Precision steel tube is cold drawn tube whose outside diameter, wall, roundness and surface are controlled closely enough to machine, hone, bend or assemble without a second sizing operation. We supply it to the main European, American and Japanese standards, cut to length and oiled, with the bore and wall tolerance set by the standard on your drawing.
This page is the entry point to the individual standard pages. If the drawing already names DIN 2391, EN 10305-1, ASTM A519 or SAE J525, go straight to that page; if the enquiry only says “precision tube”, use the comparison below to identify the construction and grade first.
Products in this group
DIN 2391 Seamless Precision Steel TubeDIN 2391 · St35 / St45 / St52 · NBK, BK, BKWView tube →
DIN 2393 Welded Precision Steel TubeDIN 2393 · St37.4 / St52.4 · welded + cold drawnView tube →
EN 10305-1 E355 Hydraulic Cylinder TubeEN 10305-1 · E235 / E355 · +C, +LC, +SRView tube →
EN 10305-4 Hydraulic Precision Steel TubeEN 10305-4 · E235 / E355 · hydraulic linesView tube →
SAE J524 Seamless Low Carbon Steel TubingSAE J524 · 1008–1026 · seamlessView tube →
SAE J525 Welded Low Carbon Steel TubingSAE J525 · 1008–1026 · welded + cold drawnView tube →Precision tube, precision steel pipe and precision metal tubing
The words are often used interchangeably, but they answer different questions. One describes the tolerance, one the material, and one the way the part is sized.
| Term in the enquiry | What it normally means | What to confirm before quoting |
|---|---|---|
| precision tube | Cold drawn tube with a controlled OD, wall and bore; may be seamless or welded and drawn | Standard, size, tolerance and the next operation |
| precision steel tube | The same product with the material fixed as carbon or alloy steel | Grade, heat treatment and certificate |
| precision steel pipe | Precision tube sold under pipe wording; often for fluid lines or fittings | Whether the part is sized by OD and wall or by nominal bore |
| precision metal tubing | Broader wording that can include stainless steel, aluminium or copper alloy | Confirm steel before a price is compared |
A precision steel pipe enquiry is not automatically a pipe-schedule product. In hydraulic and pneumatic work the drawing usually gives an outside diameter and wall, which is tube sizing even when the buyer calls it pipe. We quote to the drawing rather than to the label.
Which standard fits the part?
The standard decides the seam, the grade list, the tolerance table and the certificate language. The table links each family to its detailed page.
| Standard | Construction | Common grades | Typical part |
|---|---|---|---|
| DIN 2391 | Seamless, cold drawn | St35, St45, St52 | Hydraulic lines, bushes, machined sleeves |
| EN 10305-1 | Seamless, cold drawn | E235, E355 | General precision tube, cylinder shells |
| DIN 2393 / EN 10305-2 | Welded, then cold drawn | St37.4, St52.4 | Shock absorber bodies, bushes, medium pressure |
| EN 10305-4 | Cold drawn for hydraulic and pneumatic power systems | E235, E355 | Hydraulic lines, fittings, control blocks |
| ASTM A519 | Seamless mechanical tubing | 1020, 1045, 4130 | Machined parts, chromoly fork and frame tube |
| ASTM A513 Type 5 | Welded and drawn over a mandrel (DOM) | 1008–1026 | Shock absorber tubes, bushes, sleeves |
| SAE J524 | Seamless low carbon tubing | 1008–1026 | Automotive lines and fittings |
| SAE J525 | Welded and cold drawn low carbon tubing | 1008–1026 | Automotive parts where a drawn weld is acceptable |
The choice between a seamless and a welded-and-drawn route is commercial as well as technical. A seam is acceptable in many bushings and shock absorber bodies; it is normally avoided where the bore is a pressure boundary or where the part is machined through the wall.
For cylinder work, continue to hydraulic cylinder tube, which covers honed and SRB bores. For motorcycle fork blades, see motorcycle fork tube.
Sizes, tolerances and delivery condition
| Item | Usual range | Note |
|---|---|---|
| Outside diameter | 4–80 mm | Other sizes quoted as a special draw |
| Wall thickness | 0.6–10 mm | Wall to drawing where the OD allows |
| OD tolerance | ±0.05 to ±0.10 mm | Fixed by the final draw |
| Wall tolerance | ±10% | Closer where the bore will be honed |
| Length | 4–7 m random, or fixed | Cut to length and deburred on request |
| Delivery condition | BK, BKW, BKS, GBK, NBK, or +C to +N | Chosen for the next operation |
Condition matters more than the headline grade on parts that are bent, welded or honed. BKW is the softer drawn condition for forming; BKS is stress relieved for stability; BK keeps the highest strength after the final draw. EN 10305-1 expresses the same conditions as +C, +LC, +SR, +A and +N.
Comparing precision steel tube manufacturers
Most quotations name the same standard and the same grade. The differences appear in what is measured and what is written on the certificate, so these are the points worth checking:
- Bore control, not only OD. Ask how the ID, roundness and wall eccentricity are inspected if the bore is a running or sealing surface.
- Certificate and traceability. A 3.1 certificate to EN 10204 should carry the heat number and the actual test results, not only a conformity statement.
- Condition for the next operation. A tube that will be honed, bent or welded needs a different delivery condition from one that goes straight into a machining centre.
- One source for both routes. Seamless and welded-and-drawn tube can be compared on the same drawing, which avoids forcing a part onto the wrong construction.
As a precision steel tube manufacturer we quote from the drawing, state the standard and condition in the offer, and confirm the inspection record before shipment. Brand names on a drawing are not reproduced here; the governing standard, grade and tolerance are what we work to.
What to send with an enquiry
- Standard, or the drawing number if the standard is not named
- Outside diameter, wall and length, or the finished part drawing
- Steel grade, or the working pressure and application if the grade is open
- Delivery condition and quantity
- Certificate, end finish and surface protection required
Send these details and we reply with price, tolerance and lead time within one working day.
FAQ
Is precision tube the same as DOM tubing?
No. DOM tubing is welded and then drawn over a mandrel, so it has a drawn weld. Precision tube can be seamless or welded and drawn; the tolerance may be similar, but the seam and the standard are not.
Can you supply small quantities?
Yes, from one length. Small orders are supplied as straight lengths or small bundles, cut to length and deburred; the price is confirmed against the size and grade on the day of the order.
Which grade should I choose for a hydraulic cylinder?
E355 or St52 is usual where the wall carries a high working pressure; E235 or St35 is sufficient for moderate pressure and general machine parts. The bore condition and the honing allowance matter as much as the grade.
Do you issue a 3.1 certificate?
Yes, on request. The certificate is issued to EN 10204 3.1 with the heat number and the test results for the delivered lot.