ASTM A513 Type 5 carries the name "DOM," which stands for Drawn Over Mandrel. This designation reflects the tube's defining production step: after electric resistance welding, the tube is drawn through a die and over a steel mandrel that reshapes the inner diameter, eliminating the internal weld flash and tightening wall thickness uniformity. The result is an ASTM A513 tube with OD/ID tolerances often within ±0.003 inches — far tighter than standard ERW product. For manufacturers machining bushings, automotive frames, or precision structural parts, that accuracy is what sets Type 5 apart.
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ASTM A513 Type 5: What Is DOM?
The Origin of the Name
The word "DOM" is only used for tasks. ASTM A513 lists five types of mechanical tubes. These are based on how the strip or skelp is dealt with. Different hot-rolled and cold-rolled ERW shapes are in Types 1 through 4. Type 5 adds one more step: drawing cold over a mandrel. In this step, its DOM name is given.
Why Only Type 5 Gets This Treatment
For Types 1–4, the weld bead on the inside wall is left alone. When you do Type 5 cold drawing, you break up that bead and also make the steel stronger. When ERW steel is hot-rolled, its yield strength goes from about 32,000 psi to 70,000 psi or more in DOM stress-relieved steel. This type of ASTM A513 tube is the only one that can measure so accurately and have such a high tensile strength.
What Makes DOM Different From Seamless
People sometimes mix up cold-drawn seamless (CDS) tubing and DOM tubing. DOM is different because it starts out as a tube that has been glued together. Because DOM improves the weld seam instead of getting rid of it, it costs less than CDS. It still gives the same level of accuracy and surface finish, which is good enough for most precision machining tasks.
Detailed Specifications of ASTM A513 Type 5 Tubes
Chemical Composition
Low-carbon types like 1010, 1015, and 1020 are used to make Type 5 of ASTM A513 tube. The amount of carbon stays between 0.05% and 0.23%, which makes it simple to shape and join. The amounts of sulfur, phosphorus, and manganese are carefully watched to make sure that the properties of the metal don't change from one batch of production to the next. This directly answers buyers' worries about how the carbon levels in different batches might be different.
Mechanical Properties
The cold-drawing process makes the wall of the tube harder. This makes the tensile strength much higher than what the annealed base steel grade can offer. Depending on the grade, stress-relieved DOM tubes can have tensile strengths of 58,000 to 87,000 psi. This means they can handle heavy loads and a lot of use in factories and cars.
Dimensional Range and Tolerances
Longma Group's DOM-class A513 tubes come in a range of outside sizes, from 21.3 mm to 406.4 mm, and wall thicknesses, from SCH10 to SCHXXS. By controlling the size of the mandrel, the ID tolerance stays at the normal ±0.005 inches, and the OD tolerance stays the same. You can get lengths that are cut just for you, which saves you money because you won't have to waste time cutting it again in-house.
Manufacturing Process and Heat Treatment of DOM Tubes
From ERW Blank to DOM Tube
To begin making something, a flat piece of steel is rolled out and then resistance-welded into a round tube. After being ERW, the blank goes to a cold-drawing station. It is drawn over a mandrel and through a carbide die at the same time. The bore is burnished and the weld flash is smoothed out by the mandrel. This makes the inside of the tube as clean and even as the outside.
Heat Treatment for Microstructural Integrity
At a controlled temperature, stress-relief annealing makes the metal flexible again after it has been cold drawn. It does this without taking away the strength that it gained through work hardening. This step also evens out any pressures that are still there along the weld line. Companies that make parts for cars and furniture use this method every day to make sure that the tube always works the same way when it is bent, flared, or formed.
Quality Control and Certification
Every batch of materials is tested for its tensile strength, yield strength, stretch, and ability to stay the same size. Longma Group is certified by ISO 9001 for quality management and keeps track of all of its materials, from the raw steel coil it gets from mills like Bao Steel, HBIS, and Shougang to the finished tube. There are inspection test plans (ITP) and mill test certificates (MTC) for every order.
Applications and Advantages of ASTM A513 DOM Tubes in B2B Sectors
Many industries that need accuracy use DOM tubes because they are easy to machine and meet strict standards. This is where ASTM A513 tube Type 5 really makes a difference:- Steering columns, hydraulic cylinders, and suspension links all need to have tight bore tolerances in the car business. It takes less time and material to make DOM tubes because the hole is close to the net width.
For actuator housings, roller shafts, and bearing sleeves in industrial machinery, walls that are the same thickness are good because they keep wall stress even when radial loads are put on them.
