What Is The Difference Between Cold Drawn Seamless And DOM?
In the world of metal tubing, two terms often come up: Cold Drawn Seamless (CDS) and Drawn Over Mandrel (DOM). Both are popular choices for various industrial applications, but they have distinct characteristics that make them suitable for different purposes. This article explores the differences between these two types of tubing by addressing three key questions.
1. What Are the Manufacturing Processes for CDS and DOM Tubing?
Cold Drawn Seamless (CDS):
CDS tubing is manufactured by taking a solid billet and piercing it to create a hollow tube. This tube is then cold-drawn through a die and over a mandrel to achieve the desired dimensions and surface finish. The cold drawing process enhances the mechanical properties of the tube, such as tensile strength and hardness, while also improving dimensional accuracy and surface quality.
Drawn Over Mandrel (DOM):
DOM tubing starts as Electric Resistance Welded (ERW) tubing. The ERW process involves forming a strip of steel into a tubular shape and welding the seam. The welded tube is then drawn over a mandrel and through a die, similar to the CDS process. This drawing process eliminates the weld seam, resulting in a product with uniform wall thickness and improved mechanical properties.
2. How Do the Mechanical Properties Compare?
CDS Tubing:
CDS tubing is known for its superior strength and uniformity. The seamless nature of the tube means there are no weak points, such as weld seams, which can be potential failure points under stress. The cold drawing process further enhances the tube’s mechanical properties, making it ideal for high-pressure applications.
DOM Tubing:
While DOM tubing starts with a welded seam, the drawing process significantly improves its mechanical properties. The seam is virtually eliminated, resulting in a tube with uniform strength and excellent surface finish. Although DOM tubing is generally not as strong as CDS tubing, it offers a good balance of strength, cost, and availability, making it suitable for many applications.
3. What Are the Typical Applications for Each Type?
CDS Tubing:
Due to its high strength and seamless construction, CDS tubing is often used in applications where safety and reliability are critical. Common uses include hydraulic systems, automotive components, and high-pressure applications in the oil and gas industry.
DOM Tubing:
DOM tubing is widely used in applications where cost-effectiveness and good mechanical properties are required. It is commonly found in automotive parts, agricultural machinery, and general engineering applications. Its excellent surface finish also makes it a popular choice for aesthetic applications.
