SA350 GR.LF2 CL1 Self Reinforced Nozzle Low Temp Pressure Vessel Parts

SA350 GR.LF2 CL1 Self-Reinforced Nozzle: Low-Temp Pressure Vessel Part​

1. Introduction

The ASME SA350 GR.LF2 CL.1 Self-Reinforced Nozzle is a high-integrity forged steel component used in pressure vessels and piping systems operating at cryogenic temperatures (down to -46°C/-50°F). Its integral reinforcement eliminates the need for separate weld-on pads, enhancing structural reliability and reducing failure risks in services like LNG, petrochemical, and refrigeration.

2. Technical Specifications

Material Standard

• Designation: ASME SA350 (Equivalent to ASTM A350)

• Grade: LF2 (Carbon steel optimized for low-temperature toughness)

• Class: CL.1 (Stringent impact testing requirements)

Chemical Composition (Typical)

*Nickel enhances low-temperature toughness.

Mechanical Properties

3. Self-Reinforced Design

• Integral Hub: Forged as a monolithic thickening around the branch opening.

• Purpose:

  • Compensates for material removed during penetration (per ASME BPVC Section VIII Area Replacement Method).

  • Reduces stress concentration at nozzle-vessel junctions.

• Advantages vs. Weld-On Pads:

  • Eliminates pad-to-shell crevices (reduces corrosion/fatigue risks).

  • Simplified NDE inspection (no weld fusion zone).

  • Improved pressure cycle fatigue resistance.

4. Manufacturing & Quality Control

Production Process

1. Forging: Hot-forged to shape (press/hammer/ring rolling).

2. Heat Treatment:

   • Normalizing + Tempering (mandatory for grain refinement and toughness).

3. Machining: Precision CNC to final dimensions (weld bevels, bore, reinforcement contour).

Mandatory Testing

• NDE:

  • 100% UT (ASTM A388) for internal defects.

  • 100% MT/PT for surface flaws.

• Impact Testing: CL.1 requires triple specimens @ -46°C.

• Hardness Survey: Post-PWHT to ensure ≤ 200 HB (typical).

5. Welding & Fabrication

• Preheat: 95–200°C (prevents hydrogen cracking).

• PWHT (Post-Weld Heat Treatment):

  • Mandatory per ASME BPVC Sec. VIII (UCS-56) to relieve stresses.

  • Typical cycle: 595–650°C for 1 hr/inch thickness.

• Welding Standards: Qualified per ASME Sec. IX.

6. Applications

• Industries: LNG storage, cryogenic plants, ethylene units, ammonia refrigeration.

• Typical Services: Liquid nitrogen (-196°C), propane (-42°C), CO₂ (-78°C).

7. Compliance & Standards

8. Key Advantages

• Low-Temperature Toughness: CL.1 impact certification for -46°C service.

• Reduced Weld Joints: Monolithic design minimizes leak paths.

• Lifecycle Cost Savings: Lower inspection/maintenance vs. pad-reinforced nozzles.

9. Limitations

• Cost: Higher initial cost than carbon steel nozzles without reinforcement.

• Lead Time: Complex forging/heat treatment extends manufacturing.

For fabrication, always reference ASME BPVC Section VIII and MSS-SP-97 for dimensional tolerances. Testing must include triplicate impact tests at the design temperature to validate CL.1 compliance.

Yuhong Holding Group equipments production base at Jiangsu Jiangyin City, Jinjiang City and Yancheng City. Total production area around 184000 square meters, main products : Heat Exchanger, Condenser, Pressure Vessel , Fired Heater, Economizer, Columns, Reactor.  

Jinjiang Factory: 
Main Products: Heat Exchanger, Pressure Vessel ,Condenser, Economizer, Evaporator, Column, Fired Heater;

Certificates: ASME PP, ASME S, ASME U, ASME NB, ISO3834, GB/T24001-2016/ISO 14001:2015, GB/T9001-2016/ISO9001:2015,
                      GB/T45001-2020/ISO45001:2018, TS2232A55-2026
Factory Info.: Workshop 6000 square meters, 160 workers, 1000sets/year.

 

Jiangyin Factory:
Main Products: Heat Exchanger, Pressure Vessel ,Condenser, Economizer, Evaporator;

Certificates: ASME U, ASME NB, GB/T9001-2016/ISO9001:2015,GB/T24001-2016/ISO 14001:2015, 
                      GB/T45001-2020/ISO45001:2018, GB/T9022.1-ISO10012-1.
Factory Info.: Workshop 24000 square meters, 120 workers, 600sets/year.
 

Yancheng Factory:
Main Products: Air-cooled Heat Exchanger, Cooling Tower, Pressure Vessel, Economizer, Evaporator;

Certificates: ASME U, CTI Certification, Air Cooler safety registration certificate, Pressure Vessel TS,
                      GB/T9001-2016/ISO9001:2015,GB/T24001-2016/ISO 14001:2015, GB/T45001-2020/ISO45001:2018                      
Factory Info.: Workshop 100000 square meters, 450 workers, 2000sets/year.