EN 10305 is a European precision-tube family covering several products and routes. Buyers should specify the approved part, grade, delivery condition, dimensions and tolerances, bore class if finished, surface finish, and inspection-document type. The written Kanpur quotation must confirm the exact offered size and condition; this page provides no stock band.
Which EN 10305 part should a buyer put on the purchase order?
Use EN 10305-1 for seamless cold-drawn precision tubes, EN 10305-2 for welded cold-drawn precision tubes, and EN 10305-4 for seamless tubes for hydraulic and pneumatic power systems. The part number prevents a supplier from quoting the wrong manufacturing route.
EN 10305 is a family, not one product. Part 1 covers seamless cold-drawn tubes for precision applications. Part 2 covers welded cold-drawn tubes. Part 3 and Part 5 cover welded sized tubes and square/rectangular precision sections. Part 4 is the key hydraulic and pneumatic power-system reference. A vague RFQ saying “EN 10305 tube” can therefore return several technically different offers. Kanpur buyers should write the part number on the PO so a welded EN 10305-2 offer is not treated as seamless EN 10305-1 or as EN 10305-4 hydraulic tube.
Many drawings still mention DIN 2391, DIN 1629, or an older grade name. Do not rewrite that controlled requirement into EN 10305 or E355 without a line-by-line technical comparison and approval from the drawing owner.
The part number also affects documentation and inspection expectations. Hydraulic power-system tube normally needs tighter control on ID, cleanliness, and surface condition than a general mechanical precision tube. If the tube will be honed after delivery, state who performs honing and who certifies the final bore.
How are EN 10305 grades E235 and E355 selected?
Select E235, E355, or another grade only from the approved design and applicable EN 10305 part. A strength label or application name does not establish forming, welding, pressure, fatigue, or machining suitability.
Compare the properties and condition required by the design with the offered standard, part, grade, and inspection document. Do not map E235 or E355 to automotive, furniture, hydraulic, loaded, forming, or machining use from a generic buyer guide.
A higher nominal strength is not automatic permission to substitute. Bending, flaring, swaging, welding, fatigue, pressure, heat treatment, and machining requirements must be assessed by the responsible engineer for the actual component.
When substituting grade names, ask the supplier to quote both the grade and standard together. “E355” without EN 10305 part and condition is incomplete. “ST52” without MTC values can also be ambiguous because older market language is not always used consistently.
Which delivery condition is right: BK, BK+S, NBK, or GBK?
Choose BK, BK+S, NBK, GBK, or another condition only from the approved standard, material, design, and process plan. Do not map a condition to strength, hydraulic use, machining, welding, forming, stability, or cost from this page.
Delivery-condition terminology must be verified against the invoked standard edition and offered inspection document. The label alone does not establish final properties, dimensional stability, weldability, formability, machinability, or application suitability.
Give the responsible engineer every downstream operation, including honing, skiving, boring, welding, bending, or flaring. The approved plan should then state the grade and condition; procurement should not change it from a price or component-name assumption.
The purchase order should make condition a separate line item, not a note hidden in the description. Inspection documents should repeat the condition. If a supplier offers equivalent condition names from DIN 2391, ask for a written cross-reference to EN 10305 language.
How should EN 10305 tolerances be written for OD, ID, wall, and bore finish?
Write OD, ID or wall thickness, tolerance class, straightness, surface condition, and any honed-bore H8/H9 requirement separately. EN 10305 controls precision tube dimensions, while ISO 286 describes H tolerances and ISO 4287 describes measurable roughness values.
A complete EN 10305 enquiry should not rely on nominal tube size. State the outside diameter, inside diameter or wall, length, quantity, and the tolerance class required by the drawing. If only OD x wall is specified, the ID tolerance may not be controlled enough for assemblies that locate on the bore. If only ID is critical, say so clearly.
For a hydraulic barrel, add the final bore dimension, approved tolerance, geometry, and surface-texture requirements after the named finishing route. Do not default to H8, H9, or a roughness band from the application name.
Also state straightness and cut-end requirements. Precision tube is often cut, bored, threaded, or welded after purchase. A slightly bowed length can waste machining time even if the OD and wall are within tolerance.
How do mechanical designers calculate mass for EN 10305-1 tubes?
Estimate nominal steel mass from the listed OD and wall before comparing quotations or dispatch documents. The result is theoretical, so final commercial acceptance should follow the PO, measured dimensions, MTC, and actual scale weight.
