GB/T 39245.2-2020 in English
VALIDGrooved metal gaskets with covering layers for pipe flanges—Part 2:Class designated
- Issued on:2020-11-19
- Implemented on:2021-06-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$243.00
| Standard No: | GB/T 39245.2-2020 |
| Document status: | VALID |
| Title in English: | Grooved metal gaskets with covering layers for pipe flanges—Part 2:Class designated |
| Title in Chinese: | 管法兰用金属齿形组合垫片 第2部分：Class 系列 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 1~3 business days |
| Issued on: | 2020-11-19 |
| Implemented on: | 2021-06-01 |
| ICS Classification: | 23.040.60-Flanges, couplings and joints |
| Chinese Classification: | J15-Pipeline fittings |
| Professional Classification: | GB-National Standard |
| Related Keywords: | grooved metal gaskets
metal core steel pipe flanges pipe flanges metal |
| Related Topics: | class rules
class system Gasket 2-pole tube Tooth shape Toothed gasket what? GB/T 39245.2 GB/T 39245.2-2020 Metal tooth gasket chemical industry Pressure vessel flange toothed gasket |
《GB/T 39245.2-2020管法兰用金属齿形组合垫片 第2部分：Class 系列》由TC237（全国管路附件标准化技术委员会）归口，主管部门为中国机械工业联合会。
Introduction
Analysis of the core content of the standard
This standard specifies the technical requirements for metal toothed combination gaskets with covering layer for Class marked steel pipe flanges, including three structural types:
| Type | Code | Applicable sealing surface | Structural features |
|---|---|---|---|
| Basic type | A | Tongue and groove surface/concave and convex surface | Without locating ring |
| Type with integral locating ring | B | Flat surface/raised surface | Locking ring and metal core integrated |
| With movable locating ring type | C | Flat/raised face | Separable locating ring |
Key technical indicators
Material specifications
The metal core is made of 18 grades of stainless steel or nickel alloy such as 06Cr19Ni10, and the covering layer is flexible graphite (FG) or polytetrafluoroethylene (PTFE):
- The flexible graphite layer must meet the thermal weight loss of 670℃/4h≤4%
- Recycled materials are prohibited for the PTFE layer
- The movable locating ring can be made of carbon steel (CS code)
Performance requirements comparison
| Test Items | Test Conditions | Indicator Requirements |
|---|---|---|
| Sealing Performance | DN80-Class300/45MPa Preload | Nitrogen Leakage Rate≤1×10-4cm3/s |
| Dimension Deviation | DN≤600 | Inner and Outer Diameter Tolerance±0.8mm |
| Flatness | Full Size Range | ≤Outer Diameter 1% and ≤5mm |
Implementation Points
Manufacturing Process Control
- DN≥350 is allowed to be welded, full penetration + stress relief is required
- Coating layer joints ≤4, metal matrix shall not be exposed
- Tooth processing should be carried out after welding process
Inspection rules
Type test includes full test of sealing performance, which must be performed in the following situations:
- Major process changes
- Resume production after 3 months of suspension
- Requirements of quality supervision department
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