stainless steel pipe flanges manufacturers&suppliers



1, What is stainless steel pipe flange? 


Stainless steel pipe flange is a part that connects pipe to pipe with each other. Bland flange connected at the end of the pipe.


The flange has an eyelet for a bolt so that the two flanges are tightly connected. The flange is sealed with a gasket. Flanged pipe fittings are pipe fittings with flanges (flanges or splice plates). It can be cast from, can also be threaded or welded composition.


A flange connection consists of a pair of flanges, a gasket, and a number of bolts and nuts. Gasket placed between the two flange sealing surface, tighten the nut, the gasket surface of the specific pressure to reach a certain value after the deformation, and fill the sealing surface on the bump so that the connection is tight and does not leak.


Some pipe fittings and equipment already come with flanges, which also belong to the flange connection. Flange connection is an important connection method for pipeline construction.

Flange connections are easy to use and can withstand large pressures. In industrial piping, flange connections are widely used. Within the home, the pipeline diameter is small and low pressure, and flange connections are not visible. If you are in a boiler room or production site, there are flange connections everywhere for pipes and equipment.


The role of the flange is to make the pipe connection is fixed and sealed.


The flange is also used in the flange on the import and export of equipment, for the connection between two devices, such as the reducer flange. A flange connection or flange joint is a detachable connection consisting of the flange, gasket, and bolt interconnected as a set of the combined sealing structures.


The flange is divided into threaded connection flange, welding flange, and clamp flange.


Flanges are used in pairs, the low-pressure pipeline can use the threaded connection flange, more than four kilograms of pressure use of welding flange. Different pressure flange uses different thickness flange and uses different bolts.


Pumps and valves, in connection with the pipeline, the localization of this equipment and equipment, also made corresponding flange shape, also known as flange connection. Where the two planes are a close connection and use of bolts to close the connection parts at the same time, generally known as "flange", such as the connection of ventilation ducts, this type of parts can be called "flange parts". But this connection is only partial equipment, such as the flange and the connection of the pump, it is not good to call the pump "flange parts". Smaller ones, such as valves, can be called "flange-type parts".
Reducer flange, used for the connection between the motor and the reducer, and the connection between the reducer and other equipment.


2, YS Stainless Steel Pipe Flanges Main function


(1),  Connect the pipeline and maintain the sealing performance of the pipeline;

(2),  To facilitate the replacement of a section of the pipeline;

(3),  Easy to dismantle and check the pipeline situation;

(4), To facilitate the closure of a section of the pipeline.

In the maintenance of the piping system, the use of flanges can increase flexibility, making it easier to disassemble and easier access to system components.


3, YS Stainless Steel Pipe Flanges Standard classification


Specification: 1/2″~80″(DN10-DN5000)

Pressure grade: 0.25Mpa ~250Mpa(150Lb ~2500Lb)

Commonly used standards:

Chinese standard: GB9112-88(GB9113-1-88~GB9123-36-88)

American Standard: ANSI B16.5, ANSI 16.47 Class150, 300, 600, 900, 1500 (TH, LJ, SW)

Japanese Standard: JIS 5K, 10K, 16K, 20K (PL, SO, BL)

German Standard:DIN 2527, 2543, 2545, 2566, 2572, 2573, 2576, 2631, 2632, 2633, 2634, 2638 (PL, SO, WN, BL, TH)

Italian standard:UNI2276, 2277, 2278, 6083, 6084, 6088, 6089, 2299, 2280, 2281, 2282, 2283(PL, SO, WN, BL, TH)

British Standard: BS4504, 4506

Ministry of Chemical Industry standards:

HG5010-52~HG5028-58, HGJ44-91~HGJ65-91

HG20592-97 (HG20593-97~HG20614-97)

HG20615-97 (HG20616-97~HG20635-97)

