Carbon steel for pipelines and process

Most oil and gas piping is carbon steel. API 5L line pipe in Grade B to X70, PSL1 or PSL2, is used for pipelines, flowlines and gathering lines; carbon steel seamless pipes to ASTM A106 Grade B are used for plant piping. ASTM A105 flanges and A234 WPB fittings complete the system, with A350 LF2, A333 Grade 6 and A420 WPL6 for low-temperature service and A694 flanges and WPHY fittings for high-strength pipelines.

Sour service – NACE MR0175 / ISO 15156

Where produced fluids contain hydrogen sulphide, carbon and low-alloy steels can suffer sulphide stress cracking and hydrogen-induced cracking. NACE MR0175 / ISO 15156 sets hardness limits, heat-treatment conditions and testing for each material class. We supply carbon steel, duplex and nickel alloy pipes, flanges, fittings and bolting to NACE MR0175 / ISO 15156 on request, with HIC and SSC testing for line pipe and plate where the project specification requires it.

Duplex and super duplex

Duplex steel pipes and tubes (2205) and super duplex pipes and tubes (2507, S32760) are used offshore and onshore for produced water, seawater cooling and injection, firewater ring mains, and process lines carrying chlorides and CO₂. Their high strength allows thinner walls and lighter piping, and their resistance to pitting and stress corrosion cracking far exceeds that of 316L. Flanges, fittings and fasteners are supplied in matching grades.

Inconel 625 and other nickel alloys

For the most severe conditions – high H₂S and chloride content, high temperatures, or where weight and wall thickness must be minimised – Inconel pipes and tubes, especially alloy 625, and Incoloy 825 are used for flowlines, risers, wellhead equipment, control and chemical injection tubing, and as the corrosion-resistant layer inside clad and lined pipe. Nickel alloy bolting is used subsea and in splash zones.

Products for oil and gas

• Seamless pipes and tubes and welded pipes and tubes
• Flanges – weld neck, RTJ, high-class and large-diameter
• Pipe fittings – butt-weld, forged and olets
• Plates and sheets – including HIC-tested pressure vessel plate
• Round bars and fasteners – B7, B7M, L7 and CRA bolting

All industries we serve are on the industries page.

Low-temperature and LNG service

Gas processing and LNG plants handle fluids from ambient down to −162 °C. Low-temperature carbon steel – A333 Grade 6 pipe, A350 LF2 flanges and A420 WPL6 fittings, impact tested at −46 °C – is used for chilled lines, while austenitic stainless steel 304L and 316L, which keeps its toughness at cryogenic temperatures, is used for LNG lines, with impact-tested stainless flanges and B8 bolting.

Documents and inspection

Oil and gas projects specify detailed documentation and testing. All material is supplied with mill test certificates, and supplementary tests – impact, hardness, PMI, ultrasonic, HIC, SSC, ferrite and ASTM A923 for duplex – can be arranged as the project specification requires. Third-party inspection by the buyer's nominated agency is available on request. Our company is certified to ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018.

For offshore projects, packing, marking and colour coding are often specified in detail, and we follow the purchase order requirements for each shipment.