Cold Rolled Automotive Steel Tubes EN 10305-1 Standard for Shock Absorber Cylinders with 8-100 mm OD
Basic Properties
Place of Origin:
ZHEJIANG
Brand Name:
TORICH
Certification:
ISO 9001
Model Number:
EN10216-1 DIN17175
Trading Properties
Minimum Order Quantity:
3 Tons
Price:
800-1000 USD/Tons
Payment Terms:
L/C,D/A,D/P,T/T,Western Union,
Supply Ability:
200 Tons Per Month
Product Summary
Round Shape Automotive Steel Tubes Cold Rolled For Shock Absorber Cylinder Round automotive precision steel tubes for shock absorber cylinders are manufactured by cold drawing or cold rolling to obtain controlled outside diameter, inside diameter, wall thickness and surface condition. They are ...
Product Details
Highlight:
low carbon steel pipe
,steel mechanical tubing
Product Type:
Round Precision Automotive Steel Tube
Material:
Non-alloy Carbon Steel / Precision Engineering Steel
Typical Grades:
E215, E235, E255, E355, E410
Manufacturing Process:
Cold Drawn Or Cold Rolled
Outside Diameter:
8-100 Mm Typical Production Range
Wall Thickness:
1-8 Mm Typical Production Range
Length:
1-12 M, Customized Cut Lengths Available
Heat Treatment / Delivery Condition:
+C, +LC, +SR, +A, +N
Product Description
Round Shape Automotive Steel Tubes Cold Rolled For Shock Absorber Cylinder
Round automotive precision steel tubes for shock absorber cylinders are manufactured by cold drawing or cold rolling to obtain controlled outside diameter, inside diameter, wall thickness and surface condition. They are intended particularly for shock absorber working cylinders where piston guidance, seal performance and dimensional consistency depend directly on tube geometry and bore quality.
EN 10305-1 seamless cold-drawn precision tubing is particularly suitable for this type of application because the standard defines dimensional accuracy, surface requirements, mechanical properties and delivery conditions. Typical materials include E215, E235 and E355, while E255 and E410 can be specified when different strength levels are required.
Specifications
| Item | Specification |
|---|---|
| Product Type | Round precision automotive steel tube |
| Material | Non-alloy carbon steel / precision engineering steel |
| Main Standard | EN 10305-1 |
| Alternative Standard | DIN 2391 |
| Typical Grades | E215, E235, E255, E355, E410 |
| DIN Reference Grades | St35, St45, St52 |
| Manufacturing Process | Cold drawn or cold rolled |
| Outside Diameter | 8-100 mm typical production range |
| Wall Thickness | 1-8 mm typical production range |
| Length | 1-12 m, customized cut lengths available |
| OD Tolerance | Cold rolled: typically up to ±0.05 mm; cold drawn: typically up to ±0.10 mm, depending on dimension and order specification |
| ID Tolerance | Can be controlled according to shock absorber cylinder drawing requirements |
| Wall Thickness Tolerance | According to applicable standard and dimensional combination |
| Straightness | Controlled according to EN 10305-1 or customer drawing |
| Cross Section | Round |
| Surface Condition | Bright, oiled, polished or phosphated as specified |
| Surface Roughness | EN 10305-1 specifies Ra ≤4 μm for applicable tubes with D ≤260 mm; tighter functional bore finish can be produced by additional processing |
| Heat Treatment / Delivery Condition | +C, +LC, +SR, +A, +N |
| DIN Traditional Delivery Designations | BK, BKW, BKS, GBK, NBK |
| Inspection Document | EN 10204 inspection certificate available according to order requirements |
| Primary Use | Automotive shock absorber working cylinder |
Main Characteristics
Controlled Cylinder Geometry
Cold drawing or cold rolling improves dimensional consistency compared with conventional hot-finished tubing. For shock absorber cylinders, accurate control of inside diameter, outside diameter, ovality and wall eccentricity helps maintain stable piston-to-cylinder clearance throughout the working stroke.
For precision production, outside diameter tolerance can typically be controlled to ±0.05 mm on suitable cold-rolled dimensions. Tighter ID requirements should be specified directly on the customer's cylinder drawing because the functional bore, rather than only the OD, determines piston and seal clearance.
Defined Surface Roughness
EN 10305-1 requires smooth internal and external surfaces and specifies maximum roughness values. For tubes with outside diameter up to 260 mm, the standard specifies maximum Ra values of 4 μm under the applicable delivery conditions.
Shock absorber working cylinders may require a considerably finer functional inner surface than the general standard limit. Honing, skiving and roller burnishing or other bore-finishing processes can therefore be specified when low-friction piston and seal movement is required.
Stable Mechanical Properties
The final tube properties depend on both steel grade and delivery condition.
- +C provides the highest cold-worked strength but relatively low ductility.
- +LC uses a light final drawing pass after heat treatment and provides improved formability.
- +SR is stress relieved after cold drawing and offers a balance between dimensional stability and mechanical strength.
- +A is soft annealed for increased ductility.
- +N is normalized and provides standardized strength and elongation values suitable for subsequent machining and forming.
