Ductile iron Archives

Valve Parameters

August 20, 2024

Nominal Diameter

The nominal diameter (DN) is a numerical designation used to define the size of all piping system components, distinguishing it from those parts that are designated by thread or outside diameter.

Another method for specifying valve sizes is the American system, which uses inches as the unit of measurement. For example, a DN50 valve corresponds to a 2-inch valve.

2.Rounded Numbers

All piping system components with the same nominal pressure (PN) value and the same nominal diameter (DN) have the same connection dimensions that correspond to the type of end connection. In China, when referring to nominal pressure, the unit of measurement is usually specified for clarity and is expressed as “MPa.” In countries like the UK and the US, although the concept of nominal pressure has been included in relevant standards, the imperial unit of pounds per square inch (psi) is still used in practice.

Because the reference temperature for nominal pressure and the pound system differs, there is no strict correlation between them. A general correspondence between them can be found in the table below. The Japanese standard includes a “K” system, such as 10K, 20K, 40K, etc. This pressure rating concept is similar to the pound system in imperial units, but the unit of measurement is metric. The relationship between the “K” rating and the pound system can be found in the table below.

Pressure markings are indicated by “PN” followed by a pressure value (in MPa). For example, PN1.0 indicates a valve with a nominal pressure of 1.0 MPa. However, in everyday use, it is common to refer to a PN10 valve as a 1.0 MPa valve, which is also referred to as a 10 bar/10 kg valve.

3. Common Unit Conversion Relationships

1 inch = 25.4 mm

1 MPa = 10 kgf/cm² (kilogram-force) = 10 bar

1 psi = 0.0069 MPa

1 ksi = 6.9 MPa

Psi: pounds per square inch

kgf/cm²: kilogram-force per square centimeter

Bar: bar

Fahrenheit to Celsius Conversion:

°C = (℉ – 32) * 5/9

Celsius to Fahrenheit Conversion:

℉ = ℃ * 9/5 + 32

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here: https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

Application of Concentric type Resilient Seated Butterfly Valve in Marine Vessel

August 13, 2024

Concentric type resilient seated butterfly valves are commonly used in marine vessels for several reasons:

Leakage Prevention: The resilient seat provides a tight seal, reducing the risk of leakage in critical applications. This is crucial in marine environments where leaks can lead to significant safety and operational issues.

Corrosion Resistance: These valves are often made from materials that resist corrosion, which is essential for marine applications due to the harsh saltwater environment.

Compact Design: The concentric design allows for a compact and lightweight valve, which is beneficial in the space-constrained environment of a marine vessel.

Ease of Operation: These valves generally have a simple design that makes them easy to operate, which is important for maintaining efficient and reliable operation on a vessel.

Flow Control: They provide effective flow control, which is necessary for managing various systems on a marine vessel, such as cooling systems, ballast systems, and fuel systems.

Maintenance: The design typically allows for easier maintenance and replacement, which is advantageous for keeping the vessel in good working condition.

The concentric type resilient seated butterfly valve is valued in marine applications for its reliability, resistance to corrosion, and ease of maintenance, all of which contribute to the safe and efficient operation of marine vessels.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/.

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.

We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

Classification of valve

August 5, 2024

There are many types of valves, and they can be classified in various ways.

Classification by automation and actuation

Automatic Valves: These valves operate automatically relying on the medium (liquid, gas, steam, etc.) itself. Examples include safety valves, check valves, pressure reducing valves, and automatic exhaust valves.

Actuated Valves: These valves are operated manually, electrically, hydraulically, or pneumatically. Examples include butterfly valves, gate valves, and ball valves.

II.Classification by purpose and function

Shut-off Valves: Primarily used to stop or start the flow of the medium. This includes gate valves, globe valves, plug valves, ball valves, butterfly valves, etc.

Regulating Valves: Primarily used to regulate the flow, pressure, etc., of the medium. This includes control valves, throttle valves, pressure reducing valves, etc.

Check Valves: Used to prevent the backflow of the medium. This includes various types of check valves.

Diverting Valves: Used to distribute, separate, or mix the medium. This includes various types of distribution valves, three-way valves, and steam traps.

Safety Valves: Used for overpressure safety protection, releasing excess medium to prevent pressure from exceeding the specified value. Examples include safety valves.

Multi-function Valves: Used to replace two, three, or more types of valves, such as globe check valves, check ball valves, etc.

Other Special Valves: Examples include drain valves, pigging valves, etc.

