Five Common Problems And Solutions For Stainless Steel Screws

The application of stainless steel screws has been popularized in our daily life, but many friends still don't know much about the common problems of stainless steel screws, such as broken stainless steel screws, locked stainless steel screws, blackening of stainless steel screws, etc. . Then based on the specific understanding, Xiaorui summarizes some common problems of stainless steel screws and the corresponding solutions here, hoping to have some understanding of stainless steel screws for everyone.

【1】. Blackening of stainless steel screws

The reasons for the blackening of stainless steel screws:

The blackening of stainless steel screws is usually caused by too much heat generated during cold heading or rubbing. Usually occurs in the cross groove part. During the production process, the supply of lubricating oil can realize the timely dispersion of heat, and the speed of the machine can also be appropriately lowered to avoid problems. Of course, in addition to technical reasons for the blackening of stainless steel screws, it is also possible that the material problems of the stainless steel screws themselves will also cause the surface of the stainless steel screws to turn black.

Solution process for blackening of stainless steel screws

Degreasing - water - cross groove cleaning agent - water - neutralization - water - drying; heat the stainless steel screw cross groove cleaning agent to 70 degrees, and then put the stainless steel screw product into the cross groove cleaning agent after degreasing Medium, soak for 5-15 minutes, rinse with clean water, neutralize, and blow dry.

【2】. The problem of anti-loosening of stainless steel screws

The main reasons for the loosening of stainless steel screws:

Spontaneous Bolt Loosening - Shock, Vibration, Dynamic Loads

relaxation - settlement, creep, relaxation

To prevent spontaneous loosening, sliding between connected parts needs to be eliminated, or at least reduced below a critical level. This can be achieved by increasing axial tension, increasing friction between clamped parts or reducing cyclic loads - for example, shock, vibration or cyclic thermal loads.

Stainless steel screw anti-loosening solution:

The first one is to use the resilience of special materials, such as engineering resin materials, which have better resilience. Attach it to the thread of the stainless steel screw. Make it mechanically rub against nuts, or material products. Generate vibration and absolute resistance. Completely solve the problem of loose screws.

The second, simply speaking, is to apply a layer of glue on the thread of the stainless steel screw, the so-called dispensing. This kind of glue is called drop-resistant glue. This glue has good properties such as high adhesion and non-toxicity. This glue is applied to stainless steel screws and when it dries, it adheres super strong. It can make the stainless steel screw thread combine with the nut thread or connect with the threaded hole of the product to produce super fastening effect. Play a super anti-loose effect.

【3】. Corrosion and rust of stainless steel screws

Common factors for corrosion and rust of stainless steel screws:

1. The attachment of dust or heterogeneous metal particles, in the humid air, the attachment and the condensed water of the stainless steel screw connect the two into a micro battery, which triggers an electrochemical reaction and destroys the protective film, which is called electricity. chemical corrosion.

2. Organic juices (such as vegetables, noodle soup, sputum, etc.) adhere to the surface of stainless steel screws. In the presence of water and oxygen, organic acids are formed, and organic acids will corrode the metal surface for a long time.

3. The surface of stainless steel adheres to acid, alkali and salt substances (such as alkaline water and lime water splashed on the wall for decoration), causing local corrosion.

4. In polluted air (such as an atmosphere containing a large amount of sulfide, carbon oxide, and nitrogen oxide), when it encounters condensed water, it will form sulfuric acid, nitric acid, and acetic acid liquid points, causing chemical corrosion.

The solution to the corrosion and rust of stainless steel screws:

1. The surface of the decorative stainless steel must be cleaned and scrubbed frequently to remove attachments and eliminate external factors that cause modification.

2. The seaside area should use 316 material stainless steel, 316 material can resist seawater corrosion.

3. The chemical composition of some stainless steel pipes on the market cannot meet the corresponding national standards, and cannot meet the requirements of 304 material. Therefore, it will also cause rust, which requires users to carefully choose products from reputable manufacturers.

After the surface of the stainless steel screw is rusted, it will not only affect the appearance of the product, but also affect the performance of the product itself to a certain extent. Therefore, care and maintenance should also be paid attention to when using stainless steel screws to prevent premature rust and corrosion. Specifically, you can also deal with it according to the method introduced above. For more knowledge about mechanical parts, the Fuxin.com platform will continue to provide you with it.

