Each standard has requirements for the logo on the flange. Today, let's take the chemical standard (PN series) as an example to introduce the flange logo.
I. Standard number
"HG20592-2009" is the standard number implemented by the flange. HG/T 20592-2009 here is the "PN series" standard in the chemical standard, while the "Class series" standard is HG/T 20615-2009.
Due to the large number of flange standards, in order to facilitate identification, it can be remembered that the beginning of HG is the chemical standard, the beginning of GB is the national standard, the beginning of JB is the mechanical standard, the beginning of SH is the petrochemical standard, and the beginning of CB is the marine standard.
As for foreign standards, ANSI begins with the American standard, DIN begins with the German standard, EN begins with the European standard, and JIS begins with the Japanese standard.
II. Nominational size
"DN25" represents the nominal size of the flange, which can be followed by the outer diameter series of the applicable steel pipe.
According to the requirements of the current chemical standards, the marking of the overall flange, flange cover, lining flange cover, threaded flange, and the applicable steel pipe outer diameter series can be omitted. The flange applicable to the A series steel pipe of this standard, the marking of the outer diameter series of the steel pipe can be omitted; the flange applicable to the B series steel pipe of this standard is marked as "DNXXX (B)".
Supplement: The outer diameter of steel pipes applicable to chemical standards includes two series, A and B. Series A is an international general series (commonly known as British pipe), and Series B is a domestic series (commonly known as metric pipe).
III. Public pressure
"PN16" indicates the nominal pressure level of the flange, in addition to different pressure levels such as PN2.5, PN6, PN10, PN25, PN40 and so on.
IV. Flangen type code
"PL" refers to the flange type code - plate flat welding flange. In addition, there are also: SO (necked flat welding flange), WN (necked butt-welding flange), IF (inthole flange), SW (plug-in welding flange), Th (threaded flange), BL (flange cover) and PJ/SE (but-welded ring loose sleeve method Lan).
V. Sealed surface
The type code "RF" refers to the sealed surface form of the flange. "RF" here refers to the protruding flange. In addition, there are also: FF (plane flange), MFM (concave and convex flange), TG (tenon groove flange), RJ (ring connection flange).
VI. Material brand number
"S30408II" here, the previous "S30408" refers to the material grade, and "II" refers to the forging grade. The domestic forgings are divided into four grades according to the national standard. The one in the figure is a secondary forging.
Regarding the material grade, it is relatively complicated. At present, there are different known classifications such as stainless steel (such as 304, 316, etc.), carbon steel (such as Q235A, Q235B, etc.), alloy steel and so on.
In addition, 304 can also be represented by 06Cr19Ni10, 304L can be represented by 022Cr19Ni10, of which "06" and "022" indicate that the carbon content is 0.06% and 0.022%, "Cr19" means that the chromium content is about 19%, and Ni10 means The nickel content is about 10%. Other material brands also have similar corresponding representations.
VII. The thickness of the steel pipe of the flange connection
As for the marking of the thickness of the steel pipe on the flange, not all flanges need to be marked. According to the requirements of chemical standards, only the necked butt-welded flanges and butt-welded rings (loo loose sleeve flanges) should be marked with the thickness of the steel pipe.
The above are all introduced with the PN series standards in the current flange chemical standards as an example, and the Class series will be slightly different.
