Stainless steel screws becoming stuck and immovable due to “galling” or “seizing” is a problem that significantly reduces work efficiency. In this article, we will explain in detail the causes of galling in stainless steel screws, effective prevention methods, and how to deal with them if galling occurs.

Why Stainless-Steel Screws Are Prone to Seizing

Thread seizing is a phenomenon that occurs when frictional heat generated during screw tightening causes the threads to expand, leading the metals to fuse together and seize. If tightening is forced further, the screw may even break.

＜The main reasons stainless steel screws are prone to seizing include>
✓ High coefficient of friction and heat buildup
Stainless steel has a higher coefficient of friction compared to carbon steel, and once frictional heat occurs, it tends to accumulate locally.
✓ High thermal expansion rate
When heated, the male and female threads come into even tighter contact, which promotes galling.

In addition, seizing is also more likely under the following conditions:
• Tightening with excessive torque
• Contamination in the threads, such as metal shavings or debris
• Poor thread surface quality, roughness, or burrs
• Forcing misaligned screws into holes
• Use in high-temperature environments (such as outdoors in summer, near heating equipment, or during welding work)

Effective Countermeasures to Prevent Galling in Stainless Steel Screws

To prevent seizing, it is important to implement the following measures:

1. Proper Tightening Methods

• Tighten slowly by hand
Avoid using high-speed power tools, as they rapidly increase frictional heat.
• Ensure proper torque management
Excessive tightening force is a major cause of galling.
• Clean the threads
Remove chips, dust, and burrs in advance to reduce friction.

2. Use of Lubricants
Applying lubricants helps lower the coefficient of friction and effectively prevents galling.

3. Use of Specially Processed or Pre-Coated Screws
Using fasteners that are pre-coated with fluor resin or lubricants improves work efficiency and helps prevent galling.

How to Deal with Galling in Stainless Steel Screws

• Cutting or drilling for removal (in cases of complete seizure)
• Use of special penetrating lubricants
• Use of an impact driver

Key Points to Prevent Galling in Stainless Steel Screws

• Tighten slowly by hand
• Clean the threads and apply lubricants
• Use screws with special surface treatments or pre-applied coatings

At Hanshin Neji (Thailand), we offer anti-galling solutions, optimal lubricants, and specially processed screws. If you have any concerns related to fasteners, please feel free to contact us. Our expert staff will provide the most suitable recommendations according to your situation.