What is the chemical composition of ST45.8 pipe?

The chemical composition for ST45.8 pipe varies slightly depending on the specific manufacturing standard it conforms to (primarily DIN 17175 or EN 10216-2). Below are the typical compositions based on these standards:

1. DIN 17175 (German Standard)

ST45.8 is identified by Material Number 1.0405 under DIN 17175. Its composition is:

Element	Composition (%)
Carbon (C)	0.10 - 0.20
Silicon (Si)	≤ 0.40
Manganese (Mn)	0.40 - 1.20
Phosphorus (P)	≤ 0.025
Sulfur (S)	≤ 0.020
Chromium (Cr)	≤ 0.30
Molybdenum (Mo)	≤ 0.08
Nickel (Ni)	≤ 0.30
Copper (Cu)	≤ 0.40

Notes:

Total alloying elements (Cr + Mo + Ni + Cu) ≤ 0.70%.

Carbon content may be reduced for welded pipes to improve weldability.

2. EN 10216-2 (European Standard)

Under EN 10216-2, ST45.8 corresponds to P235GH or P265GH, but historically aligns with P235GH:

Element	Composition (%)
Carbon (C)	≤ 0.16
Silicon (Si)	≤ 0.35
Manganese (Mn)	0.60 - 1.20
Phosphorus (P)	≤ 0.025
Sulfur (S)	≤ 0.015
Chromium (Cr)	≤ 0.30
Molybdenum (Mo)	≤ 0.08
Nickel (Ni)	≤ 0.30
Aluminum (Al)	≥ 0.020 (if killed)

Key Characteristics & Applications:

Material Type: Carbon steel for high-temperature service.

Temperature Range: Designed for pressures at elevated temperatures (up to ~450°C).

Applications: Widely used in:

Boiler systems (superheaters, headers).

Steam pipelines.

Power plants and thermal energy systems.

Comparable Grades:

ASTM A106 Gr B (USA).

BS 3602-430 HFS27 (UK).

JIS G3454 STPG38 (Japan).

Notes:

Weldability: Good due to controlled carbon/sulfur content.

Heat Treatment: Supplied in normalized or normalized + tempered condition.

Testing: Requires hydrostatic testing, non-destructive examination, and certification for pressure use.

Always confirm the specific standard (DIN 17175 vs. EN 10216-2) when sourcing ST45.8 pipe, as compositions differ slightly. For critical applications, verify with the mill test certificate (MTC).

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