ASTM A178 Steel Pipe


ASTM A178 Steel Pipe

At UNIACERO, we are proud to introduce our premium range of electric-resistance-welded tubes, meticulously crafted to meet the ASTM A178 standard. These tubes, with their minimum wall thickness, are made from the finest carbon steel and carbon-manganese steel, ensuring durability and efficiency. Designed for use in boiler tubes, boiler flues, superheater flues, and safe ends, our ASTM A178 tubes are the epitome of quality and precision. Whether you’re looking for Grades A, C, or D, we have them all, tailored to your specific needs. When you choose our products, you’re investing in tubes that have undergone rigorous heat treatment post-welding, ensuring their longevity and performance.

ASTM A178 Specification

Our ASTM A178 tubes are a testament to precision engineering. Ranging in outside diameter from 1/2 to 5 inches (12.7 to 127 mm) and a minimum wall thickness of 0.035 to 0.360 inches (0.9 to 9.1 mm), they are versatile and adaptable. We offer tubes in Grades A, C, and D, each with distinct chemical and tensile requirements. While our standard dimensions cater to most needs, we also provide custom dimensions, ensuring that the tubes align perfectly with your requirements. Each tube undergoes electric-resistance welding, followed by a stringent heat treatment at temperatures exceeding 1650°F (900°C). With UNIACERO, you receive products that are not only compliant with international standards but also tailored to your unique needs.

Production StandardASTM A178/A178M
Manufacturing ProcessesERW/ Electric Resistance Welding
Outside Diameter12.7mm – 127mm (1/2″ – 5″)
Wall Thickness0.9mm – 9.1mm
Pipe Length3 – 12 mtrs meters
Steel GradeASTM A178  Gr. A
ASTM A178  Gr. C
ASTM A178  Gr. D
Corrosion PreventionLacquer, Varnish, Oiling, Galvanizing
End ProcessesSquare Cut, Bevelling, Threading, Grooving , Shouldering
Further ProcessingWelding, Bending, Hole Drilling, Punching, Swaging, Tapering, Flaring, Expanding

ASTM A178 Dimension Table


Our ASTM A178 tubes are available in a variety of dimensions to suit diverse applications. Typically, the outside diameter ranges from 1/2″ to 5″ (12.7 mm to 127 mm), and the minimum wall thickness spans from 0.035″ to 0.320″ (0.9 mm to 9.1 mm). However, at UNIACERO, we understand that one size doesn’t fit all. Hence, we offer custom dimensions, ensuring that the tubes seamlessly integrate into your systems. Every dimension is meticulously crafted, ensuring that the tubes not only meet but exceed the ASTM A178/ ASME SA-178 standards.

Outside Diameter:1⁄2 to 5 in. [12.7 to 127 mm]
Wall Thickness:0.035 to 0.360 in. [0.9 to 9.1 mm]
Tubing having other dimensions may be furnished, provided such tubes comply with all other requirements of this specification.

Chemical Requirements of ASTM A178 Steel Pipe

Our commitment to quality is evident in the chemical composition of our ASTM A178 tubes. Whether you opt for Grade A (low-carbon steel), Grade C (medium-carbon steel), or Grade D (carbon-manganese steel), rest assured that the tubes conform to the stipulated compositions of carbon, manganese, phosphorus, sulfur, and silicon. At UNIACERO, we ensure that each tube undergoes rigorous testing to validate its chemical composition, guaranteeing that you receive products of the highest caliber.

ElementComposition, %
Grade A, Low-Carbon SteelGrade C, Medium- Carbon SteelGrade D, Carbon- Manganese Steel
Carbon0 06–0 180 35 max0 27 max
Manganese0.27–0.630.80 max1.00– 1.50
Phosphorus, max0 0350 0350 030
Sulfur, max0.0350.0350.015
Silicon0. 10 min

Mechanical Requirements of ASTM A178 Tube

Mechanical integrity is paramount for the performance of our ASTM A178 tubes. Adhering to the ASTM standards, our tubes in Grades C and D meet specific tensile requirements, including tensile strength, yield strength, and elongation. Furthermore, each tube is subjected to a battery of tests, such as flattening, flange, tension, and reverse flattening, ensuring their mechanical robustness. With UNIACERO, you’re not just purchasing a product; you’re investing in reliability and performance.

Tensile Requirements
Mechanical PropertiesGrade AGrade CGrade D
Tensile strength, min, ksi [MPa]47 [325]60 [415]70 [485]
Yield strength, min, ksi [MPa]26 [180]37 [255]40 [275]
Elongation in 2 in. or 50 mm, min, %353030
For longitudinal strip tests a deduction for each 1⁄32-in. [0.8 mm] decrease in wall thickness below 5⁄16    in. [8 mm] from the basic minimum elongation of the following percentage points shall be made.1.50A1.50A
A  See Table 3 for the computed minimum values.
Minimum Elongation Values
Wall ThicknessElongation in 2 in. or 50 mm, min, %A
A  Calculated  elongation  requirements  shall  be  rounded  to  the  nearest  whole number.

Steel Grades in ASTM A178 Boiler Tube

At UNIACERO, we offer ASTM A178 tubes in three distinct steel grades: Grade A (low-carbon steel), Grade C (medium-carbon steel), and Grade D (carbon-manganese steel). Each grade is tailored to specific applications, ensuring optimal performance. Grade A is perfect for general use, while Grades C and D are designed for more demanding applications, with Grade D steel being killed for enhanced durability. Our experts are always on hand to guide you in selecting the perfect grade for your needs, ensuring that you benefit from the best that UNIACERO has to offer.

Our Advantages

  1. Over 25 years of experience in pipeline production and installation.
  2. Comprehensive inspection equipment.
  3. Independent product serial numbers for traceability.
  4. Advanced production equipment – Seamer high-frequency welding machine from the United States.
  5. Complete qualifications – API 5L/API 5CT/FM/UL fire pipe certification, etc.
  6. Wide range of products – independently developed solar torque tubes, highly favored in the European market.
  7. Customers spread across the globe.
  8. Excellent after-sales service and sense of responsibility.

Application Scenarios

Our steel pipes are engineered to withstand high temperatures, corrosive environments, and varying pressures, ensuring reliability and safety in the complex petrochemical processes. 

Whether it’s transferring crude oil, natural gas, or chemical intermediates, the robustness and versatility of steel pipes make them indispensable components of the plant’s infrastructure, contributing to efficient production and maintenance of stringent safety standards.

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