A179 is a seamless cold-drawn low-carbon steel tube for American standard heat exchangers and condensers. It is usually made of low-carbon steel and produced by hot rolling or cold drawing processes. It has the advantages of high strength, high pressure resistance and corrosion resistance.
A179 Technical Requirements
- Raw Material Requirements: Raw materials must meet the requirements specified in the new version of A450/A450M.
- Production Process: The steel pipe must be seamless and cold-drawn.
- Heat Treatment: The steel pipe must undergo heat treatment at 1200 degrees Fahrenheit (650 degrees Celsius) or higher after the final cold drawing.
- Appearance Requirements: Finished pipes must be free of peeling; a small amount of oxides is not considered peeling.
- Chemical Composition: The chemical composition of the steel pipe must meet certain requirements, including a carbon content between 0.06% and 0.18%, a manganese content between 0.27% and 0.63%, and a maximum phosphorus and sulfur content of 0.035%. Alloy steels have other requirements for the content of special elements and are not subject to the above restrictions.
- Hardness Requirements: The hardness coefficient of the steel pipe must not exceed 72 HRB.
A179 Inspection and Testing
- Product Analysis: When the purchase order specifies the need for product analysis, the supplier shall randomly select 1 pipe from every 250 pipes for analysis. Additionally, if there are differences in the steel pipes due to heat treatment, 1 pipe shall be randomly selected from each heat-treated batch for analysis. The chemical composition must be consistent with that specified in the order.
- Flattening and Flaring Tests: A certain number of samples shall be randomly selected from each batch of steel pipes for flattening and flaring tests (or bending tests, when the pipe wall thickness is less than 10% of the outer diameter).
- Hardness Testing: Two pipes shall be randomly selected from each batch of steel pipes for Rockwell hardness testing.
- Hydraulic Pressure Testing: Every steel pipe shall undergo a hydraulic pressure test, or, if the purchaser requires otherwise, a non-destructive electrical test may be used instead.
Why it's Used:
ASTM A179 seamless steel tubes are cold-drawn low-carbon seamless steel tubes designed specifically for heat transfer equipment such as heat exchangers and condensers under the American standard system. Due to their excellent processing and mechanical properties, they are widely used in industrial fields. These standard steel tubes are formed using a cold-drawing process, with diameters ranging from 3.2 to 76.2 mm and wall thickness accuracy up to ±0.1 mm. They have no oxide layer on either the inner or outer walls, a high surface finish, can withstand high pressure without leakage, and do not deform when cold-bent. They also exhibit no cracks when flared or flattened, meeting the manufacturing requirements of high-precision equipment.