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ASTM A519 Seamless Hydraulic Cylinder Tube – Honed & SRB

Dongmeng Group supplies ASTM A519 seamless hydraulic cylinder tubes for hydraulic cylinder barrels, telescopic cylinders, industrial actuators and other precision fluid-power applications.

Available material grades include SAE 1020, 1026, 1035, 1045, 4130 and 4140, with cold-finished, stress-relieved, normalized or other specified delivery conditions according to the project.

Finished cylinder bores can be supplied by precision honing or skiving and roller burnishing (SRB) with specified finished ID, H8/H9 tolerance, surface roughness, straightness and inspection requirements.

Unlike ordinary mechanical tubing, a ready-to-machine hydraulic cylinder barrel requires more than an ASTM A519 material designation. Bore tolerance, surface texture, material condition, minimum wall thickness, geometry and inspection level must all be defined according to the cylinder design.

Send us:

Finished Bore ID × OD or Minimum Wall Thickness × Length + Grade + Delivery Condition + Working Pressure + H Tolerance + Surface Roughness + Quantity

and our team can review the specification before quotation.

ASTM A519 is a specification covering several grades of seamless carbon and alloy steel mechanical tubing.

For round tubing, ASTM A519 covers seamless hot-finished and cold-finished mechanical tubing up to and including 325 mm outside diameter.

ASTM A519 tubing is widely used as raw material for hydraulic cylinder barrels because seamless mechanical tubing can provide good material uniformity and is available in carbon and alloy grades suitable for machining, heat treatment and precision bore finishing.

However:

ASTM A519 compliance alone does not mean that a tube is a finished hydraulic cylinder barrel.

The cylinder manufacturer or purchaser should separately specify the requirements that affect piston and seal performance.

These normally include:

Finished bore diameter

Bore tolerance class

Surface roughness

Surface texture

Roundness

Cylindricity

Taper

Straightness

Minimum wall thickness

Material grade

Delivery condition

Mechanical properties

NDT requirements

Inspection frequency

Certification

End machining

Bore protection

This distinction is particularly important when comparing quotations from different hydraulic tube suppliers.

ASTM A519 should not be used to describe every seamless mechanical tube regardless of diameter.

ASTM A519 Round Tube Scope

Outside Diameter: Up to and including 325 mm

Larger seamless or honed cylinder tubing may be available under another applicable specification or a project-specific technical agreement, but should not automatically be described as ASTM A519.

For requirements above 325 mm OD, please provide the dimensions, grade, pressure requirement and applicable engineering specification so that the correct manufacturing standard can be confirmed.

Material selection should be based on more than grade name alone.

The delivery condition and heat treatment can significantly affect mechanical properties, machinability, welding procedure and cylinder performance.

Important

Do not select a cylinder barrel using statements such as:

"SAE 1026 tensile strength = one fixed value."

The actual mechanical properties depend on:

Tube manufacturing route

Cold work

Heat treatment

Wall thickness

Ordered condition

Applicable purchase requirements

For critical cylinders, the purchase order should specify the required mechanical properties and they should be verified through the MTC.

The following table is intended as a grade-selection reference. Final acceptance should be based on the ordered ASTM A519 grade, applicable standard edition and actual Material Test Certificate.

Other elements and exact acceptance limits should be confirmed against the applicable material specification.

This is one of the most frequently overlooked issues when sourcing hydraulic cylinder tubing.

Two tubes described as:

"ASTM A519 SAE 1026"

may not provide identical mechanical performance if their delivery conditions are different.

Common Conditions

Depending on grade and manufacturing route, tubing may be supplied in conditions such as:

Hot finished

Cold finished

Annealed

Normalized

Stress relieved

Quenched and tempered for applicable alloy grades

The quotation and purchase order should therefore state both:

Material Grade + Required Delivery Condition

For example:

ASTM A519 SAE 1026, cold-finished and stress-relieved, honed to finished ID according to drawing.

For alloy steels such as 4130 or 4140, heat-treatment condition becomes especially important.

Terms such as:

BK / BKW / GBK / NBK

are commonly associated with European precision tube delivery conditions.

They should not simply be inserted into an ASTM A519 specification without explaining which condition and mechanical-property requirement is actually intended.

