(2) Flux material selection Flux plays the role of isolating air, protecting weld metal from air immersion and participating in the metallurgical reaction of molten pool metal in the welding process. When the welding wire is determined, the matching flux becomes the key material, which directly affects the mechanical properties (especially plasticity and low-temperature toughness), crack resistance, occurrence rate of welding defects and welding productivity of the weld metal.

Inspection, cleaning and detection of pneumatic butterfly valve accessories
In order to improve the application safety of pneumatic butterfly valves, Nova Pipeline has repeatedly paid attention to the standards in the process of application and home care, helping many customers. In order to help customers very well, Jiangyan Xinxing Pipe Fittings Factory specifically summarized some common sense about the inspection, cleaning and inspection of pneumatic butterfly valve fittings in use, so as to facilitate broad customers to refer to them in the application process.
1、 View of application period. Before using the pneumatic butterfly valve that has not been used for a long time, in addition to the visual inspection of whether there is mechanical damage, the resistance between the flange diameters should also be measured according to the rules of GB/T9572-2001. They can be put into use from the beginning only after their review and review results are qualified. Attention shall be paid to the following items when checking: if there is a hose that fits one of the appearances, it shall be scrapped: 1. The appearance is concave and distorted. 2. The inner and outer steel wires present a moving appearance. 3. The outer steel wire is corroded or worn. 4. A loose connector may reveal the appearance. 5. Use an ohmmeter to measure the two ends of the hose to show the appearance of no path. 6. Other wear may be damaged, such as corrosion of the connector, wear may be damaged by external force.
2、 Cleaning during use. 1. The accessories of pneumatic butterfly valve should be stopped cleaning after use, before inspection, or even before long-term storage. The cleaning method should be determined according to the environment and the use of hoses. 2. According to the practical situation, clean water, hot water, detergent and ordinary solution at room temperature can be selected to stop washing. 3. If the hose is used to transport strong acid media before cleaning, the remaining media must be drained before cleaning to prevent heating appearance due to resistance during cleaning. After the transmission of colloidal medium, there should be no residue in the tube to prevent the reaction of the hose during the next use. In addition, steam or compressed air can also be used to clean the hose, but the temperature cannot be too high, and the end of the hose must be open to avoid damage to the fabric and film in the pipe. During the cleaning process, the hose must be grounded.
3、 Check the pneumatic butterfly valve. 1. The viewing place shall be non explosion proof area, and the viewing operation must be stopped under the heading of safety. After the viewing, the person in charge shall make account records. 2. Check at least once a year. 3. Evacuate and clean the hose, and check whether the two end connectors can conduct electricity. 4. The hose whose two end connectors cannot conduct electricity cannot be checked. 5. Put the hose straight and flat on the support or roller bed to ensure that the hose can move under pressure. 6. Close the end of the hose, fill the hose with water, and drain the air inside the hose. 7. Pressurize to 1.5 times of the design pressure, and keep it for more than ten minutes. Check whether there is leakage, and check whether the connectors at both ends of the pneumatic butterfly valve can be powered on under pressure. 8. Release the pressure and drain the liquid in the hose. 9. After the review, it is also necessary to review the conductivity of the hose from the beginning. 10. Under pressure, if the extension length of the hose is significantly greater than that of the rubber hose, this is a normal appearance, and do not mistake the hose as unqualified.
As long as you strictly follow the above process, not only can you ensure the normal and stable operation of pneumatic butterfly valve accessories during the operation period, but also can extend its service life as far as possible. How to distinguish the quality of rubber joint raw materials?