ASTM A420 CARBON STEEL

For over 85 years, Merit Brass has been a trusted partner in delivering top-quality piping solutions. Our most recent addition to our product offering includes products that are compliant with ASTM A420 Carbon Steel. ASTM A420 material is crucial in the PVF industry because of its exceptional strength and versatility.  

In 2023, we added CarbonPress®, our line of carbon steel press fittings, to our press technology product offering. Merit's CarbonPress® fittings are constructed of ASTM A420 carbon steel and have a corrosion resistant Zn-Ni (zinc nickel alloy) plating surface protection to ensure years of trouble-free service. 

With over 400 SKUs, CarbonPress® fittings are available in sizes 1/2" - 4" and in three sealing elements -  EPDM (Ethylene Propylene Diene Monomer) for water applications, HNBR (Hydrogenated Nitrile Butadiene Rubber) for gas applications, and FKM (Fluorelastomer) for industrial applications (available upon request). 

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What is ASTM A420? 

ASTM A420 is the specification for wrought carbon steel and alloy steel pipe fittings of seamless and welded construction. ASTM A420 carbon steel fittings are engineered for use in pressure piping and pressure vessel services at low temperatures. This ensures reliability and exceptional performance under the most challenging conditions. 

Grades

• Grade WPL6: The most common grade known for its excellent toughness and strength at low temperatures.
• Grade WPL9: Offers improved weldability and toughness at even lower temperatures compared to WPL6. This allows it to perform under more demanding conditions.
• Grade WPL3: Demonstrates exceptional mechanical properties at sub-zero temperatures, boasting high impact resistance and excellent machinability.
• Grade WPL8: Offers superior impact resistance and strength, making it a highly robust option for low-temperature service.

Material Composition

ASTM A420 carbon steel fittings are manufactured using steel that has been completely deoxidized, also known as killed steel. This consists of forgings, bars, plates, sheets, and seamless or fusion-welded products. These materials are produced through recognized melting practices such as open-hearth, basic-oxygen, or electric-furnace processes. These practices ensure the fittings meet the stringent impact requirements of ASTM A420.

Manufacturing Processes 

The manufacturing process uses a combination of forging, or forming operations, such as:

• Hammering: Involves shaping the metal by repeated blows with a hammer. Ideal for producing strong and durable fittings with improved mechanical properties.
• Pressing: Uses a hydraulic or mechanical press to shape the metal. Provides precise control over the shaping process, resulting in consistent and accurate fittings.
• Piercing: Involves punching a hole or cavity through the metal. Suitable for creating fittings with complex internal geometries.
• Extruding: Forces the metal through a die to create long shapes with uniform cross-sections. Efficient for producing fittings with consistent dimensions and smooth surfaces.
• Upsetting: Involves increasing the diameter of a portion of the metal by compressing its length. Used to form thicker sections on fittings, enhancing their strength and durability.
• Bending: Involves deforming the metal to create angles and curves. Essential for producing elbow fittings and other components that require precise angles.
• Fusion-Welding: Joins metal pieces by melting and fusing them together, with or without the addition of a filler material. Creates strong, leak-proof joints, essential for the integrity of the fittings.
• Machining: Involves cutting away excess material to achieve the final dimensions and shape. Provides high precision and smooth finishes, ensuring the fittings meet exact specifications.

Heat Treatment

The heat treatment process for ASTM A420 carbon steel fittings is designed to enhance their mechanical properties. This ensures optimal performance in low-temperature environments. All welding operations must be completed before the austenitizing heat treatment.

To ensure that the fittings achieve the desired physical properties and are suitable for a wide range of applications, they are subjected to one of the following heat treatment processes:

• Normalization: Involves heating the steel to a temperature above its critical range and then cooling it in air. Refines the grain structure, enhancing the toughness and strength of the fittings.
• Normalization and Tempering: After normalizing, the steel is reheated to a lower temperature and then cooled in air. This two-step process reduces brittleness and improves ductility, making the fittings more resilient to stress.
• Annealing: Annealing involves heating the steel to a specific temperature and then slowly cooling it, usually in a furnace. This process softens the steel, making it more workable and enhancing its machinability.
• Quenching and Tempering: The steel is heated to a high temperature and then rapidly cooled (quenched) in water or oil, followed by tempering at a lower temperature. Quenching increases the hardness and strength of the steel, while tempering reduces brittleness and improves toughness.

A post-weld heat treatment may be necessary if specified. Additionally, all fittings must cool below their lower critical temperature before any heat treatment can begin. To meet industry standards and ensure reliable performance, these methods offer versatility in creating high-quality fittings that deliver exceptional results.

Mechanical Properties

ASTM A420 carbon steel fittings must conform to stringent mechanical property requirements such as:

• Chemical Composition:
• Tensile Strength
• Yield Strength
• Elongation
• Wall Thickness
• Charpy V-Notch Impact Value

These properties ensure the material’s strength, durability, and suitability for low-temperature applications. All fusion-welded joints undergo radiographic examination, ensuring integrity, reliability, and that there are no hidden defects. Although hydrostatic testing is not required, our supplier does a leak check on all fittings as a part of their manufacturing process. Our commitment to quality ensures that every product meets or exceeds industry standards. 

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Merit's ASTM A420 Carbon Steel Fitting Solutions: CarbonPress®

By choosing Merit's CarbonPress® fittings for your next project, you benefit from:

• Exceptional Quality: Manufactured with precision, CarbonPress® fittings adhere to the highest quality standards. Rigorous quality control processes ensure each fitting meets ASTM A420 specifications.
• Industry Expertise: With over 85 years of experience, we understand the unique challenges and demands of your projects. Our expert team is committed to providing solutions that meet your specific needs.
• Reliable Supply: We maintain a robust inventory which allows for an efficient supply chain ensuring timely delivery and consistent availability.

At Merit Brass, we provide our customers with the highest quality ASTM A420 carbon steel fittings. Our quality assurance processes guarantee that our products meet the demanding needs of the pipe, valves, and fittings industry. Explore our range today and discover why Merit Brass is the go-to source for all your PVF needs.

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