Showing 81–100 of 176 results

The Sealing of Fully Welded Forged Ball Valves for Natural Gas Pipelines (Part one)

The sealing of fully welded forged ball valves in long-distance natural gas pipelines will directly affect the reliability of pipelines, so its sealing effect should be strengthened. The advantages of fully welded forged ball valves for long-distance natural gas pipelines are analyzed, and the design points of the sealing structure of the all-welded forged ball valve are discussed from the aspects of the scientific calculation of the maximum bending load, reasonable design of key component parameters,...

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Design of Small-diameter Supercritical Fully Forged Gate Valves

Design parameters and main materials of small-diameter supercritical fully forged gate valves are as follows: Working temperatures: 369°C Working pressure: 313MPa Nominal diameter: DN 150 Matching pipes: 219 to 35   The valve is mainly used in the secondary desuperheating water main pipeline of the superheater to cut off the medium. The materials of the main parts are shown in Table 1.   Table 1 Materials of main parts Components Materials Valve bodies A105 Discs 25 Packing rooms 25...

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Working Principles & Structural Characteristics of Supercritical Forged Gate Valves

Small boiler thermal power plants have high energy consumption, low efficiency, and serious environmental pollution. The development of coal as the main raw material for thermal power generation is increasingly exhausted. In terms of national policies, the construction of thermal power plants with a unit of less than 600 MW has been stopped in China. However, the main steam pressure of the 600 MW supercritical unit has reached 24.2MPa and the temperature is 538°C or 566°C, and the main steam...

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Socket-welded Forged Steel Gate Valves

There are three designs for bonnets of forged steel gate valves, that is, bolted bonnets, welded bonnets and self-sealing bonnets. The valve body and the bonnet are connected with bolts and nuts and sealed by a spiral wound gasket made from 316 flexible graphite for bolted gate valves. Metal rings can also be used when special requirements are put forward by customers. The valve body and the valve bonnet are connected by screw threads, and are fully welded for welded forged gate valves. The valve...

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The Rolling Process of the Valve Stem

The valve stem is an important part in the valve, and its machining accuracy and quality directly affect the performance of the finished valve, especially the trapezoidal thread and bare stem. Forged valves with small diameters whose valve stems are made from martensitic stainless steel 2Crl3 and austenitic stainless steel OCrl8Ni9 manufactured by a company have the following disadvantages: (1) They contain a large amount of cf, Ni, Mn and other elements, and have good plasticity, toughness, high-temperature...

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Abnormal Hardness in Welding Heat Affected Zones of F91 Forged Valves (Part Two)

3. Measures To improve the hardness and metallographic structure of F91 low alloy steel after welding, combined with the above welding process analysis, the following measures are proposed.   (1) Welding processes According to DL/T 869-2012 "Welding Technical Regulations for Thermal Power Plants", the welding process and evaluation are compiled, and the welding operation is carried out according to the welding process; the preheating of welding and the temperature between welding...

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Abnormal Hardness in Welding Heat Affected Zones of F91 Forged Valves (Part One)

In view of the problem of hardness reduction in the welding adjacent parts of the F91 valve used in the thermal power plant pipeline and the pipeline, the location of the failure and cause were determined, and the valve welding and on-site welding process were improved, and the valve’s hardness reached the standard requirements. It has been verified that there is no problem with hardness reduction in the welded heat-affected zone after the improvement, and the valve operates well.   1....

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Processing forged Stainless Steel Valve Bodies with Large Diameters

Abstract: The performance and characteristics of forged stainless steel valve bodies are discussed, and the processing difficulties and solutions are put forward. The process of machining valve body by a boring and milling machine is provided.   1. Overview  Forged steel valves are widely used in supercritical thermal power and nuclear power plants because of their high strength, corrosion resistance and good material quality. The forged stainless...

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Q367N Forged Steel Fully Welded Ball Valves

The forged fully welded ball valve is a special valve used under maintenance-free conditions. It is an important device for long-distance safe transportation of oil and natural gas. It has the characteristics of high strength, zero leakage, safety, reliability, and long service life. It can meet various complex requirements of long-distance safe transportation of oil and natural gas and is undoubtedly one of the valves with high technique.   Given that oil and natural gas are flammable and...

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Nested Forged Steel Ball Valves

Descriptions of nested forged steel ball valves Nominal sizes: DN15 to DN350 Nominal pressure: PN16 to PN420 (150Lbs to 2500Lbs) Applicable temperatures: -29 to 680℃ Applicable media: acids, alkalis, oils, and special media with high viscosity, fibers and granules.   The nested forged steel ball valve complies with "The Catalog of China High-tech Products" and overcomes the limitations of traditional ball valves not being resistant to high temperatures and high pressure. It is widely...

