Requirements for seamless cold-drawn single-wall tubes using in diesel engines
Wall thickness 4-30mm
Diameter 1-12.5mm
Length 5-6m Upon request
Application :Diesel(compression-ignition)engines
Automobile pipes are used in the production of automobile steering systems, clutch systems, brake systems, engine high-pressure oil injection pipes, universal shafts, shock absorbers and air springs, chassis components, axles, chassis and axle structural components, steering components, seat structures, support instrument panels. Used in hydraulic systems, automobiles and high-precision occasions, brightness, cleanliness and mechanical properties of pipes are required.


Process routing summary: high-quality carbon steel —cold drawing —non-oxidizing heat treatment (NBK state) — non—destructive testing —flushing the inner holes with special equipment under high pressure -treating the surface with anti-rust oil -plastic capping at both ends.

The raw materials we choose: high-quality Baosteel, Xingcheng Iron and Steel and Huai Steel will undergo physical and chemical inspections to ensure that each batch of products is within the qualified range. After splicing, check whether each tube is in the allowable dimensional deviation, which can ensure higher thickness tolerances and concentricity.

Quality control of the production process: We use domestic first-class wire drawing machines, and the production process is controlled by the internal and external substrates of high-hardness alloys. Therefore, the dimensional tolerances and ovality of the products are strictly controlled at a high level.Pass the first, middle and end process inspection to ensure product quality.

Internal and external surface cleaning: We use automatic internal surface cleaning machine, rotating brush cleaning and high-pressure oil flushing to clean the internal and external surfaces.The new steel pipe production process can effectively remove all particles attached to the inner and outer surfaces of the steel pipe, so as to achieve maximum surface cleanliness and polishing.

Delivery condition: NBK/GBK.

Outside surface condition
0: No
1:Outside surface as processed, without any additional finish. Tubes annealed or normalized in a controlled atmosphere may be discoloured,but shall be free from loose scale.
2.Zinc electroplated with a coating layer thickness of 8μm minimum and an additional colourless chromating^a
3. Zinc electroplated with a coating layer thickness of 8μm minimum and an additional yellow chromating
4 ,5,6,7,8 Reserved for further application
9 As specified subject to agreement
A: Chromating as described in ISO2080 and ISO4520

Characteristic :
Mechanical properties

Tolerance is
Inside diameter ,d
d≤4mm:±0.05mm for class2 (for diesel (compression-ignition)engines)
±0.025mm for class 1(for fuel injection pump testing)
d＞4mm:±0.10mm
Outside diameter,D
D＜8mm:±0.06mm
D≥8mm: ±0.10mm
For Class 1 and Class2 Please refer above explain.
The maximum value of the concentricity of the tube outside diameter relative to inside diameter shall be proportional to the wall thickness, as shown in Figure1.


Normative references: ISO404 Steel and steel products—General technical delivery requirements.
ISO6507-1 Metallic materials—Vickers hardness test—Part1: Test method
ISO6892-1 Metallic materials—Tensile testing—Part1:Method of test at room temperature
ISO12345 Diesel engines—Cleanliness assessment of fuel injection equipment