Standard for stainless steel flanges

National standard flange (GB / T 9112 ~ 9124-2010) refers to the flange produced by Zhi according to the national standard Du of the peoples Republic of China (GB / T 9112 ~ 9124-2010).

The national standard law Daolan standard was jointly issued by the General Administration of quality supervision, inspection and Quarantine of the peoples Republic of China and the National Standardization Administration of China on January 10, 2011. It is a recommended standard implemented from October 1, 2011.

GB / T 9112 ~ 9124-2010 includes 13 standards as follows:

The national standard GB / t9112-2000 and GB / t10745-1989 are replaced

GB / T 9112-2010 steel pipe flange types and parameters

GB / T 9113-2010 integral steel pipe flange

GB / T 9114-2010 ribbed steel pipe flange

GB / T 9115-2010 butt welded steel pipe flange

GB / T 9116-2010 flat welded steel pipe flange with neck

GB / T 9117-2010 socket welded steel pipe flange with neck

GB / T 9118-2010 butt welded ring neck loose sleeve steel pipe flange

GB / T 9119-2010 flat welded steel pipe flange

GB / T 9120-2010 butt welded ring plate loose sleeve steel pipe flange

GB / T 9121-2010 welding ring plate loose sleeve steel pipe flange

GB / T 9122-2010 flanged ring plate loose sleeve steel pipe flange

GB / T 9123-2010 steel pipe flange

GB / T 9124-2010 steel pipe flange

technical conditions

The pressure marking specified in this standard is divided into PN mark and class mark.

The PN mark has 12 pressure levels

They are: pn2.5; pn6; PN10; PN16; PN25; PN40; pn63; PN100; pn160; PN250; pn320; pn400

The class mark has six pressure levels

They are: Class 150; class 300; class 600; class 900; class 1500; class 2500

Another meaning of national standard flange is: flange produced according to the size and tolerance range required by national standards, which is different from the flange not produced according to the standard size, also known as the second standard flange (some people call it non-standard flange is incorrect). Generally, some unscrupulous businesses will reduce the flange thickness and outer diameter to achieve the purpose of saving materials, and also use waste steel or scrap materials Steel processing flange, usually this kind of steel is the chemical composition and mechanical properties of the waste, even more private steel-making black steel factory to produce flange, this kind of private steel-making technology used obsolete, can not guarantee the mechanical properties and welding performance, when using it may not be able to weld with the steel pipe, or the steel itself has cracks, pores, etc. after welding, it will also leak water. Therefore, when purchasing flange, try to choose national standard flange. If the funds are limited, the flange size must be carefully observed and measured to avoid being cheated.


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