The application of stainless steel screws has been popularized in our daily life, but many of the common problems of stainless steel screws are still well understood, such as broken stainless steel screws, locked stainless steel screws, blackened stainless steel screws, etc. . According to specific understanding, China Standard Parts Network summarized some common problems and corresponding solutions of stainless steel screws, so that everyone can have a more comprehensive understanding of stainless steel screws.
1. Blackening of stainless steel screws
Reasons for blackening of stainless steel screws:
The blackening of stainless steel screws is usually caused by the heat generated when cold heading or rubbing teeth. Usually occurs in the cross groove part. In the production process, through the supply of lubricating oil, the heat can be distributed in time, and the speed of the machine can be appropriately adjusted down to avoid problems. Of course, in addition to technical reasons, the blackening of stainless steel screws may also cause the material of the stainless steel screws themselves to cause blackening of the surface of the stainless steel screws.
Stainless steel screw blackening solution process flow
Degreasing-over water-cross groove cleaning agent-over water-neutralization-over water-drying; warm 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 Neutralize, soak for 5-15 minutes, clean water, neutralize, and blow dry.
Second, the problem of stainless steel screws
The main reasons for loose stainless steel screws:
Spontaneous bolt loosening-shock, vibration, dynamic loads
Relaxation-settlement, creep, relaxation
In order to prevent spontaneous loosening, it is necessary to eliminate the sliding between the connecting parts, or at least reduce it below the critical level. This can be achieved by increasing the axial tension, increasing the friction between the clamping components or reducing the cyclic load-for example, shock, vibration or cyclic thermal load.
Stainless steel screw anti-loosening solution:
The first kind uses the rebound of special materials, such as engineering resin material, which has good rebound. Attach it to the stainless steel screw thread pattern. Make it mechanically friction with the nut, or material products. Generate vibration and absolute resistance. Completely solve the problem of loose screws.
The second way is to simply put a layer of glue on the threads of stainless steel screws, so-called dispensing. This kind of glue is called anti-drop glue. This glue has good properties such as high adhesion and non-toxicity. This glue is coated on stainless steel screws, after drying, the adhesion is super strong. The stainless steel screw thread can be combined with the screw thread of the nut, or after the product screw hole is joined, to produce a super-fast fastening effect. Play a super good anti-loosening effect.
3. Corrosion and rust of stainless steel screws
Common factors of stainless steel screw corrosion and rust:
1.The attachments of dust or heterogeneous metal particles, in humid air, the attachments and the condensate of the stainless steel screws connect the two into a microbattery, which triggers an electrochemical reaction and the protective film is damaged. Chemical corrosion.
2. The organic matter juice (such as melon and vegetable, noodle soup, sputum, etc.) adheres to the surface of the stainless steel screw. In the presence of water and oxygen, it forms an organic acid, which will corrode the metal surface for a long time.
3. The surface of stainless steel contains acid, alkali and salt substances (such as alkali water and lime water splashing on the decoration wall), causing local corrosion.
4. In contaminated air (such as an atmosphere containing a large amount of sulfides, carbon oxides, and nitrogen oxides), when it encounters condensed water, it forms sulfuric acid, nitric acid, and acetic acid liquid spots, causing chemical corrosion.
The solution after stainless steel screw corrosion and rust:
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. 316 stainless steel should be used in the seaside area, which can resist seawater corrosion.
3. The chemical composition of some stainless steel pipes on the market can not meet the corresponding national standards, and can not meet the requirements of 304 materials. Therefore, it will also cause rust, which requires users to carefully select products from reputable manufacturers.
After the surface of the stainless steel screw is rusted, it will not only affect the appearance of the appearance, but also affect the performance of the product itself to a certain extent. Therefore, care should be taken when using stainless steel screws to prevent premature rust and corrosion. Specifically, it can also be processed according to the method introduced above. For more knowledge of mechanical accessories, Fuxin Network platform will continue to provide you with follow-up.
Fourth, the problem of stainless steel screw breakage
Reasons for breaking stainless steel screws:
Sometimes, iron screws are often broken, and sometimes stainless steel screws are broken. But in general, stainless steel screws rarely break. Because the stainless steel screw wire 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 fracture of stainless steel screws are as follows:
1. The quality of raw materials used for stainless steel screws is not good. There are many impurities, impure, which leads to insufficient hardness of stainless steel screws.
2. The process of producing stainless steel screws. For example, the eccentric stainless steel screw, and the Q value is too deep and the R position design is too small during the down punching operation during manufacturing.
3. The customer uses too much force when using stainless steel screws. Generally, you do the torque test to see what the minimum breaking force is, and then adjust the torque.
Ways to prevent stainless steel screws from breaking:
1. Sega horn;
2. Improve the screw processing technology;
3. Improve the standard section processing technology.
5. The problem of stainless steel screw locking
Causes of stainless steel screw lock
1. The deflection angle of the thread fit and the softer characteristics of stainless steel can easily cause the locking of stainless steel screws
1. The combination of stainless steel screws and stainless steel nuts is a clearance fit, which has their own implementation of international standard tolerances. Therefore, the center axis of the internal and external threads is basically not on the same straight line when they are fitted. The contact surface of the internal and external threads should be reduced for inclination.
Causes and solutions of stainless steel screw lock
2. The greater the deflection angle of the stainless steel screw and the stainless steel nut, the smaller the force-bearing area of the thread fit, and the more easily the tooth pattern is damaged.
3. The uneven force or tilt during the locking process causes the central axis of the stainless steel screw and stainless steel nut to be tilted to the maximum, so that the action surface of the stainless steel screw and the stainless steel nut thread is not completely in contact, and the surface force is changed to point The force or the force on each unit becomes larger.
4. Stainless steel screws are softer than carbon steel screws. If iron chips are rubbed off during the locking process, they will stick and not fall, thereby interfering with the smooth entry and exit of the thread, causing the tooth bottom to die on the top of the tooth.
2. The excessive locking force and the low thermal conductivity of stainless steel can easily lead to the locking of the thread
1. Due to the heat generated by friction during the rotation of the screw nut, the thermal conductivity of stainless steel is relatively low.When the generated pressure and heat destroy the chromium oxide layer (the oxide layer that is not easy to rust in stainless steel), the metal tooth pattern occurs directly. Blockage, coupled with the softer properties of stainless steel, causes sticking. The greater the locking force, the greater the heat generated, and the more easily the stainless steel of the screw mountain is stuck.
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 before the nut can be turned. When the nut rotates down along the thread line, the stainless steel screw will be stretched due to the reaction force. When the torque (locking force) exceeds the screw's yield point (that is, the safe torque), the screw will have residual strain and remain in the elongated state . When the screw extends beyond its elastic range, it will permanently deform and cause the thread to lock.
The solution of stainless steel screw lock
In view of the above-mentioned reasons that are prone to lock-up, the use of stainless steel screws requires as much attention as possible:
1. Keep the central axis of the stainless steel screw and stainless steel nut perpendicular to the locked surface to reduce the deflection angle.
2. Use a manual wrench as much as possible to slow down the locking speed and keep the threads clean. Use lubricating oil to reduce the friction coefficient and reduce heat energy, thereby reducing adhesion.
3. Use torque wrench or socket wrench as much as possible to avoid excessive force and control the torque within the safe torque range.
4. Choose relatively high hardness products to reduce thread shear.
5. The use of stainless steel anti-locking agent has obvious effect on reducing the locking ratio.
Link to this article：Five Major Problems And Solutions Of Stainless Steel Screws
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