The Quality Problem Of The Carriage Bolt Manufacturer

At present, China is already the world’s largest bolt producer, but it has been facing claims for quality problems. The case of quality problems caused by the quality of steel products is a big part of China. Bolted steel still needs to be expanded under the premise of meeting strict quality standards.

At present, China is already the world’s largest bolt producer, but it has been facing claims for quality problems. The case of quality problems caused by the quality of steel products is a big part of China. Bolted steel still needs to be expanded under the premise of meeting strict quality standards.

In recent years, Chinese bolt companies have been claimed by customers because of the quality of their products. In these cases, it is largely due to the use of bolt steel.

At present, there are roughly 400,000 varieties and bolts of various sizes and sizes at home and abroad. Their use and environment are ever-changing. The bolt acts as the connecting part of the main unit and the component, and together with the mainframe, bears the basic performance of the main body and the basic functions of the component.

With the host, it is tested in a variety of harsh service environments. There are various occasions such as high temperature, high pressure, low temperature, vibration, corrosion, heavy load, alternating stress, anti-shear and anti-torsion. For example, the bolts used in some parts of the spacecraft must withstand the test of high temperature, high pressure and vibration. After entering the track, they must withstand the test of temperature premature change, low temperature and pre-tightening failure under weightless conditions. The probability of an accident or disaster caused by the failure and damage of the bolt is very high. Therefore, the materials used to make the bolts must be strictly selected beforehand. Currently commonly used materials are titanium alloy, steel, copper, aluminum, nylon and other metals, non-metal and other materials.

The steel for bolts (including alloy steel, low alloy steel, carbon steel) has very good ductility and plasticity, which determines its adaptability to various processing techniques, and at the same time has good strength, especially after specific After heat treatment, the expected better overall mechanical properties can be obtained.

Steel (wire or bar) is a finished product for steel mills. It cannot be fully inspected at the time of shipment. Some of them are destructive test items. The factory inspection can only be a sampling test. For bolt manufacturers, it is the raw material for production. When using these materials to make bolts, it is equivalent to 100% inspection of the material. Users of certain specific situations now require bolt manufacturers to provide “zero defect” bolt products. Therefore, in addition to the manufacturer’s strict implementation of the quality control of each process in the production process, the careful and scientific inspection of various quality indicators before leaving the factory, the quality of the selected raw materials is decisive for the final quality of the finished bolts.

Many performance quality indicators for bolts are provided by the parent metal. It is a very large number of commodity bolts that are generally required. Due to the application of advanced technology, such as the application of high-speed cold heading and fully automatic continuous heat treatment production line, the hardness of the raw materials used for cold rolling, the mass fraction of chemical components, and the raw materials. The uniformity of the performance of the bars has higher requirements.

In this regard, in addition to the need to strengthen innovative R&D, domestic Carriage Bolt Manufacturer need to expand their production capacity while ensuring quality.

Haiyan Yihui Has Rich Experience In Manufacturing DIN 603 Bolts

  1. tempering test
    Bolts, screws and studs of class 8.8~12.9 shall be tempered according to the minimum tempering temperature in actual production and kept at 10 °C for 30 min. On the same sample, the difference between the average values ​​of the three points before and after the test shall not exceed 20 HV.
    The tempering test can check the incorrect operation due to insufficient quenching hardness and too low temperature tempering to barely reach the specified hardness range, and ensure the comprehensive mechanical properties of the parts. In particular, threaded fasteners made of low-carbon martensitic steel are tempered at low temperatures. Although other mechanical properties can be achieved, the residual elongation fluctuates greatly when measured to ensure stress, much larger than 12.5 um. Moreover, sudden breakage can occur under certain conditions of use. In some automotive and construction bolts, sudden breakage has occurred. This can be reduced by tempering with a minimum tempering temperature. However, special consideration should be given to the manufacture of 10.9 bolts from low carbon martensitic steel.
    2. Hydrogen embrittlement inspection
    The sensitivity of hydrogen embrittlement increases as the strength of the fastener increases. For the externally threaded fasteners of 10.9 and above or the surface hardened self-tapping screws and the combination screws with hardened steel washers, the hydrogen removal treatment shall be carried out.
    The hydrogen removal treatment is generally carried out in an oven or a tempering furnace at 190 to 230 ° C for 4 hours or more to diffuse hydrogen.
    Threaded fasteners can be tightened by tightening on a special clamp to maintain the screw with a relatively constant stress, for 48 hours. After the loosening, the threaded fasteners will not break. This method is used as a method of checking for hydrogen embrittlement.
    Haiyan Yihui Hardware Technology Co., Ltd. is a professional bolt design and manufacturer. We have rich experience in designing and manufacturing DIN 603bolts, which can provide you with quality products and comprehensive after-sales service, so quickly put your needs. Tell us.

Carriage Bolt Manufacturer Introduce Products

What is the scope of use of body bolts now? What is the name of the body bolt? What is the way to body bolts? Let’s analyze and analyze together.