【4】. The problem of broken stainless steel screws

Causes of stainless steel screw breakage:

Sometimes, iron screws are often seen broken, and sometimes stainless steel screws are also seen broken. But generally speaking, stainless steel screws are rarely broken. Because the stainless steel screw wire itself is relatively hard. But under certain circumstances, stainless steel screws will still break. So what are the main reasons for the breakage of stainless steel screws?

The reasons for the breakage of stainless steel screws are as follows:

1. The quality of raw materials used in stainless steel screws is poor, and the quality of stainless steel screw wires is not good. There are many impurities and impurity, which leads to insufficient hardness of stainless steel screws.

2. Process problems in the production of stainless steel screws. For example, stainless steel screws with eccentric heads, and the Q value is too deep and the R position design is too small during the undershoot operation during production.

3. The customer used too much force when using stainless steel screws. Generally, you do a torque test to see how much the minimum breaking force is, and then adjust the torque.

Ways to prevent stainless steel screws from breaking:

1. Saijia Horn;

2. Improve the screw processing technology;

3. Improve the processing technology of the standard section.

【5】, stainless steel screw locking problem

The cause of stainless steel screw locking

1. The deflection angle of thread fit and the softness of stainless steel can easily cause the locking of stainless steel screws

1. The cooperation of stainless steel screws and stainless steel nuts is a clearance fit, and has their respective international standard tolerance ranges. Therefore, when the internal and external threads are matched, the central axes are basically not on the same straight line, and the contact surface of the internal and external threads should be reduced due to inclination.

Causes and solutions of stainless steel screw locking

2. The larger the deflection angle between the stainless steel screw and the stainless steel nut, the smaller the force-bearing area of the thread fit, and the easier the thread is damaged.

3. Uneven force or inclination during the locking process results in the inclination of the central axis of the stainless steel screw and the stainless steel nut being maximized, so that the stainless steel screw and the stainless steel nut thread are not in full contact with the action surface, and the surface force is transferred to the point force force, or the force acting on each unit becomes larger.

4. Compared with carbon steel screws, stainless steel screws are softer. If iron filings fall off due to friction during the locking process, they will stick and not fall off, which will interfere with the smooth entry and exit of the thread, resulting in the bottom of the tooth being stuck on the top of the tooth.

2. Excessive locking force and low thermal conductivity of stainless steel can easily lead to thread locking

1. During the rotation of screws and nuts, heat is generated due to friction, and the thermal conductivity of stainless steel is relatively low. When the generated pressure and heat destroy the chromium oxide layer (the oxide layer that makes stainless steel not easy to rust), the metal teeth will directly occur. Blockage, coupled with the soft nature of stainless steel, and then the phenomenon of adhesion occurs. The greater the locking force, the greater the heat generated, and the easier it is for the stainless steel at the screw teeth to stick.

2. When locking the stainless steel nut, the torque (locking force) must be greater than the friction force of the stainless steel screw and the stainless steel nut itself before the nut can be turned. When the nut rotates and descends along the thread line, the stainless steel screw will be stretched due to the reaction force, and when the torque (locking force) exceeds the screw's yield point (that is, the safe torque), the screw will have residual strain and maintain an elongated state . When a screw is stretched beyond its elastic range, permanent deformation occurs and the threads lock.

The solution to the locking of stainless steel screws

In view of the above-mentioned reasons that are prone to lockup, it is necessary to pay attention to the use of stainless steel screws:

1. Keep the central axis of stainless steel screws and stainless steel nuts perpendicular to the locked surface to reduce the deflection angle.

2. Try to use a manual wrench to slow down the locking speed, keep the thread clean, and use lubricating oil to reduce the friction coefficient and heat energy, thereby reducing adhesion.

3. Use a torque wrench or socket wrench as much as possible to avoid excessive force and control the torque within the safe torque range.

4. Choose products with relatively high hardness to reduce thread shearing.

5. The use of stainless steel anti-lock agent has a significant effect on reducing the lock-up ratio.