| 20MnV6 Hollow Bar |
| 20MnV6 is a carbon-manganese steel micro alloyed with vanadium, generally supplied in the black hot rolled condition with a typical tensile strength range of 600 - 790 Mpa and a high typical yield strength range of 440 - 570 Mpa.
Characterized by excellent machinability due to silicon - calcium treatment and precise control of the sulphur content, excellent weldability with high yield and tensile strengths due to the micro - alloying effect of the vanadium.
The low carbon content and the vanadium addition allows surface hardening by carburising, carbonitriding or nitriding. It will also respond to high or medium frequency induction hardening and can be through hardened and tempered producing a moderate improvement in tensile and yield strength, this varying depending upon wall thickness.
20MnV6 hollow bar is used extensively by all industry sectors for a wide range of applications utilizing it's considerable saving on machining time and weight over solid bar.
Typical applications are: Bushes, Cylinders Various, Conveyor Rolls, Hollow Shafts, Hollow Parts and components, Nuts, Rings, etc.
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Colour Code
 |
ISO Hollow Bar
Yellow Bar end |
 |
EN Hollow Bar
Magenta Bar end |
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ISO Stocked Sizes
ISO Chart (pdf)
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32 mm to 660 mm OD |
| EN Stocked Sizes
EN Chart (pdf)
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30 mm to 250 mm OD
More Euro Norm Information
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| Bar Finish |
Cold Rolled and Hot Rolled |
| Related Specifications |
| |
Europe |
EN 10294-1 |
| France |
NF A49312 20MV6 |
| Germany |
W.Nr 1.5217 20MV6
W.Nr 1.8905 StE 460 |
| Great Britain |
BS4360 GR 55 |
| USA |
UNS K01907 and K12202 |
| Chemical Composition |
Min. % |
Max. % |
| |
Carbon |
0.16 |
0.22 |
| Silicon |
0.10 |
0.35 |
| Manganese |
1.30 |
1.60 |
| Vanadium |
0.08 |
0.15 |
| Phosphorous |
0 |
0.03 |
| Sulphur |
0.02 |
0.04 |
| Mechanical Property Requirements - As Supplied in the Black Hot Rolled Condition |
Tensile Strength
Mpa Min.
Wall Thickness (mm)
<16 <25 >25 |
0.2% Yield Strength
Mpa Min.
Wall Thickness (mm)
<16 <25 <30 <40 <50 <70 |
Elongation
5.65 % Min. |
Hardness
Brinell Min. |
|
| 620 610 550 |
470 460 430 420 410 400 |
18 |
180 |
| Typical Mechanical Properties - As Supplied in the Black Hot Rolled Condition |
| |
Tensile
Strength
Mpa |
Yield
Strength
Mpa |
Elongation
% |
Hardness
HB |
|
| 690 |
500 |
21 |
210 |
| Typical (Minimum) Mechanical Properties - Water Quenched at 925 oC and Tempered at 580 oC. |
Tensile Strength
Mpa
Wall Thickness (mm)
<20 <25 <30 |
0.2% Yield Strength
Mpa
Wall Thickness (mm)
<20 <25 <30 |
Elongation
%
Wall Thickness
<20 >20 |
Impact
+20oC 0oC -20oC
J |
Hardness
HB |
| 750 700 650 |
650 620 570 |
16 17 |
40 32 28 |
220 |
| Heat Treatment |
| 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.
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| 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.
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| Case Hardening |
Water quench from 760 oC - 780 oC.
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| 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.
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| 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.
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| 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.
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| 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.
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| Normalizing |
Heat to 900 oC - 925 oC, hold until temperature is uniform throughout the section, soak for 30 minutes and cool in still air.
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| Stress Relieving Following Welding |
Heat the weld area to 550 oC - 650 oC, soak for 30 minutes and cool in still air or furnace.
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| 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.
Please consult your heat treater for best results.
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| Machining |
20MnV6 has excellent machinability due to the silicon - calcium treatment and precise control of the sulphur content resulting in an excellent break-up of swarf, increasing feeds and speeds plus an increase in tool life for all machining operations.
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| Welding |
20MnV6 due to it's low carbon content has excellent weldability and may be welded by all of the standard welding processes.
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| Welding Procedure |
| A pre-heat or post heat is not generally required, however a post weld stress relieve can be beneficial if this is possible as can pre-heating larger sections.
For suitable welding electrodes please consult your welding consumables supplier.
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