Body bolts alias carriage bolts, semi-circular head square neck bolts! This bolt was produced and used earliest 20 years ago! The original purpose is used for the combination of iron and wood on the carriage, so it is also called the body bolt. Because the head is a semi-circular head, there is a square neck under the head, also called semi-circle. Head square neck bolts, or large round head square neck bolts! The international code for body bolts can be divided into three types, GB14 GB12 GB794, and German standard can be divided into DIN603/Inch American-made, American-made British body bolts. Today’s modern body bolts are widely used in applications such as: electronics manufacturing, machinery and equipment, chemical industry, Valve industry, medical equipment industry, automobile industry, aviation industry, etc.

After reading the above content, I believe everyone will already know the scope of use of body bolts. If you want to buy reliable body bolts, then Haiyan Yihui is your choice not to be missed. We are a professional Carriage Bolt Manufacturer, can provide you with comprehensive solutions and product design and manufacture. I believe we will not let us choose. You are disappointed.

What Is The DIN 603 Bolt Installation Requirement?

DIN 603 bolts must comply with the relevant requirements during the installation process, so that the quality of DIN 603 bolts can meet the standard. Let’s take a look at the installation requirements of DIN 603 bolts.

  1. When assembling the DIN 603bolt connection pair, the side of the nut with the round table should face the chamfered side of the washer. For large hexagonal DIN 603bolted couplings, the chamfered side of the lower bolt head should face the bolt head.
    2. When installing DIN 603 bolts, it is strictly forbidden to force the bolts (such as hammering). If it is not free to be introduced, the hole shall be trimmed with a tap. The maximum diameter of the hole after trimming shall be less than 1.2 times the bolt diameter. When repairing holes, in order to prevent iron filings from falling into it, the bolts around the holes should be tightened before reaming. It is forbidden to cut the hole by gas cutting.
    3. When installing DIN 603 bolts, the friction surface of the components should be kept dry and should not be used in the rain.
    4. When the DIN 603 bolt is tightened, only the torque is applied to the nut. Allow bolts only when space is limited.
    5. The tightening of DIN 603 bolts is divided into initial screwing, double screwing and final screwing. The initial tightening torque is 50% of the construction torque, and the first bolt tightening is performed symmetrically with a quick wrench. The re-twisting torque is equal to the initial tightening torque, and the tower connecting bolts are fastened in a symmetrical star shape with a hydraulic wrench. In order to prevent omission, the high-strength bolts after initial screwing, double-threading, and final screwing should be marked with a color on the nut. After inspection, the DIN 603 bolt is marked with a different color on the nut.
    6. When the DIN 603 bolt is screwed at the beginning, the second twist and the final screw, the bolts at the joint should be screwed in a certain order. Generally, the bolts should be tightened outward in the center of the bolt group.
    7. The initial, double and final screwing of DIN 603 bolts should be completed on the same day. Do not finish the final screwing until the next day.

After reading the above, I believe everyone knows the installation requirements for DIN 603 bolts.

DIN 603 Bolt Material Selection

What are the main considerations for the selection of DIN 603 bolt materials?
Requirements for the mechanical properties of the bolt material, in particular the strength;
Requirements for the corrosion resistance of materials under working conditions;
The operating temperature requirements for the heat resistance (high temperature strength, oxidation resistance) of the material;
Requirements for material processing performance in terms of production process;
Other aspects, such as weight, price, and purchasing factors, should be considered.
After comprehensive consideration of these five aspects, determine the grade, variety, specifications and material standards of the selected bolts.
There are many kinds of bolts for the manufacture of materials. Among them, the bolts made of stainless steel are more textured in appearance, have better performance in strength, and have the advantages of corrosion resistance, easy manufacture, and good welding. Stainless steel bolts can be plated or heat treated for better performance and can be recycled.
The use of stainless steel as the material of the bolt can be said to have great advantages in all aspects of manufacturing, use or handling. Therefore, although the bolt is made of stainless steel, the cost itself is relatively high, and the cycle life is relatively short, but in the bolt solution However, it still belongs to a more economical one.
Use of nickel in bolts
Bolts used to rely on the use of nickel in the process of using stainless steel, but the price of bolts has also been greatly affected by the global price of nickel. In order to reduce the cost pressure and improve the competitiveness of the bolts, bolt manufacturers have found alternative materials and produced low-nickel DIN 603 bolts.
Stainless steel magnetic problem with bolts
If the bolt is made of stainless steel as the main material, you should also understand the magnetic problem of the stainless steel itself. Stainless steel is generally considered to be non-magnetic, but in fact, austenitic series materials may be magnetic after a certain processing process, but if it is considered that magnetic is the standard for judging the quality of DIN 603 bolts, it is also inaccurate.

DIN 603 Bolt Production Details

Haiyan Yihui Hardware Technology Co., Ltd. and everyone to understand the specific standards of DIN 603 bolt production, and other details that need attention, together with us to understand all aspects of DIN 603 bolt production.

Other standards for DIN 603 bolt production are standards for the production of DIN 603 bolting work, drawing the drawing standards for the screw samples given by the customer, the tolerance standards for the production, the standard of the heads of the production masters, and the production of the screws. Electroplating standards and some testing standards, etc.