Drawn Over Mandrel Tubing ERW Welded Alloy Steel Tube For Mechanical Equipment

Drawn‑Over‑Mandrel (DOM) ERW welded alloy steel tube is produced by cold‑drawing electric‑resistance‑welded (ERW) tube through a mandrel to achieve precise dimensions, smooth inner surfaces, and enhanced mechanical properties. It combines the cost‑efficiency of ERW fabrication with mechanical performance approaching that of seamless tubing. Typical outside diameters range from 12 mm to 114 mm, wall thicknesses from 1.5 mm to 6 mm, and lengths up to 12 m, with tolerances meeting or exceeding ASTM A519 DOM requirements. Its high yield strength, tight dimensional tolerances, and excellent surface finish make it ideal for precision mechanical components.

Material Description

Drawn‑Over‑Mandrel tubing begins as ERW strip steel that is longitudinally welded, then cold‑drawn through a mandrel. The cold‑drawing process refines the microstructure, eliminates weld‑zone discontinuities, and imparts higher strength and better circularity than as‑welded ERW. The base alloy is controlled‑chemistry carbon–molybdenum steel, offering a balanced combination of strength, toughness, and machinability.

Specifications

• Outside Diameter (OD): 12 mm – 216 mm

• Wall Thickness: 1 mm – 80 mm

• Length: Up to 12 m (custom lengths available)

• Tolerances (OD/Wall): ± 0.05 mm / ± 0.10 mm (in accordance with ASTM A519 DOM)

• Surface Finish: Inner Ra ≤ 0.8 µm; outer black‑drawn or optional polishing

Chemical Composition

Mechanical Properties

Key Features

• High Precision: Tight dimensional tolerances and excellent roundness.

• Enhanced Strength: Cold‐drawing yields yield strengths up to ~980 MPa for high‐alloy grades.

• Smooth Internal Surface: Ideal for hydraulic cylinder liners and bearing applications.

• Good Machinability: Especially in annealed condition for ease of fabrication.

• Uniform Properties: Controlled weld‐zone microstructure for consistent performance.

Standards Conformance

• ASTM A519/A519M: Standard specification for ERW mechanical tubing – DOM condition.

• EN 10305-1/2: Cold‐drawn welded precision steel tubes – non‐alloy and alloy steel.

• GOST 8732-78: Seamless precision steel tubes – cold‐finished.

• JIS G3445: Carbon steel tubes for mechanical structuring – cold‐drawn.

• GB 3639: Cold‐drawn carbon steel precision seamless tubes.

Application Areas

General Fields:

• Hydraulics & Pneumatics: Cylinder rods, liners, pistons.

• Automotive: Steering components, suspension links, transmission shafts.

• Industrial Machinery: Gear shafts, pins, rollers.

• Aerospace & Defense: Landing‐gear actuators, control linkages.

• Construction Equipment: Hydraulic booms, jack legs.

Specific Uses Within Each Field:

• Hydraulic Cylinders: DOM tube liners for smooth sealing and minimal wear.

• Steering Systems: Tie rods and drag links requiring high fatigue strength.

• Gear Assemblies: Precision bore tubes for pinion and roller shafts.

• Landing‐Gear Actuators: Tubes with fatigue‐resistant microstructure.

• Crane Booms & Jacking Systems: High-strength tubes resisting bending and torsion.

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock, it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.

Who We are ?

-------A professional steel pipes materials inventor, manufacturer and solution provider
Torich International Limited is a professional manufacturer and exporter of steel pipes materials. It is an international marketing and sales company specialized in steel tubes, which holds the factories of Seamless Steel Tubes with Carbon and Alloy Steel Grade, Welded Precision Steel Tubes,DOM Steel Tubes, Seamless & Welded Stainless Steel Tubes with Nickel and Alloy Steel Grade.
Our factory was established since 1997, with the name of TORICH INTERNATIONAL LIMITED. The factories’ technicians are of great engineering experience in steel pipe industry for more than 20 years, which are in great command of production technology for Cold Drawing and Cold Rolling. So we have strong technician team and manufacturing capability.

