Precision & Hydraulic Tubes in Kanpur — Cold Drawn Wholesale

A Kanpur RFQ for hydraulic or machined components should identify controlled dimensions, delivery condition, tolerance, finish and inspection documents from the approved drawing. A DIN 2391 or EN 10305 reference does not itself prove that an offered tube meets that drawing. Submit grade, dimensions, tolerance, finish, quantity and destination so the proposed material and document scope can be compared in writing.

What a precision hydraulic tube is

A precision tube is a steel tube ordered by controlled outside diameter, inside diameter or wall, delivery condition, and dimensional tolerance. Cold drawing reduces the section to its final dimensions and produces a more controlled surface than a general-purpose hot-finished pipe. Hydraulic-cylinder buyers often add honing or skiving and roller burnishing when the bore becomes a working seal surface.

DIN 2391 remains common language on Indian drawings. EN 10305-1 covers seamless cold-drawn precision tubes, while EN 10305-4 addresses seamless cold-drawn tubes for hydraulic and pneumatic power systems. A buyer should name the standard, grade, condition, and tolerance together. A grade name by itself does not define the finished bore.

Precision tube is not a substitute for ordinary structural hollow section, water pipe, fire-system pipe, or IBR boiler tube. Those products have different service rules and inspection documents. Use the DIN 2391 ST52 product reference when the drawing calls for a finished hydraulic barrel.

Who should specify it, and who should choose another tube

Hydraulic-cylinder shops use precision tubes where the bore controls seal contact, piston guidance, and machining allowance. Printing-cylinder shops use controlled tube geometry when the blank must run true through later machining and surface work. Automotive and machine-part fabricators may use cold-drawn tube for steering, shock-absorber, sleeve, shaft, and formed-component work when the drawing defines the final dimensions.

The product should not be selected from pressure alone. The designer must consider pressure, temperature, load cycle, end closure, weld detail, corrosion allowance, seal system, and any regulatory boundary. A hydraulic line, cylinder barrel, mechanical bush, and printing-cylinder blank can share an OD while needing different grades, walls, conditions, and inspection records.

Boiler and steam-pressure work belongs on the Kanpur boiler-tube page with IBR documentation where required. General ERW utility and fabrication requirements belong on the Kanpur MS ERW page. This separation prevents a close dimensional match from being treated as approval for the wrong service.

Build a drawing-led precision-tube RFQ in Kanpur

The component drawing, not a Kanpur neighbourhood or industry label, should control the tube enquiry. Name the component use, CDS or CDW route, standard, grade, delivery condition, OD/ID or wall, finished-bore tolerance if applicable, surface-roughness parameter and limit, cut length, quantity, packing and destination PIN. That detail lets hydraulic, printing-cylinder, automotive or equipment requirements be compared without claiming that local firms share one specification or buying pattern.

A finished bore requires its own acceptance evidence in addition to the parent-material record. State end protection, bundle support, unloading checks and any buyer-nominated inspection in the purchase order. Require each written offer to identify its proposed dispatch timing, freight, payment terms and document availability; this page does not promise those terms or a generic lead time.

How wholesale pricing works for this product

DIN 2391 and IS 3601 are product references, not pricing rules. Compare precision-tube offers only after material, dimensions, delivery condition, machining allowance, bore finishing, inspection, quantity, packing and delivery scope match. The offer should separately state its source basis, billing unit, legally applicable tax, freight, validity and delivery terms rather than implying that the standard fixes them.

• Record the offered billing unit: kg, MT, piece, length, or another stated basis.
• Require theoretical, actual or piece-based billing and the applicable tolerance to be stated.
• Ask for vehicle, legal payload, route, packing and unloading terms; quantity alone does not prove a freight saving.

Collection or delivery terms for finished-bore tubes

State whether the enquiry is for Kanpur collection or delivery to a named PIN. The written quotation should identify whether the proposed material is locally held or mill-sourced, its dispatch estimate, freight basis, bore protection, packing and unloading responsibility. Those details remain proposed terms until accepted in the purchase order.

Documents to name in the RFQ

Traceability requirements differ by mill, finish, and project. State the required MTC type, dimensional report, roughness report, inspection, marking, weighment, and statutory records in the RFQ so their availability and cost can be confirmed before the purchase order.

• Mill Test Certificates (MTC), where specified and available for the offered material.
• Delivery challan and weighment record on the basis agreed in the order.
• Applicable e-way bill and tax-invoice requirements, confirmed for the accepted transaction.

How to place an order

1. Send your Bill of Quantities (BOQ) with exact specifications, sizes, and destination pin code.
2. Require the written response to identify technical exceptions, proposed substitutions or missing drawing inputs.
3. Approve the quotation and issue a Purchase Order (PO).
4. Record the accepted dispatch basis, collection or delivery terms and shipment evidence in the purchase order.

Trust signals

Common precision tube size references

The size table is a procurement reference reviewed on 23 May 2026. OD is stated in millimetres. The buyer must add wall or ID, tolerance, grade, delivery condition, bore finish, and length before the row becomes an orderable specification. Availability remains subject to the quotation.

