EN 10305-1 E155 Seamless Precision Steel Tubes Supplier

Specification Chemical Composition Mechanical Properties

EN 10305-1 E155 Seamless Precision Steel Tubes Specification

The table below captures the essential mechanical properties defined under EN 10305-1 for Grade E155 seamless precision tubes. All values are shown in both SI and imperial units to support dual-standard procurement specifications.

Parameter	Details
Standard	EN 10305-1
Steel Number	1.0033
Manufacturing Process	Seamless cold drawn
Delivery Conditions	+C (+BK), +LC (+BKW), +SR (+BKS), +A (+GBK), +N (+NBK)
Quality Grades	Quality A (standard) / Quality C (project-specific)
OD Range	4 mm to 120 mm
Wall Thickness	0.5 mm to 15 mm
OD Tolerance	± 0.03 mm (precision class)
WT Tolerance	± 10% (standard); ± 0.1 mm (precision)
Standard Length	6 m (custom cut lengths available)
Surface Condition	Bright drawn (NBK); oiled for transit
End Finish	Plain ends standard; deburred/chamfered on request
Test Certificates	EN 10204 3.1 / 3.2
Third Party Inspection	TUV, BV, SGS, DNV, Lloyds available

For a broader view of the precision tube family, see our Cold Drawn Seamless Mechanical Tubing page, which covers all cold-finishing routes and tolerance classes available from our facility.

Chemical Composition of EN 10305 E155 Tubes

The ultra-low carbon ceiling of 0.07% is what makes EN 10305-1 E155 ideal for severe cold-forming operations. The table below lists the maximum permitted elemental content per the standard.

Element	C (max)	Mn (max)	P (max)	S (max)	Si (max)
E155 (1.0033)	0.07%	0.11%	0.35%	0.70%	0.025%

For traceability to a named DIN equivalent, our DIN 2391 ST30 Seamless Precision Tubes page cross-references the identical chemical limits under the German designation.

Mechanical Properties of EN 10305 E155 Tubes

Property	BK (Cold Hard)	BKW (Cold Soft)	BKS (Stress Relieved)	GBK (Annealed)	NBK (Normalised)
Tensile Strength Rm (MPa / ksi)	430 / 62	380 / 55	380 / 55	280 / 41	290–420 / 42–61
Yield Strength ReH (MPa / ksi)	—	—	280 / 41	—	155 / 22
Elongation A% (min)	8%	12%	16%	30%	32%
Hardness (HRB approx.)	~90	~80	~75	~60	~55–65

Dimensional Tolerances of EN 10305-1 E155 Tubes

OD / Wall Tolerance

Execution	Size Range	OD Tolerance	Wall Tolerance
Hot-rolled Tube	OD – 80 mm / OD > 80 mm / Wall < 12 mm / Wall ≥ 12 mm	± 0.4 mm / ± 0.5% of OD	± 0.7 mm / ± (5% × wall thickness + 0.1 mm)
Hot-rolled peeled tube	All sizes / Wall < 12 mm / Wall ≥ 12 mm	+0.25 / −0 mm	± 0.8 mm / ± (5% × wall thickness + 0.2 mm)
Cold Worked tube (cold-rolled or cold-drawn)	OD < 40 mm / OD 40–80 mm / OD > 80 mm / WT < 6 mm / WT 6–8 mm / WT > 8 mm	+0.30 / −0 mm* / +0.35 / −0 mm* / +0.40 / −0 mm*	± 0.30 mm / ± 0.35 mm / ± 0.40 mm

Standard Length Tolerances

Component Length (mm)	OD 30–100 mm	OD 100–254 mm
10–100	+1.0 / −0	+2.0 / −0
100–600	+2.0 / −0	+3.0 / −0
600–1200	+3.0 / −0	+4.0 / −0
1200–5000	+5.0 / −0	+6.0 / −0

EN 10305-1 E155 Seamless Precision Steel Tubes Grade Comparison

Understanding where EN 10305-1 E155 fits within the full grade ladder helps specifiers avoid the most common procurement error: ordering E195 when E155 is sufficient, or ordering E155 when E355 is required. The table below is your grade selector.

If your application calls for E195, visit our EN 10305-1 E195 Precision Tubes page for dedicated specification, stock, and pricing information.

Applications of EN 10305 E155 Tubes

The ultra-low carbon content and high elongation of EN 10305-1 E155 make it the first-choice grade for cold-forming intensive industries. Key application categories include:

• Deep-draw tube forming. E155 is the preferred input tube for draw bench and deep-drawing press operations, where the 32% minimum elongation prevents cracking and tearing in thin-wall sections.
• Automotive body pressings and chassis components. Thin-wall E155 precision tubes are blanked and formed into structural pressings for door reinforcements, seat rail tubes, and body-in-white sub-assemblies.
• Fuel feed lines, coolant interconnects, and low-pressure brake conduits requiring complex bend radii and flare terminations. Suitability for a given pressure class must be confirmed by the system designer in accordance with applicable fluid power standards.
• Bicycle and two-wheel frame tubes. E155 cold-drawn sections are widely used for butted bicycle tube sets where mandrel draw finishing achieves variable wall profiles.
• Furniture and fitness equipment. Light-gauge E155 precision tubes are bent and formed into ergonomic chair frames, rack systems, and gym equipment uprights.

Buyers sourcing for automotive applications can explore our complete Automotive Steel Tubes hub for related precision grades, tolerances, and OEM-approved documentation. For broader carbon steel tube options beyond precision grades, visit our Carbon Steel Pipes and Tubes product category.

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