Comprehensive analysis of API 5L BQ seamless steel tube

1、 Product parameters and standards

Material and specifications

Steel grade: API 5L BQ seamless steel tube belongs to PSL2 (Product Specification Grade 2), with steel grades covering BQ (S/O/P), X42Q (S/O/P) to X70Q (S/O/P), etc., suitable for high-pressure and highly corrosive environments.

Chemical composition:

Carbon (C) ≤ 0.18%, sulfur (S) ≤ 0.015%, phosphorus (P) ≤ 0.025%, titanium (Ti) ≤ 0.040%.

Micro alloying elements such as niobium (Nb) and vanadium (V) are added to enhance corrosion resistance and strength.

Mechanical properties:

Yield strength ≥ 245MPa, tensile strength 415-585MPa, yield ratio ≤ 0.93 18.

Size range: outer diameter 34mm-762mm, wall thickness 3mm-120mm, supports customized production.

Execution standards

Compliant with API SPEC 5L 46th edition specification, and also meets the type test requirements of TSG D7002 pressure pipeline components.

Delivery status: normalizing rolling, normalizing forming, or normalizing and tempering.

2、 Application Fields

Oil and gas transportation: used for long-distance oil and natural gas pipelines, especially for the transportation of corrosive media such as sulfur and hydrogen.

Chemical and Power: High pressure resistant boiler tubes, chemical reactors, and heat exchanger pipelines, suitable for high temperature and high pressure conditions.

In the field of new energy: hydrogen transmission pipelines with hydrogen purity ≥ 99.99%, PSL2 grade steel pipes with outer diameter ≤ 610mm.

3、 Production process and quality control

Core process

Adopting hot rolling, cold rolling or cold drawing processes to ensure seamless pipe body without welds, improving compressive and fatigue resistance performance.

Surface treatment includes painting, chamfering, and bundling galvanized steel strips to enhance corrosion resistance.

Quality inspection

Mandatory requirements include chemical composition analysis, mechanical property testing (such as yield strength, tensile strength), and non-destructive testing.

The hydrostatic test pressure should be ≥ 1070psig, and the holding time should be ≥ 5 seconds to ensure pressure safety.

4、 Market supply and selection suggestions

Supply capability: Mainstream manufacturers can provide full-size coverage with an outer diameter of 34mm-762mm, supporting small batch customization and bulk procurement.

Key selection points:

Select sub models such as BQ and BQH (high hydrogen resistance type) based on the corrosiveness of the medium.

Pay attention to carbon equivalent (Ceq) and impact toughness indicators to ensure suitability for low-temperature environments.