What is Hydraulic Steel Pipe?

Hydraulic steel pipeis basically divided into the hydraulic system with fluid pipe and oil cylinder, also known as honing tube, and cold drawn or cold rolled precision seamless steel pipe also contains hydraulic tube.
Hydraulic pipe after finishing, no oxidation bright heat treatment of raw materials (NBK), nondestructive testing, steel pipe inner hole through high pressure washing, pickling, block on both ends of the steel tube inside and outside wall with anti-rust oil antirust processing, used as a dustproof. To produce steel pipes with high precision, finish good, tube inside and outside wall without oxidation layer, steel pipe can bear the high pressure of fluid flow through, and the steel tube cold bending deformation, flaring, flattening without cracks.Mechanical properties can be bending deformation under any Angle.

Honed Tubes for Hydraulic/ Pneumatic Cylinder

The honed tubes suitable for various kinds of Precision Mechanical Tube, Honed Cylinder Tubing and Hydraulic Cylinder, Construct use Multi Joint Tube, Steel Axis Pipe, Injection Machine and Robotic Arm. This tubing is ready to use for hydraulic cylinder applications without further ID processing.

Grade:

ST 52,ST52.3,CK45, E355, 16Mn, STKM13C, SAE1020, SAE1026, SAE1045

Size range

Inside diameter from 40 to 1000mm, Max length 20 meters.

Straightness: 0.5 /1000

Tolerance EXT: DIN 2391

Tolerance INT: ISO H8

Roughness(Ra): 0.2 to 0.4µ

Type:

cold drawing, normalizing treatment, honing.

Chemical composition(%)

Si(Max)	Mn (Max)	C Max)	P (Max.)	S (Max)
0.55	1.60	0.22	0.025	0.25

Mechanical properties:

Tensile strength Min	Yield Point Min	Elongation % Min
580 N/mm2	420 N/mm2	10

Marking: Yaang, ID, OD

Length: unfixed length or fixed length

Package: banding with steel strips, braiding parcel at outside

Conservation: Anti rust oiled coating on the inside and outside of the surface, plastic caps at both ends.

Impact test: -20℃, 27 J (only for special requirement)

High precision cold drawn tube (ready to honed tube) can also be supplied.

Tolerance standard:

ID(mm)	TOLERANCE(mm)
	H7	H8	H9	H10
≦30	+0.021/0	+0.033/0	+0.052/0	+0.084/0
30 – ≦50	+0.025/0	+0.039/0	+0.062/0	+0.100/0
50 – ≦80	+0.030/0	+0.046/0	+0.074/0	+0.120/0
80 – ≦120	+0.035/0	+0.054/0	+0.087/0	+0.140/0
120 – ≦180	+0.040/0	+0.063/0	+0.100/0	+0.160/0
180 – ≦250	+0.046/0	+0.072/0	+0.115/0	+0.185/0
250 – ≦315	+0.052/0	+0.081/0	+0.130/0	+0.210/0
315 – ≦700	+0.057/0	+0.089/0	+0.140/0	+0.230/0

Precision Seamless Pipe

Precision seamless pipe is a pipe material producing by a cold drawn process with high precision and high-quality finish.

CDS is popular in the hydraulics, being used to make hollowed chrome plated telescopic cylinders and hydraulic rods. It is also popular for large bore, heavy walled, high pressure hydraulic cylinders. Cold Drawn Seamless tubes also find uses in heavy equipment manufacturing such as cranes and garbage trucks.

Due to the characteristics of high-precision, in precision machinery manufacturing, auto parts, hydraulic cylinders, construction (steel sleeve) industry has a very wide range of applications.

General process of cold drawing

A considerable proportion of the seamless tubes and pipes manufactured through the cold roll piercing technology undergo subsequent cold forming. The principal reasons behind cold drawing are:

• Achievement of closer wall thickness and diameter tolerance

• Improvement in surface finish

• To enhance serviceability

• No premature failure

• Suitable for critical forming Such as 180˚ Bends

• Enhancement of mechanical properties of the tube

• Expansion of product mix towards the lower end of the OD and wall thickness scales.

THERE ARE THREE BASIC PROCESSES EMPLOYED FOR THE COLD DRAWING OF TUBE:

• Hollow drawing

• Stationery drawing or floating plug drawing and

• Drawing over a mandrel (also known as drawing on-the-bar)

ANNEALING

After the goods are cold drawn to sizes, the tubes are put on annealing furnace for heat treatment and normalising.

STRAIGHTENING

Post annealing, the goods are passed through a seven roller straightening machine to achieve proper straightening of the tubes.

EDDY CURRENT

Post straightening, each tube is passed through eddy current machine to detect for surface cracks and other defects . Only the tubes that pass eddy current are fit for delivery to customers.