What products we do?

------- Invent and produce various Precision Steel Pipes

Our steel pipes cover the following ranges:
Seamless Precision Steel Pipes

Bearing Steel Tubes
Welded Precision Steel Pipes, with DOM production
Seamless Heat Exchanger Steel Pipe
Seamless Boiler Steel Pipes

Honed Tubes

Hydraulic Cylinder Steel Tubes

Hydraulic Telescopic Cylinder Tubes
Seamless Structural Steel Pipes
Seamless Mechanical Steel Pipes
Seamless Alloy Steel Tubes & Pipes
Seamless Stainless Steel tubes
Welded Stainless Steel Tubes
Seamless Stainless Steel Tubes & Pipes
Welded Stainless Steel Tubes & Pipes
Seamless Carbon Steel Tubes & Pipes
Nickel Alloy Steel Tubes & Pipes

What TORICH do:
1. Producing Steel Tubes
2. Selling both on Domestic and International Market
3. Precisely Targeting Customers’ Requirement- Sourcing the right factory for right products for Customers

Products Application:
Oil Cylinders
Air Cylinder, 
Automotive Cylinder Liners
Boilers, Pressure Vessels
Shell & Heat Exchangers
Jack Lifting
Telescopic Systems
Pneumatic Cylinders
Agricultural Machineries

Size range is: 
O.D. 4-350mm, 
W.T. 0.5-30mm, 
Length: according to customer’s requirement and agreement
 

Steel Grade:
Carbon Steel Grade:
ST35.8, ST37.0, ST44, ST52;
E155, E195, E215, E235, E275, E355;
195GH, P235GH, P265GH, P195TR1, P195TR2, P235TR1, P235TR2, P265TR1, P265TR2;
SAE1010, SAE1020, SAE1026, SAE1035, SAE1045;

Carbon steel tube: SA178, A179, A192, A210, SA213, SA214, etc.
Alloy Steel Grade:
T2, T5, T9, T11, T12, T17, T21, T22, T91,T92, 15Mo3,16Mo3, 13CrMo44;
SAE4130, SAE4140, 40Cr, 40Cr4, 10CrMo910, 12CrMo910, 11CrMo910,
25CrMo4, 35CrMo, 35CrMo4, 42CrMo4, 34CrMo4, 20MnV, 20MnV6,20CrMn;
Carbon steel tube: A179,A192,A210,DIN17175,etc.

Bearing Steel Grades:
GCr15 52100 suj2 suj3 100Cr6 SKF3S SKF3S 20CrNiMo 8620H 4118H;

Nickel Alloy Grade:
N02200/2201, N04400, N06600, N06601, N06625, N06852, N06219, N06690, N08800/8810/8811, N08825, N08028, N08535, N08904, N08925, N08926, N010276, N06022, etc.

Austenitic/Super Austenitic Stainless Steel Grade:
304/304L, 316/316L, 314, 321, 347H, 316Ti, 316LMod, 317L/N, 310S, 253MA, 330, 904L, S31254, XM-19, etc. 

Ferrite/Martensite Stainless Steel Grade:
TP410, TP405, TP420, TP430, TP430Ti, TP403, TP409, TP444, TP439, TP446, etc. 

Duplex/Super Duplex Stainless Steel Grade:
S31803, S32304, S31500, S32550, S32750, S32760, etc. 
Corporate Culture:
We focus on Quality First, Quality Traceability, and Quality Stability!
We focus on Customer First, People First, and Quality-Oriented!
Success:
First factory started in 1997, in the name of Torich , now covers 50000 square meters of factory building, with more than 100employees, and over 45 million RBM assets.
In 2008, we started the company of Torich International Limited for international business and marketing.
Welcome partners from all over the world for long term cooperation!