Views: 2 Author: Monica Publish Time: 2025-10-27 Origin: Site
ASTM B165 UNS N04400 seamless pipe is a corrosion-resistant pressure pipe made of nickel alloy. This standard specifies the dimensions, tolerances, chemical composition, and mechanical property requirements for seamless cold-finished and hot-finished pipe.
Regarding dimensional specifications, B165 seamless pipe typically follows the size series defined by the American National Standards Institute and the American Society of Mechanical Engineers, such as ASME B36.10M and B36.19M. The nominal pipe size range generally spans from NPS 1/8 to NPS 8 or larger, with wall thicknesses defined by different Schedule numbers (e.g., Sch 40, Sch 80, Sch XS, etc.).
The core advantage of N04400 alloy lies in its exceptional resistance to seawater and brine corrosion, outstanding tolerance to non-oxidizing acids, and the maintenance of high strength and good toughness across a wide temperature range. These properties make it an ideal choice for marine engineering, chemical processing equipment, and the oil and gas industry.
UNS N04400 (Monel 400) is a nickel-copper alloy. According to ASTM B165, alloy 400 is primarily composed of nickel and copper. The nickel content must be at least 63.0%, while the copper content is typically between 28% and 34%.
UNS N04400 alloy strictly limits the content of impurity elements such as iron, manganese, and silicon. In particular, the sulfur content is kept to extremely low levels to ensure excellent resistance to stress corrosion cracking and pitting corrosion in a variety of harsh environments, while also maintaining good machinability and weldability.
Composition | Value |
Nickel + Cobalt | ≥ 63.0 |
Copper | 28.0 - 34.0 |
Iron | ≤ 2.50 |
Manganese | ≤ 2.00 |
Carbon | ≤ 0.30 |
Silicon | ≤ 0.50$ |
Sulfur | ≤ 0.024 |
The ASTM B165 specification covers UNS N04400 (Monel 400) in the form of seamless pipe and tube. The specific dimensional size requirements (outside diameter and wall thickness) for these pipes are not detailed within the B165 standard itself but rather reference the established industry piping codes.
Therefore, the dimensions for ASTM B165 pipes, including the wall thickness determined by the schedule number, follow the criteria established in ASME B36.10M and ASME B36.19M.
Since Monel 400 is frequently used in corrosive applications requiring specific pressure ratings, the size chart below presents common Nominal Pipe Sizes (NPS) and their corresponding Schedule wall thicknesses, according to the standard dimensional tables referenced by B165.
Nominal Pipe Size (NPS) | Outside Diameter (OD) [in / mm] | Schedule 10S Wall Thickness [in / mm] | Schedule 40S/STD Wall Thickness [in / mm] | Schedule 80S/XS Wall Thickness [in / mm] |
1/2" | 0.840 in / 21.3 mm | 0.083 in } / 2.11 mm | 0.109 in / 2.77 mm | 0.147 in / 3.73 mm |
1" | 1.315 in / 33.4 mm | 0.109 in / 2.77 mm | 0.133 in / 3.38 mm | 0.179 in / 4.55 mm |
2" | 2.375 in / 60.3 mm | 0.109 in / 2.77 mm | 0.154 in / 3.91 mm | 0.218 in / 5.54 mm |
4" | 4.500 in / 114.3 mm | 0.120 in / 3.05 mm | 0.237 in / 6.02 mm | 0.337 in / 8.56 mm |
6" | 6.625 in / 168.3 mm | 0.134 in / 3.40 mm | 0.280 in / 7.11 mm | 0.432 in / 10.97 mm |
8" | 8.625 in / 219.1 mm | 0.148 in / 3.76 mm | 0.322 in / 8.18 mm | 0.500 in / 12.70 mm |
Note: Dimensions are nominal. The B165 specification itself outlines the chemical, mechanical, and testing requirements for the UNS N04400 material but requires compliance with ASME dimensional standards for pipe sizing.
UNS N04400 alloy has a high density of approximately 8.80 g/cm³, significantly higher than stainless steel. Its melting point typically ranges from 1300°C to 1350°C.
Monel 400 offers good thermal conductivity, superior to austenitic stainless steels, and a relatively low coefficient of thermal expansion.
Mostly, Monel 400 alloy is non-magnetic in the solution-annealed state.
Property | Typical Value |
Density | 8.80 g/cm3 |
Melting Range | 1300 - 1350 ℃ |
Thermal Conductivity | 21.8 W/(m·℃) |
Specific Heat | 427 J/(Kg·℃) |
Magnetic Permeability | ~ 1.00 |
UNS N04400 excels in low- and medium-temperature applications. It cannot be hardened by heat treatment and can only be strengthened by cold working.
In the standard annealed condition, Alloy 400 has a minimum tensile strength of approximately 550 MPa and a minimum yield strength of approximately 240 MPa, while maintaining good ductility.
Tensile Strength | 550 MPa |
Yield Strength | 240 MPa |
Elongation | 35% |
Modulus of Elasticity | 179 GPa |
Recent quotes for ASTM B165 UNS N04400 Monel 400 seamless tubing range from $20 to $25 per kilogram (minimum order quantity 100 kg), with some offers at $16 to $25 per kilogram (minimum order quantity 300 kg). Additionally, some suppliers quote factory-direct prices between $29.70 and $39.60 per kilogram.
The price of ASTM B165 UNS N04400 seamless pipe is primarily determined by factors including material costs, production processes, specifications and dimensions, procurement volume, and quality certifications. Its core material, Monel 400, inherently possesses high corrosion resistance and heat resistance, resulting in a significant proportion of raw material costs.
Regarding production processes, seamless pipes are typically manufactured using techniques such as extrusion or piercing. These processes are complex and demand high-specification equipment, directly impacting production costs.
Product specifications and dimensions also contribute to price variations, with non-standard or custom products commanding significantly higher prices than standard offerings.
Furthermore, purchase volume is a key factor affecting unit pricing, as bulk orders typically secure more favorable rates.
Finally, obtaining reliability certifications such as ISO, CE, or SGS also impacts pricing. Certified products offer greater quality assurance and consequently carry higher price tags.
The pressure rating of Monel 400 seamless pipe is not a fixed value; it depends primarily on the pipe's outer diameter and wall thickness.
Pressure rating calculations typically follow industry-standard specifications, such as ASME B31.3, the Pressure Piping Code. Monel 400 is a high-strength nickel alloy that provides excellent high-pressure load-carrying capabilities, even in harsh environments requiring corrosion resistance.
O.D. [inch] | Wall Thickness [inch] | Maximum Allowable Working Pressure [PSI] |
1/8 in | 0.028 in | 8,000 |
1/8 in | 0.035 in | 10,450 |
1/4 in | 0.035 in | 4,800 |
1/4 in | 0.049 in | 7,000 |
3/8 in | 0.049 in | 4,450 |
1/2 in | 0.035 in | 2,300 |
1/2 in | 0.049 in | 3,300 |
1 in | 0.065 in | 2,250 |