For international projects, we recommend specifying the actual process or metallurgical condition rather than assuming that different standards are automatically interchangeable.

One of the most important corrections to conventional hydraulic tube specifications is that:

H8, H9 and H10 are not fixed ± tolerances.

For an ISO basic hole tolerance zone H, the lower deviation is zero and the permitted positive deviation changes according to the nominal finished bore diameter.

ISO Bore Tolerance Reference

Always confirm the applicable ISO 286 table and project drawing before production.

H8 Hydraulic Cylinder Bore Examples

Ø50 mm H8 Bore

Permitted finished bore:

50.000–50.039 mm

Ø80 mm H8 Bore

Permitted finished bore:

80.000–80.046 mm

Ø100 mm H8 Bore

Permitted finished bore:

100.000–100.054 mm

Ø160 mm H8 Bore

Permitted finished bore:

160.000–160.063 mm

This is why a statement such as:

"H8 = ±0.025 mm"

should not be used for all cylinder tube sizes.

The tolerance should be selected according to the piston, guide and sealing system rather than simply specifying the tightest tolerance available.

H8

Typically selected when the application requires tighter finished bore control.

Suitable for:

Precision hydraulic cylinders

OEM cylinder production

Applications with controlled piston/seal clearance

Higher repeatability requirements

H9

Provides a wider dimensional tolerance and may be appropriate where the cylinder design does not require H8 accuracy.

Potential advantages include:

Lower finishing cost

Easier production on some large bore sizes

Suitable for less demanding tolerance requirements

H10

May be used when a wider bore tolerance is acceptable or when additional machining is planned by the customer.

The correct tolerance should always be confirmed against the cylinder drawing and seal design.

A tube can technically meet an ID size tolerance and still create cylinder assembly or seal problems.

Therefore, critical applications may also require limits for:

Roundness

Controls deviation of the bore from a true circular profile.

Cylindricity

Controls the three-dimensional form of the bore along its length.

Taper

Controls unwanted increase or decrease in bore size from one end to the other.

Straightness

Important for long cylinder barrels and long-stroke cylinders.

Eccentricity

Eccentricity can reduce the actual minimum wall thickness, even when nominal OD and ID appear acceptable.

For demanding cylinders, these requirements should be specified separately on the drawing or purchase order.

Honing uses abrasive stones to remove a controlled amount of material from the inside diameter.

The process is commonly selected when the finished bore requires:

Accurate finished ID

Improved bore geometry

Controlled surface texture

Removal of minor internal imperfections

Cross-hatched surface pattern

Good compatibility with reciprocating sealing systems

The amount of stock left before honing should be considered when ordering the mother tube.

SRB combines two operations.

Skiving

A cutting tool removes material from the bore.

Roller Burnishing

Rollers plastically smooth the surface peaks and create a finished bore.

SRB is widely used for hydraulic cylinder tubing where production efficiency and repeatable bore finishing are important.

Neither process should automatically be described as "better."

The correct process depends on:

Seal material

Required Ra/Rz

Bore geometry

Cylinder speed

Lubrication

Duty cycle

Production volume

Cost target

Many hydraulic tube pages state only:

Ra 0.2–0.4 μm

and treat this as a complete cylinder bore specification.

That is not always sufficient.

For reciprocating hydraulic seals, surface performance may also be influenced by:

Ra

Rz

Rp

Rt

Rmr

Surface direction

Plateau structure

Peaks and valleys

Two surfaces with the same Ra value can behave differently against a hydraulic seal.

The correct surface specification depends on the seal material and seal supplier recommendations.

As an engineering reference, dynamic sealing surfaces commonly require carefully controlled roughness.

Rz and material ratio should also be considered where required.

These values should not replace the specification issued by the seal manufacturer.

Recommendation

When requesting a hydraulic cylinder tube, provide:

Required Ra + Rz + Seal Type

where possible.

This allows a much more reliable surface recommendation than specifying "mirror finish" or Ra alone.

A lower Ra number does not automatically produce longer seal life.

An excessively smooth surface may affect lubricant retention and may not be optimal for every rubber or polyurethane seal system.

Likewise, a surface with excessive peaks can accelerate seal wear.