For an EN 10305-1 E355 tube with 50.0 mm OD and 4.0 mm wall, the unrounded site formula is (50.0 − 4.0) × 4.0 × 0.02466 = 4.53744 kg per metre, displayed as 4.54 kg/m. Using that displayed value, a 6-metre length is 27.24 kg. A quantity schedule can multiply 4.54 kg/m by the ordered cut length and number of pieces, which keeps the planning total consistent with the figure shown on the comparison sheet.
The 50.0 mm OD row in the site's indicative precision-tube price list shows ₹100 to ₹125 per kg for DIN 2391 tube. Use that size-matched band only as a budget reference when comparing an EN 10305-1 E355 offer. The supplier still needs to confirm whether the quoted product, condition, certificate, tolerance, and finishing route match the enquiry.
Actual dispatch weight can differ from theoretical weight when permitted dimensional variation, cut length, or finishing allowance changes the steel volume. Investigate a mismatch by measuring OD, wall, and length and checking the piece count. Do not infer pressure capacity from invoice weight; engineering acceptance must use the applicable design basis and the minimum finished wall.
Specifying EN 10305 cold-drawn tubes for UP and Bihar industrial projects
For state and industrial work in Uttar Pradesh, Bihar, and Madhya Pradesh, put the EN 10305 part number, grade, delivery condition, dimensions, inspection document, and ex-warehouse Kanpur basis on the PO. Delivery timing remains subject to stock and destination confirmation.
JJM, PWD, sugar-mill, and industrial buyers should copy the drawing requirement into the enquiry rather than treating every EN 10305 tube as interchangeable. A useful line is: "EN 10305-1 or EN 10305-4 as applicable, E355, BK+S or NBK as approved, stated dimensions and tolerances, ex-warehouse Kanpur, EN 10204 3.1 MTC." The part and condition must match the actual use; the sample wording is not a substitute for engineering review.
RP Sales operates from 83/124, Steel Market, Bartan Bazar, Afim Kothi, Basanti Nagar, Juhi, Kanpur 208014. Kanpur Dehat, Fazalganj, Unnao, Jajmau, Chakeri, and Lucknow are service areas, not stockyard addresses. Local buyers may arrange inspection at the Kanpur yard before loading. Intra-city pages put Dada Nagar about 8 km, Jajmau about 10 km, and Panki about 12 km from that yard. Buyers outside Kanpur should provide the exact consignee and required date so availability, freight, and delivery can be confirmed in the quotation.
Commercial documents should separate the material price, the legally applicable GST rate stated on the current quotation, freight basis, inspection scope, and certificate requirement. Ask the written quotation to confirm whether TPI at the Kanpur yard is included when the contract requires it. The inspector should compare the marking and heat number with the MTC, then check the specified dimensions and surface condition before release. Acceptance depends on those recorded checks, not on a blanket delivery claim.
How to specify EN 10305 cold-drawn tubes on an RFQ
Put the EN 10305 part number, grade, delivery condition, dimensions, tolerance class, inspection document, and ex-warehouse Kanpur basis on separate lines. Confirm every offered size, quantity, condition, and manufacturing route on the written quotation.
Write the approved EN 10305 part, grade, delivery condition, OD, ID or wall, length, and tolerance from the drawing. If the bore will be finished, add its approved numerical limits, surface-texture parameters, and inspection method rather than a generic H-class default.
Require the written quotation to confirm material location, whether inspection is available, the legally applicable GST rate, freight, packing, and TPI scope. Copy the controlled drawing instead of converting an industry or project label into a material-condition shorthand.
Do not treat a welded, seamless, hydraulic-system, DIN, or EN offer as equivalent without a line-by-line technical comparison and approval. Destination, quantity, and required date belong on the RFQ so order-specific terms can be confirmed.
Attach a controlled requirement sheet to the enquiry. Give each dimension its nominal value, upper and lower limit, measurement stage, and specified method. List straightness, end condition, surface condition, cleanliness, marking, traceability, and packaging separately so the supplier can respond to each field without relying on a general precision-tube description.
- Name EN 10305-1, EN 10305-2, or EN 10305-4 rather than “EN 10305 tube”.
- State E235 or E355 and the delivery condition as separate fields.
- Give OD, ID or wall, length, and the tolerance or honed-bore class from the drawing.
- Require the inspection-document type named by the PO, and add a bore report when finishing is included and the PO requires it.
- Quote ex-warehouse Kanpur, then add consignee and required date for freight.