Carbon Steel-A105

ASTM A105 is the standard specification for carbon steel forgings used in moderate-temperature piping systems. It offers good strength, ductility, and weldability, making it ideal for flanges, fittings, and valve components in oil & gas, chemical, and power industries. However, it is not suitable for low-temperature, high-temperature creep, or corrosive service without additional measures.

Heat Treatment

As-forged condition is acceptable per ASTM A105.
Optional normalization may be performed to refine grain structure or improve uniformity.
Post-weld heat treatment (PWHT) is not required by the standard but may be specified for:
Stress relief in high-restraint joints
Compliance with NACE MR0175/ISO 15156 (for sour service)
Code requirements (e.g., ASME B31.3 for severe cyclic conditions)

Temperature Service Range

Recommended Design Temperature Range:
–29°C to 425°C (–20°F to 800°F)
Not suitable for low-temperature service (e.g., LNG, cryogenic applications) because:
It is not impact-tested (no Charpy V-notch requirements)
May exhibit brittle fracture below –29°C
❗ For low-temperature applications, use ASTM A350 Grade LF2 instead.

Typical Applications

ASTM A105 forgings are widely used in:

Pipe flanges (Weld Neck, Socket Weld, Blind, Threaded) per ASME B16.5/B16.47
Forged fittings (Socket Weld and Threaded elbows, tees, couplings) per ASME B16.11
Valve bodies and bonnets (per MSS SP-70, API 600, API 602)
Pressure vessel nozzles and manways
Petrochemical, oil & gas, power generation, and water treatment systems handling non-corrosive or mildly corrosive media

Weldability

Excellent weldability due to low carbon and low alloy content.
Preheat recommendations (per ASME B31.3):
Not required for thickness < 25 mm (1 in) in benign environments
93–149°C (200–300°F) recommended for:
Thickness > 25 mm
High restraint joints
Low ambient temperatures

Use low-hydrogen welding consumables (e.g., E7018, ER70S-6) to minimize hydrogen-induced cracking.