ASTM A333 Seam Pipe And Seamless Pipe

ASTM A333 is a standard specification for seamless and seam carbon steel pipe and alloy steel pipe for low-temperature service or other applications requiring notch toughness, established by the American Society for Testing and Materials (ASTM International). This standard provides stringent requirements for the chemical composition, mechanical properties, dimensions, tolerances, heat treatment, and testing of steel pipe to ensure safety and reliability in extremely low-temperature environments.

ASTM A333 Standard Range

1. Applicable Steel Pipe Types

Seam pipe and seamless pipe.

2. Manufacturing Process Requirements

No filler metal may be used in the welding of seam pipe.

3. Microstructure Control

All pipe must undergo appropriate heat treatment to ensure a uniform microstructure.

4. Testing

These include tensile testing, impact testing, hydrostatic pressure testing, and nondestructive testing (e.g., electromagnetic or ultrasonic) to ensure product compliance.

ASTM A333 Size Range

1. Outside Diameter

NPS 1/8" to 30".

2. WT

2.0mm-60mm.

2. Specifications

SCH40, SCH60, XS, SCH80, SCH100, SCH120, SCH140, SCH160, XXS.

3. Grades

This standard covers several grades of ferritic steel: ASTM A333 Gr. 1, Gr. 3, Gr. 4, Gr. 6, Gr. 7, Gr. 8, Gr. 9, Gr. 10, Gr. 11.

ASTM A333 Seam Pipe and Seamless Pipe: Heat Treatment

All seam pipe and seamless pipe manufactured in accordance with ASTM A333 (except Grades 8 and 11) shall be heat treated to control the microstructure by one of the following methods:

1. Normalizing

Heat to a uniform temperature of not less than 1500°F [815°C], then cool in air or in the cooling chamber of a controlled atmosphere furnace. Alternatively, normalize as described above and reheat to the appropriate tempering temperature as specified by the manufacturer.

2. Controlled Rolling + Cooling (Seamless Pipe Only)

For seamless processing only, hot working and hot finishing operations should be reheated and controlled to a finishing temperature range of 1550 to 1750°F [845 to 945°C], starting from an initial temperature of not less than 1550°F [845°C] and cooling in air or a controlled atmosphere furnace.

3. Special Grade Treatments

Grades 6 and 10 seamless pipe may be heat treated by heating to a uniform temperature of not less than 1500°F [815°C], then quenching in liquid and reheating to the appropriate tempering temperature.

ASTM A333 Grade 8 pipe shall be heat treated by the manufacturer using either of the following methods: quenching and tempering; or secondary normalizing and tempering. If necessary, Grade 11 pipe should be annealed and then normalized at a temperature of 1400 to 1600°F [760 to 870°C].

ASTM A333 Chemical Composition Requirements

For Grades 1 and 6 steel, the carbon content may be reduced by 0.01% for amounts below 0.30%, and the manganese content may be increased by 0.05% for amounts above 1.06%, to a maximum of 1.35%.

For Grade 6 steel, the niobium limit may be increased to 0.05% in heat analysis and to 0.06% in product analysis.

Generally, the carbon equivalent (CE) = [C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15] may not exceed 0.43% in heat analysis.

ASTM A333 Mechanical Properties

Elongation values are based on standard round 2-inch or 50-mm (or 4D) specimens.

Grade 11 elongation applies to all wall thicknesses and sub-size specimens tested in full cross-section.

ASTM A333 Impact Testing

ASTM A333 seam pipe and seamless pipe is supplied in the normalized condition and is always subjected to a Charpy impact test at a specific temperature to ensure that the product meets the temperature range specified in the standard (Carbon Steel Temperature Limits for ASTM A333 Seamless Carbon Steel Pipe).

ASTM A333 Mechanical Testing

Mechanical testing of ASTM A333 seam pipe and seamless pipe shall be conducted in accordance with the following specifications:

1. Transverse/Longitudinal Tensile/Flattening/Hardness/Bend

Five percent of each batch of pipe shall be sampled for testing. For smaller batches, at least one pipe shall be tested.

For material heat-treated using a continuous process, a sufficient number of pipes shall be sampled for testing to represent 5% of the batch, but not less than two pipes.

2. Hydrostatic/Impact/Single-Notched-Bar Impact

Tests shall be performed on specimens collected from finished pipe for each heat treatment load representative of the heat treatment load.

Summary

ASTM A333 seam pipe and seamless pipe is a material standard specifically designed for cryogenic environments. Its stringent chemical composition control, heat treatment requirements, and guaranteed mechanical properties have led to its widespread use in critical applications such as oil and gas pipelines, chemical equipment, liquefied natural gas (LNG) storage tanks, and cryogenic pressure vessels. It is a vital material for ensuring safe and efficient operation in the energy industry.