DRIVE CHAINS - Tsubaki

Before Use For Safe UseStandard Roller Chains Lube-Free Roller Chains Heavy Duty Roller Chains Corrosion Resistant Roller Chains Specialty Roller Chains Accessories Selection Handling8. Cautions on Use in Special EnvironmentsAs a general rule, roller chain should be used in a clean air flow; however, when used in a specialatmosphere, reference should be made to the various items that follow.8.1 Use in wet conditionsIf the chain is used in a sterilizing machine or water screen, for example, where the chain is splashed withwater or goes through heated vapor, the following problems may occur.1) An increase in abrasive stretch due to improper or insufficient lubrication.2) Decrease in fatigue strength from rust and corrosion (pitting) of the chain.1) Countermeasures(1) Reduce bearing pressure using a larger sized chain to improve wear resistance.(2) Use corrosion resistant roller chain for rust prevention.8.2 Use in acidic or alkaline conditionsIf roller chain is exposed to acids or alkaline conditions, such as battery acid and liquid used in platingprocesses, the following problems may occur.1) Embrittlement fracture of link plates and pins.2) Fatigue breakage of link plates and pins due to rust and pitting corrosion.3) Wear from usual mechanical abrasion and corrosion.4) Reduction in volume of the whole chain from corrosion.5) In special cases where the chain is underwater (immersed in liquid),electrochemical corrosion may occur.6) There are also circumstances where even stainless steel roller chain willcorrode. Fig. 31 shows an example of chain that was used in a platingapparatus. The chain fell to pieces within one month due to the affect ofthe acid.Fig. 31 Corrosion of stainless steel roller chain1) Countermeasures for embrittlement fractures (Stress corrosion cracking) Adopt a brittleness countermeasure that lowers crack susceptibility. Install a cover or casing to prevent acids or alkalis from contacting the chain. Adopt a high-grade material with anti-corrosive properties.2) Countermeasures for corrosion Use surface-treated chain. Install a cover or casing to prevent acids or alkalis from contacting the chain. Adopt a high-grade material with anti-corrosive properties.In general, embrittlement fractures (stress corrosion cracking) occur aroundthe link plate holes. This is the area where the pin and bush are press-fitted Fig. 32. Hydrogen embrittlement crackingto the link plate having the highest concentration of stress. Cracks aregenerated even when there is no tension on the chain. Roller chain ingeneral is more susceptible to acids than alkalis, and in special cases,embrittlement fractures (stress corrosion cracking) are generated byseawater or pit water.8.3 Use under conditions where abrasion is a problemIf the chain is exposed to strong abrasive materials that promote wear such as sand, coke and metalparticles, the following problems may occur:1) When abrasive materials penetrate between the pins and bushes, chain wear is promoted and poor articulationoccurs.2) When abrasive materials penetrate between the bushes and rollers, chain wear is promoted and poor rollerrotation occurs.3) When the abrasive materials penetrate between the link plates, poor articulation occurs.1) CountermeasuresApply a dust-protection casing.Remove foreign particles by regularly washing the roller chain.Reduce bearing pressure using a larger sized chain to improve wear resistance.Increase abrasion resistance by applying special processing to the parts of the chain where abrasion is aproblem.169