Application：

Tubular parts for the automotive, oil and gas, construction, general engineering and agricultural industry, such as bushes, hydraulic cylinders, hollow shafts, rings, hollow rolls for conveyors, nuts, gear wheels, shafts, axles, stuffing boxes, spindles, drill jigs, rolls etc.

Standard:

1. BS EN10294 Hollow bars
2. BS 6258 Hollow Steel Bars for Machining

Steel Grades:

1. EN10294: E470
2. BS6258: Grade 600

Sizes Range:

OD10.2mm-810mm, WT: 1.6mm-100mm

Cooperated Enterprise

USA: AARIS LLC ; NOV GRANT PREDECO ; NATIONAL TUBE SUPPLY

JAPAAN: SUMITOMO CORPORATION ; SC PIPE SOLUTIONS CO LTD

KOREA: ILJIN STEEL CORPORATION ; YCP CO LTD ; GOOD FORTUBE ; DY POWER

ITALY: INTERPUMP GROUPS.P.A

INDONESIA: PT. BAJAINDO ERAPRIMA

CHINA: XCMG ; Sany ; Zoomlion ; Liugong

Chemical Composition(%):

Grades	C	Si	Mn	P	S	V	Al	N	Nb
20MnV	0.17-0.24	0.17-0.37	1.30-1.60	0.025 max	0.025 max	0.07-0.12	0.10 min	0.020 max	0.07 max
E470	0.18-0.22	0.10-0.50	1.30-1.70	0.03 max	0.015-0.030	0.08-0.15	0.10 min	0.020 max	0.07 max
Grade 600	0.22 max	0.50 max	1.60 max	0.05 max	0.05 max	0.08-0.12	0.02 min	/	/

Outer Diameter Tolerances

+/-1%, or +/-0.5mm (Chose the bigger one)

Wall Thickness Tolerances

Scope of Outer Diameter	Ratio of Wall Thickness and Outer Diameter (WT/OD)	Tolerance
102mm max	/	+/12.5% or +/-0.4mm (Chose the bigger one)
102mm min	0.05 max	+/15% or +/-0.4mm (Chose the bigger one)
102mm min	0.05-0.10	+/12.5% or +/-0.4mm (Chose the bigger one)
102mm min	0.10 min	(-10%, +12.5%)

Delivery Conditions

1. Hot Rolled only.
2. Stress Relieved.
3. Annealed.
4. Normalized.
5. Quenched and Tempered.

Surfaces Conditions

1. Black surface with oxygen skin.
2. Grinded for external or internal surface, or external and internal surface.
3. Peeled for external or internal surface, or external and internal surface.

Mechanical Properties(T=20°C if not differently stated)

Wall Thickness (mm)	Tensile Strength (Mpa)	Yield Strength(Mpa)	Elongation A5 (L) (%)
16 max	650 min	470 min	17 min
16-25	620 min	460 min	17 min
25-40	600 min	430 min	17 min
40-50	550 min	430 min	17 min

Surface Hardening Treatments:

Carbonitriding:

Heat to 870 oC – 880 oC in a gaseous media consisting of carbon monoxide/hydrocarbon plus ammonia, hold for sufficient time to develop the required case depth, carbon and nitrogen content, followed by quenching in oil or water as required. Typical case hardness achieved up to Rc 60. Tempering immediately while still hand warm at 150 oC – 200 oC will reduce stresses and improve the toughness of the case.

Carburising:

Pack, salt or gas carburise at 880 oC – 920 oC, holding for sufficient time to develop the required case depth and carbon content, followed by a suitable heat treatment cycle to optimise case and/or core properties.Typical case hardness achieved up to Rc 63.

Case Hardening:

Water quench from 760 oC – 780 oC or Core Refining

Oil quench from 870 oC – 880 oC prior to water quench as above.

Tempering immediately following water quench at 150 oC – 200 oC will reduce stresses and improve toughness of case.High or Medium Frequency Induction.

Hardening:

The black hot rolled surface on 20MnV6 Hollow Bar will first require to be machined sufficiently to remove any de-carburised layer otherwise less than satisfactory results will likely be obtained. The feed material can be either in the as supplied condition or pre hardened and tempered for higher core strength.

Heat to the austenitic temperature range (870 oC – 925 oC), and required case depth, quench immediately in oil or water as required. Typical case hardness achieved up to Rc 48.

Tempering immediately at 150 oC – 200 oC will reduce stress and improve the toughness of the case.
Nitriding:

20MnV6 either in the as supplied condition, or pre-hardened and tempered for higher core strength will respond successfully to nitriding due to the vanadium content. Typical case hardness achieved up to Rc 55.

Nitriding is carried out at 490 oC – 530 oC followed by slow cooling (no quench) reducing the problem of distortion.

Parts can therefore be machined to near final size, leaving a grinding tolerance only.

If pre-hardened and tempered feedstock is used always ensure that the tempering temperature employed is at least 15 oC above the nitriding temperature.The tubes are protected internally and externally with oil, which provides temporary protection against oxidisation when undercover.

Pipe Body Heat Treatment:

Hardening:

Heat to 870 oC – 925 oC as required, hold until the temperature is uniform throughout the section, soak 10 – 15 minutes per 25mm of section and quench in oil or water as required.Temper immediately while still hand warm.
Tempering: Re heat to 500 oC – 600 oC as required, hold until temperature is uniform throughout the section, soak for 1 hour per 25mm of section. Cool in still air.

Normalizing:

Heat to 900 oC – 925 oC, hold until temperature is uniform throughout the section, soak for 30 minutes and cool in still air.

Stress Relieving:

Heat the weld area to 550 oC – 650 oC, soak for 30 minutes and cool in still air or furnace.
*Notes on Heat Treatment: Heating temperatures, rates of heating, cooling and soaking times will vary due to factors such as work piece size/shape, also furnace type employed, quenching medium and workpiece transfer facilities etc.

Welding:

Excellent weldability as supplied but welding not recommended when surface hardened or through hardened.
Apre-heat or post-heat required however, pre-heating larger sections can be beneficial as can a post-weld stress relieve. (Ave. Ceq = 0.50)

Surfaces Protection:

The tubes are protected internally and externally with oil, which provides temporary protection against oxidisation when undercover.

Tube ends:

The hollow bar comes with square cut and deburred ends.

Certification:

The hollow bar is supplied with 3.1.B inspection certificate,according to the standards EN 10204 and ISO 10474.

Identification and Marking:

The hollow bar is marked in indelible ink, the details being repeated along the entire length of each tube and on a label, as follows:
Manufacturer’s trademark – manufacturing standard – dimensions -steel grade – supply condition – cast no. – item number.

Packaging:

The hollow bar comes in strapped bundles. The minimum weight of each bundle is 2000kg; the maximum bundle weight being 5000kg, with a minimum of 4 pieces