Views: 18 Author: Site Editor Publish Time: 2023-12-06 Origin: Site
ASTM A420/A420M is a standard issued by the American Society for Testing and Materials (ASTM) to specify the technical requirements for the manufacture, inspection, and use of carbon steel and low alloy steel pipe fittings for low temperature applications.The standard applies to seamless and welded butt-welding pipe fittings, including butt-welding elbows, butt-welding tees, butt-welding reducers, butt-welding caps, and other pipe fittings used in low temperature pressure pipelines and pressure vessels.
Material Grade And Properties
The ASTM A420/A420M standard includes four grades of materials: WPL6, WPL9, WPL3, and WPL8.The standard provides detailed requirements for the chemical composition, mechanical properties, impact properties, and impact test temperatures of these four materials.
Chemical Composition
CHEMICAL | LIMITS | C | Mn | P | S | Si | Ni | Cr | Mo | Cu | Cb | V |
ASTM A420 WPL6 | MIN | 0.50 | 0.15 | |||||||||
MAX | 0.30 | 1.35 | 0.035 | 0.040 | 0.40 | 0.40 | 0.30 | 0.12 | 0.40 | 0.02 | 0.08 | |
ASTM A420 WPL9 | MIN | 0.40 | 1.60 | 0.75 | ||||||||
MAX | 0.20 | 1.06 | 0.030 | 0.030 | / | 2.24 | / | / | 1.25 | / | / | |
ASTM A420 WPL3 | MIN | 0.31 | 0.13 | 3.20 | ||||||||
MAX | 0.20 | 0.64 | 0.050 | 0.050 | 0.37 | 3.80 | / | / | / | / | / | |
ASTM A420 WPL8 | MIN | 0.13 | 8.40 | |||||||||
MAX | 0.13 | 0.90 | 0.030 | 0.030 | 0.37 | 9.60 | / | / | / | / | / |
Mechanical Properties
MATERIAL | ASTM A420 WPL6 | ASTM A420 WPL9 | ASTM A420 WPL3 | ASTM A420 WPL8 |
T.S (MPA) | 415-655 | 435-610 | 450-620 | 690-865 |
Y.S (MPA) | 240 min | 315 min | 240 min | 515 |
Elongation equirements | WPL6 | WPL9 | WPL3 | WPL8 | ||||
Longi-tudinal | Trans-verse | Longi-tudinal | Trans-verse | Longi-tudinal | Trans-verse | Longi-tudinal | Trans-verse | |
Standard round specimen, or small proportionaspecimen, min %e in 4 D | 22 min | 12 min | 20 min | / | 22 min | 14 min | 16 min | / |
Rectangular specimen for wall thickness e in. 0.94mm and over, and for all small sizes tested in fusection: min % o in 2 in. or 50 mm | 30 min | 16.5 min | 28 min | 18 min | 30 min | 20 min | 22 min | / |
Impact Requirements
Charpy lmpact Requirements for WPL6, WPL9, and WPL3 | ||||
Size of Specimen | Charpy V-Notch ImpactValue Required forAcceptance(Average of Three Specimens) | Minimum Charpy V-NotchImpact Value WithoutRequiring Retest(OneSpecimen Only of a Set) | ||
ft.lbf | J | ft.lbf | J | |
10*10 | 13 | 18 | 10 | 14 |
10*7.5 | 10 | 14 | 8 | 11 |
10*5.0 | 7 | 9 | 5 | 7 |
10*2.5 | 4 | 5 | 3 | 4 |
Charpy lmpact Requirements for WPL8 | ||||
Size of Specimen | Charpy V-Notch ImpactValue Required forAcceptance(Average of Three Specimens) | Minimum Charpy V-NotchImpact Value WithoutRequiring Retest(OneSpecimen Only of a Set) | ||
ft.lbf | J | ft.lbf | J | |
10*10 | 25 | 34 | 20 | 27 |
10*7.5 | 21 | 29 | 17 | 23 |
10*5.0 | 17 | 23 | 14 | 19 |
10*2.5 | 8 | 11 | 6 | 8 |
lmpact Test Temperature
lmpact Test Temperature | |
GRADE | TemperatureF°[C°] |
WPL6 | -50[-45] |
WPL9 | -100[-75] |
WPL3 | -150[-100] |
WPL8 | -320[-195] |
The purpose of the ASTM A420 low-temperature steel impact test is to check whether the material's impact resistance is acceptable under low-temperature conditions.Through low-temperature impact testing, the material's impact resistance can be determined, which can help determine whether it has sufficient strength and reliability before being used.Low-temperature impact testing is commonly used to test aerospace components, electronic devices, automotive and building materials, etc. In the fields of space exploration, aerospace, military, and civilian applications, many aerospace components and building materials must undergo low-temperature impact testing to ensure that they can work properly in low-temperature environments.
Heat Treatment
ASTM A420/A420M standard stipulates that all butt-welded pipe fittings require heat treatment, including normalizing, normalizing plus tempering, annealing, or quenching plus tempering, in order to improve the performance of the metal material, so that it can achieve the normal working state of the pipe fitting in low temperature environment, and it has better performance and longer service life.The principle of heat treatment is to change the crystal structure of the metal material by heating and cooling it, which can change its mechanical properties.There are many methods of heat treatment, the most common of which are quenching, tempering, annealing, and normalizing.Quenching is to heat the metal material to a certain temperature and then rapidly cool it to produce a high-hardness and high-strength structure.Tempering is to heat the quenched metal material to a certain temperature and then cool it to produce a certain toughness and corrosion resistance.Annealing is to heat the metal material to a certain temperature and then slowly cool it to produce a certain toughness and plasticity.Normalizing is to heat the metal material to a certain temperature and then cool it to produce a certain hardness and strength.
Application And Advantages of ASTM A420 WPL6
Among the grades of materials included in the ASTM A420/A420M standard, WPL6 is currently the most commonly used material in the market. It is an alloy steel that is resistant to low temperature environments by adding an appropriate amount of one or more alloying elements to ordinary carbon steel.This steel is mainly used in low temperature pressure pipelines and pressure vessels, and its advantages are mainly reflected in the following aspects:
Widly application: ASTM A420 WPL6 is suitable for low-temperature pressure pipelines and pressure vessels, which has a wide range of applications and therefore has high market application value.
Excellent low temperature resistance: ASTM A420 WPL6 has good low temperature performance, maintaining good mechanical properties and corrosion resistance at lower temperatures, making it suitable for use in pipelines and vessels in low temperature environments.
Good welding performance: ASTM A420 WPL6 has good welding performance, making it easy to perform welding operations. The welded joints have high strength and durability, making it suitable for manufacturing pipe fittings that require welding.
Corrosion resistance: ASTM A420 WPL6, after proper treatment, has good corrosion resistance and is suitable for pipelines and containers used in corrosive environments.
In conclusion, ASTM A420 WPL6 is an alloy steel with excellent properties, suitable for the manufacture and inspection of low-temperature pressure pipelines and pressure vessels, with a wide range of applications and market prospects.
