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Stress Relieved E355+SR Alloy Steel Seamless Tubes for Shafts with High Machinability and EN 10305 Compliance

Product Summary
E355+SR steel tubes for shafts, offering 355 MPa yield strength, stress-relieved for dimensional stability. Ideal for rotating shafts, hydraulic cylinders, and precision components requiring good machinability and fatigue resistance.

Product Details

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Stress Relieved Alloy Steel Seamless Tubes

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EN 10305 Compliant E355+SR Tubes

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High Machinability Seamless Shaft Tubes

Product Description
Tubes suitable for shafts E355+SR
If you're looking for tubes suitable for shafts in grade E355+SR, you're essentially talking about a specific condition of a well-known engineering steel (EN 10305 family). Because these tubes are often used for mechanical parts like shafts, cylinders, and precision components, knowing the chemical composition is crucial for strength, machinability, and reliability.
What "E355+SR" Actually Means
  • "E355" is a non-alloy quality steel grade according to EN 10305 and EN 10294/EN 10297 families
  • The "355" refers to a minimum yield strength of around 355 MPa for typical product forms
  • "+SR" means "Stress Relieved" – the tubes have been heat treated to relieve internal stresses, which is important for dimensional stability, especially in shaft applications (e.g., to avoid distortion during machining or use)
Typical Applications (and Why It Fits Shafts)
From usage of E355 steel pipes in practice, this grade is widely chosen for:
  • Rotating shafts and axles
  • Hydraulic and pneumatic cylinder tubes and rods
  • Mechanical components where moderate to high strength and good machinability are required
  • Parts that may later be induction hardened on the surface
The balance of carbon and manganese gives E355 good strength while still being reasonably machinable and weldable for most standard applications.
Typical Chemical Composition of E355 (Base Steel)
Exact limits can vary slightly depending on the specific EN standard (e.g., EN 10305-1 / -2 / -4, EN 10294-1) and the manufacturer, but for E355 the typical nominal composition is approximately:
Element Composition Range
Carbon (C) 0.17–0.22 %
Manganese (Mn) 1.20–1.60 %
Silicon (Si) ≤ 0.55 % (often around 0.15–0.35 % in practice)
Phosphorus (P) ≤ 0.025 %
Sulphur (S) ≤ 0.025 %
Nitrogen (N) often limited, e.g. ≤ 0.012 % (depending on the specification)
Cr, Ni, Mo, Cu usually not intentionally added; if present, they're typically residuals with low maximum limits (e.g., each ≤ 0.30–0.40 % depending on the standard)
For mechanical tubes in EN 10305, the official spec often simplifies to maximum values, for example (typical EN 10305-1/-2 style limits for E355):
Element Maximum Value
C ≤ 0.22 %
Mn ≤ 1.60 %
Si ≤ 0.55 %
P ≤ 0.025 %
S ≤ 0.025 %
"+SR" does not change the chemical composition; it only defines the heat-treatment condition (stress relieved).
Why This Composition Works Well for Shafts
That chemistry gives you:
  • Enough carbon (around 0.2 %) for decent strength and the possibility of surface hardening (e.g., induction hardening) if needed
  • Relatively high manganese (up to ~1.6 %), which supports strength, toughness, and improves hardenability slightly
  • Low P and S levels, which is important to avoid brittleness and ensure good toughness and fatigue resistance – key factors for shafts under cyclic loading
  • Good machinability for turning, drilling, and milling, especially in the +SR condition, where the internal stresses are reduced, so the part stays stable during machining
Practical Advice When Choosing Tubes for Shafts in E355+SR
If you're sourcing tubes specifically for shaft applications:
  • Ask for the exact standard: e.g., EN 10305-1 (cold drawn), EN 10305-2 (welded cold-drawn), or other relevant EN standards. The mechanical properties and dimensional tolerances may differ slightly
  • Request the mill test certificate (MTC/3.1) to see:
    • Confirmed chemical composition for that specific heat
    • Mechanical properties (yield, tensile strength, elongation, hardness)
    • Heat treatment condition (+SR)
  • If you'll be doing heavy machining or tight-tolerance work, stress-relieved (+SR) is a strong choice, as it greatly reduces distortion compared to as-drawn or as-welded tubes
  • For shafts that need very high surface hardness or wear resistance, E355 can be used as a base material and then surface-hardened (e.g., induction hardening) on the finished shaft surface
Summary – Composition You Can Safely Work With
For E355+SR tubes suitable for shafts, you can expect, in practical terms, something in this ballpark:
  • C: up to 0.22 %
  • Mn: up to 1.60 %
  • Si: up to ~0.55 %
  • P: max 0.025 %
  • S: max 0.025 %
(with minor residual alloying elements only)
If you need the precise limits for a specific project or certification, always refer to the exact EN standard your supplier is using (EN 10305-x, EN 10294, EN 10297, etc.) and the mill certificate for the batch you're buying.
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