1. **What is ASTM A672?**
ASTM A672 is a standard specification for **electric-fusion-welded steel pipe** designed for **high-pressure service at moderate temperatures**. It covers pipes intended for use in **low-temperature environments** where notch toughness is required. The pipe is manufactured by forming flat steel plate or sheet into a cylindrical shape and welding the seam using an automatic arc or gas welding process. Pipes made to this standard **must undergo post-weld heat treatment** (PWHT) to ensure optimal mechanical properties and weld integrity.
2. **What is the difference between A106 and A672?**
* **A106:** Covers **seamless** carbon steel pipe for high-temperature service. It's made without a weld seam by piercing a solid billet. Used primarily in refineries, power plants, and high-temperature process piping.
* **A672:** Covers **electric-fusion-welded** carbon and alloy steel pipe for **high-pressure, low/moderate-temperature** service. It's formed from plate/sheet and welded. Crucially, it **requires post-weld heat treatment (PWHT)** and often requires impact testing for low-temperature toughness. Used for critical low-temperature applications like cryogenic service.
3. **What material is A672 C60 pipe made of?**
ASTM A672 C60 pipe is made from **carbon steel**. The "C60" designation specifically indicates:
* **Grade:** The base material grade is typically **Grade A, B, C, or D** carbon steel (as defined within A672).
* **Strength Class:** The "60" signifies a **minimum specified tensile strength of 60,000 psi (415 MPa)**.
* **Key Requirement:** Regardless of the specific grade, all A672 C60 pipe undergoes **mandatory post-weld heat treatment (PWHT)** after welding to achieve the required properties.
4. **What is the difference between ASTM A671 and ASTM A672?**
Both ASTM A671 and A672 cover **electric-fusion-welded steel pipe** requiring **post-weld heat treatment (PWHT)**. The key difference is their **intended service conditions**:
* **ASTM A671:** Covers pipe for **atmospheric and lower temperature service**. It focuses on pipes used at **ambient or cold temperatures**, where resistance to brittle fracture is critical. Impact testing requirements are defined based on the specified design temperature.
* **ASTM A672:** Covers pipe for **high-pressure service at moderate temperatures**. While it can also be used for **low-temperature service** (and often requires impact testing for those conditions), its primary scope includes pipes operating at **higher pressures** compared to typical A671 applications. The emphasis is on the combination of pressure capability and suitability for low/moderate temperatures.
5. **What is A671 pipe?**
ASTM A671 is a standard specification for **electric-fusion-welded steel pipe** intended for use in **atmospheric and lower temperature service**. The pipe is formed from steel plate or sheet, welded along a seam using an automatic process (arc or gas), and crucially **must undergo post-weld heat treatment (PWHT)**. Its defining characteristic is its suitability for environments where **low-temperature toughness** (resistance to brittle fracture) is essential, such as in cryogenic storage, LNG facilities, or cold climate piping. Impact testing requirements are specified based on the design temperature.