III. Classification by main parameters

1, Classification by nominal diameter The nominal diameter is a rounded integer value used as a convenient reference to indicate the valve size. It is an approximate value rather than an exact measurement. The nominal diameter is marked with the letters “DN” (nominal diameter) followed by a value in millimeters. For example, a valve with a nominal diameter of 50 millimeters is marked as DN50.

Small diameter valves: Valves with DN≤40mm
Medium diameter valves: Valves with DN50-DN300mm
Large diameter valves: Valves with DN350-DN1200mm (4) Extra-large diameter valves: Valves with DN≥1400mm

2, Classification by pressure Nominal pressure refers to the design-specified pressure related to the mechanical strength of the pipeline components. The pressure is marked with “PN” followed by a pressure value (MPa). For example, PN1.0 indicates a valve with a nominal pressure of 1.0 MPa. (1) Vacuum valves: Valves with a working pressure lower than standard atmospheric pressure. (2) Low-pressure valves: Valves with a nominal pressure of PN<1.6 MPa. (3) Medium-pressure valves: Valves with a nominal pressure of PN 2.5–6.4 MPa. (4) High-pressure valves: Valves with a nominal pressure of PN 10.0–80.0 MPa. (5) Ultra-high-pressure valves: Valves with a nominal pressure of PN≥100 MPa.

3, Classification by working temperature of the medium (1) High-temperature valves: Valves with t > 450℃ (2) Medium-temperature valves: Valves with 120℃ ≤ t < 450℃ (3) Normal-temperature valves: Valves with -40℃ ≤ t < 120℃ (4) Low-temperature valves: Valves with -100℃ ≤ t < -40℃ (5) Ultra-low-temperature valves: Valves with t < -100℃

4, Classification by valve body material (1) Non-metallic material valves: Such as ceramic valves, fiberglass valves, plastic valves (2) Metallic material valves: Such as copper alloy valves, Monel alloy valves, cast iron valves, carbon steel valves, alloy steel valves (3) Metal body lined valves: Such as lead-lined valves, plastic-lined valves, enamel-lined valves.

5, Classification by connection method to the pipeline (1) Flange connection valves: Valves with flanges on the body, connected to the pipeline using flanges. (2) Threaded connection valves: Valves with threads on the body, connected to the pipeline using threads. (3) Welded connection valves: Valves with weld ends on the body, connected to the pipeline using welding. (4) Clamp connection valves: Valves with clamps on the body, connected to the pipeline using clamps. (5) Ferrule connection valves: Valves connected to the pipeline using ferrules.

III. Common Classification This classification method is based on principle, function, and structure and is the most commonly used classification method domestically and internationally. It generally includes gate valves, globe valves, plug valves, ball valves, butterfly valves, diaphragm valves, check valves, throttle valves, safety valves, pressure reducing valves, steam traps, and control valves.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here: https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

Standards for Use of Marine Valves

July 9, 2024

Specifies dimensions for metal valves used in marine applications.

butterfuly valve manufacturer

Classification Societies

Classification societies provide additional guidelines and standards specific to marine applications. Some of the major classification societies include:

American Bureau of Shipping (ABS):

ABS Rules for Building and Classing Marine Vessels: Includes requirements for the design, construction, and testing of valves used in marine vessels.

Lloyd’s Register (LR):

Rules and Regulations for the Classification of Ships: Contains specific sections on the requirements for marine valves, including materials, design, and testing.

Bureau Veritas (BV):

Rules for the Classification of Steel Ships: Provides guidelines on the use of valves in marine applications, including specifications for materials and testing.

Det Norske Veritas (DNV):

DNV Rules for Classification of Ships: Outlines the requirements for valves used in marine systems, covering aspects such as design, materials, and performance testing.

National Standards

Different countries may have their own standards and regulations for marine valves. Some notable examples include:

ASTM (American Society for Testing and Materials):

ASTM F1199: Standard Specification for Ferrous Valves for Shipboard Use – Covers the requirements for ferrous valves used on ships.

BS (British Standards):

BS 6364: Valves for cryogenic service – Specifies the requirements for valves used in cryogenic applications, which can be relevant for certain marine applications.

Key Considerations for Marine Valves

Corrosion Resistance: Materials used for marine valves must be highly resistant to corrosion due to exposure to seawater and harsh marine environments.

Pressure and Temperature Ratings: Valves must be able to withstand the specific pressure and temperature conditions encountered in marine systems.

Safety and Reliability: Ensuring that valves operate reliably under the dynamic conditions of marine environments is crucial for safety.