FINISHING

Each tube is either oiled with corrosion resistant oil or varnished for surface protection and corrosion resistant as per customers requirement, each tube end is covered by plastic end caps to avoid damage in transit, the marking and specs are put and the goods are ready for dispatch.

Technical standard

The seamless precision steel tubes can be used for a wide range of precision mechanical spare for car and cylinder accord to standard:

• DIN 2391

• EN10305-1

• DIN17175

DIN 2391-1 Cold Drawn or Cold Rolled Steel Tube

DIN 2391 standard specifies the Seamless steel tubes used forMechanical and Automobile. The main products of steel / steel grade: DIN2391-1(ST35, ST45, ST52).

Features Specifications

EN 10305-1 seamless precision steel tube

EN 10305 is for seamless precision steel tube applications.
Yaang offers an extensive range of EN 10305 seamless precision steel tube.

EN 10305 european standard specifies the technical delivery conditions for seamless cold drawn steel pipe of circular cross section used in hyhydraulic and pneumatic power systems.

Tubes according to this EN 10305 European standard are characterised by having precisely defined tolerances on dimensions and a specified surface roughness. The allowed pressure rates and temperatures are the responsibility of the customer in accordance with the state of the art and in application of the safety coefficients specified in the application regulations, codes or standards.

Standard and Steel grade:

• EN10305-1 E215

• EN10305-1 E235

• EN10305-1 E355

EN 10305 seamless precision steel tube shall be manufactured from hot finished seamless tubes by cold drawning. Other suitable methods of cold working are permitted. The tubes shall be delivered in the delivery condition +N which means that after the final cold drawing operation the tubes are normalized in a controlled atmosphere.

NBK means protective heat-treating under the non-oxidation enviroment to get a bright and smooth surface for the tubes.

Chemical composition(%) of EN 10305-1

Steel grade Name	Steel Number	C(% max)	Si(% max)	Mn(% max)	P(% max)	S(% max)
E215	1.0212	0.10	0.05	0.70	0.025	0.015
E235	1.0308	0.17	0.35	1.20	0.025	0.015
E355	1.0580	0.22	0.55	1.60	0.025	0.015

Mechanical and technological properties of EN 10305-1

Yield strength (min Mpa)	Tensile strength (min Mpa)	Elongation (min %)
215	290-430	30
235	340-480	25
355	490-630	22

Note:

• The yield point for the annealed (GBK)condition on delivery is at least 50% of the (ultimate) tensile strength. Depending upon the degree of deformation in the drawing operation, the yield point of tubes delivered in the cold-finished/hard (BK)and cold-finished/soft(BKW) conditions, may be increased to a level close to the tensile strength.

• In calculating the yield point, the following values are recommended : cold-finished/hard condition on delivery ≥ 80% of the tensile strength, cold-finished/soft condition on delivery ≥ 70% of the tensile strength.

Quality grade of EN 10305-1

The tubes are supplied in the following quality grades:

A) precision steel tubes intended primarily for mechanical stressing, without any particular quality requirement and without acceptance test certificate.
B) precision steel tubes intended primarily for mechanical stressing, with special quirement and exclusively with acceptance test certificate.
C) precision steel tubes with special requirement according to section 12. Theses requirements and corresponding tests must be agreed, with the customer having to specify his requirements at the time of enquiry and on ordering.

Condition on delivery of EN 10305-1:

Term	Symbol	Explanation
Cold-finished/hard (cold-finished as-drawn)	BK	No heat treatment after the last cold-forming process. The tubes therefore have only low deformability.
Cold-finished/soft (lightly cold-worked)	BKW	After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits.
Annealed	GBK	After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum.
Normalized	NBK	The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum.

DIN17175/EN10216 standard specification

DIN 17175 steel pipes are used in boiler installations, high-pressure pipelines and tank construction and special machinery for both high temperature and high-pressure devices. This alloy steel pipe is just a big class,and it has many classifivations.We mainly produce DIN 17175 ST35.8,DIN 17175 ST45.8, and 10CrMo910 steel pipes.

Features Specifications

Application:
Used in hydraulic & pneumatic cylinder ,automobile and other mechanical device.

Feature:
high precision and high brightness, the inner and outer surface of the tubes have high cleanness without oxid, mechanical properties of the final tubes also come out excellent, promising no leakage under high pressure, no deformation after cold-bent and no cracks when flaring and flattening, ensuring the efficient operation in all service.

NBK means protective heat-treating under the non-oxidation enviroment to get a bright and smooth surface for the tubes. ?

DIN 2391-81 Part 2 Seamless Precision steel tubes (DIN2391-81)

Standard DIN 2391 defines the technical delivery conditions for seamless precision steel tubes according to DIN 2391 Part 1 which are made from the steel grades listed in section 5.
Tubes according to this Standard are mainly used where accuracy to dimension and, possibly, small wall thicknesses and good surface condition are required.