1.1 Valves containing corrosive media According to data, the economic loss caused by replacing valves due to corrosion in a certain year in the United States was about 120 million US dollars, and the loss caused by boric acid corrosion was about 93 million US dollars. Corrosion of valves will pose a danger to the service life and safety performance of valves. Corrosion of valves mainly includes electrochemical corrosion, pitting corrosion, stress corrosion and...
Problems Occurred in Dedicated Valves Read
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What are WCB, LCB, LCC, WC6 and WC? W means casting and C carbon steel; A, B and C indicate the strength value of steel grade from low to high. WCA, WCB, WCC represent carbon steel. ABC represents the strength level, and WCB is commonly used. The pipe material corresponding to WCB is A106B, and the corresponding forging material is A105. WC6 is a casting of alloy steel. The corresponding pipe material is A355 P11, and the corresponding forging...
Materials and Standards for Valves Read
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The steam turbine drainage system is an important part of the steam turbine thermal system, especially the steam turbine body, main steam, reheat steam, high and medium pressure valves, feed pump steam turbine new steam drainage and other important drainage valves. When the heating pipe is working, the water can be drained normally in time. When the unit is in normal operation, the valve is required to be reliably isolated without leakage. If these traps leak, the impact on the efficiency...
The Overhaul of Traps in Power Plants Read
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A check valve is a valve used to prevent backflow of media in pipes and equipment. The steam extraction check valve is set on each extraction pipe of the external heater of the extraction steam regenerative system in the steam turbine unit. Its function is to automatically close the valve plate when the unit rejects the load to prevent the steam in the steam side of the heater and the steam inlet pipe from returning to the steam turbine, avoiding the steam turbine to overspeed and accidents. ...
The Overhaul of Check Valves in Power Plants Read
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1. Stainless steel 304 Stainless steel 304 is the cheapest and most widely used austenitic stainless steel for equipment used for food, chemical, atomic energy and other industry. It is suitable for general organic and inorganic media, for example, nitric acid with concentration less than 30%, temperature less than and equal to 100°C or concentration higher than and equal to 30%, temperature less than 50°C, carbonic acid, ammonia and alcohols with various concentrations and...
Stainless Steel in Water Solutions Containing Chlorine Read
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Various corrosion and measures of valves are as follows: 1. Stress corrosion Stress corrosion is generated for stainless steel in a corrosive medium environment containing oxygen and chloride ions. The proportion of the failure caused by stress corrosion is as high as about 45%. Commonly used protective measures for stress corrosion Reasonable selection of materials: the selection of stress corrosion resistant materials mainly include austenitic chromium-nickel steel with...
Various Corrosion and Measures of Valves Read
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(2) Cracks in the valve body due to external environmental factors The external environment such as low temperature, high temperature and high pressure will cause the valve body to undergo creep, fatigue and impact, which will cause the valve body to break. Some literature mentions that the reason for the breaking of the valve body of the coke oven ascending tube is mainly the long-term compound corrosion of high temperature and other working conditions, resulting in deformation,...
The Failures of the Valve & Its Cause Analysis (Part Two) Read
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Valve failures and cause analysis 1. Leakages Leakages are mainly divided into external leakages and internal leakages. External leakages mainly refer to the fluid flowing to the outside of the system due to sealing failures and other reasons, and while the fluid flowing to the inside of the system is called internal leakage. The main reason for the leakage of the valve is the sealing failure. The valve of a 300MW steam turbine...
The Failures of the Valve & Its Cause Analysis (Part One) Read
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A valve is a control component in the fluid delivery system, which has the functions of cutting off and adjusting the fluid, preventing the reverse fluid, stabilizing the pressure, dispersing the fluid, overflowing and relieving the pressure. There are many types and specifications of valves such as globe valves and ball valves with simple structures, as well as complex valves suitable for automatic control systems. With the increasing manufacturing demand and the improvement...
Solutions to Failures of Valves Read
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