API 2W GR50, GR55, and GR60 are steel standards published by the American Petroleum Institute for the manufacture and application of offshore structural platform tubes. These steel grades also represent different strength levels, similar to the previously mentioned DR50, DR55, and DR60. These steels are mainly used in the manufacture of offshore structural platform tubes, which can meet the requirements of high strength and corrosion resistance in the field of Marine engineering.

In offshore engineering, API 2W GR50, GR55 and GR60 offshore structural platform tubes can be used in the following areas:

1. Platform support structure: These steel pipes are suitable for manufacturing support structures of offshore platforms, such as legs, piles, etc., to ensure the structural stability and carrying capacity of the platform in the Marine environment.

2. Pipeline system: These steel pipes can be used as an important part of the pipeline system of the offshore platform for transporting oil, gas, water and other media to ensure the normal operation and production of the offshore platform.

3. Marine structure construction: API 2W GR-grade steel pipes can also be used to build other structures in Marine engineering, such as submarine pipelines, offshore wind power platforms, etc., to withstand the impact of vibration and corrosion in the Marine environment.

4. Protective facilities: These steel pipes can also be used to manufacture Marine protective facilities, such as Marine platform guardrail, Marine damage repair, etc., to protect Marine facilities from external influences.

API 2W GR50, GR55 and GR60 steels offer excellent strength, toughness and corrosion resistance for the harsh working environments of Marine engineering. In the design and selection, it is necessary to determine the appropriate steel grade and specification according to the specific engineering requirements and design specifications to ensure the safety and reliability of the Marine structure and long-term stable operation.

The chemical composition and mechanical properties of API 2W standard steel are very important parameters, which can directly affect the performance and application range of steel. The following are the general chemical composition and mechanical properties requirements for API 2W DR50, DR55 and DR60 steels:

Chemical composition requirements (typical value) :

Carbon content (Carbon):0.18% Max

- Silicon content :0.15-0.50%

- * Manganese content:

- GR50: 1.15-1.60%

- GR55: 1.45-1.60%

- GR60: 1.45-1.60%

- Phosphorus content :0.015%, maximum

Sulfur content :0.006% maximum

Welding performance: Low sulfur and phosphorus content required

Mechanical performance requirements:

- Tensile Strength:

- GR50: Minimum strength 71,000 psi (490 MPa), maximum strength 90,000 psi (620 MPa)

- GR55: Minimum strength 75,000 psi (520 MPa), maximum strength 95,000 psi (655 MPa)

- GR60: Minimum strength 81,000 psi (550 MPa), maximum strength 100,000 psi (690 MPa)

- Yield Strength :**

- GR50: Minimum strength 50,000 psi (345 MPa)

- GR55: Minimum strength 55,000 psi (380 MPa)

- GR60: Minimum strength 60,000 psi (415 MPa)

- Energy absorption performance (Charpy V-Notch Impact Test):

-GR50: Tested at -40°F (-40°C), absorbs at least 50 ft-lbs (68 J)

-GR55: Tested at -40°F (-40°C), absorbs at least 50 ft-lbs (68 J)

-GR60: Tested at -40°F (-40°C), absorbs at least 50 ft-lbs (68 J)

These chemical composition and mechanical properties parameters are essential for evaluating the scope and performance of steel, ensuring that the steel can achieve safe and reliable performance in a variety of applications in the field of Marine engineering.