Tubes for Mechanical and Automobile are seamless steel tubes designed for high-precision mechanical components and automotive parts, such as hydraulic systems, drive shafts, and suspension components. Compliant with standards like DIN 2391, EN 10305-1, and ASTM A519, these seamless mechanical tubes offer exceptional strength, dimensional accuracy, and durability for demanding applications.

Manufactured from high-quality carbon and alloy steels, such as St35, St45, St52, or 4130, these precision automotive tubes are produced through cold-drawing or cold-rolling processes to achieve tight tolerances and smooth surface finishes. Available in outer diameters from 6 mm to 323.9 mm and wall thicknesses from 1 mm to 30 mm, they are ideal for applications requiring high strength and precision, such as automotive steering systems, shock absorbers, and mechanical bushings. The seamless design ensures uniform strength and eliminates weld-related weaknesses.

High-strength steel tubes undergo rigorous testing, including tensile, hardness, and non-destructive tests (e.g., ultrasonic, eddy current), to ensure compliance with industry standards. With tensile strengths ranging from 340 MPa (St35) to 620 MPa (St52), these tubes provide excellent resistance to mechanical stress and fatigue. Surface treatments like phosphating, galvanizing, or oil coating enhance corrosion resistance, making them suitable for harsh automotive and industrial environments.

Compared to welded tubes, mechanical steel tubing offers superior structural integrity and dimensional precision, critical for applications like automotive propeller shafts and hydraulic cylinders. These tubes are customizable to meet specific requirements, such as thin-walled designs for lightweight automotive components or thicker walls for heavy-duty mechanical parts. Their high precision and smooth surfaces reduce machining costs and improve manufacturing efficiency.

By addressing challenges like high mechanical stress, corrosion, and precise tolerances, tubes for mechanical and automobile deliver reliable, high-performance solutions for automotive and industrial applications. From vehicle manufacturing to heavy machinery, these tubes ensure durability, safety, and efficiency.

Seamless Steel

Specifications for Seamless Steel Tubing

Seamless steel tubing, crafted with precise tolerances and high-quality materials, meets strict minimum quantity and configuration requirements for mechanical engineering applications.

Minimum quantities include hot-finished (10,000 lb/4,536 kg) and cold-drawn (5,000 lb/2,268 kg or 125 ft/38.1 m, whichever is greater), with ±10% weight or ±25 ft/7.61 m variation; special configurations use grades like ASTM A511 for enhanced tolerances and finishes via cold drawing over mandrels or through dies.

Hollow bar tolerances favor plus-range OD and minus-range ID, while ASTM A511 mechanical tubing centers tolerances; size ranges span 1.375″ to 7.750″ OD and 0.188″ to 1.625″ wall thickness for diverse applications.

Minimum Quantities

Hot-finished carbon and alloy—10,000 pounds, or 4,536 kilograms minimum.
Cold-drawn carbon and alloy—5,000 pounds minimum or 125 feet minimum, 2,268 kilograms minimum or 38.1 meters minimum, whichever is greater.
Quantity variation—standard ±10% of the ordered weight, or ±25 feet or 7.61 meters, whichever is greater.

Special Configurations

Tubular Products special seamless tubing configurations start with the highest quality steels.
Grade, chemical analysis and surface condition are carefully considered, and production processes are tailored to achieve the best tubing for the end use.
The configurations are formed from round tube by cold drawing.
The tube is drawn over a shaped mandrel or through a shaped die, or both. Improved tolerances, finishes and mechanical properties result.

Production standards for seamless steel tubes

Mechanical and Automobile

Tubes Production Standard, Grade, Steel No

Seamless steel tubes adhere to stringent international standards like DIN, ASTM, EN, and JIS, ensuring precision and strength for hydraulic, pneumatic, and mechanical applications.

DIN2391 St35, St45, St52
ASTM A519 1010, 1020, 1025, 1035, 1045
ASTM A513 1010, 1020, 1025, 1035, 1040
EN10305-1 E215, E235, E355
JIS G4053: JIS SCr420, JIS SCr440, SCM415, SCM420
JIS3441/JIS3444/JIS3445: SCM432/SCRRM3, SCM4

Tubes for Mechanical and Automobile Standard Specifications

Unlike standard pipes, which primarily transport fluids, mechanical tubing is produced to meet specific performance requirements like strength, dimensional accuracy, and surface finish.