Maintenance and Inspection: Valves should be designed for ease of maintenance and inspection, considering the limited access and challenging conditions on marine vessels.

Compliance and Certification: Marine valves should comply with relevant standards and regulations, and obtaining certification from recognized classification societies is often required.

By adhering to these standards and guidelines, marine valves can provide safe, reliable, and efficient performance in various marine applications, ensuring the safety and operational integrity of marine vessels and structures.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here: https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

The Application of Concentric Type Butterfly Valve in Petroleum(oil and gas) Industry

June 25, 2024

Concentric type butterfly valves play vital roles across various sectors within the petroleum (oil and gas) industry due to their reliability, versatility, and cost-effectiveness. Here are the main applications of concentric type butterfly valves in the petroleum industry:

Flow Control in Pipeline Systems:

Crude Oil Pipelines: Regulating the flow of crude oil within pipelines during transportation from production fields to refineries or terminals.

Natural Gas Pipelines: Controlling the flow of natural gas in transmission and distribution pipelines.

Refined Product Pipelines: Managing the flow of refined petroleum products like gasoline, diesel, and jet fuel.

Wellhead and Production Systems:

Flow Control: Regulating the flow of crude oil, natural gas, or water at wellheads and production facilities.

Water Injection Systems: Controlling the injection of water for secondary or tertiary oil recovery methods.

Refining Processes:

Cooling Systems: Regulating the flow of cooling water for heat exchangers and condensers.

Process Fluids: Controlling the flow of various process fluids during refining operations.

Chemical Injection Systems: Regulating the flow of chemicals for process treatment and corrosion inhibition.

Storage Terminal Operations:

Tank Farm Operations: Handling the flow of crude oil, refined products, and

chemicals within storage tank farms.

Loading and Unloading: Controlling the flow of petroleum products during loading onto tankers and unloading from ships or trucks.

Offshore Platforms and Floating Production Systems:

Seawater Systems: Regulating seawater flow for cooling, firewater, and other offshore operations.

Ballast Systems: Controlling ballast water for stability adjustment on offshore platforms.

Firewater Systems: Emergency firefighting systems on offshore platforms.

Petrochemical Plants:

Feedstock Handling: Controlling the flow of feedstocks such as ethylene, propylene, and other petrochemical products.

Process Fluids: Regulating the flow of various chemicals and fluids during production processes.

Key Advantages in the Petroleum Industry:

Corrosion Resistance: Materials selected are often resistant to corrosion from petroleum products and chemicals.

Space Efficiency: Compact design is suitable for installations where space is limited, such as offshore platforms.

Quick Operation: Rapid open/close operation for emergency shutdown situations.

Reliable Sealing: Provides tight shut-off to prevent leaks, crucial for safety and environmental protection.

Cost-Effective Solution: Butterfly valves offer cost savings compared to other valve types.

Concentric type butterfly valves are indispensable components in the petroleum industry, serving critical functions in transportation, production, refining, storage, and distribution of oil and gas products. Their versatility, reliability, and cost-effectiveness make them widely used in various applications throughout the industry. Proper selection, installation, and maintenance of these valves are essential to ensure safe and efficient operations in the petroleum sector.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here: https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/，

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

Marine valves in the shipbuilding industry（tanghai Valve)

June 7, 2024

Marine valves play a crucial role in shipbuilding, managing the flow of various fluids such as water, fuel, oil, and gases throughout a vessel. These valves are essential for the operational efficiency, safety, and maintenance of a ship. Here are some common types of marine valves used in shipbuilding and their functions:

Gate Valves

Function: Used for on/off control of fluids.

Application: Often used in systems where the valve remains either fully open or fully closed, such as in ballast and bilge systems.

Globe Valves

Function: Used for regulating flow and pressure.

Application: Typically found in cooling water, fuel oil, and lubricating oil systems where flow needs to be controlled.

Ball Valves

Function: Provide tight shut-off and control flow.

Application: Commonly used in low-pressure systems like potable water and compressed air.

Butterfly Valves

Function: Regulate or isolate flow with a rotating disc.

Application: Used in large diameter pipes, such as those in ballast systems, due to their compact design and lightweight.

Check Valves

Function: Prevent backflow.

Application: Installed in bilge lines, ballast systems, and various other systems to ensure one-way flow of fluids.

Safety Relief Valves

Function: Protect systems from overpressure.

Application: Essential in steam systems, hydraulic systems, and any pressurized tanks to release excess pressure.

Control Valves

Function: Regulate flow, pressure, temperature, and level.

