What is the material A335 P5B alloy steel pipe

1. Basic Definition

A335 P5B is an American standard ferritic alloy seamless steel pipe for high-temperature use, belonging to the ASTM A335/ASME SA-335 standard system, which falls under the Cr-Mo (chromium-molybdenum) alloy steel series, designed for high temperature and high pressure working conditions.

2. Chemical Composition and Grade Characteristics

Core Composition

Chromium (Cr): 4.0~6.0% (to enhance high-temperature oxidation resistance)

Molybdenum (Mo): 0.45 ~ 0.65% (to enhance creep resistance)

Carbon (C): ≤ 0.15 ~ 0.20% (balance of strength and weldability)

Others: manganese (Mn) ≤ 1.0%, silicon (Si) ≤ 0.5%, sulfur and phosphorus content is strictly limited (≤ 0.03%)

Grade Differences

The suffix 'B' may indicate composition or process optimisation (e.g. heat treatment adjustment or elemental fine-tuning), but the specific differences need to be referred to the latest standard documents.

3. Core Performance

High-Temperature Performance

Long-term temperature resistance up to 650~700°C, excellent creep resistance and thermal fatigue performance, suitable for continuous high-temperature environments.

Mechanical Properties

Tensile strength ≥ 415MPa, yield strength ≥ 205MPa, both with high toughness.

Corrosion Resistance

Resistant to high-temperature sulphur corrosion and oxidation corrosion, suitable for sulfur-containing oils, acid, and alkali media, and other harsh working conditions.

4. Applications

Petrochemical: cracking device piping, hydrogenation reactor fittings.

Power energy: high-pressure boiler superheater, nuclear power plant cooling system piping.

Industrial equipment: heat exchangers, steam transport pipelines.

5. Production Process and Testing

Forming Process: hot-rolled or cold-drawn seamless forming, subject to normalising + tempering heat treatment.

Quality Inspection: ultrasonic flaw detection, hardness test, high temperature tensile test, etc.