ASTM standards for Mechanical tubing
Abbr.	Corresponding	Application
A511	ASTM A511 / A511M	Specification for Seamless Stainless Steel Mechanical Tubing
A512	ASTM A512 / ASME SA512	Specification for Cold-Drawn Buttweld Carbon Steel Mechanical Tubing
A513	ASTM A513 / A513M	Specification for Electric-Resistance-Welded Carbon and Alloy Steel Mechanical Tubing
A519	ASTM A519 / A519M	Specification for Seamless Carbon and Alloy Steel Mechanical Tubing
A554	ASTM A554	Specification for Welded Stainless Steel Mechanical Tubing

OD and ID Tolerances for Tubing (Inches and Millimeters)
OD Size Range (Inches, Inclusive)	Wall Percent of OD	OD (Inches)		ID (Inches)		Quenched & Tempered OD & ID (± Inches)	OD Size Range (mm, Inclusive)	Wall Percent of OD	OD (mm)		ID (mm)		Quenched & Tempered OD & ID (± mm)
OD Size Range (Inches, Inclusive)	Wall Percent of OD	Over	Under	Over	Under	Quenched & Tempered OD & ID (± Inches)	OD Size Range (mm, Inclusive)	Wall Percent of OD	Over	Under	Over	Under	Quenched & Tempered OD & ID (± mm)
0.500-1.699 1.700-2.099 2.100-2.499	All All All	.005 .006 .007	.000 .000 .000	.000 .000 .000	.005 .006 .007	.015 .020 .023	12.70-43.16 43.17-53.32 53.33-63.48	All All All	0.13 0.15 0.18	0.00 0.00 0.00	0.00 0.00 0.00	0.13 0.15 0.18	0.38 0.51 0.58
2.500-2.899 2.900-3.299 3.300-3.699 3.700-4.099	All All All All	.008 .009 .010 .011	.000 .000 .000 .000	.000 .000 .000 .000	.008 .009 .010 .011	.025 .028 .030 .033	63.49-73.64 73.65-83.80 83.81-93.96 93.97-104.12	All All All All	0.20 0.23 0.25 0.28	0.00 0.00 0.00 0.00	0.00 0.00 0.00 0.00	0.20 0.23 0.25 0.28	0.64 0.71 0.76 0.84
4.100-4.499 4.500-4.899 4.900-5.299 5.300-5.549	All All All All	.012 .013 .014 .015	.000 .000 .000 .000	.000 .000 .000 .000	.012 .013 .014 .015	.036 .038 .041 .044	104.13-114.28 114.29-124.44 124.45-134.60 134.61-140.95	All All All All	0.30 0.33 0.36 0.38	0.00 0.00 0.00 0.00	0.00 0.00 0.00 0.00	0.30 0.33 0.36 0.38	0.91 0.97 1.04 1.12
5.550-5.999	Under 6 6 to 7½ Over 7½	.010 .009 .018	.010 .009 .000	.010 .009 .009	.010 .009 .009	.047 .047 .047	140.96-152.38	Under 6 6 to 7½ Over 7½	0.25 0.23 0.46	0.25 0.23 0.00	0.25 0.23 0.23	0.25 0.23 0.23	1.19 1.19 1.19
6.000-6.499	Under 6 6 to 7½ Over 7½	.013 .010 .020	.013 .010 .000	.013 .010 .010	.013 .010 .010	.050 .050 .050	152.39-165.08	Under 6 6 to 7½ Over 7½	0.33 0.25 0.51	0.33 0.25 0.00	0.33 0.25 0.25	0.33 0.25 0.25	1.27 1.27 1.27
6.500-6.999	Under 6 6 to 7½ Over 7½	.015 .012 .023	.015 .012 .000	.015 .012 .012	.015 .012 .012	.057 .053 .053	165.09-177.78	Under 6 6 to 7½ Over 7½	0.38 0.30 0.58	0.38 0.30 0.00	0.38 0.30 0.30	0.38 0.36 0.30	1.45 1.35 1.35
7.000-7.499	Under 6 6 to 7½ Over 7½	.018 .013 .026	.018 .013 .000	.018 .013 .013	.018 .013 .013	.065 .056 .056	177.79-190.48	Under 6 6 to 7½ Over 7½	0.46 0.33 0.66	0.46 0.33 0.00	0.46 0.33 0.33	0.46 0.33 0.33	1.65 1.42 1.42
7.500-8.000	Under 6 6 to 7½ Over 7½	.020 .015 .030	.020 .015 .000	.020 .015 .015	.020 .015 .015	.070 .060 .060	190.49-203.20	Under 6 6 to 7½ Over 7½	0.51 0.38 0.76	0.51 0.38 0.00	0.51 0.38 0.38	0.51 0.38 0.38	1.78 1.52 1.52

Seamless mechanical tubing is furnished in both cold-drawn and hotfinished form in a wide range of sizes, from 1.375" to 7.750" OD and from 0.188" to 1.625" wall thickness, as shown on the chart to the right.