Machinery Ministry standards: JB81-59~JB86-59, JB/T79-94~JB/T86-94

Pressure vessel standards: JB1157-82~JB1160-82, NB/T47020-2012~NB/T47027-2012

Marine flange standards: GB/T11694-94, GB/T3766-1996, GB/T11693-94, GB10746-89, GB/T4450-1995, GB/T11693-94, GB573-65, GB2506-89, CBM1012-81, CBM1013, etc.
Flange production standards

Chinese National standard: GB/T9112-2010 (GB9113-1-2010~GB9123-4-2010)

Ministry of Chemical Industry standards: HG5010-52~HG5028-58, HGJ44-91~HGJ65-91, HG20592-2009 series, HG20615-2009 series

Ministry of Machinery standards: JB81-59~JB86-59, JB/T79-94~JB/T86-94, JB/T74-1994
Pressure vessel standards: JB1157-82~JB1160-82, JB4700-2000~JB4707-2000 B16.47A/B B16.39 B16.48


4, YS Stainless Steel Pipe Flanges flange connection type




A weld neck flange has a long conical hub and the inside diameter of the flange needs to match the inside diameter of the pipe. The pipe flange is connected by welding the pipe to the neck of the flange. This transfers the stress from the flange to the pipe. It also reduces the stress concentration from the bottom of the hub. Welded neck flanges are typically used for higher pressure applications.


The conical hub allows for smooth distribution of mechanical stresses between the pipe and the weld neck flange, making it easy to perform radiographic inspections to detect possible leaks and weld defects.





Long weld neck flanges are generally used on vessels, columns, or barrels. some use on the balustrade. The flange connects the balustrade post with the floor.





A slip on flange is a flange with a slip on ring inside the flange. The hole diameter of the slip on flange is a little larger than the outside diameter of the connected pipe, and the pipe extends into the flange. The pipe extends far enough out from the front of the flange to be welded to the back of the flange and the front of the flange. Compared to weld neck flanges, slip-on flanges are less costly in materials and easier to align.





Threaded pipe flanges have tapered threads in the bore. Threaded pipe flanges are used for pipes that have external threads. The advantage of these pipe flanges is that they can be connected without welding. Threaded pipe flanges are usually used for small diameter of the high-pressure pipe, pipe pressure cannot be more than 4kgs






Socket weld pipe flanges are pipes inserted into the socket end of the flange and welded fillet weld around the top of the flange. This allows for smooth pipe bores and better fluid or gas flow through the pipe. Socket weld pipe flanges are typically used for smaller sizes of high-pressure pipe.




They're a two-part flange consisting of a Lap Joint Stub End which is butt-welded to the pipe and a backing lap joint flange which is slid onto the pipe before welding the Stub End.



A blind flange without a central hole is used to block or seal a pipe, valve/pressure vessel and to block the flow of fluid. Pipe flanges are used to seal the end of a piping system or pressure vessel opening. They are often used to test the flow of gases or liquids in a pipeline or vessel.

Blind pipe flanges also allow easy access to the pipeline while work is being performed in the pipeline. They are typically used in high-pressure applications.





Special flanges are special purposes using custom flanges. They are usually custom-shaped flanges for engineering needs. The flange shape, size is not for regular use.



5, PN meaning


PN is the nominal pressure, in the international system of units is 0.1MPa, in the engineering unit system is kgf/cm2. pipe flange commonly used bar (that is, kilogram force kgf/cm2, 1bar = 0.1MPa) equipment flange commonly used MPa.

Nominal pressure is determined not only according to the highest working pressure but also according to the highest working temperature and material characteristics, rather than just to meet the nominal pressure is greater than the working pressure. Flange there is a parameter DN, DN is the parameter that indicates the size of the flange.



6, YS tell you the use of precautions


(1), in order to prevent inter-eye corrosion due to flange cover heating, the welding current should not be too large, about 20% less than the carbon steel welding rod, the arc should not be too long, inter-layer fast cooling, to narrow welding channel is appropriate.


