EN10210 TUBE

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EN10210 HOLLOW SECTION

Standard: EN10210

Grade: S235JRH, S275J0H,S275J2H,S355J0H,S355J2H

Length:1-25M, WALL THICKNESS:1.2MM-50MM

Application: Structural Buidling

Surface Of Pipe Treatment: 3PE/3PP/3LPE/PAINTING/GALVANIZING

Ends: Plain, Beveled, Grooved

Outside dimension: ±1% with a minimum of + 0.5 mm.
Wall thickness:- 10% (- 12,5% for max 25% of the perimeter).For deviations above the nominal value, tolerances on mass rule.

Concavity and convexity of sides：On external sides: 1%.

External corner radius：Max 3 times the w.t.

Twist: Up to max 2 mm, plus 0.5 mm for each meter on the whole tube length.

Straightness: The max. tolerance must be ≤ 0.20% on the whole tube lengt. Deviations on the local straightness: max 3 mm on each meter length.

Squareness of sides: 90°±1.

Mass: Seamless tubes: + 8% /- 6% on the single section

This part of this European Standard specifies technical delivery conditions for hot finished hollow sections of circular, square, rectanqular or elliptical forms and applies to hollow sections formed hot, with or without subseauent heat treatment. or formed cold with subseauent heat treatment to obtain equivalent metallurgical conditions to those obtained in the hot formed product.

1. Smelting

First of all, the steel is smelted, and the chemical composition and smelting and continuous casting process of the steel are strictly controlled to ensure the quality of the tube billet and the mechanical and technological performance indicators of the finished steel pipe.

2. Continuous casting 

After smelting, molten steel is made into billet by continuous casting process. In the continuous casting process, the hot metal, raw material preparation, converter smelting control, refining furnace and round billet casting machine operation are made clear regulations, in order to ensure the quality of steel, the converter steel slag, slag failure must be skimmed, refined after feeding Si-Ca wire, continuous casting superheat is not more than 30℃.

3. Rolling

The billets obtained from continuous casting then enter the rolling process and are made into steel pipes by rolling mills. During the rolling process, each process is strictly controlled to ensure that the size and geometry of the steel pipe meet the requirements.

4. Heat treatment (See below for details)

Some steel pipes may need heat treatment to meet specific performance requirements, such as normalizing treatment to improve the mechanical properties of the steel. It is mentioned in the EN10210 standard that in order to obtain the same properties as normal rolling, cold-worked hollow profiles should be heat treated in order to meet the requirements of this standard.

5. Quality control

The chemical composition of steel and smelting and continuous casting process are strictly controlled during the production process, and the internal control standards for chemical composition are shown in Table 2. In the control points of smelting continuous casting process, the hot metal, raw material preparation, converter smelting control, refining furnace and round billet casting machine operation are specified.

6.Quality Inspection 

Steel pipe in the production process needs to carry out strict quality control, including chemical composition analysis, mechanical properties testing, size and geometry inspection, etc., to ensure that the steel pipe meets the requirements of the EN10210 standard.

7. Surface treatment

The surface of the steel pipe may need to be treated, such as removing the oxide, cleaning, etc., to meet the requirements of surface quality.

8. Marking and packaging

Finally, the steel pipe needs to be marked and packaged in accordance with the standard requirements in order to facilitate identification and transportation.

Heat treatment is a material processing technique primarily used to change the physical and chemical properties of metals in order to improve their properties or make them more suitable for specific applications. The heat treatment process usually involves heating a material to a specific temperature, holding it for a period of time, and then cooling it at a specific rate. Here are some common types of heat treatment and their purposes:

1. Annealing 

• The metal is heated to a certain temperature, held for a period of time, and then cooled slowly, usually in a furnace.
• The purpose is to reduce hardness, improve workability, reduce residual stress, and improve cutting performance.

2. Normalizing 

• After heating the metal to a certain temperature, it is usually cooled in air.
• The purpose is to refine the grain, improve the hardness and strength, and prepare for subsequent processing or heat treatment.

3. Quenching

• The metal is heated to a certain temperature and then cooled quickly, usually using water, oil or other media.
• The aim is to obtain high hardness and strength, usually used for tool steel and high carbon steel.

4. Tempering 

• The quenched metal is reheated to a lower temperature and kept there for some time, then cooled.
• The purpose is to reduce the brittleness generated during the quenching process, improve toughness and plasticity, and adjust the hardness.

5. Case Hardening 

• Only the metal surface is hardened, while the heart remains soft.
• Common surface hardening methods include Carburizing, Carbo-Nitriding and Nitriding.

6. Stress Relieving 

• The metal is heated to a certain temperature, held for a period of time, and then slowly cooled.
• The purpose is to reduce residual stress generated during processing and prevent deformation and cracking.

7. Solution Treatment 

• The alloy is heated to a certain temperature, held for a period of time, so that the second phase in the alloy is completely dissolved.
• The aim is to improve the uniformity and corrosion resistance of the alloy.

8. Aging 

• The alloy is cooled naturally or artificially at accelerated rate after solution treatment and then kept at room temperature or slightly higher temperature for a period of time.
• The purpose is to increase the strength and hardness of the alloy by precipitation hardening.

Heat treatment is a very important part of metal processing, which can significantly improve the performance of materials, extend the service life of parts, and meet specific engineering needs.