Wall Thickness Tolerances (Percent of Nominal)
Wall Thickness Percent of OD	Maximum Percent Over & Under Nominal		Wall Thickness Percent of OD	Maximum Percent Over & Under Nominal
Wall Thickness Percent of OD	Under 1.499" ID	1.500" ID & Over	Wall Thickness Percent of OD	Under 38.07mm ID	38.07mm ID & Over
Under 10	10.0	7.5	Under 10	10.0	7.5
10 to 25	10.0	6.0	10 to 25	10.0	6.0
Over 25	12.5	7.5	Over 25	12.5	7.5

Comparison of Honed Tubes with Standard Tubes
Feature	Honed Tubes	Standard Tubes
Material Type	Carbon/Alloy Steel (ST52, E355)	Carbon Steel
Surface Finish	Ra ≤0.4 µm (Honed/SR-B)	Ra ≥1.0 µm
Tolerance	H7–H9	H11 or lower
Tensile Strength (MPa)	515–600	400–500
Applications	Hydraulic/Pneumatic Cylinders	General Piping
Cost	Higher (precision processing)	Lower
Key Advantage	Precision bore, extended seal life	Cost-effective for non-precision uses

Comparison of Mechanical Tubes with Hydraulic Tubes and Structural Tubes
Feature	Mechanical Tubes	Hydraulic Tubes	Structural Tubes
Material Type	Carbon/Alloy/Stainless Steel	Carbon/Stainless Steel	Carbon Steel
Surface Finish	Ra ≤ 0.8 µm	Ra ≤ 0.4 µm	Ra ≥ 1.0 µm
Tolerance	H8–H10	H7–H9	H11 or lower
Tensile Strength (MPa)	420–850	340–630	400–600
Applications	Machinery, Automotive, Structural	Hydraulic/Pneumatic Systems	Construction, Frameworks
Cost	Moderate	Moderate to High	Low to Moderate
Key Advantage	Versatility, precision	High precision, pressure resistance	Cost-effective for structural use

Note: Mechanical tubes offer a balance of precision and strength, making them suitable for both machinery and structural applications, while hydraulic tubes prioritize pressure resistance and surface finish.

High-Quality Steel Pipes

SCM4 Grade Seamless Steel Pipe

SCM4 Grade Seamless Steel Pipes are designed for high-performance applications in machinery manufacturing, construction engineering, and various industrial sectors. Crafted from premium SCM4 alloy steel, these high-pressure steel tubes deliver outstanding strength, corrosion resistance, and reliability, making them ideal for industrial piping systems in challenging environments.

The seamless construction of SCM4 pipes eliminates weak points, ensuring superior structural integrity under high pressure and temperature conditions. This makes them a trusted choice for hydraulic systems, structural supports, and precision machinery components.

Key Features and Benefits

Why SCM4 Seamless Steel Pipes?

With excellent corrosion resistance, SCM4 seamless steel pipes perform reliably in harsh conditions, including exposure to moisture and chemicals, reducing maintenance costs and extending service life.

The precision manufacturing process ensures consistent quality, tight tolerances, and smooth surface finishes, enabling seamless integration into complex industrial piping systems. These pipes are versatile, supporting applications in automotive manufacturing, construction projects, and engineering frameworks.

Compliant with industry standards, SCM4 grade pipes offer robust performance and cost-effectiveness, making them a preferred solution for engineers seeking durable and high-quality high-pressure steel tubes for critical industrial applications.

Key Benefits

Superior Strength

SCM4 alloy steel ensures exceptional strength for demanding industrial uses.

Corrosion Resistance

Withstands harsh environments, ensuring long-lasting performance.

Seamless Reliability

Seamless design enhances durability under high pressure.

Precision Manufacturing

Tight tolerances for perfect fit in machinery and construction.

Versatile Applications

Suitable for machinery, construction, and engineering projects.

Cost-Effective Solution

Reduces maintenance costs with durable, long-lasting performance.

Industrial Applications

Mechanical Tubes are critical for a wide range of industries, delivering high strength, precision, and versatility in applications from automotive to renewable energy.

Automotive Industry

Used in exhaust systems, chassis, suspension components, and fuel delivery systems.

Construction & Infrastructure

Supports structural frameworks, scaffolding, bridges, tunnels, and plumbing/HVAC systems.

Manufacturing & Machinery

Used in conveyors, robotic arms, hydraulic systems, shafts, cylinders, and machine frames.

Energy & Renewable Power

Supports wind turbine frameworks, solar tracking systems, oil/gas pipelines, and power generation components.

Aerospace & Defense

Used in aircraft structures, rocket components, defense equipment, and hydraulic systems.

Agriculture

Supports tractor components, ground clearing equipment, and irrigation systems.

Furniture

Used in frames, supports, and aesthetic elements for durable furniture designs.

Other Applications

Used in playground equipment, greenhouse structures, restaurant equipment, hospital beds, and garden tools.

Why Mechanical Tubes?
Their precision manufacturing, high-strength materials, and versatile applications ensure reliable performance across diverse industries.

Tubes for Mechanical and Automobile