The objective is therefore:

Controlled surface texture appropriate for the chosen reciprocating seal system - not simply the lowest possible Ra value.

The following dimensions illustrate common tube combinations. They are not mandatory ASTM sizes.

Final availability should be confirmed according to grade, delivery condition and quantity.

Metric and imperial dimensions can be quoted according to drawings.

For a finished cylinder barrel, use:

Finished ID × OD × Length

or:

Finished ID × Minimum Required Wall Thickness × Length

Example:

ASTM A519 SAE 1026
Finished ID: 100 mm H8
OD: 125 mm
Length: 2,500 mm
Honed bore
Specified surface finish
Stress-relieved condition

This provides much more useful procurement information than requesting only:

"100 mm hydraulic tube."

One of the most common buyer questions is:

"What wall thickness do I need for a 160 bar, 250 bar or 350 bar hydraulic cylinder?"

There is no safe universal answer based only on pressure.

Cylinder barrel design should consider:

Finished bore diameter

Actual minimum wall thickness

Material grade

Delivery condition

Yield strength

Working pressure

Peak pressure

Proof pressure

Fatigue cycles

Stroke

Operating temperature

Hydraulic fluid

End construction

Welded ports

Threads

Machining depth

Stress concentration

Applicable design code

Safety factor

Nominal Wall Thickness

For a simple concentric tube:

Nominal Wall Thickness = (OD − ID) / 2

However, engineering design should consider the minimum actual wall thickness, not only the nominal value.

Eccentricity, OD tolerance, ID tolerance and machining can all reduce the minimum remaining wall.

A statement such as:

"ASTM A519 tube maximum pressure = 350 bar"

is technically incomplete.

ASTM A519 identifies the mechanical tubing specification and material grade. It does not give one universal hydraulic cylinder pressure rating for every:

Grade

Bore

Wall thickness

Heat treatment

End design

Duty cycle

For pressure-critical cylinders, the wall thickness should therefore be verified according to the actual cylinder design.

Please provide:

Finished cylinder bore

OD or available envelope

Material grade

Delivery condition

Normal working pressure

Maximum/peak pressure

Proof test requirement

Stroke

Operating temperature

Hydraulic medium

Expected duty cycle

End connection or welding details

Applicable cylinder design standard

Required safety factor

We can then review the tube manufacturing and material requirements against your specification.

These standards should not be treated as interchangeable names for the same product.

No.

DOM means Drawn Over Mandrel.

Under ASTM A513, Type 5 DOM tubing starts as electric-resistance-welded mechanical tubing and is subsequently drawn over a mandrel.

The drawing process can greatly improve:

Dimensional accuracy

Concentricity

Surface finish

Mechanical consistency

but it does not change the manufacturing route into seamless tubing.

Therefore:

ASTM A519 seamless tube and ASTM A513 DOM tube should not be listed as the same product condition.

SAE J524 covers cold-drawn and annealed seamless low-carbon steel pressure tubing intended for hydraulic lines and applications requiring bending and flaring.

That is a different procurement intent from a precision-finished hydraulic cylinder barrel.

For cylinder barrels, specify the actual mechanical tube standard, material condition, finished bore and geometric requirements.

EN 10305-1 covers seamless cold-drawn steel tubes for precision applications.

It places strong emphasis on defined dimensional tolerances and surface characteristics.

A customer drawing may reference either ASTM A519 or EN 10305-1 depending on region and engineering practice.

They should not automatically be considered equivalent.

If a project asks for:

ASTM A519 / E355 / EN 10305 / ST52

our team should first confirm which standard actually controls:

Chemistry

Mechanical properties

Delivery condition

Dimensions

Testing

before quotation.

"ST52" is frequently used commercially when discussing European hydraulic tubing.

However, ST52, E355 and SAE 1026 should not be described as universally identical materials.

They originate from different material and standard systems.

Substitution should be approved according to:

Chemical composition

Mechanical properties

Delivery condition

Dimensional requirements

Project specification

For technical quotations, we recommend using the exact standard and grade required by the drawing rather than relying only on the word "equivalent."

A typical ASTM A519 seamless hydraulic cylinder tube route may include:

1. Raw Material Verification

Steel chemistry and heat identification are checked against the ordered grade.

