ASTM A671/A672 CL42 HFW Low-Temperature High-Pressure Welded Pipe

1. Concise Version

Our ASTM A671/A672 CL42 high-frequency resistance welded steel pipes are engineered for low-temperature high-pressure cryogenic service, with sub-grades like CC60 and CC65 classified by critical operating temperature. Manufactured from hot-rolled coils via HFW welding, sizes range OD 114–1422mm, wall thickness 3–40mm. All weld seams undergo full stress-relief heat treatment to eliminate forming residual stress. The standard prioritizes extreme low-temperature Charpy V-notch toughness. CC65 grade delivers minimum 27J impact energy at -45°C. Its hydrostatic test threshold reaches 1.5 times working pressure, stricter than API 5L pipeline specifications. A671 fits moderate low-temp environments while A672 suits elevated pressure loads. Widely deployed for LNG receiving terminals and cryogenic storage piping, custom chemical composition and mechanical performance can be tailored to unique project demands.

2. Detailed Version

ASTM A671/A672 CL42 HFW Cryogenic High-Pressure Fusion Welded Pipe

ASTM A671 and A672 standards govern high-frequency electric fusion welded steel tubes specially designed to withstand combined low-temperature and high-pressure operating loads. Multiple performance grades such as CC60 and CC65 are categorized according to minimum service temperature limits. CC65 is the premium cryogenic variant optimized for -45°C service.

Production Process & Dimensional Range

These pipes are fabricated from hot-rolled steel coils through precise high-frequency resistance welding. The finished products feature consistent weld integrity and ultra-tight dimensional precision.

• Outer diameter spectrum: 114 mm to 1422 mm
• Wall thickness range: 3 mm to 40 mm

A core mandatory production step is full post-weld heat treatment for all welded zones. This process completely relieves internal residual stress generated during coil forming and welding, stabilizing long-term mechanical performance under temperature cycling.

Standard Difference Between A671 & A672

• ASTM A671: Designed for general low-temperature and ambient pressure industrial piping systems
• ASTM A672: Formulated for projects with higher internal working pressure, with tightened hydrostatic inspection standards

Core Performance & Testing Requirements

Low-temperature impact toughness is the primary performance focus of this standard, enforced via mandatory Charpy V-notch impact testing at designated cryogenic temperatures. As a typical example, CC65 grade must maintain no less than 27 Joules impact energy at -45°C to avoid brittle fracture under freezing operating conditions. Compared with conventional API 5L transmission pipes, ASTM A671/A672 imposes more rigorous hydrostatic pressure testing requirements. Test pressure is set at 1.5 times the rated service working pressure to validate pressure bearing safety margin.

Main Application Scenarios

This series of welded pipes is the primary piping material for critical cryogenic energy infrastructure, most prominently liquefied natural gas receiving stations and cryogenic liquid storage tank connecting pipelines. Mass installations of this standard pipe are adopted for coastal liquefied natural gas terminal cryogenic pipeline networks across domestic coastal energy hubs. Customization support is available for special chemical element ratios and targeted mechanical property indicators to match unique extreme environment engineering parameters, delivering reliable safety safeguards for cryogenic high-pressure pipeline operation.

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