Nickel-based alloy powders are commonly used in plasma transfer arc welding (PTAW) due to their excellent corrosion resistance, high temperature strength, and good weldability. These alloys are typically composed of nickel as the base metal, with various alloying elements added to enhance specific properties. Inconel Powder,Nickel Powder,Pta Welding Ni Alloy Powder,Laser Cladding Ni Base Powder Luoyang Golden Egret Geotools Co., Ltd , https://www.xtchvof.com
Some commonly used nickel-based alloy powders for PTAW include:
1. Inconel 625: This alloy powder is widely used for PTAW due to its high strength, excellent resistance to corrosion, and oxidation at elevated temperatures. It is commonly used in applications involving seawater, chemical processing, and aerospace industries.
2. Hastelloy X: This alloy powder is known for its high-temperature strength and oxidation resistance. It is commonly used in applications involving gas turbine engines, industrial furnace components, and chemical processing.
3. Monel 400: This alloy powder is known for its excellent resistance to corrosion, particularly in marine environments. It is commonly used in applications involving seawater, chemical processing, and oil refining.
4. Inconel 718: This alloy powder is known for its high strength, excellent resistance to corrosion, and good weldability. It is commonly used in applications involving aerospace, oil and gas, and nuclear industries.
5. Inconel 601: This alloy powder is known for its excellent resistance to high-temperature oxidation and corrosion. It is commonly used in applications involving heat treatment equipment, chemical processing, and power generation.
These nickel-based alloy powders can be used in PTAW processes to create high-quality welds with excellent mechanical properties and resistance to corrosion and high temperatures.
Do you know the error of grounding resistance test and repair?
Earth resistance testing is one of the most important maintenance methods involved in the normal operation of safety and electrical equipment. In the past spring maintenance work, we found that individual units are often grounded only when the socket grounding socket tester checks correctly, the grounding device has a grounding resistance value, whether the electrical equipment has a grounding wire, and whether the bolts are tightened. After the resistance test is completed, only the grounding resistance values ​​of several grounding devices in the factory are reported in the grounding resistance report of the electrical equipment, so as to represent the grounding resistance value of the whole plant electrical equipment. However, in actual work, even if these three items are all qualified, they cannot represent all electrical settings.
The prepared grounding is qualified.
1 socket grounding test
1.1 The grounding of the test socket is not sufficient if only measuring the grounding resistance of the grounding device and not measuring the resistance of the PE wire (protective grounding wire). Because if the PE wire is in poor contact or disconnected, the grounding resistance of the grounding device will not function properly even if it meets the requirements. As electrical equipment maintenance personnel must not be paralyzed and negligent.
1.2 In the grounding of the test socket, we found that the failure rate of the PE wire connected to the device far exceeds the failure rate of the grounding device.
The fault phenomenon is usually loose PE connection, disconnection, leakage and so on. For these failures, if they can only be found by visual inspection, they can only be confirmed by actual measurement. For example, the company's subordinate water quality monitoring center has a total of more than 30 laboratory and office rooms on three floors, and more than 150 sockets for three eyes. If visual inspections are used, it is difficult to ensure the correctness of the wiring due to the large number of inspections. Whether the PE line is faulty. Since the PE line involves personal safety and the life of high-precision experimental instruments, the importance of checking the PE line exceeds the phase line and the zero line is reversed.
At present, the socket tester used in our test can only check whether the PE line is connected and whether it is connected to the wrong one. However, whether the zero line to the ground is short-circuited or whether the connection between the ground line and the ground line is reliable cannot be tested. The grounding resistance value of the PE line (including The resistance value is not measured at all, so it is impossible to determine whether the socket grounding resistance is acceptable. The method for testing the grounding resistance of the socket is as follows: Cut off the power first, and use a multimeter to measure the resistance value between the socket PE wire and the grounding trunk (or the total grounding terminal). However, because the grounding trunk is away from the outlet, it is difficult to measure the resistance value between the PE line of each outlet and the grounding trunk.
So we can use the neutral wire in the socket instead of the measurement line, short the PE wire and the neutral wire in each sub-light distribution box, and then use a multimeter to measure the resistance value between the PE wire and the zero wire of each outlet. . Because the length and cross-sectional area of ​​the zero line and the PE line are almost equal, half of the measured value is the grounding resistance value of the socket to the sub-light distribution box, which is generally not more than 1 ohm. The result of this measurement can only ensure that the PE line from the socket to the sub-lighting distribution box is good, and it cannot guarantee that the ground connection between the sub-light distribution box to the grounding mains or the total grounding terminal is good, only after measuring again The value between the two ensures that the grounding of all outlets is truly reliable.
2 Electrical equipment grounding test
The grounding resistance test of electrical equipment is not only to check whether there is a ground wire, whether the ground wire is corroded, whether the connection bolt of the ground wire is tightened, etc., but also whether the grounding resistance value of the electrical equipment meets the requirements. A lightning accident occurred in the water plant of the company during the rainy season, resulting in damage to the automatic control system of the water tower's upper water motor. After measurement, it was found that the control cabinet had no grounding resistance, but the PE wire on the cabinet was connected properly and the screw was tightly tightened. After continuing investigations, it was found that the nuts connecting the grounding wire and the grounding electrode of the entire water tower were not tightened, which caused the grounding wire to be virtually void and would not provide protection. The maintenance personnel tighten the nut and then measure the grounding resistance on the control cabinet. The resistance is acceptable. The staff recalled that the cause of the accident was that when the maintenance personnel replaced the motor grounding wire, the work was negligence, and the connection nuts of the grounding wire and the grounding electrode were forgotten to be tightened. Then, in the spring grounding resistance test, the testers Only tested the grounding device grounding resistance value of the water tower, and did not measure the grounding resistance value of the device shell. Based on experience, the device's grounding bolt and the grounding wire connection were verified to be compact, and the equipment grounding resistance value was determined to be qualified.
Electrical equipment grounding resistance test method is as follows: first cut off the power, use a multimeter to measure the resistance value between the shell of the electrical equipment and the grounding mains (or the total grounding terminal), if the site does not have a grounding trunk, you can use the neutral wire or one of the phase wire (Three-phase electrical equipment) Instead of the measuring line, connect the grounding line (or the total grounding terminal) to the other end of the neutral line (or phase line).
3 Earth resistance test
The grounding device is a general term for the grounding wire and the grounding electrode.
When testing the independently set grounding resistance value, it is usually disconnected and the grounding resistance measuring instrument is connected below the breakpoint. Check whether the measured grounding resistance at this time meets the requirements. In fact, even if the results of the above tests meet the requirements, it does not mean that
PE line grounding is reliable. As shown in Fig. 1, if the grounding resistance is measured with a resistance tester on the grounding terminal, this indicates that the grounding terminal and the grounding pole are normal and the resistance value meets the requirements, but if the PE wire connected to the grounding terminal is If A is disconnected, the electrical equipment will not be grounded and the equipment will not be able to protect it. Therefore, the value of the test grounding resistance must be measured together with the PE wire of the connected device so that it can be confirmed whether the grounding device meets the requirements. If the system has multiple PE lines, the ground resistance value should be tested at the end of each PE line. Otherwise, it cannot be confirmed.