2. Seamless Tube Production

Tube hollows are produced through an appropriate seamless manufacturing process.

3. Cold Drawing

Where required, cold drawing improves dimensional control and prepares the tube for subsequent precision finishing.

4. Heat Treatment

Annealing, normalizing, stress relieving or other heat treatment is applied according to grade and ordered condition.

5. Straightening

Tube straightness is controlled before precision internal finishing.

6. Bore Preparation

The bore is prepared with adequate machining allowance for the finishing process.

7. Honing or SRB

The ID is finished to the specified bore dimension, tolerance and surface requirement.

8. Cleaning

The finished bore is cleaned to remove abrasive residue, metal chips, oil contamination or other debris.

9. Inspection

Dimensions, bore tolerance, roughness and other specified characteristics are checked.

10. Bore Protection

Rust preventive oil, clean end caps and protective packaging are used before shipment.

For OEM hydraulic cylinder projects, a complete dimensional inspection plan may include:

Inspection method and frequency should be agreed before production for critical projects.

Typical Inspection Options

 

Hydraulic cylinder tubes should not be purchased based solely on a statement such as:

"Strict Quality Control."

The quotation should identify which inspections will actually be performed.

"performed when specified"

unless the purchase specification requires 100% testing.

01

Raw Material Verification

Heat number verification

Material grade confirmation

Chemical composition

02

Mechanical Testing

According to material specification and purchase requirements:

Tensile strength

Yield strength

Elongation

Hardness where required

03

Dimensional Inspection

OD

ID

Wall thickness

Length

Bore tolerance

Straightness

Geometry where specified

04

Bore Surface Inspection

Ra

Rz where required

Visual finish

Surface defects

Depending on purchase requirements:

Ultrasonic Testing

Eddy Current Testing

Other agreed NDT

ASTM A519 is a mechanical tubing specification.

Hydrostatic testing should therefore not automatically be advertised as a standard test performed on every ASTM A519 hydraulic cylinder tube.

Where a project requires hydrostatic, pressure or proof testing, the exact requirement should be agreed separately.

EN 10204 Type 3.1 inspection documentation can be supplied when specified.

A Type 3.1 certificate is not simply another name for third-party inspection.

It is issued within the manufacturer's authorized inspection system according to the applicable EN 10204 requirements.

Typical information may include:

Manufacturer

Purchase order

Material specification

Grade

Heat number

Chemical composition

Mechanical test results

Product identification

Inspection authorization

EN 10204 3.1

Inspection certificate issued under the manufacturer's authorized inspection system according to the standard requirements.

EN 10204 3.2

Includes independent validation involving the purchaser's authorized representative or an officially designated inspection representative, as applicable.

If independent third-party inspection is required, please state this during RFQ.

Possible inspection agencies include:

SGS

Bureau Veritas

TÜV

Other buyer-nominated inspection organization

For projects requiring traceability, the inspection plan can link the supplied tube to:

Purchase Order → Grade → Heat/Lot → Inspection Record → MTC

Additional marking and traceability requirements should be specified before production.

For cut lengths, customers should clarify whether individual pieces must retain heat or lot identification after cutting.

Welding procedure depends on:

Grade

Carbon content

Alloy content

Wall thickness

Heat-treatment condition

Joint design

Restraint

Required post-weld properties

1020 / 1026

Low-carbon grades generally offer better weldability than medium-carbon or Cr-Mo grades.

The qualified welding procedure should still reflect the actual cylinder design.

1045

The higher carbon content requires more careful welding procedure control.

4130 / 4140

Cr-Mo grades require particular attention to:

Preheat

Heat input

Filler material

Cooling rate

Hardness

Hydrogen cracking

Post-weld treatment where required

Do not use a universal preheat or PWHT temperature without reviewing the actual grade, wall thickness and welding procedure.

Dongmeng Group can support project-specific processing requirements subject to drawing review.

Available services can include:

Precision honing

Skiving and roller burnishing

Cut-to-length

End facing

Chamfering

CNC turning

Threading

Drilling

Port preparation

External machining

Custom packaging

For machined parts, provide STEP, DWG or dimensioned PDF drawings where available.