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High-pressure Resistant Forged Floating Ball Valves

At present, the valve is used to open and close gas pipelines or liquid pipelines. Because the gas or liquid entering the pipeline is mostly transported into the pipeline after being pressurized, the pressure in the middle cavity of the valve body is abnormally increased due to the increase in temperature for gas or liquid remaining in the valve body cavity when the valve is used. This may cause the valve body to be damaged due to excessive pressure, resulting in leakages. On the basis of fully...

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Control Systems of ARM Automatic Forged Steel Ball Valve Core Lathes (Part Two)

According to the different materials used in the ball valve seat, the ball valve can be divided into soft seated ball valves and hard seated ball valves. The commonly used materials for soft-seated ball valve seats are PTFE and filled PTFE, and the temperature is generally not more than 200°C. The material for valves seats of hard seated ball valve is metal or ceramic, and the high-temperature valve seat adopts hard sealing. The manufacturing processes of the ball valve spool are: die forging...

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Control Systems of ARM Automatic Forged Steel Ball Valve Core Lathes (Part One)

Abstract：The research and development of forged steel ball valve core automatic lathes and control systems include the mechanical structure of the automatic lathe, its electrical and hydraulic drive devices, and the electrical control system of the automatic lathe. The mechanical structure and its driving device include frames, main shafts and motor driving devices, turntables and servo driving devices, feeding and unfeeding and hydraulic driving devices. The electrical control system includes logic...

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High-pressure Cryogenic Large-diameter Three-piece Forged Ball Valves

Product: High-pressure cryogenic large-diameter three-piece forged ball valves Nominal pressure: CL600 Nominal diameter: NPS 24X20 Working temperature: -196℃ Applicable media: liquid oxygen, liquid nitrogen, liquid methane, liquid ethylene and other low-temperature media Drive modes: worm gear drive Connection: flanges Design standards: BS 6364-1999 Inspection and acceptance criteria: API 598-2009 Valve Testing and Inspection   The high-pressure cryogenic large-diameter three-piece forged ball...

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Ultra-high-pressure Forged Steel Gate Valves

The prospect of the forged steel gate valve The U.S has always taken the lead in the development of gate valves and began to study high-pressure gate valves of 105MPa in the 1960s. The structure of the gate valve has undergone tremendous changes due to the increased pressure, from a rising stem to a non-rising stem. People focused on materials and processes of gate valves in the 1970s. People concentrated on gate valves with higher pressure and reasonable structure in the 1980s. Gate valves developed...

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Sphere Forged Steel Check Valves

The opening and closing parts of the sphere forged steel check valve are composed of spheres, guide grooves and springs, which automatically open and close the valve discs, depending on the flow of the medium to prevent the backflow. The ball, guide groove and spring of the valve are all installed inside the valve body. The body bonnet is sealed by a spiral wound gasket, and there is no leakage as a whole, thus eliminating the possibility of leakage of valves and ensuring the safety of the work....

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Low-pressure Forged Steel Gate Valves

Features of 150LB low-pressure integral flanged forged steel gate valves 1. The design of the packing Graphite packing is one of the commonly used materials for valve stem packing. The packing will lose after being scoured by the pressure medium for a long time. If it is not refilled in time, the packing force will gradually decrease and fail, which will easily cause the leakage of the medium. The low-pressure forged steel gate valve adopts a disc spring-loaded joint bolt structure...

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Low-pressure Forged Swing Check Valves

We have carried out independent innovation research on low-pressure whole flange forged steel swing check valves after doing a lot of market research, fully communicating with users and collecting users' technical requirements. It is found that when the series of valves are in operation, once failures of the valve occur, such as leakages caused by the sealing surface, breaking of valves, results in economic losses and poses a great threat to personnel safety....

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-196℃ High-pressure Large Ultra-low Temperature Forged Trunnion Ball Valves

The side entry high-pressure large-diameter ultra-low temperature forged steel trunnion ball valve has been tested by many tests to show that the product has reliable sealing performance and flexible opening and closing. It will be widely used in various low-temperature equipment, such as liquefied natural gas, petrochemical and air separation industries.   Descriptions Nominal pressure: Class 600 Nominal diameter: NPS 24X20 Applicable temperatures: -196℃ Media: low-temperature...

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Quality Control of Pressure Bearing Forged Parts (Part Two)

3.3 Quality Control (1) Both JB/T 12000 and NB/T 47008 standards stipulate the quality requirements for pressure-bearing F91 steel forgings used for valve bodies and bonnets. The JB/T12000 standard is divided into four levels, that is, I, II, III, and IV. Level I is generally not applicable. The inspection items of each level are as specified in Table 4. Forgings with pressure above 900lb shall meet the requirements of level III and above. In the design drawings and purchase list,...

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