1. Purpose
In order to strengthen the inspection and management of flange forgings, control the quality before the product is used, and reduce the loss as much as possible, this regulation is specially formulated. As flange forgings, in addition to the design, manufacture, inspection and test standards specified in the contract technical accessories and the contract, it should also meet the requirements and serve as the basis for incoming inspection. If there is a conflict between the technical accessories, the design, manufacture and test standards stipulated in the contract, and this requirement, the one with the higher requirement shall be implemented.
2. Scope of application
This requirement applies to commonly used flange forgings of various specifications.
3. Flange Types and Flange Sealing Face Types
3.1 Flange types include: Slip On (SO) Flanges, Welding Neck (WN) Flanges, Compact Flanges, Socket Welding (SW) Flanges, Threaded Flanges, Stud End Lap Joint (LJ) Flanges, Long Welding Neck (LWN) Flange and Blind Flanges, As shown below:
Flange Type Codes are as follows:
|
Type Code |
Flange Type |
Type Codes |
Flange Type |
|
SO |
SLIP ON FLANGE |
SW |
SOCKET WELD FLANGE |
|
WN |
WELDING NECK FLANGE |
TH |
THREADED FLANGE |
|
LWN |
LONG WELDING NECK FLANGE |
LF/SE |
LAP JOINT FLANGE |
|
IF |
INTEGRAL FLANGE |
BL |
BLIND FLANGE |
3.2 Flange Sealing Surface Types include: Raised surface (RF), Flat Surface (FF), Ring Type Joint Surface (RTJ) Male/Female Surface (MFM), Tongue/Groove (TG) Surface, tenon/groove Surface, etc
Flange Sealing Surface Type Code
|
Flange Face |
Raised Face |
Female |
Male |
Tongue |
Groove |
Flat Face |
Ring Type Joint |
|
Code |
RF |
FM |
M |
T |
G |
FF |
RJ |
4. Inspection will be done according to flange standards.
Such as ASME B 16.5, HG/T 20615 and other requirements, the dimensional inspection and visual inspection will be done piece by piece.
4.1 Dimension Inspection
|
1 |
Inspection measuring tool caliper, straight board ruler, depth caliper, tape measure |
|
2 |
Measure the following dimensions with a caliper, ruler, or tape measure: Inner diameter, outer diameter, thickness, outer diameter of sealing surface, flange neck, outer diameter of neck end, bolt hole center circle diameter, bolt hole spacing, bolt hole diameter |
|
3 |
Place the flange on the platform and measure the height of the flange with a depth caliper |
|
4 |
Inspection of the flange inner diameter to the eccentricity of the center point of the bolt hole and the center of the sealing surface: 4.1 Put the flange on the platform, and measure the distance between the corresponding bolt hole and the inner wall of the flange with a caliper, and the maximum value of the corresponding difference is the eccentricity; 4.2 Put the flange on the platform, measure the corresponding width of the sealing surface with a caliper, and the maximum value of the corresponding difference is the eccentricity. |
|
5 |
For non-standard flanges such as LWN type and forged parts, the dimensions must be checked one by one according to the external processing drawing |
4.2 Visual Inspection
|
1 |
Machined surfaces must be free of burrs, detrimental scratches and other defects that reduce flange strength and connection reliability |
|
2 |
The sealing surfaces should be inspected one by one, and there should be no surface defects such as cracks, bumps and scratches that affect the sealing performance |
|
3 |
Pay attention to check whether the machined surface (sealing surface) has water lines (concentric or helical serrated surfaces), and the processing tool is 1.5mm or more. The water line requirements are applicable to the following flange sealing surfaces: RF FM M FF (HG/T 20615) RF FM M FF (ASME B16.5) |
|
4 |
If required, flange surface roughness shall be compared with standard samples of the same material |
Flanges shall be marked as specified below
A. HG/T20615& NB/T47008~47010
|
1 |
Manufacturer's name (or trademark) |
|
2 |
Standard number: HG/T20165A (or B) |
|
3 |
Flange type code |
|
4 |
Flange nominal size DN |
|
5 |
Flange nominal pressure Class |
|
6 |
Sealing surface type code |
|
7 |
The WN flange should be marked with the wall thickness of the steel pipe |
|
8 |
Material code (including forging grade) |
|
9 |
Batch number |
|
10 |
Other markings specified such as product markings |
B. ASME B16.5 & SA105
|
1 |
Manufacturer's name (or trademark) |
|
2 |
ASME Code Level Designator and Furnace Number |
|
3 |
Rating mark such as 1500 |
|
4 |
Compliance B16.5 or ASME B16.5 |
|
5 |
NPS Size |
|
6 |
Flange type and sealing surface type |
|
7 |
Heat treatment state |
|
8 |
Other designated markings such as part number Note: All markings on the parts should be fully copied on the inspection form |
5. Product quality certificate
5.1 NB/T47008~47010Quality certification documents include: quality certificate, heat treatment curve (but a copy).
5.1.1 The quality certificate shall not be less than the following contents:
|
1 |
Manufacturer's name and date of manufacture |
|
2 |
Product name, specification, pressure grade, material, material manufacturing standard, forging grade and number of forgings |
|
3 |
Chemical composition and mechanical properties of raw materials |
|
4 |
Heat number of raw materials |
|
5 |
Heat treatment number |
|
6 |
Manufacturing batch number |
|
7 |
Official seal of the quality department of the manufacturer |
|
8 |
Quality inspector's signature and inspection date |
|
9 |
Product test results |
5.2. ASME material quality certification is detailed in the relevant chapters of ASME II A
6. Other special requirements
|
1 |
If there is a re-inspection requirement, the samples in the box should be processed accordingly and re-inspected. Only the materials that pass the re-inspection can be used. |
|
2 |
The flange after inspection should be well protected, especially the sealing protection, and kept clean. |