ASTM A519 seamless hydraulic cylinder tubing is commonly considered for:

Construction Machinery

Excavators

Loaders

Bulldozers

Cranes

Concrete equipment

Agricultural Equipment

Tractors

Harvesters

Agricultural implements

Lift systems

Material Handling

Forklifts

Lift tables

Scissor lifts

Loading equipment

Mining Equipment

Heavy-duty actuators

Mining machinery

Support systems

Industrial Hydraulic Systems

Hydraulic presses

Automation equipment

Production machinery

Machine tools

Mobile Equipment

Dump trucks

Trailers

Refuse equipment

Utility vehicles

Marine and Offshore Equipment

For marine environments, corrosion protection and material selection should be specified according to service conditions.

The finished bore is one of the most valuable surfaces of a hydraulic cylinder tube.

Packaging should therefore protect against:

Corrosion

Moisture

Dust

Steel particles

Mechanical impact

Damage to tube ends

Typical Export Protection

Clean finished bore

Rust preventive oil

Plastic end caps

Protective wrapping

Steel bundles

Wooden cases or plywood crates where required

Custom seaworthy packaging

Special cleanliness requirements should be stated before ordering.

1. Specification Review Before Production

We focus on the complete cylinder tube requirement rather than quoting only by grade and OD.

Important parameters such as:

Finished ID

H tolerance

Surface requirement

Delivery condition

Length

Inspection

Certification

can be reviewed before production.

2. Multiple Material Options

Carbon and alloy steel options can be selected according to the application rather than applying one material to every cylinder.

3. Honed and SRB Options

Different internal finishing processes allow customers to specify the most suitable bore finish for their production system.

4. Inspection Based on Purchase Requirements

Dimensional inspection, surface roughness testing, mechanical testing and NDT can be included according to the agreed inspection plan.

5. Material Traceability

MTC and heat/lot traceability can be supplied according to the purchase specification.

6. Processing Support

Cutting, honing, SRB and further machining can reduce the amount of processing required after delivery.

7. Export Packaging

Finished bores are protected against corrosion, contamination and handling damage during international shipment.

For the fastest technical review, please send the following information.

Best RFQ Format

ASTM A519 SAE 1026 / Stress Relieved / 125 OD × 100 ID H8 × 2500 mm / Honed / Surface Finish per Drawing / 100 pcs

If working pressure is important, also provide the cylinder design conditions.

1. What is ASTM A519 hydraulic cylinder tube?

ASTM A519 is a seamless carbon and alloy steel mechanical tubing specification. Suitable grades can be used as raw material for hydraulic cylinder barrels and subsequently honed or SRB-finished to the required bore specification.

ASTM A519 itself does not define every finished hydraulic cylinder bore requirement.

2. What is the most common ASTM A519 grade for hydraulic cylinder tubing?

SAE 1026 is commonly selected for general mechanical and hydraulic cylinder applications because it offers a practical balance of strength, machinability and processing characteristics.

However, the correct grade depends on required strength, heat treatment, welding, wall thickness and cylinder duty.

3. When should I use ASTM A519 4140?

4140 may be selected when the cylinder design requires the properties achievable from a Cr-Mo alloy steel and suitable heat treatment.

The required heat-treatment condition and mechanical-property limits should be clearly specified rather than ordering only "4140."

4. What is the H8 tolerance for a 100 mm hydraulic cylinder bore?

A nominal 100 mm H8 hole falls in the >80–120 mm size range.

The H8 limits are approximately:

100.000–100.054 mm

subject to the applicable ISO 286 specification.

5. Is H8 always ±0.025 mm?

No.

H8 is an ISO tolerance class whose tolerance width changes according to nominal size.

For an H hole, the lower deviation is zero.

For example:

Ø50 H8: 50.000–50.039 mm

Ø80 H8: 80.000–80.046 mm

Ø100 H8: 100.000–100.054 mm

6. Which is better, H8 or H9?

H8 is tighter than H9, but tighter is not automatically better for every cylinder.

The bore tolerance should match:

Piston design

Seal dimensions

Guide system

Manufacturing capability

Assembly clearance

7. Should I choose honed tube or SRB tube?

Choose according to surface texture, bore geometry, seal system, production volume and cost.

