Principles for Chain Selection

1. Match Load Requirements

• Load type:

• Static loads: For stable, low-vibration loads (e.g., conveyor systems), prioritize chains with sufficient tensile strength (refer to the manufacturer’s specified rated breaking load).

• Dynamic/impact loads: For scenarios involving frequent starts/stops, sudden load changes, or vibrations (e.g., construction machinery), select chains with high fatigue resistance and impact toughness, such as alloy steel chains or those with reinforced pins.

• Load magnitude: Calculate the actual working load (including impact factors and safety margins) to ensure it does not exceed the chain’s allowable working load. Typically, chain specifications (e.g., pitch, chain number) are determined using formulas or manufacturer-provided selection manuals based on parameters like transmission power and rotational speed.

2. Adapt to Working Environment

• Temperature conditions:

• For high-temperature environments (e.g., drying equipment, metallurgical machinery), use high-temperature-resistant chains. Their pins, rollers, and other components employ high-temperature lubricants and heat-resistant materials (such as nickel-chromium alloys) to prevent lubrication failure or reduced material strength.

• For low-temperature environments (e.g., cold storage conveyors), select chains with good low-temperature toughness to prevent brittle fracture, paired with low-temperature-specific lubricants.

• Corrosive environments:

• In humid, dusty, acidic, alkaline, or salt-spray environments (e.g., food processing, chemical equipment), prioritize stainless steel chains (e.g., 304 or 316 grades) or chains with anti-corrosion treatments (such as galvanizing or chrome plating) to reduce the impact of rust on transmission.

• Dusty/abrasive environments:

• For dusty or particle-laden scenarios (e.g., mining, construction), use enclosed chains or those with dust covers. Additionally, enhance lubrication and regular cleaning to prevent abrasive particles from entering hinges and accelerating wear.

3. Match Transmission Parameters

• Rotational speed and velocity:

• For high-speed transmission (e.g., machine tool spindles, automotive engine timing systems), select small-pitch chains (e.g., 08A, 10A) for stable operation and reduced centrifugal force. For low-speed, heavy-load scenarios (e.g., lifting equipment), large-pitch chains are suitable due to their higher load-carrying capacity.

• At excessively high speeds, consider the chain’s critical rotational speed to avoid slack or tooth skipping caused by excessive centrifugal force.

• Transmission ratio and center distance:

• For large transmission ratios, multi-stage transmission or toothed chains (silent chains) are recommended to reduce uneven wear in single-stage transmission. For small center distances, prioritize small-pitch chains to minimize impact; for large center distances, appropriately increase the pitch and add tensioning devices to prevent excessive chain sag.

4. Compatibility with Sprockets

• Consistent pitch: The chain pitch must strictly match the sprocket pitch to avoid poor meshing, increased vibration, or even tooth skipping and chain breakage.

• Tooth profile adaptation: Roller chains must match standard roller sprocket tooth profiles, while toothed chains must align with the groove shape of toothed sprockets to prevent localized stress concentration due to mismatched profiles.

• Material coordination: The hardness of chains and sprockets should be reasonably paired (typically, sprocket surface hardness is slightly higher than chain roller hardness) to reduce mutual wear. For example, high-strength chains require quenched sprockets to prevent premature sprocket wear.

5. Consider Maintenance and Economy

• Maintenance convenience: For scenarios with difficult frequent maintenance (e.g., high-altitude equipment, underwater transmission), prioritize maintenance-free chains (such as self-lubricating chains) or easily detachable chains to reduce maintenance frequency.

• Cost balance: Standard roller chains (e.g., ISO-standard chains) are suitable for general working conditions due to their low cost and high versatility. Special working conditions (e.g., high temperature, corrosion) require specialized chains; although initial costs are higher, long-term failure rates and replacement costs are reduced.

• Service life expectations: Select chain grades based on the equipment’s design life. For example, economical chains may suffice for short-term temporary equipment, while high-strength, high-fatigue-life chains (e.g., carburized chains) are necessary for long-term continuous operation of critical equipment.

6. Adhere to Industry Standards and Specifications