASME B29.21 (700 Class Chains, Attachments, and Sprocket Teeth for Water and Sewage Treatment Plants) stipulates the tensile strength of stainless steel chain. Chain manufacturers usually produce stainless steel chain referring to the sizes of carbon steel / alloy steel chain standards. However, the tensile strength of stainless steel chain is lower than carbon steel chain. Thus, they are not able to meet the tensile strength standards.
6. Following is the tensile strength comparison table for ISO 606, JIB B1801, ASME B29.1 standards and MCC chain average tensile strength.

Tensile strength of roller chain stipulated by ISO 606, JIS B 1801 and ASME B29.1
Unit (kN)	25	35	41	40	50	60	80	100	120	140	160	180	200	240
ISO/JIS	3.5	7.9	6.7	13.9	21.8	31.3	55.6	87.0	125.0	170.0	223.0	281.0	347.0	500.0
ASME	3.47	7.83	6.67	13.9	21.71	31.27	55.6	86.87	125.1	170.27	222.4	281.47	347.5	500.4
MCC average	4.41	10.29	11.76	18.13	30.38	43.12	76.44	112.7	147.0	196.0	274.4	372.4	470.4	671.3

Reference: Roller Chain References and Standards

MCC’s Chain Testing Machines

MCC has two novel chain testing machines. One is horizontal strength testing machine with 200 tons (2000 kn) and the other is a 20 tons (200 kn) vertical strength testing machine. Both machines are able to test the full range of standard roller chains and leaf chains.

Machine Specifications and Drive System

• The chain testing machines are powered by either hydraulic pressure or electric drive.
• Load is measured using either load cells or hydraulic pressure sensors, ensuring accurate force detection.
• MAXTOP currently operates:
  • A horizontal chain testing machine with a capacity of 200 tons (2000 kN)
  • A vertical chain testing machine with a capacity of 20 tons (200 kN)

Both machines are capable of performing tensile strength tests across the entire range of standard roller chains and leaf chains.

Key Features and Capabilities

• Equipped with latest-generation computer-controlled systems for precision testing.
• Capable of displaying stress-strain curves, as well as calculating elastic limits, yield points, and other critical mechanical properties.
• Customizable test parameters, including:
  • Tensile speed
  • Displacement control
  • Load rate adjustments
• All test results are automatically recorded and stored in a digital database, allowing traceability and data-driven analysis for chain quality improvement and failure prevention.

Applications and Benefits of Chain Testing

Tensile strength testing plays a vital role in ensuring the mechanical performance and long-term reliability of roller chains and leaf chains. Below are the key purposes and advantages of tensile testing in chain manufacturing and quality assurance:

1. To ensure the quality of the MCC’s chains meet or exceed standard requirements.
2. To continually improve and inspect the chain quality. If any abnormalities are found in the chain testing results, they can be further analyzed and improved. Possible abnormal causes are listed below.
   • Material issues: Poor-quality material, using wrong material.
   • Heat treatment errors: Wrong heat treatment condition, abnormal heat treatment equipment.
   • Component defects: Punching position of the plate hole is deviated, short pins.
   • Assembly problems: Missing parts, material mixture.
3. To improve the strength of the chain by testing new material and new heat treatment method.
4. New product development: Testing the strength of the new chain to make sure if it meets the related requirements.