(2), the use of electrodes should be kept dry, titanium calcium type should be dried by 150 ℃ for 1 hour, low a hydrogen type should be dried by 200-250 ℃ for 1 hour (can not be repeated drying, otherwise the flux skin is easy to crack and flake), to prevent the electrode flux skin sticky oil and other dirt, so as not to cause the weld to increase the carbon content and affect the quality of the weld.


(3), stainless steel flange pipe welding, subject to repeated heating precipitation carbide, reducing corrosion resistance and mechanical properties.


(4), chrome stainless steel flange pipe fittings after welding hardening American Standard flange larger, easy to produce cracks. If the same type of chromium stainless steel welding rod (G202, G207) welding, must be more than 300 ℃ preheating and post-weld slow cooling treatment of about 700 ℃. If the welded parts can not be post-weld heat treatment, the stainless steel flange fittings welding electrode (A107, A207) should be used.


(5), stainless steel flange, in order to improve corrosion resistance and weldability and the appropriate amount of stability elements Ti, Nb, Mo, etc., weldability is better than chromium stainless steel flange. When using the same type of chromium stainless steel flange welding rod (G302, G307), should be more than 200 ℃ preheating and tempering treatment after welding about 800 ℃. If the welded parts can not be heat-treated, stainless steel flange fittings welding rod (A107, A207) should be used.


(6), stainless steel flange fittings, butt welding flange welding rod with good corrosion resistance and oxidation resistance, widely used in chemical, chemical fertilizer, petroleum, medical machinery manufacturing.



7. Stainless steel classification


Stainless steel is usually divided into 304, 304L, 316, 321, 316L, and several other categories.



8. Standard


In addition to some specially customized flanges that need to be customized, the current common flange standards.

1、AWWA, American Water Industry Standard

2、ASME, American Society of Mechanical Engineers standards

3、ANSI, American National Standard

4、DIN, the standard of German Standardization Society

5、HG, the People's Republic of China Chemical Industry Standard

6、GB, National Standard of the People's Republic of China

9, YS Stainless Steel Pipe Flanges Size:


1/2'' to 60'', DN15 to DN1500




 10, YS Stainless Steel Pipe Flanges Sealing faces


Sealing faces: flat (FF), protruding (RF), concave and convex (MFM), tongue and groove (TG), ring joint (RJ)



 11, YS Tell You Technical conditions


The pressure markings specified in this standard are divided into PN markings and Class markings.


PN mark has 12 pressure levels
PN2.5; PN6; PN10; PN16; PN25; PN40; PN63; PN100; PN160; PN250; PN320; PN400, respectively

Classmark has 6 pressure classes
Class 150; Class 300; Class 600; Class 900; Class 1500; Class 2500, respectively.


The exact pressure and temperature tolerances will vary depending on the material used, the flange design, and flange size. The only constant is that in all cases, the pressure rating decreases as the temperature increases.


Another layer of meaning of the standard flange: in accordance with the standard requirements of the size, tolerance range, etc. production of flange, as distinguished from the standard size of the production of flange pieces also known as two standard flanges (someone called non-standard flange is incorrect).


 12, Price


Stainless steel pipe flange price $2-100



Usually, some unscrupulous businessmen will reduce the flange thickness, the outer diameter of the two sizes to achieve the purpose of saving materials, and scrap steel or scrap steel processing flange, usually, this steel Is the chemical composition and mechanical properties of the scrap do not meet the standard, and even more with the black steel mill private steel production flange, the use of this private steelmaking technology is obsolete can not guarantee the mechanical properties and welding properties, the use of steel may not be able to weld with the steel pipe, or the steel itself has cracks, porosity, etc. After welding up will also leak. So try to use the standard flange when buying flanges and buy flange for quality manufacturers.


If you have questions about the stainless steel pipe flange, please contact us, Yongsheng specializes in stainless steel for more than 15 years, exporting to more than 50 countries, and you can have stainless steel flange experts. YS will recommend the best flanges for you. Click the red button on the top right to send us an inquiry!