YanHao is a reliable flange manufacturer in China. Their factory has strong production capabilities, including 8 production lines with an annual capacity of over 80,000 tons. Today, YanHao Flange will present A Comprehensive Guide to Understanding Chinese Flange and Pipe Fitting Standards.

Understanding Chinese Flange and Pipe Fitting Standards

In China, there are three main standards for flanges and pipe fittings: GB (Chinese National Standard), JB (Mechanical Industry Standard), and HG (Chemical Industry Standard).

GB standards are developed by the National Standardization Management Committee of China and are widely used in various industries. GB standard flanges and pipe fittings cover a wide range of materials, sizes, and pressure ratings, and are commonly used in industries such as construction, oil and gas, and water supply.

JB standards are developed by the Mechanical Industry Standardization Technical Committee of China and are more specific to mechanical engineering. JB standard flanges and pipe fittings have a narrower range of materials, sizes, and pressure ratings compared to GB standards and are commonly used in machinery manufacturing and related industries.

HG standards are developed by the Chemical Industry Standardization Technical Committee of China and are specific to the chemical industry. HG standard flanges and pipe fittings have strict requirements for materials, manufacturing processes, and pressure ratings and are commonly used in chemical plants, petroleum refineries, and other chemical-related industries.

Overall, the main difference between these standards lies in their scope of application and the industries they serve. GB standards are more general and widely used in various industries, while JB and HG standards are more specific to mechanical engineering and the chemical industry, respectively. Understanding the differences between these standards is crucial for selecting the appropriate flanges and pipe fittings for different applications in various industries.

Types of Flanges and Pipe Fittings

There are different types of flanges and pipe fittings, including socket weld flanges, butt weld flanges, threaded flanges, lap joint flanges, and blind flanges. Each type serves a specific purpose and has its own unique advantages.

Socket weld flanges are used for small-diameter pipes and have a socket that the pipe is welded into, providing a strong and reliable connection. Butt weld flanges are commonly used in high-pressure and high-temperature applications, and the flange is welded directly to the pipe, creating a smooth and seamless connection.

Threaded flanges are similar to socket weld flanges, but instead of welding the pipe, it is screwed into the flange. This makes it easier to disassemble and reassemble the connection, but it may not be as strong as welded connections.

Lap joint flanges are used with stub ends to allow for easy alignment and disassembly. The flange itself is not welded to the pipe, but rather the stub end, making it easy to replace the flange without having to replace the entire connection.

Blind flanges are used to close off the end of a pipe or valve, providing a seal and preventing any leakage. They are commonly used in systems where maintenance or inspection is needed.

In addition to flanges, there are also various types of pipe fittings, including elbows, tees, reducers, and caps. Elbows are used to change the direction of the pipe, while tees are used to split the flow of fluid into two directions. Reducers are used to connect pipes of different sizes, and caps are used to close off the end of a pipe.

Overall, each type of flange and pipe fitting serves a specific purpose and is chosen based on the requirements of the application. Proper selection and installation of these components are crucial for maintaining the integrity and safety of the overall system.

Materials Used in Flange and Pipe Fitting Manufacturing

Flanges and pipe fittings can be made from various materials, including stainless steel, alloy steel, and carbon steel. Each material has its advantages and limitations.

Stainless steel is a popular choice for its corrosion resistance and durability. It is suitable for use in applications where the fitting will come into contact with corrosive substances or be exposed to extreme temperatures. However, stainless steel flange is generally more expensive than other materials and may not be necessary for applications where corrosion resistance is not a concern.

Alloy steel is a high-strength material that is suitable for use in high-pressure and high-temperature applications. It can withstand harsh operating conditions and provides excellent corrosion resistance. However, alloy steel flange may be more expensive than carbon steel flange and may require special handling and welding techniques.

Carbon steel is a common and cost-effective material for flanges and pipe fittings. It is widely used in various industries due to its strength and durability. Carbon steel flange is also easily machinable and weldable, making it a versatile option for various applications. However, it is prone to rust and corrosion, especially in harsh environments.

