E355 (High-Strength Seamless Tube Steel)

Description

E355 per EN 10305-1 (1.0580). The tube-specific designation paralleling S355 structural plate strength, but produced to the tighter dimensional tolerances, surface finish and internal cleanliness requirements of the EN 10305 precision tube standards. Standard for hydraulic cylinder barrel tube, structural tubing in machine frames, and precision mechanical tubes requiring both S355-class strength and tube-specific quality control.

Key Properties — Normalized / Cold Drawn+Annealed

Rm (Tensile Strength)

490 – 630

MPa

Re / Rp0.2 (Yield)

355

MPa

A₅ (Elongation)

≥ 16.0

E (Young's Modulus)

210

GPa

Density

7.85

g/cm³

Main Designations (4)

Standard Body	Designation	Country / Region	Note
EN 10305-1	E355 / 1.0580	EU
DIN W.Nr	1.0580	Germany
ASTM (nearest)	A519 Grade 1026 (nearest mechanical tube)	USA
JUS	Nema direktnog; precizna cijev E355	Yugoslavia/BiH	E355 precizna celicna cijev

Standards (4)

#	Standard Body	Designation	Country / Region	Note
1	EN 10305-1	E355 / 1.0580	EU	—
2	DIN W.Nr	1.0580	Germany	—
3	ASTM (nearest)	A519 Grade 1026 (nearest mechanical tube)	USA	—
4	JUS	Nema direktnog; precizna cijev E355	Yugoslavia/BiH	E355 precizna celicna cijev

All values in wt.%

Carbon

≤ 0.2000

Manganese

0.9000 – 1.5000

Silicon

≤ 0.5500

Element	Symbol	Min %	Max %	Typical %
Carbon	C	—	0.2000	0.1700
Manganese	Mn	0.9000	1.5000	1.2000
Silicon	Si	—	0.5500	0.2800

Mechanical Properties

Condition	Code	Rm min MPa	Rm max MPa	Re min MPa	Re max MPa	A₅ min %	Z %	KV J	HB min	HB max	HRC min	HRC max	E GPa
Normalized / Cold Drawn+Annealed	+NBK	490	630	355	—	16.0	—	—	—	—	—	—	210.0

Physical Properties

Density

7.850

g/cm³

Melting Point

1485–1525

°C

Young's Modulus

210.0

GPa

Poisson's Ratio

0.297

—

Thermal Conductivity

48.0

W/m·K

Thermal Expansion

12.00

×10⁻⁶ /K

Specific Heat

490

J/kg·K

Electrical Resistivity

0.2120

µΩ·m

Magnetic

Yes

Heat Treatment

Normalizing (hot-finished tube)

Temperature:870°C – 910°C

Medium:Still Air

Duration:-

Cooling:Air cool

Hardness After:Re>=355 MPa

For hot-finished seamless tube route.

Cold Drawing + Stress Anneal (cold-finished tube)

Temperature:600°C – 650°C

Medium:Furnace (after cold draw)

Duration:1-2 h

Cooling:Air cool

Hardness After:Re>=355 MPa with tight OD/wall tolerance

For cold-drawn precision tube route -- tighter tolerances than hot-finished.

Internal surface finish control

Medium:Precision tube internal bore finish critical for hydraulic cylinder honing compatibility

Duration:N/A

Cooling:N/A

Hardness After:N/A

Key quality distinction from ordinary structural tube.

Non-Destructive Testing (typical for hydraulic application)

Medium:Ultrasonic and/or hydrostatic testing per EN 10305 supplementary requirements

Duration:N/A

Cooling:N/A

Hardness After:N/A

Common requirement when tube is destined for hydraulic cylinder barrel use.

Machinability

Machinability Rating

relative to AISI B1112 = 100%

56.0%

Difficult

Turning Speed (HSS)

m/min

Turning Speed (Carbide)

145

m/min

Feed Rate (Turning)

0.160

mm/rev

Drilling Speed (HSS)

m/min

Milling Speed (Carbide)

148

m/min

Coolant	Soluble oil 5-8%
Chip Formation	Medium chips
Tool Material	Carbide P20; HSS M2
Surface Finish	Ra 0.8-1.6 um

Good machinability -- similar to S355.

Applications

Hydraulic Cylinders

Hydraulic cylinder barrel tube -- honed internally for piston seal running surface.

Structural Tubing

Machine frame and structural tubing requiring S355-class strength in tube form.

Precision Mechanical Tube

General precision mechanical tubing applications.

Technical Notes

✅

E355 vs S355J2 -- plate vs tube designation

S355J2 designates the same strength level in PLATE/section form per EN 10025. E355 designates it in precision TUBE form per EN 10305, with tube-specific dimensional, surface and (often) NDT requirements that plate specifications do not address. When a hydraulic cylinder or precision tube application is involved, specify E355 (or the relevant EN 10305 grade) rather than simply citing S355.