Application: Used in automated systems for precise control, often integrated with sensors and actuators.

Diaphragm Valves

Function: Control flow with a flexible diaphragm.

Application: Suitable for corrosive or abrasive fluids, often found in sanitary or chemical systems.

Materials Used

Marine valves must withstand harsh marine environments, including exposure to saltwater, chemicals, and varying temperatures. Common materials include:

Bronze: Excellent corrosion resistance, commonly used for smaller valves.

Brass: Good corrosion resistance and machinability.

Stainless Steel: High strength and corrosion resistance, used in more demanding applications.

Cast Iron: Durable and cost-effective for non-corrosive applications.

Ductile Iron: Offers more strength and flexibility compared to cast iron.

Installation and Maintenance

Installation: Proper installation ensures the longevity and functionality of marine valves. This includes correct orientation, secure mounting, and adherence to manufacturer specifications.

Maintenance: Regular inspections, cleaning, and lubrication are crucial. Valves should be checked for leaks, corrosion, and proper operation. In high-wear applications, routine part replacement might be necessary.

Regulatory Standards

Marine valves must comply with international and national maritime regulations to ensure safety and performance. Key regulatory bodies include:

International Maritime Organization (IMO)

American Bureau of Shipping (ABS)

Lloyd’s Register (LR)

Det Norske Veritas (DNV)

Bureau Veritas (BV)

In summary, marine valves are integral components in shipbuilding, ensuring the safe and efficient operation of various ship systems. Their selection, installation, and maintenance are vital for the vessel’s overall performance and safety.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/.

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.

We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

The difference between carbon steel and cast steel

November 24, 2020

What is the difference between cast steel and carbon steel? First, steel is classified by chemical composition
(1) Carbon steel: a. Low carbon steel (C≤0.25%) b. Medium carbon steel (C≤0.25~0.60%) c. High carbon steel (C≤0.60%)
Steel is classified according to the forming method: (1) Forged steel (2) Cast steel (3) Hot rolled steel (4) Cold drawn steel. The so-called cast steel and carbon steel are just the names produced by the different classifications of steel.

What is the difference between forged steel valve and cast steel valve? Forging and casting are two different

flanges

processing techniques.
Casting: The molten liquid metal fills the cavity and cools. Pores are easy to produce in the middle of the workpiece.
Forging: It is mainly formed by extrusion at high temperature. Can refine the crystal grain in the part.
Forging: Use hammering and other methods to make a metal material in a plastic state into a workpiece with a certain shape and size, and change its physical properties.
Casting: The metal is heated and melted and poured into a sand mold or mold, and solidified into a utensil after cooling.
The difference in performance
During forging, the metal undergoes plastic deformation to refine grains.

What is the difference between a cast iron valve and a cast steel valve? The main difference between cast iron and cast steel valves is the carbon content, which directly affects the strength and plasticity of the steel. Carbon steel is also called carbon steel, an iron-carbon alloy with a carbon content of less than 2% WC. In addition to carbon, carbon steel generally contains a small amount of silicon, manganese, sulfur, and phosphorus. According to its purpose, carbon steel can be divided into three types: carbon structural steel, carbon tool steel and free-cutting structural steel. Carbon structural steel is divided into building structural steel and machine-manufactured structural steel. According to the carbon content, carbon steel can be divided into low-carbon steel (WC ≤ 0.25%) and medium-carbon steel (WC0.25%-0.6%) And high-carbon steel (WC>0.6%) According to phosphorus and sulfur content, carbon steel can be divided into ordinary carbon steel (higher phosphorus and sulfur), high-quality carbon steel (lower phosphorus and sulfur) and high-quality Steel (lower phosphorus and sulfur) Generally, the higher the carbon content of carbon steel, the higher the hardness and the higher the strength, but the lower the plasticity.
The full name of carbon steel is carbon structural steel. Cast steel valves are also carbon steel valves (there are also cast iron valves). They are just made by casting methods, while common steels are made by rolling. The ingredients are the same.

What is the difference between cast steel, cast iron and carbon steel in valve materials? Simply put, you first

lug type butterfly valve, ductile iron, center lined,

distinguish between iron and steel. Both steel and iron are alloys based on iron and carbon as the main additive element, collectively referred to as iron-carbon alloys.
The cast iron is smelted in an iron melting furnace to obtain cast iron (liquid), and the liquid cast iron is cast into a casting, which is called a cast iron.
What is the difference between cast steel and carbon steel. First, steel is classified by chemical composition
(1) Carbon steel: a. Low carbon steel (C≤0.25%); b. Medium carbon steel (C≤0.25~0.60%); c. High carbon steel (C≤0.60%).
Steel is classified according to the forming method: (For valves with different pressures, different materials are used.
Medium and low pressure valve, the valve body material is cast iron. For high-pressure valves, because of the large pressure, the valve body must be made of cast steel. Special valves may use various alloy materials and stainless steel.
It is said that carbon steel is only a kind of steel, and cast steel is a processing method of steel, not a concept.