In addition to these main materials, there are also other specialty materials that can be used for flanges and pipe fittings. For example, brass and bronze may be used for low-pressure applications, while PVC and CPVC may be used for applications that require corrosion resistance and low weight.

In summary, the choice of material for flanges and pipe fittings depends on the specific application, the operating conditions, and the budget. Each material has its advantages and limitations, and it is important to consider these factors when selecting the appropriate material for the job.

Quality Control and Testing

Yanho Flange Company has a strict quality control and testing process in place to ensure the highest quality and safety of its products. The following are some of the key steps in their process:

  1. Spectroscopic Analysis: This is a chemical analysis used to identify and measure the different elements in the raw materials used in production. The results of this analysis help to ensure that the materials meet the required specifications and are of the correct composition.
  2. Non-Destructive Testing (NDT): This is a type of testing that allows the inspection of materials and components without causing any damage. Yanho Flange Company uses different NDT methods, including ultrasonic, magnetic particle, and liquid penetrant testing, to detect any surface or subsurface defects in their products.
  3. Heat Treatment: This is a process used to alter the physical and chemical properties of the materials used in production. Yanho Flange Company uses heat treatment to increase the strength, durability, and corrosion resistance of its products.
  4. Hydrostatic Testing: This is a pressure test used to check the strength and integrity of the products. Yanho Flange Company uses hydrostatic testing to ensure that its flanges can withstand the specified pressure without leaking or failing.

These processes are crucial in ensuring the quality and safety of the final products. By using advanced testing and inspection techniques, Yanho Flange Company can identify and address any potential issues early in the production process, reducing the risk of product failure or safety hazards.

Customization and Manufacturing Capabilities

Yanho is a leading manufacturer of custom flanges and pipe fittings. We are capable of producing non-standard flanges and fittings according to customer’s unique specifications and requirements. Our production capacity extends to large-diameter products, which are produced to meet our client’s needs.

At Yanho, we pride ourselves on our manufacturing capabilities. We have a large-scale production line that includes state-of-the-art equipment for forging, machining, heat treatment, and testing. Our facilities enable us to manufacture a wide range of products with different specifications and requirements, ensuring that our customers receive products of the highest quality.

Our team of experienced engineers and technicians is well-equipped to handle custom orders, from designing and prototyping to final production. We work closely with our customers to ensure that their unique needs are met and that their products are manufactured to the highest standards.

In summary, Yanho has extensive custom manufacturing capabilities, including the ability to produce non-standard flanges and fittings as well as large-diameter products. We have the advanced equipment and skilled workforce to handle any custom order and ensure the highest quality products for our customers.


Hey there, folks! We’ve just wrapped up an awesome guide that delves into the world of flanges and pipe fittings, and we couldn’t be more excited to share it with you all. One thing that really stood out to us during our research is the incredible expertise and authority that Yanhao brings to the table.

From their top-of-the-line materials to their rigorous quality control and testing processes, Yanhao is a brand you can trust when it comes to all things flanges and pipe fittings. And let’s not forget their impressive custom capabilities, including non-standard products and large-diameter options.

So if you’re in the market for high-quality, reliable flanges and pipe fittings, we highly recommend considering Yanhao. With their extensive knowledge and commitment to excellence, you won’t be disappointed.

Lewis Liu

Hello, I am Lewis Liu, a professional sales engineer with over ten years of experience in the flange fittings industry. I am highly knowledgeable in flange selection, installation, and maintenance. I am passionate about providing customers with the best solutions to ensure their pipeline systems run smoothly, safely, and reliably.

If you have any questions or concerns regarding flange fittings for your pipelines, whether it’s about selection, material choice, specification requirements, or any other aspect, please feel free to contact me at any time. I am committed to offering professional advice and assistance to help you make informed decisions and meet your needs.

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