GB/T 19326-2022
Forged branch outlet fittings (English Version)
- Standard No.
- GB/T 19326-2022
- Language
- Chinese, Available in English version
- Release Date
- 2022
- Published By
- General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
- Latest
- GB/T 19326-2022
- Replace
- GB/T 19326-2012
- Scope
- This document specifies the variety and code, pressure class, connection size, special branch socket, order content, shape, size and tolerance, material, design and manufacture, heat treatment, inspection and test, marking, surface protection and Packaging and product quality certificates and other requirements and provide installation guidelines. This document applies to branch sockets in piping systems made of forged steel materials. Note: The branch pipe seat in this document refers to the branch pipe seat with different diameters, that is, the branch pipe seat whose main pipe size is larger than the branch pipe size.
- Introduction
Analysis of the core content of the standard
Technical parameters 2012 version Main changes in the 2022 version Variety classification 3 categories and 9 types Added 5 new varieties including Flange branch seat Pressure level Class3000/6000 Added Class9000, wall thickness level expanded to Sch5S/Sch10S Inspection requirements Routine inspection Newly added 100% ultrasonic/magnetic particle testing for free forgings Key Technical Indicators
Parameter Comparison of Typical Branch Seats
Type Socket Weld 90° Branch Seat (SOL-90) Class3000 Class6000 Class9000 Main Pipe Range (DN) 8-1200 8-300 20-300 Structural Height A (mm) 11-31 20-37 24-37 Flow hole diameter d(mm) 5.5-97.2 3.9-42.8 6.4-38.2
Material and manufacturing requirements
Forging materials must comply with GB/T14383. Manufacturing process requirements:
- Ingot forging ratio ≥3, bar forging ratio ≥1.6
- Final forging temperature: carbon steel ≥700℃, stainless steel ≥1040℃
- Free forgings require 100% non-destructive testing
Heat treatment specifications
Exemption conditions Scope of application Final forging temperature meets the standard Carbon steel parts below DN100 (excluding low-temperature steel) Processed raw materials Bar machined parts Rapid water cooling Austenitic stainless steel below DN100
Installation implementation points
Welding process control
- Hole positioning deviation ≤1.5mm
- The base weld must be fully penetrated
- Multi-layer welding (5 passes) is recommended for above DN100
- The width of the fillet weld ≤2 times the wall thickness of the main pipe
Special working condition processing
When the wall thickness of the branch pipe exceeds the standard:
- Thicken the branch pipe: Select according to the wall thickness of the main pipe and recalculate the D2 size
- Thinn the branch pipe: The reinforcement effect needs to be verified by finite element analysis
Key points of quality control
Inspection items Method standard Qualified indicators Dimension tolerance Table 21 d aperture ±0.4mm(DN≤50) Surface defects NB/T47013.4/5 Grade Ⅰ Hardness value GB/T14383 110-160HBW
GB/T 19326-2022 Referenced Document
- GB/T 12459 Steel buttwelding pipe fittings—Types and parameter
- GB/T 14383 Forged fittings, socket-welding and threaded
- GB/T 18253-2018 Steel and steel products—Types of inspection documents
- GB/T 20801.3 Pressure pipng code—Industrial piping—Part 3:Design and calculation
- GB/T 28708 Specification for size selection of seamless and welded steel pipe used in piping engineering
- NB/T 47013.3 Nondestructive testing of pressure equipment Part 3: Ultrasonic testing*， 2023-12-28 Update
- NB/T 47013.4 Nondestructive testing of pressure equipments.Part 4: Magnetic particle testing
- NB/T 47013.5 Nondestructive testing of pressure equipments.Part 5: Penetrant testing
GB/T 19326-2022 history
- 2022 GB/T 19326-2022 Forged branch outlet fittings
- 2012 GB/T 19326-2012 Forged branch outlet fittings, socket-welding, threaded and buttwelding
- 2003 GB/T 19326-2003 Forged branch outlet fittings--Socket welding,threaded and butt-welding ends