Our Advantages
- Functional ID Control for Piston and Seal Matching: For shock absorber cylinders, purchasing only by OD and wall thickness can result in unacceptable bore variation. The inside diameter directly affects piston clearance, seal contact and damping consistency. Production can therefore be controlled according to OD × ID or OD × wall thickness, with ID tolerance, ovality and wall eccentricity included in the inspection plan when specified on the drawing. Precision cylinder projects can use tighter dimensional requirements than the general commercial tube tolerance.
- Bore Surface Can Be Matched to the Actual Cylinder Function: A general precision tube may satisfy dimensional requirements while still requiring additional bore processing for a hydraulic sliding surface. The required bore condition can therefore be defined separately from the general tube surface requirement. Cold-drawn, cold-rolled, honed or skived-and-roller-burnished conditions can be selected according to piston, guide and seal design. This avoids treating surface roughness as a purely cosmetic specification.
- Grade and Delivery Condition Can Be Controlled Together: Mechanical properties cannot be determined from steel grade alone. Cold-worked and heat-treated conditions produce substantially different tensile strength, yield strength and elongation. Orders can therefore specify both the material grade and final delivery condition, for example E355+SR or E355+N, rather than simply specifying E355. Heat number identification and EN 10204 inspection documentation can also be agreed for production traceability.
Execution Standards
| Standard | Scope |
|---|---|
| EN 10305-1 | Seamless cold-drawn steel tubes for precision applications |
| DIN 2391 | Traditional German specification for seamless precision steel tubes; commonly associated with St35, St45 and St52 |
| ASTM A519 | Seamless carbon and alloy steel mechanical tubing |
| JIS G 3445 | Carbon steel tubes for machine structural purposes |
| GB/T 3639 | Cold-drawn or cold-rolled precision seamless steel tubes |
| GOST 9567 | Precision steel tubes with controlled dimensional accuracy |
For new European projects, EN 10305-1 grade designations and delivery-condition symbols should normally be used instead of relying only on older DIN 2391 terminology.
Application
Automotive Shock Absorber Working Cylinder
The tube is used as the working cylinder of an automotive hydraulic shock absorber. Inside the cylinder, the piston assembly moves repeatedly through hydraulic oil while the piston seal maintains controlled contact with the bore. The cylinder tube therefore requires consistent internal diameter, low ovality, controlled wall eccentricity, adequate straightness and a smooth functional inner surface.
E235 and E355 precision steel tubes are commonly selected depending on required strength, tube dimensions and subsequent processing. Final material selection should be based on the shock absorber drawing, operating load, forming operations and required delivery condition.
Chemical Composition
| Grade | Steel No. | C % | Si % | Mn % | P % | S % | Other Requirements |
|---|---|---|---|---|---|---|---|
| E215 | 1.0212 | ≤0.10 | ≤0.05 | ≤0.70 | ≤0.025 | ≤0.025 | Al total ≥0.025 |
| E235 | 1.0308 | ≤0.17 | ≤0.35 | ≤1.20 | ≤0.025 | ≤0.025 | Al total ≥0.015 |
| E255 | 1.0408 | ≤0.21 | ≤0.35 | 0.40-1.10 | ≤0.025 | ≤0.025 | Annex A grade |
| E355 | 1.0580 | ≤0.22 | ≤0.55 | ≤1.60 | ≤0.025 | ≤0.025 | Al total ≥0.020 |
| E410 | 1.0509 | 0.16-0.22 | 0.10-0.50 | 1.30-1.70 | ≤0.030 | ≤0.035 | V 0.08-0.15; Al 0.010-0.060; Nb ≤0.07; Ti ≤0.05 |
Mechanical Properties
| Grade | Delivery Condition | Tensile Strength Rm | Upper Yield Strength ReH Min. | Elongation A Min. |
|---|---|---|---|---|
| E215 | +N | 290-430 MPa | 215 MPa | 30% |
| E235 | +N | 340-480 MPa | 235 MPa | 25% |
| E255 | +N | 440-570 MPa | 255 MPa | 21% |
| E355 | +N | 490-630 MPa | 355 MPa | 22% |
| E410 | +N | 550-700 MPa | 410 MPa | 22% |
Delivery Conditions
| Symbol | Traditional DIN Designation | Description |
|---|---|---|
| +C | BK | Cold drawn hard; no final heat treatment after final cold drawing |
| +LC | BKW | Cold drawn soft; final heat treatment followed by a light drawing pass |
| +SR | BKS | Cold drawn and stress relieved in a controlled atmosphere |
| +A | GBK | Soft annealed after final cold drawing |
| +N | NBK | Normalized after final cold drawing in a controlled atmosphere |
Product Images
Frequently Asked Questions
Are you trading company or manufacturer?
Manufacturer, also can do trading.
How long is your delivery time?
Generally speaking, it is 10-15 days if the goods are in stock, or it is 30-40 days if the goods are not in stock, according to quantity.
Do you provide samples? Is it free or extra?
Yes, we could offer the sample for free charge but need pay the cost of freight.
What is your terms of payment?
Payment ≤ 2000 USD, 100% in advance. Payment ≥ 2000 USD, 30% T/T in advance, balance before shipment. If you have another question, please feel free to contact with me.
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