- Automotive components: Steering columns, hydraulic cylinders, and suspension links all demand tight bore tolerances. DOM tubes reduce boring stock and cycle time because the bore arrives at near-net dimension.
- Industrial machinery: Actuator housings, roller shafts, and bearing sleeves benefit from consistent wall thickness, which keeps wall stress uniform under radial loads.
- Furniture and fitness equipment: Frame tubes for chairs, gym machines, and racking systems gain a clean, defect-free outer surface that accepts powder coating or plating without pre-grinding.
One thing all three of these uses have in common is that they all need a tube that still works well during secondary operations. Normal ERW goods can't do this over and over again, but DOM can. Smooth options cost about 15–25% more per kilogram than DOM options that are the same size and shape accuracy. When you buy a lot of it every year, like $100,000 or more, this makes a big difference.
How to Choose and Procure ASTM A513 Type 5 DOM Tubes?
Matching Grade to Load Requirement
If you only need to shape and decorate, grade 1010 is fine. Grade 1015 has a small amount of carbon, which makes it good for building frames and general structure parts. Grade 1020 is stronger, so it can be used for parts of cars and machines that have to hold heavy loads for a long time. If you pick the right grade during the design phase, you can avoid making too many requirements and keep the cost of materials low.
Evaluating Supplier Credibility
Third-party approvals, such as ISO 9001 and API 5L, show that a company's processes have been checked out. They don't just say they follow the rules; they have been checked out. You can get the heat and lot numbers from MTCs. Check to see if the chemicals match the grade you bought. Before you commit to the full amount for your first order, ask for samples. In corporate buying, you usually have two to four weeks to try something out. This time is well spent.
Negotiating Terms That Fit Your Operation
Short-term orders and planned blanket drops are both fine for Longma Group because they keep 100–200 tons in stock and can deliver in as little as 7 days. It's easier to plan production when you talk about custom cut lengths, surface treatment choices (like hot-dip galvanizing, FBE, and 3LPE), and payment terms right away. Someone in the supply chain who is willing to talk about these things is more than just a material provider.
Conclusion
ASTM A513 Type 5 DOM tubing is an excellent choice for manufacturers that require consistent dimensional accuracy, a smooth surface finish, and reliable performance in precision mechanical applications. By combining electric resistance welding with cold drawing over a mandrel, DOM tubing offers improved dimensional consistency and machining performance, making it suitable for automotive components, industrial machinery, furniture frames, and fitness equipment.
Choosing the right steel grade, tube dimensions, wall thickness, and manufacturing condition is essential to achieving the desired balance between product performance and procurement costs. Buyers should also evaluate supplier capabilities, inventory availability, lead times, quality certifications, and material traceability to ensure a reliable supply for both small-batch projects and ongoing production.
Longma Group supplies ASTM A513 tube in grades 1010, 1015, and 1020, with reported inventory of 100–200 tons in common sizes and shipment lead times as short as seven days for eligible in-stock products. Custom cutting, surface treatment options, and supporting quality documentation can help manufacturers meet specific production requirements.
FAQ
What grades are available in ASTM A513 Type 5?
Most of the time, these numbers are used: 1010, 1015, and 1020. Which grade you pick will depend on how strong and simple the final part needs to be. The carbon percentage of 1020 is a little higher than that of 1010. This makes it stronger at yield but less flexible.
Can DOM tubes be used in outdoor or corrosive environments?
The carbon steel used to make standard DOM tubes is bare, so if it gets wet, it will rust. Putting things on the surface with hot-dip galvanizing, epoxy sealing, or 3LPE all makes them last a lot longer. Before you sign off on the plan, talk to your supplier about your surroundings.
How does the DOM process improve machining outcomes?
The cold-drawing step gets rid of the internal weld bead and lowers the OD/ID tolerances to ±0.003–0.005 inches. This reduces the quantity of boring stock needed to reach the target hole diameter. This cuts down on the time it takes for CNC lathes and boring mills to do their work and makes cutting tools last longer.
Is there a minimum order quantity for DOM tubes?
A lot of sellers have minimum orders that help people who buy a lot. Longma Group takes orders for small amounts, which is good for test runs and pilot projects. Talk to the team to find out what the minimums are right now for different sizes and grades.
Get a Quote From Longma Group — ASTM A513 Tube Manufacturer
Since 2003, Longma Group has been making nice ASTM A513 tubes for people in over 90 different countries. We have 100–200 tons in stock, so we can deliver quickly (within 7 days). We can also cut to your specifications, treat the surface, and give you all the paperwork you need. You can get in touch with our tech support team at info@longma-group.com or visit longma-group.com to get a quote or browse our product list.