What is the difference between carbon steel gate valve and cast steel gate valve. Many people think that carbon steel gate valves and cast steel gate valves are two kinds of materials.
1. The cast steel check valve and carbon steel check valve are check valves of the same material, both of which are made of WCB A216 carbon steel.
2. Cast steel check valve, because the valve body of WCB material is cast, so the name suggests, it is called cast steel check valve.
3. Carbon steel check valve, because the main material of WCB material is carbon steel, it is named carbon steel check valve.

The forging process of steel is different in processing form. Cast steel The steel used for pouring castings. A kind of casting alloy. Cast steel is divided into cast carbon steel, cast low alloy steel and cast special steel. Cast steel refers to a type of steel casting produced by casting methods. Cast steel is mainly used to manufacture some parts with complex shapes, difficult to forge or cutting and forming, but require high strength and plasticity. Forged steel: Forged steel refers to various forgings and forgings produced by forging methods. The quality of forged steel parts is higher than that of cast steel parts, can withstand large impact forces, and have plasticity, toughness and other mechanical properties.

What is the meaning of cast steel and carbon steel of the valve? What is the meaning of cast steel and carbon steel. Thank you. Carbon steel is represented by CS, but it is generally not mentioned in the case of cast steel. Detailed materials such as WCB, WCC, LCC, etc. will be stated.

The valve is a control component in the fluid conveying system. It has the functions of cut-off, regulation, diversion, prevention of reverse flow, stabilization, diversion or overflow and pressure relief. Valves used in fluid control systems, ranging from the simplest shut-off valve to the various valves used in extremely complex automatic control systems, have a wide variety and specifications.
Valves can be used to control air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media. >>Cast steel has less carbon content, good toughness, and higher pressure and temperature resistance than cast iron. Cast iron valves are not suitable for diesel, sea water and acid media. Cast iron valves are cheaper. Their materials are obviously different, and they are used in different environments! The cost is also different. In short, the price is analyzed in detail, and the properties of various materials are different. Temperature resistant. Cast steel valves can withstand high temperatures, but cast iron valves cannot be used with water.

Valve body and material classification

August 24, 2020

The valve body is a main part of the valve; there are different mechanical manufacturing methods according to the pressure level. For example: casting, forging, etc.

lug type butterfly valve body

Material Description
Introduction

Valve bodies of medium and low pressure specifications are usually produced by casting process.
The valve body of medium and high pressure specification is produced by forging process.
It can effectively withstand medium pressure after forming a seal together with the valve core and valve seat sealing ring.
definition
The definition of “valve” is a device used to control the direction, pressure, and flow of fluid in a fluid system. A valve is a device that allows the medium (liquid, gas, powder) in the piping and equipment to flow or stop, and can control its flow

The material of the valve body is selected according to different process media.

Common materials are: cast iron, cast steel, stainless steel, carbon steel, plastic, copper, etc. [1]

Material Description:
1. grey cast iron:

Grey cast iron valves are used in various fields of industry because of their low price and wide application range. They are usually used in the case of water, steam, oil and gas as the medium, and are widely used in chemical industry, printing and dyeing, oil chemical, textile and many other industrial products that have little or no impact on iron pollution. It is suitable for low pressure valves with working temperature between -15～200℃ and nominal pressure PN≤1.6MPa.

2. Ductile cast iron

Ductile cast iron is a kind of cast iron. In this cast iron, the flake graphite in gray cast iron is replaced by clump or nodular graphite. The change in the internal structure of this metal makes its mechanical properties better than ordinary gray cast iron, and does not damage other properties. Therefore, valves made of ductile iron have higher pressures than those made of gray cast iron. It is suitable for medium and low pressure valves with working temperature between -30～350℃ and nominal pressure PN≤4.0MPa. Applicable media are water, sea water, steam, air, gas, oil, etc.

