Product Parameters

GB/T3639 Precision Seamless Steel Tubes

Material and Specification

GB/T3639 Precision Seamless Steel Tubes are made of high-quality carbon structural steel and alloy structural steel.

Key Features

High Precision: Produced with high precision to meet specific requirements.

Smooth Surface: The inner and outer surfaces are smooth, making them suitable for various precision applications.

Uniform Wall Thickness: Ensures consistent performance and structural integrity.

Good Concentricity: Provides reliable performance in mechanical structures.

Excellent Mechanical Properties: High strength, toughness, and durability.

Chemical Composition

Element	C (%)	Si (%)	Mn (%)	P (%)	S (%)
Composition	0.22-0.29	0.15-0.35	0.30-0.60	≤0.030	≤0.025

Mechanical Properties

Steel Grade	Tensile Strength (MPa)	Yield Strength (MPa)	Elongation (%)	Hardness (HB)
10	≥335	≥205	≥24	≤95
20	≥410	≥245	≥20	≤105
35	≥510	≥305	≥17	≤120
45	≥590	≥335	≥14	≤155
45Mn2	≥590	≥335	≥14	≤155
45Mn2V	≥610	≥365	≥13	≤160

Physical Properties

Property	Value
Density (g/cm³)	7.85
Melting Point (℃)	1420-1460
Thermal Conductivity (W/m·K)	12.5
Specific Heat Capacity (J/kg·K)	460

Process Performance

Property	Value
Weldability	Good
Machinability	Excellent
Cold Bending	Good
Hot Formability	Good
Surface Treatment	Good

Steel Grade

10: Represents the carbon content of steel, 0.10%.

20: Represents the carbon content of steel, 0.20%.

35: Represents the carbon content of steel, 0.35%.

45: Represents the carbon content of steel, 0.45%.

45Mn2: Represents the carbon content of steel, 0.45%, and the presence of manganese.

45Mn2V: Represents the carbon content of steel, 0.45%, and the presence of manganese and vanadium.

Application

GB/T3639 Precision Seamless Steel Tubes are widely used in machinery, automobiles, bicycles, furniture, appliances, and other mechanical parts where high precision, smooth surface, and excellent mechanical properties are required.