🎓 Hello and welcome to the 14th session of the ASME B31.3 Course! This is Ali, and I hope you are doing well.

In today's session, we will delve into two crucial methods used for the manufacturing of pipes, and then we'll explore how ASME B31.3 considers these methods in its code.

Seamless Pipe:
Seamless pipes boast the strongest structure among all pipe types due to their homogeneous composition throughout the length. While they come in various sizes and schedules, manufacturing seamless pipes is pricier compared to other methods. However, there are restrictions on manufacturing large diameter pipes. Despite the cost, seamless pipes find extensive use in manufacturing pipe fittings such as bends, elbows, and tees.

Welded Pipe:
Welded pipes are manufactured by rolling plates or coil strips into circular sections. They can be welded with or without filler material. Welded pipes can be made in large sizes without restrictions, but they are cheaper and weaker compared to seamless pipes due to the weld. ASME B31.3 accounts for this weakness by considering Ej (Longitudinal Weld Joint Quality Factor) in the wall thickness calculation formula.

Different welding methods are used for pipe welding, including Furnace butt weld, continuous weld, Electric resistance Weld, and Electric fusion weld, which includes Shield Metal Arc Welding (SMAW), MIG (Metal Inert Gas), TIG (Tungsten Inert Gas), and SAW (Submerged Arc Welding).

While discussing welding methods isn't the focal point of this course, it's highly recommended to familiarize yourself with them as they can be invaluable in your work. 🛠️

Now, let's examine how different manufacturing methods are considered by B31.3:

ASME B31.3 Paragraph 302.3.4 discusses the Weld Joint Quality Factor, Ej. It outlines basic quality factors for welded joints and indicates higher factors that can be substituted for certain kinds of welds with additional examination.

For example, Ej for seamless pipes is 1, indicating no welds. For welded pipes, Ej is less than 1, causing increased thickness. Table A-1B provides basic quality factors for longitudinal weld joints, and additional examinations may lead to higher Ej values.

Paragraph 341.5.1 outlines the criteria for using Ej=0.9 by radiography for Longitudinal Welds and circumferential Butt Welds and Other Welds, allowing for increased thickness.

The choice of pipe manufacturing method depends on various factors such as cost, availability, project limitations, and size requirements. Seamless pipes are ideal for smaller sizes, while Electric Resistance Weld (ERW) pipes are suitable for intermediate sizes, and Submerged Arc Welding (SAW) pipes may be preferred for larger sizes.

It's crucial to evaluate all conditions for selecting the best method. Consider the cost, availability, and project limitations. Seamless pipes may be expensive but reliable, while welded pipes offer cost savings but require careful consideration of thickness due to welds.

Thank you for joining us on this educational journey! 🌟🚀