3. Carbon steel:

The initial development of cast steel was to meet the production needs that exceeded the capabilities of cast iron valves and bronze valves. However, because the carbon steel valve has good overall performance and high resistance to stress caused by thermal expansion, impact load and pipeline deformation, it has expanded its use range, usually including the working conditions of cast iron valves and bronze valves. . Suitable for medium and high pressure valves with working temperature between –29～425℃. Among them, the temperature of 16Mn and 30Mn is between -40～400℃, and they are often used to replace ASTM A105. The applicable medium is saturated steam and superheated steam. High and low temperature oil, liquefied gas, compressed air, water, natural gas, etc.

What is the material of the main parts of the butterfly valve?-(1)

August 17, 2020

Selection of butterfly valve parts materials:
There are many materials for manufacturing butterfly valves, including ferrous and non-ferrous metals and their

16 U-type-flange-butterfly-vlave-body

alloys of different brands, and various non-metallic materials. The materials for manufacturing valve parts should be selected based on the following factors:

1. Pressure, temperature and characteristics of working medium.

2. The force of the part and its function in the valve structure.

3. It has better manufacturability.

4. If the above conditions are met, there must be a lower cost.

The material of the valve body, bonnet and disc (disc) The body, bonnet and gate (disc) are one of the main parts of the valve, which directly bear the pressure of the medium, and the material used must meet the “pressure and temperature rating of the valve” Provisions.

Commonly used material types for butterfly valves:

1. Gray cast iron: Gray cast iron is suitable for water, steam, air, gas, oil and other media with a nominal pressure of PN≤1.0MPa and a temperature of -10℃~200℃. The commonly used grades of gray cast iron are: HT200, HT250, HT300, HT350.

2. Malleable cast iron: Suitable for water, steam, air and oil media with a nominal pressure

17 center-line-butterfly-valve-plate-disc-parts-4

of PN≤2.5MPa and a temperature of -30~300℃. Commonly used grades are: KTH300-06, KTH330-08, KTH350-10.

3. Ductile iron: suitable for water, steam, air and oil with PN≤4.0MPa and temperature of -30~350℃. Commonly used grades are: QT400-15, QT450-10, QT500-7. In view of the current level of domestic technology, the plants are uneven, and users are often not easy to inspect. According to experience, it is recommended that PN≤2.5MPa, and the valve should be made of steel for safety.

4. Acid-resistant high-silicon ductile iron: suitable for corrosive media with nominal pressure PN≤0.25MPa and temperature below 120℃.

5. Carbon steel: suitable for water, steam, air, hydrogen, ammonia, nitrogen and petroleum products with a nominal pressure of PN≤32.0MPa and a temperature of -30~425℃. Commonly used grades are WC1, WCB, ZG25 and high-quality steel 20, 25, 30 and low-alloy structural steel 16Mn. Six, copper alloy: suitable for water, sea water, oxygen, air, oil and other media with PN ≤ 2.5MPa, and steam media with a temperature of -40 to 250 ℃, commonly used brands are ZGnSn10Zn2 (tin bronze), H62, Hpb59-1 (Brass), QAZ19-2, QA19-4 (aluminum bronze).

18 buttefly-valve-stem-shaft-parts-1

7. High temperature steel: suitable for steam and petroleum products with nominal pressure PN≤17.0MPA and temperature≤570℃. Commonly used grades are ZGCr5Mo, 1Cr5M0. ZG20CrMoV, ZG15Gr1Mo1V, 12CrMoV, WC6, WC9, etc. The specific selection must be in accordance with the valve pressure and temperature specifications. 8. Low temperature steel, suitable for nominal pressure PN≤6.4Mpa, temperature≥—196℃ ethylene, propylene, liquid natural gas, liquid nitrogen and other media, commonly used grades) ZG1Cr18Ni9, 0Cr18Ni9, 1Cr18Ni9Ti, ZG0Cr18Ni9.

9. Stainless acid-resistant steel, suitable for nitric acid, acetic acid and other media with nominal pressure PN≤6.4Mpa and temperature≤200℃. Commonly used grades are ZG0Cr18Ni9Ti, ZG0Cr18Ni10<nitric acid>, ZG0Cr18Ni12Mo2Ti, ZG1Cr18Ni12Mo2Ti<acid and urea>.

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Valve Parameters

Application of Concentric type Resilient Seated Butterfly Valve in Marine Vessel

Classification of valve

Standards for Use of Marine Valves

The Application of Concentric Type Butterfly Valve in Petroleum(oil and gas) Industry

Marine valves in the shipbuilding industry（tanghai Valve)

The difference between carbon steel and cast steel

Valve body and material classification

What is the material of the main parts of the butterfly valve?-(1)

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