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Understand Thread Scratches in Threaded Parts

Apr. 07, 2020

Scuffing refers to the wear that occurs due to friction when two metal surfaces happen to be in sliding contact with each other. Screw fittings are common in threaded fasteners made of stainless steel, steel, aluminum or brass. Therefore, the correct steps must be taken from the beginning to reduce the risk and occurrence of thread wear. What is the impact of thread wear? What precautions must be taken to protect threaded components such as fasteners, nuts and screws from wear? Read the following posts to get answers to these questions.

How does scratching affect the design of threaded parts?

Scratches can cause threaded fasteners, screws and bolts to bulge, wear or tear. When the surface of the threaded component is eroded, they leave a small cavity or hole in it. This causes microscopic particles to accumulate in the cavity of the threaded portion. This will affect the design and efficiency of threaded components such as fasteners, nuts and screws. The following are some of the negative effects of wear, which seriously affect the design and structure of mechanical components. Opportunities for early failure: Scuffing causes stress, stress and tears in the thread. This may eventually lead to structural deformation of the threaded component.

Threaded Fittings

Threaded Fittings

Harsh operating environment: One of the main problems is the entry of tiny particles and debris inside the threaded fittings. These particles may affect the efficiency of mechanical parts.

Expensive repairs: The threads of fasteners, nuts or screws may require repair. As the structure of the threaded parts deforms, it becomes difficult to repair them. External thread wear is easy to repair, while internal thread wear is expensive due to the structure of the mechanical components.

How to take care of thread scratches?

Take various effective measures to prevent thread wear. Here are some measures:

Thread lubrication: The use of special anti-wear lubricants can help reduce the coefficient of friction and wear in threaded fasteners. In addition, various threads are coated with polytetrafluoroethylene (PTFE) to eliminate any chance of rust or corrosion between the threads. These coatings are most suitable for stainless steel fasteners that require abrasion resistance and chemical resistance.

Minimize wrench speed: Heat is the main cause of wear of stainless steel screwed fittings. During fastener installation, as the speed of the wrench increases, more heat is generated. Therefore, reducing the speed of the wrench helps to reduce the heat it generates.

Use coarse threads: Choosing coarse threads on fine threads helps reduce wear. Thick threads are more tolerant of abuse during processing. In addition, due to the larger thread margin (gap between actual and basic thread profile) helps prevent fasteners and nuts from wearing out.

Ensure tight tolerances: High tolerances for threaded fasteners can help avoid wear. This also makes the fastener less prone to any slippage or friction. Thread rolling ensures that threaded fasteners, nuts or bolts have the same dimensions and tolerances.

All these strategies to prevent scratches help to extend the life and efficiency of threaded fasteners, nuts or screws. If planned in advance, it can also help avoid expensive repairs and maintenance.