ENGINEERING STEELS + ALLOYS
4140 High Tensile Steel Hollow Bar |
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| 4140 is a 1% chromium - molybdenum medium hardenability general purpose high tensile steel - generally supplied hardened and tempered in the tensile range of 860 - 1130 Mpa. Brinell hardness range 265 - 330 (Rc 28 - 36).Characterised by high strength and good impact properties with good machinability, but low weldability.Pre hardened and tempered 4140 can be further surface hardened by flame or induction hardening and by nitriding.
4140 is used extensively in most industry sectors for a wide range of applications utilising it's considerable savings on weight and machining time over solid bar. Typical applications are: Bearings, Bushes, Cylinders (Various), Gears, Conveyor Rolls, Hydraulic Shafts, Hollow Shafts, Hollow Parts (Various), Nuts and Rings. |
| Colour Code | Stocked Sizes | |
| ISO Hollow Bar Dark Blue (Bar end)  EN Hollow Bar Light Blue (Bar end)  |
ISO Stocked Sizes Chart (pdf) | 56 mm to 250 mm OD |
| EN Stocked Sizes Chart (pdf) | 65 mm to 230 OD | |
| Bar Finish | ||
| Cold Rolled and Hot Rolled | ||
| Related Specifications | |
| Germany | DIN 17212 W.Nr 1.7223 Type 41CrMo4 DIN 17200-1654 W.Nr 1.7225 Type 42CrMo4 |
| Japan | JIS G 3441 SCM 440 TK |
| USA | AISI 4140 ASTM A519-96 4140 SAE 4140 UNS G 41400 |
| Chemical Composition (Base Material) | ||||||||||
| Min. % | Max % | |||||||||
| Carbon | 0.38 | 0.43 | ||||||||
| Silicon | 0.15 | 0.04 | ||||||||
| Manganese | 0.75 | 1.00 | ||||||||
| Chromium | 0.80 | 1.10 | ||||||||
| Molybdenum | 0.15 | 0.25 | ||||||||
| Phosphorous | 0 | 0.04 | ||||||||
| Sulphur | 0 | 0.015 | ||||||||
| Mechanical Property Requirements for 4140 Hollow Bar As Supplied, Black Hot Rolled Finish - Hardened and Tempered Condition |
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| Tensile Strength Mpa (Min) | 862 | |||||||||
| Yield Strength Mpa Min | 758 | |||||||||
| Elongation on % Min. | 14 | |||||||||
| Hardness RC | Min | 28 | ||||||||
| Max | 36 | |||||||||
| Typical Mechanical Properties for 4140 Hollow Bar As Supplied, Black Hot Rolled Finish - Hardened and Tempered Condition |
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| Tensile Strength Mpa (Min) | 1000 | |||||||||
| Yield Strength Mpa Min | 900 | |||||||||
| Elongation on % Min | 16 | |||||||||
| Hardness | HB | 300 | ||||||||
| Rc | 33 | |||||||||
| Forging | ||||||||||
| Heat to 1150 oC - 1200 oC maximum, hold until temperature is uniform throughout the section. Do not forge below 850 oC.Following forging operation the work piece should be cooled as slowly as possible. |
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| Heat Treatment | ||||||||||
| Annealing | ||||||||||
| Heat to 800 oC - 850 oC, hold until temperature is uniform throughout the section and cool in furnace. | ||||||||||
| Flame or Induction Hardening | ||||||||||
| 4140 hardened and tempered bar can be further surface hardened by either the flame or induction hardening methods resulting in a case hardness in excess of Rc 50.The black hot rolled surface will first require to be machined sufficiently to remove any decarburised layer otherwise less than satisfactory results will be obtained.Parts should be heated as quickly as possible to the austenitic temperature range (840 oC - 870 oC) and required case depth followed by an immediate oil or water quench, depending upon hardness required, workpiece size/shape and quenching arrangements.
Following quenching to hand warm, most components should be stress relieved to remove quenching stresses in the case. |
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| Hardening | ||||||||||
| Heat to 840 oC - 875 oC, hold until temperature is uniform throughout the section, soak for 10 - 15 minutes per 25 mm section, and quench in oil, water, or polymer as required.*Temper immediately while still hand warm. | ||||||||||
| Nitriding | ||||||||||
| 4140 hardened and tempered bar can also be successfully nitrided, giving a surface hardness of up to Rc 60. 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 allowance only. The tensile strength of the core is usually not affected since the nitriding temperature range is generally below the original tempering temperature employed. | ||||||||||
| Normalizing | ||||||||||
| Heat to 870 oC - 900 oC, hold until temperature is uniform throughout the section, soak for 10 - 15 minutes and cool in still air. | ||||||||||
| Stress Relieving | ||||||||||
| Heat to 680 oC - 700 oC, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm section, and cool in still air. | ||||||||||
| Tempering | ||||||||||
| Re-heat to 550 oC - 700 oC as required, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm of section, and cool in still air. | ||||||||||
| Note | ||||||||||
| Heating temperatures, rate of heating and soaking times will vary due to factors such as work piece size/shape also furnace type employed, quenching medium and work piece transfer facilities etc..Please consult your heat treater for best results. | ||||||||||
| Machining | ||||||||||
| 4140 in the hardened and tempered as supplied condition has good to very good machinability and operations such as sawing, turning, drilling, broaching, hobbing, milling and tapping can be carried out satisfactoraly using machine manufacturers recommendations for suitable tool type - feeds and speeds. | ||||||||||
| Welding | ||||||||||
| Welding of 4140 in the hardened and tempered condition (as normally supplied), is not recommended and should be avoided if at all possible, as the mechanical properties will be altered within the weld heat affected zone. It is preferred that welding be carried out on 4140 while in the annealed condition, and that the work piece, immediately on cooling to hand warm, is then stress relieved at 595 oC - 620 oC prior to hardening and tempering.If welding in the hardened and tempered condition is really necessary, then the work piece, immediately on cooling to hand warm, should be if possible stress relieved at 15 oC below the original tempering temperature (if known). | ||||||||||
| Welding Procedure | ||||||||||
| Welding of 4140 in whatever condition should always be carried out using low hydrogen electrodes - please consult your welding consumables supplier. | ||||||||||
| Suggested pre-heat temperature | ||||||||||
| Section | 25mm | 40mm | 50mm | 75mm | 150mm+ | |||||
| oC | 370 | 400 | 425 | 455 | 510 | |||||
| Post Welding | ||||||||||
| Maximum cooling rate 95 oC per hour down to 95 oC, follow by cooling in still air. N.B. No draught. It is recommended that the work piece if possible is wrapped in an heat resistant blanket or buried in sand etc.. | ||||||||||
Interlloy believes the information provided is accurate and reliable. However no warranty of accuracy, completeness or reliability is given, nor will any responsibility be taken for errors or omissions.
