GB/T 8162 35# Seamless Structural Pipe
GB/T 8162 35# Seamless Carbon Steel Pipe for Structural and Automobile Applications
Comprehensive data sheet for 35# seamless carbon steel pipe manufactured to GB/T 8162, covering chemical composition, mechanical properties, physical constants, and international equivalents. Ideal for automotive components and general structural uses.
Hot rolling, cold drawing, cold rolling, heat treatment (normalizing, annealing, quenching and tempering), welding, machining
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GB/T 8162 35# Seamless Structural Pipe Introduction
35# seamless steel pipe is a medium-carbon structural steel defined in Chinese standard GB/T 8162, intended for structural purposes including automotive parts. It belongs to the family of high-quality carbon structural steels and offers a balanced combination of strength, ductility, and machinability. The material is typically supplied in hot-rolled, cold-drawn, or annealed condition, and can be heat-treated to further tailor its mechanical properties. Its typical tensile strength exceeds 510 MPa with good impact toughness, making it suitable for semi-axle tubes, steering knuckles, and various mechanical structures. The pipe form ensures lightweight and uniform cross-section, widely used in automobiles, machinery, and construction sectors.
GB/T 8162 35# Seamless Structural Pipe Chemical Composition
Chemical requirements of 35# steel as specified in GB/T 699 for quality carbon structural steels, referenced by GB/T 8162. Residual elements are controlled to ensure purity and performance.
| Chemical Element | Standard Value (wt%) | Remarks |
|---|---|---|
| Carbon (C) | 0.32 – 0.40 | Key strengthening element |
| Silicon (Si) | 0.17 – 0.37 | Deoxidizer, improves strength |
| Manganese (Mn) | 0.50 – 0.80 | Enhances hardenability and strength |
| Chromium (Cr) | ≤ 0.25 | Residual element |
| Nickel (Ni) | ≤ 0.30 | Residual element |
| Copper (Cu) | ≤ 0.25 | Residual element |
| Phosphorus (P) | ≤ 0.035 | Impurity; excessive content causes brittleness |
| Sulfur (S) | ≤ 0.035 | Impurity; may lead to hot shortness |
GB/T 8162 35# Seamless Structural Pipe Thermal and Electrical Physical Properties
Typical physical constants for carbon steel in the range of 35#. These values are representative for room temperature unless otherwise stated. Used for design calculations involving heat transfer, expansion, and electrical resistivity.
| Property | Standard Requirement | Unit | Test Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Modulus of elasticity (E) | 206 | GPa | 20 °C |
| Shear modulus (G) | 79.4 | GPa | 20 °C |
| Poisson's ratio (ν) | 0.30 | – | 20 °C |
| Thermal expansion coefficient (α) | 11.0 – 12.0 | ×10⁻⁶ /K | 20–100 °C |
| Thermal conductivity (λ) | 50.6 | W/(m·K) | 100 °C |
| Specific heat capacity (cp) | 480 | J/(kg·K) | Room temperature |
| Electrical resistivity (ρe) | 0.15 – 0.20 | ×10⁻⁶ Ω·m | 20 °C |
GB/T 8162 35# Seamless Structural Pipe Mechanical Properties
Mechanical performance of 35# seamless pipe per GB/T 8162-2018. Values depend on wall thickness and delivery condition. Hardness and impact energy are provided when required; bend test is not mandatory in this standard.
| Property | Standard Requirement | Unit | Test Condition / Wall Thickness |
|---|---|---|---|
| Tensile Strength (Rm) | ≥ 510 | MPa | Wall thickness ≤ 16 mm |
| Tensile Strength (Rm) | ≥ 500 | MPa | Wall thickness 16-30 mm |
| Tensile Strength (Rm) | ≥ 490 | MPa | Wall thickness > 30 mm |
| Yield Strength (ReH / ReL) | ≥ 305 | MPa | Wall thickness ≤ 16 mm |
| Yield Strength (ReH / ReL) | ≥ 295 | MPa | Wall thickness 16-30 mm |
| Yield Strength (ReH / ReL) | ≥ 285 | MPa | Wall thickness > 30 mm |
| Elongation after fracture (A) | ≥ 17 | % | All wall thicknesses (longitudinal) |
| Impact Energy (KV2, optional) | ≥ 39 | J | 20 °C, longitudinal specimen (if requested) |
| Hardness (HBW) | ≤ 187 | - | Hot-rolled delivery condition (max.) |
| Hardness (HBW) | ≤ 149 | - | Annealed delivery condition (max.) |
GB/T 8162 35# Seamless Structural Pipe Equivalent Materials by International Standards
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 8162 | 35# | Original standard and grade |
| Japan | JIS G3445 | STKM13A | Carbon steel tubes for machine structural purposes; closest match in strength and carbon range |
| USA | ASTM A519 | 1035 | Seamless carbon mechanical tubing; similar chemistry with C0.32-0.38 |
| Germany | DIN 2391-2 | St35 | Precision seamless cold-drawn tube; nominal tensile comparable but exact values differ |
| International | ISO 2937 | TS4/35 | Plain end seamless steel tubes for mechanical application; approximate equivalent |
| European | EN 10297-1 | E275 (1.0225) or E355 (1.0580) | Seamless circular tubes for mechanical and general engineering; E355 closer in strength |
GB/T 8162 35# Seamless Structural Pipe Application Introduction
The 35# seamless pipe is a versatile structural material, exploited for its medium strength, good toughness, and excellent formability. It can be machined, welded (with preheating), and heat-treated to meet varied requirements. Typical applications span automotive manufacturing, construction, and machinery.
Product Applications: Automobile semi-axle tubes, Steering knuckles, Drive shafts, Hydraulic cylinder barrels, Roll cages, Structural frames and trusses, Bicycle frames (high-end), Machinery hollow shafts
Processed into products: Semi-axle sleeves, Steering tie rods, Engine connecting rods (after forging), Bearing housings, Flanges and couplings, Spacers and bushings, Rollers and conveyor idlers, Pneumatic cylinder bodies
Application industries: Automotive industry, Machinery manufacturing, Construction and civil engineering, Agricultural equipment, Petrochemical (non-corrosive service), Power generation (structural supports)
GB/T 8162 35# Seamless Structural Pipe Similar and Alternative Materials
| Country/Region | Standard | Grade | Remarks |
|---|---|---|---|
| China | GB/T 8162 | 45# | Higher carbon content; higher strength but lower weldability and ductility |
| Japan | JIS G4051 | S35C | Carbon steel for machine structural use; similar carbon range, supplied as bars but can be compared in pipe form |
| USA | ASTM A519 | 1045 | Higher strength and hardness; often used for more demanding mechanical tubing |
| Germany | DIN EN 10083-2 | C35 | Quenched and tempered steel; comparable base chemistry but intended for different product forms |
| International | ISO 683-18 | C35E | Non-alloy quenched and tempered steel; similar composition and strength after proper heat treatment |
Notes:
Optional impact testing at 20°C with KV2 ≥ 39 J can be specified. Hydrostatic or non-destructive testing may be required per the purchase order. Dimensional tolerances follow GB/T 8162. The material is not recommended for weldments subject to low-temperature impact without post-weld heat treatment. Surface protection such as oil coating, phosphating, or galvanizing is available on request.
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