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Basic knowledge of fasteners

What is a fastener? Fastener is a kind of mechanical parts which is widely used for fastening connection. Fasteners are widely used in various industries, including energy, electronics, electrical appliances, machinery, chemical industry, metallurgy, mold, hydraulic and so on. In various machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, chemical industry, instruments and supplies, you can see all kinds of fasteners. They are the most widely used mechanical basic parts. It is characterized by a wide variety of specifications, different performance and uses, and a high degree of standardization, serialization and generalization. Therefore, some people refer to a […]

2021-01-14

The wrinkle problem of stainless steel elbow and its preventive measures

In order to prevent wrinkling of stainless steel pipe during cold bending, firstly, the advantages of the cold-bending method and its reasonable application range were investigated and evaluated from the perspective of pipe fittings manufacturing standardization, and then the “thin” wall that wrinkled in the cold-bending stainless steel was analyzed. Conditions, influencing factors, and analyzed through two typical cases. The analysis pointed out that the essence of wrinkle is the instability and inflection of the “compression bar” in the compression plastic deformation zone of the soffit. According to the “thin” wall thickness of the bend determined by the to/do and Ro/do of the […]

2021-01-11

How do metal composite materials “stick” together?

What are metal composite materials? Metal composite materials refer to composite materials formed by metallurgical combination of two or more different metals. Commonly used are titanium steel composite, copper steel composite, titanium zinc composite, titanium nickel composite, nickel steel composite, copper aluminum composite, nickel copper composite, etc. Since the respective advantages of the component materials can be used to achieve the optimal configuration of each component material resource, save precious metal materials, and achieve the performance requirements that a single metal cannot meet, metal composite materials have been widely used in more and more fields. The first time you come […]

2021-01-10

“Blasthole” of Casting Defect Series

Sand hole defect is also a defect with relatively high frequency in investment casting production. Sand hole, as the name suggests, is sand drilled into the surface or inside of the casting, occupying a place in the metal material of the casting. It is like a metal eye socket with one or more grains of sand in the eyeball, so it becomes a trachoma. See Figure 1. Figure 1 Trachoma defect The characteristic of sand hole defects is that the surface or inside of the casting is filled with sand or refractory powder. It may come from outside the shell, […]

2021-01-10

Selection principles and applicable occasions of butterfly valves

What is a butterfly valve? Butterfly valve, also called flap valve, is a kind of regulating valve with simple structure. It can also be used for on-off control of low-pressure pipeline media. Butterfly valve refers to a kind of valve whose closing part (disc or butterfly plate) is a disc, which rotates around the valve shaft to achieve opening and closing. It mainly plays a role of cutting off and throttling on the pipeline. The butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body to achieve the purpose […]

2021-01-10

The influence of boss welding on the performance of HFW welded pipe

In order to solve the problem that the improper position of the boss welder affects the overall performance of the HFW welded pipe during the installation of valves, instruments and flanges, the influence of the direct welding of the boss on the original residual stress and microstructure of the HFW welded pipe was studied. Studies have shown that the overall residual stress value on the HFW resistance welded pipe is relatively small, and the residual stress value in the straight weld area is lower than the pipe body area; after boss welding, the axial residual stress on the straight weld […]

2021-01-08

Method for measuring bending angle of pipe bend for oil and gas transportation

In order to overcome the problems of many tools, complicated measurement steps, many human interference factors, time-consuming and labor-consuming, and large measurement errors in the traditional pay-off method to measure the bending angle of bends, a new type of bending with an electronic level measuring instrument as the core device was designed. Pipe bending angle measuring device. The structure and measuring method of this new type of bending angle measuring device for bends are introduced. This measurement method uses an electronic level measuring instrument to directly read the included angle between the straight pipe section at both ends of the […]

2021-01-08

Analysis of Reasons for Low Hardness Test Value of P91 Steel Pipe

In response to the low hardness of the P91 steel pipe found during the overhaul of a thermal power plant’s supercritical unit, tests such as chemical composition analysis, mechanical properties and hardness testing, and metallographic testing were carried out, combined with many cases of low hardness of P91 pipes in the field test. , It is concluded that the phenomenon of low hardness test value of P91 steel pipe caused by surface decarburization is widespread. In view of this phenomenon, a suggestion to comprehensively inspect the P91 steel pipe with low hardness in the test is proposed to avoid misjudgment. […]

2021-01-06

Cause Analysis of Deviation in Brinell Hardness Conversion Value of Low Hardne……

Taking P91 steel pipe fittings and low-alloy steel pipe fittings with different hardnesses as the research objects, after eliminating the errors caused by external factors (sample temperature, rigidity, quality and surface condition, etc.), the hardness comparison test found that compared with the real Brinell The hardness is good, the Brinell hardness conversion value (HBLD) of low hardness P9 copper pipe fittings still has a large negative deviation. According to the mechanical performance test results, combined with the Leeb hardness detection principle and strengthening theory, the internal reasons for the deviation of the HBHLD value are analyzed. The results show that […]

2021-01-06

China’s iron ore has gone from the world’s largest production volu……

Trade frictions between China and Australia continue, and iron ore is regarded by some as Australia’s powerful weapon against China, even though Australian officials refuse to use this weapon. For iron ore, China’s output was the world’s largest iron ore a few years ago, nearly twice that of Australia, which ranked second. However, in just a few years, the situation has reversed. Australia’s output has more than doubled that of China, becoming China’s largest iron ore. import country. What happened behind China’s iron ore production from the world’s largest production to the world’s largest import? Shandong Rizhao Port, one of […]

2021-01-04

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Basic knowledge of fasteners

The wrinkle problem of stainless steel elbow and its preventive measures

How do metal composite materials “stick” together?

“Blasthole” of Casting Defect Series

Selection principles and applicable occasions of butterfly valves

The influence of boss welding on the performance of HFW welded pipe

Method for measuring bending angle of pipe bend for oil and gas transportation

Analysis of Reasons for Low Hardness Test Value of P91 Steel Pipe

Cause Analysis of Deviation in Brinell Hardness Conversion Value of Low Hardne……

China’s iron ore has gone from the world’s largest production volu……