ASTM A513 ERW Mechanical Tubing: Grades, Properties & DOM Types

ASTM A513 ERW carbon steel pipe covers round, square, rectangular, and special shape tubing. 

What is ASTM A513?

ASTM A513 is an American Society for Testing and Materials standard. Its full name is "Standard Specification for Electric-Resistance-Welded Carbon and Alloy Steel Mechanical Tubing."

Simply put, it primarily regulates carbon steel and alloy steel pipe manufactured using the electric-resistance welding (ERW) process. This type of pipe is often referred to as mechanical or structural pipe, emphasizing mechanical properties rather than pressure-tightness. Unlike ASTM A500 (which is for structural applications), ASTM A513 is specifically intended for mechanical uses where dimensional accuracy and machinability are critical.

Overview and Scope of ASTM A513 Standard

Standard Definition: 

Suitable for carbon steel and alloy steel mechanical tubing produced by the electric resistance welding (ERW) process, including round, square, and rectangular tubing made from hot-rolled or cold-rolled steel.

Manufacturing Process: 

The core process is electric-resistance welding. After cold-rolling the steel strip, an electric current is passed through the tube blank to heat the edges until they are molten, and then the tubes are welded together under pressure. Filler metal is typically not added to the weld.

Applications: 

Mechanical and structural applications. This means these pipes are primarily used to carry loads, serve as moving parts, or form product frames, rather than to transport fluids. Examples include automotive chassis components, bicycle frames, shopping carts, furniture, office equipment, agricultural machinery components, and sports equipment.

Technical Parameters: 

Covers pipe wall thickness tolerances (such as strict tolerances for unspecified thicknesses), outer diameter range (9.5-380mm), and length (3-12 meters).

Materials: 

Covers carbon steel and alloy steel. Common steel grades include:
1010, 1015, 1020, 1026 (ordinary carbon steel)
4130, 4140, 8620 (alloy steel, offering higher strength)

Applications: Automotive manufacturing, construction machinery, precision instruments, and other fields requiring high-strength welded pipes.

ASTM A513 Material Grades & Chemical Composition

An analysis of each heat of steel shall be made by the steel manufacturer to determine the percentages of the elements specified. The chemical composition for common grades is shown below:

Note – Chinese Grade Equivalents:
ASTM 4140 alloy steel corresponds to Chinese grade 42CrMo. Carbon steels such as 1015 and 1026 correspond to 20Cr and 20# steel, respectively.

Mechanical Properties

Minimum mechanical properties for common ASTM A513 grades:

Testing Requirements: When requested on the purchase order, a product analysis shall be made by the supplier. If the original test for product analysis fails, retests of two additional lengths shall be made. Both retests for the elements in question shall meet the requirements of the specification; otherwise, all remaining material in the lot shall be rejected.

Types of ASTM A513 ERW Mechanical Tubing:

ASTM A513 covers three primary types of ERW mechanical tubing, each distinguished by its manufacturing process and resulting properties. Use this table to understand the differences in size range, surface finish, and typical applications—from general structural use (Type 1) to high-precision components (Type 5 DOM).

▶ For more details on seamless mechanical steel tubing specifications, please refer to: [Mechanical Tube Size Chart].

ASTM A513 vs. ASTM A500: Key Differences

While both are ERW carbon steel tubes, they serve different purposes:

Aspect	ASTM A513 (Mechanical Tubing)	ASTM A500 (Structural Tubing)
Primary Purpose	Mechanical and machined parts	Structural load-bearing members
Key Properties	Dimensional accuracy, machinability	Strength, load-carrying capacity
Typical Shapes	Round, square, rectangular, special	Square, rectangular, round
Common Grades	1010, 1020, 1026, 4130, 4140, 8620	Grade A, B, C, D
Applications	Hydraulic cylinders, driveshafts, furniture	Building columns, bridges, frames

▶ For more detailed comparisons of mechanical and structural tubing, please refer to:[Mechanical Tubing vs. Structural Tubing].

Typical Applications

Due to its high dimensional accuracy and excellent machinability, ASTM A513 mechanical tubing is widely used in:

1. Automotive Manufacturing: Chassis components, drive shafts, steering columns, axle housings
2. Construction Machinery: Hydraulic cylinder bodies, agricultural implement frames
3. Precision Instruments: Bearing retainers, sensor housings, medical equipment frames
4. Consumer Products: Bicycle frames, exercise equipment, shopping carts, furniture, office chairs
5. General Industry: Conveyor rollers, display racks, scaffolding components

Frequently Asked Questions (FAQ)

Q1: Can ASTM A513 tubing be used for pressure applications?

→ No. ASTM A513 is a mechanical standard, not a pressure-containing standard. It is not intended for transporting fluids under pressure. For pressure applications, use ASTM A53 or API 5L.

Q2: What is the difference between Type 2 and Type 5 (DOM)?

→ Type 2 is standard ERW from cold-rolled steel with a smooth surface. Type 5 (DOM) is drawn over a mandrel after welding, which further improves dimensional accuracy, surface finish, and concentricity, making it suitable for precision applications like hydraulic cylinders.

Q3: Is ASTM A513 tubing weldable?
→ Yes. The carbon steel grades (1010, 1020, 1026) have excellent weldability. Alloy grades (4130, 4140, 8620) are weldable but may require preheating and post-weld heat treatment to prevent cracking.

Q4: Which grade of ASTM A513 is the strongest?
→ 4140 offers the highest tensile strength (≥655 MPa) and yield strength (≥586 MPa) among the listed grades. It is commonly used for high-stress mechanical components.

Q5: What size range does ASTM A513 cover?
→ Round tubing OD: 3/8" to 15" (9.92 mm to 381.0 mm). Wall thickness: 0.022" to 0.650" (0.71 mm to 16.50 mm), depending on the type and manufacturing process.

Q6: Can ASTM A513 be used as a substitute for ASTM A500?
→ Not without evaluation. They are optimized for different purposes. A513 offers better dimensional accuracy and surface finish for mechanical parts; A500 provides higher load-bearing capacity for structural frames. Selecting the wrong type could compromise performance or increase costs.

Related Resources:

●  Carbon Steel ERW Pipe Specification 

●  SAW vs ERW and EFW Welded Steel Pipe

●  ERW Pipe Thickness Chart & Sizing Guide

●  ASTM A519 Seamless Mechanical Tubing