How Kanpur shops should write the RFQ

Start with the drawing revision and component use. Then state CDS or CDW, the governing standard, grade, and delivery condition. Give OD x ID or OD x wall in millimetres. If the bore is finished, name the required H8 or H9 class and the surface-roughness limit already approved on the drawing.

• Material line: DIN 2391 ST52 or EN 10305 E355, subject to matching MTC values and buyer approval.
• Dimensions: OD, ID or wall, finished-bore tolerance, straightness, cut length, and machining allowance.
• Finish: as-drawn, stress relieved, normalized, honed, or skived and roller burnished as the drawing requires.
• Documents: EN 10204 Type 3.1 MTC, heat number, dimensional report, and roughness report for a finished bore.
• Inspection: buyer hold points, TPI if nominated, marking method, end protection, packing, and unloading checks.
• Commercial line: quantity in pieces or MT, ex-works Kanpur or delivered basis, destination PIN, and the tax basis stated on the quotation.

A phrase such as "hydraulic tube ST52" leaves too many choices open. It does not tell the seller whether the bore is finished, how much machining stock remains, or which delivery condition the machine shop expects. Attach the barrel drawing and seal-related bore requirement to the RFQ.

Worked tube-weight check for a purchase order

Use the site formula once the OD and wall are fixed: weight = (OD - t) x t x 0.02466 kg/m. For a 50 mm OD precision tube with a 4 mm wall, the exact theoretical result is (50 - 4) x 4 x 0.02466 = 4.53744 kg/m. For this purchase-order estimate, round the metre weight to 4.54 kg/m first; on that consistent two-decimal basis, one 6 m length is 4.54 x 6 = 27.24 kg before manufacturing variation and surface treatment.

This calculation checks commercial weight, not pressure suitability. Compare it with the supplier's stated theoretical basis and the actual weighment terms. If the drawing orders OD x ID, derive the nominal wall consistently before using the calculator. The weight calculator is useful for the remaining sizes in the BOQ.

Inspection points that prevent machining problems

Complete receiving inspection before cutting so any mismatch remains identifiable to its original marking and records. Check the tube marking against the MTC, then confirm OD, ID, wall, length and straightness against the PO and drawing. A tube with the correct grade can still be unsuitable when the bore class or machining allowance differs.

Inspect finished bores under clean light. Look for rust, score lines, dents, embedded debris, and damaged end protection. Keep a suspect tube segregated and photograph its marking, end, and affected area. Do not mix it into the production rack while the document and dimension check is open.

Review the report scope carefully. The MTC covers the parent material and heat. A separate dimensional or roughness report may be needed to evidence final honing or roller burnishing. If a buyer-nominated TPI is required, agree the measurement points and release stage before dispatch rather than asking for retrospective witnessing.

Packing affects acceptance. Bore-finished tubes should arrive capped and protected from metal chips and water. Bundle supports must not create local dents. Record any transit damage before unloading is signed complete, then reconcile the affected piece markings with the packing list and MTC.

Standards and documents to name on the PO

Cite DIN 2391-1:1994 when a legacy drawing controls seamless precision-tube delivery. Use EN 10305-1:2016 for seamless cold-drawn precision tubes and EN 10305-4:2016 for seamless cold-drawn tubes used in hydraulic and pneumatic power systems. ISO 286-1:2010 supplies the dimensional tolerance system behind H8 and H9 callouts. Put the drawing's approved surface-texture parameter and limit directly on the PO rather than relying on an unspecified or superseded terminology reference.

EN 10204:2004 defines inspection-document types, including Type 3.1 and Type 3.2. The order should identify the required type rather than using "test certificate" alone. The relevant standard edition and dimensional tables must match the customer drawing. Where a contract names a different edition, the contract takes priority and the supplier should record any proposed substitution for approval.

Dispatch from Kanpur for hydraulic and printing-cylinder buyers

For an ex-warehouse Kanpur or delivered enquiry, ask the written offer to state its source, freight, packing, dispatch estimate and delivery basis. Size, finish, quantity, document approval, purchase-order status and payment terms can affect that proposal; this page does not create a dispatch commitment.

Buyers in Kanpur Dehat, Unnao, Panki, Dada Nagar, Jajmau, Chakeri, and Fazalganj can use the Kanpur steel pipe page for mixed-product enquiries. Outstation teams can start with the Lucknow page, Agra page, or Patna page, then send the final destination PIN with the tube drawing.

FAQ

Sources and references

• DIN 2391-1:1994, Seamless precision steel tubes, technical delivery conditions.
• EN 10305-1:2016, Steel tubes for precision applications, seamless cold-drawn tubes.
• EN 10305-4:2016, Seamless cold-drawn tubes for hydraulic and pneumatic power systems.
• ISO 286-1:2010, ISO code system for tolerances on linear sizes.
• EN 10204:2004, Metallic products and types of inspection documents.
• RP Sales precision tube price list, reviewed 24 May 2026.
• RP Sales delivery FAQ for dispatch regions and quotation practice.