Honing offers excellent geometry correction and a traditional cross-hatched surface.

SRB offers high production efficiency and a characteristic burnished surface.

Neither process is universally superior.

8. Is a lower Ra always better for hydraulic seals?

No.

Seal life depends on the complete surface profile, not only Ra.

Rz, peaks, valleys, material ratio and surface texture can also influence lubrication, leakage and wear.

Always review the requirements of the selected seal supplier.

9. Is ASTM A513 DOM tube seamless?

No.

ASTM A513 DOM tubing is electric-resistance-welded mechanical tubing that is subsequently drawn over a mandrel.

ASTM A519 tubing is seamless mechanical tubing.

10. Is SAE J524 the same as ASTM A519 hydraulic cylinder tube?

No.

SAE J524 is intended for seamless low-carbon pressure tubing used in hydraulic lines and other applications requiring bending and flaring.

ASTM A519 is a mechanical tubing specification.

They should not be treated as equivalent standards.

11. Are ST52, E355 and SAE 1026 equivalent?

They may be compared in commercial discussions, but they should not automatically be treated as identical grades.

Each belongs to a different standard system.

Any substitution should be checked against chemistry, mechanical properties, delivery condition and project requirements.

12. Is EN 10204 3.1 a third-party inspection certificate?

No.

EN 10204 Type 3.1 is issued under the manufacturer's authorized inspection system according to the standard.

Independent third-party validation should be specified separately; EN 10204 Type 3.2 may be required depending on the project.

13. Are UT, ET and hydrostatic testing performed on every ASTM A519 tube?

Not automatically.

The inspection requirement and frequency should be defined in the purchase order.

UT, ET or other additional inspection can be arranged where specified.

Hydrostatic testing should not be assumed to be a standard ASTM A519 requirement.

14. What wall thickness do I need for a 250 bar hydraulic cylinder?

Working pressure alone is not enough to determine the correct wall thickness.

The design should also consider:

Bore

Material grade

Yield strength

Delivery condition

Minimum actual wall

Peak pressure

Fatigue

End construction

Welding

Machining

Safety factor

Applicable design standard

Send the complete operating data for technical review.

15. Can you supply custom finished bore sizes?

Yes, project-specific ID, OD, length, bore tolerance and internal finishing requirements can be quoted subject to size, material and production feasibility.

16. Can you cut the tube to finished cylinder length?

Cut-to-length services can be provided.

For precision production, specify:

Finished length

Length tolerance

End squareness

Chamfer

Machining allowance

17. Can you provide heat-number traceability?

Heat or lot traceability can be maintained according to the agreed inspection and marking requirement.

If each cut piece must retain individual traceability, specify this before production.

18. What information should I send with my RFQ?

At minimum send:

Standard + Grade + Delivery Condition + Finished ID + OD/Wall + Length + H Tolerance + Surface Finish + Quantity

For pressure-critical applications, also provide working pressure, peak pressure and cylinder design conditions.

Choosing the correct cylinder tube requires more than selecting a steel grade.

The final hydraulic cylinder performance depends on the relationship between:

Material + Heat Treatment + Minimum Wall + Finished Bore + Bore Geometry + Surface Texture + Seal System + Inspection

Dongmeng Group supplies ASTM A519 seamless mechanical tubing and precision-finished hydraulic cylinder tube solutions for OEMs, hydraulic cylinder manufacturers, repair companies and industrial equipment projects.

Send your drawing or specification for a technical quotation.

Xi'an Dongmeng Group Co., Ltd.

Phone:
+86 157 6921 4734

WhatsApp:
Dong: +86 157 6921 4734

Email:
office@dongmjd.com

Office Address:
Room 4107, Runfeng Building, Sanqiao New Street, Weiyang District, Xi'an City, Shaanxi Province, China

Website:
www.cndmmetal.com

Request a Quote

Please send:

Finished ID × OD × Length + Grade + Delivery Condition + H Tolerance + Surface Finish + Quantity

For hydraulic cylinder engineering projects, please also include:

Working Pressure + Peak Pressure + Stroke + Application + Drawing

Our team will review the material, bore finishing and inspection requirements before quotation.

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