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Nitroglycerin steel                                                                       .

EN31 is a high carbon Alloy steel which achieves a high degree of hardness with compressive strength and abrasion resistance.

Chemical Composition

Forge at 1000°/1050°C. Heat slowly, allowing sufficient time at the forging temperature for the steel to be thoroughly soaked through. Re-heat as often as necessary to keep the temperature above 850°C. After forging cool very slowly, preferably in a furnace.

Heat uniformly to 800°C, equalize, then furnace cool. (Hardness about 229 Brinell).

If machining operations have been heavy or if the tool has an unbalanced section, remove stresses before hardening by heating up to 700°C, equalize, then cool slowly.

Heat uniformly to 800/820°C until heated through. Allow 30 minutes per inch of ruling section and quench immediately in oil.

Heat uniformly and thoroughly at the selected tempering temperatures and hold for at least one hour per inch of total thickness

DIN 41Cr4 and DIN 42Cr

DIN 41Cr4 and DIN 42CrMo4 materials have been widely used in automotive driving elements. Although 42CrMo4 is more expensive than 41Cr4, it is more preferable in terms of material properties. In this study, these two materials were heat treated by austenitizing in a continuous furnace at 850 °C and quenched in oil at 90 °C. After they were tempered at various temperatures, mechanical properties were determined for each tempering temperature. The material properties for both materials were compared with each other.

Heat Treatment:

• Forging:Heat to 1150°C Hold until uniform.Minimum forging temperature 850°C.Cool slowly in ashes or sand etc.
• Annealing:Heat to 830°C – 850°C. Cool in furnace.
• Normalising:Heat to 870°C – 900°C. Cool in still air.

Heat to 1150°C Hold until uniform.Minimum forging temperature 850°C.Cool slowly in ashes or sand etc.

Heat to 830°C – 850°C. Cool in furnace.

Heat to 870°C – 900°C. Cool in still air.

Readily welded in the annealed condition but avoid when possible if hardened and tempered due to the effect on the mechanical properties. Welding in the nitrided, flame or induction hardened condition is not recommended.

BS970: 1955 EN24, BS970/PD970: 1970 onwards 817M40. Related European grades: 34CrNiMo6, Werkstoff No. 1.6582 US Grade: SAE (AISI) 4340.EN24 is usually supplied in the finally heat treated condition (quenched and tempered to “T” properties) up to a limiting ruling section of 250mm, which is superior to grades 605M36, 708M40 or 709M40 – see properties below. Please refer to our selection guide for comparisons
EN24 is a very popular grade of through-hardening alloy steel, which is readily machinable in the “T” condition. (Refer to our machinability guide). EN24T is most suitable for the manufacture of parts such as heavy-duty axles and shafts, gears, bolts and studs. EN24T can be further surface-hardened typically to 58-60 HRC by induction or nitride processes, producing components with enhanced wear resistance.

In addition to the above, EN24T is capable of retaining good impact values at low temperatures, hence it is frequently specified for harsh offshore applications such as hydraulic bolt tensioners and shipborne mechanical handling equipment.

• En 353 steel has carbon content of 0.17% and the most common form of steel as it’s provides material properties that are acceptable for many automobile applications such as heavy duty gear, shaft, pinion, cam shafts, gudgeon pins [1,8]. It is neither externally brittle nor ductile due to its lower carbon content and lower hardness. As the carbon content increases, the metal becomes harder and stronger.

• In order to ensure the material of the specimen is done with help of the optical emission spectroscope (OES). The result is obtain from the chemical analysis, carbon – 0.171 %, silicon – 0.3 %, manganese – 0.56 %, phosphorus – 0.012 %, sulphur – 0.13 %, Chromium – 0.953 %, Nickel – 0.989 %, molybdenum – 0.16 % and remaining percentage is iron respectively. A sample of 30 × 10 mm is polished using 60 grit papers and two sparks is introduced on the surface to find the chemical composition of the material. After ensuring the chemical composition, the raw material is machined according to the dimension for various tests [3]

• Machining components, Gears.

• Vickers hardness measurement is done on the specimen as per the IS 1501-2002 procedures by using Vickers hardness tester (MH6). Hardness measurement is made with 200 g loads, dwell time of 10 seconds and diamond indenter is used for test. The impression is done on the circular faces at the centre of the specimen. The hardness values are taken corresponding to the diagonal length of the indentation. Two samples (i.e. BHT and AHT) and five readings are taken from the each sample from case to core. The average value is calculated from five readings. The hardness values of BHT (case and core) samples are, 193.7 and 201.8 HV respectively. The hardness values of AHT (case and core) samples are 684.5 and 387.8 HV respectively. It is clearly noticed that the base material (BHT) has the low hardness. 

• X-Ray Diffractometer is one of the most powerful techniques for material structural analysis. Bruker AXS D8 Advance X-Ray diffractometer fit with vertical goniometers, low and high temperature attachment. The angle range is 360°, the maximum usable angular is 3° to 135° and wavelength is 1.5406 Å. X-ray diffraction analysis is carried out under the following condition: Cu radiation, 40 KV voltage, 35 mA current and maximum angular speed 30°/s. 

• CARBURISING Pack, salt or gas carburize at 910C, holding for sufficient time to develop the required case depth and carbon content, Slow cool from carburizing temperature and re-heat to 870C, hold until temperature is uniform throughout the section, quench as required in water, oil or air cool.

• Re-heat to 780C – 820C, hold until temperature is uniform throughout the section, and quench in oil,Temper immediately while still hand warm. Heat to 150C – 200C as required, Soak for 1 – 2 hours per 25mm of section, and cool in still air.

• EN36C gives a hard case with a strong core, whilst retaining a remarkable degree of toughness.

• As a carburizing steel grade it is suitable for roller and ball bearings of extra light section, aero plane and motor crankshafts requiring hard surfaces for roller paths, connecting rods with case-hardened ends, as well as highly stressed gudgeon pins, gears and certain types of collets.

• Case hardening will give a hard wear resisting surface and tough core strength to the steel. Case hardening temperatures range from 860-960°C, followed by rapid quenching which will determine the resulting hardness.

• Case hardening will give a hard wear resisting surface and tough core strength to the steel. Case hardening temperatures range from 860-960°C, followed by rapid quenching which will determine the resulting hardness.

• For optimum toughness temper at low temperatures for a minimum of 2 hours. The case hardness should be in the region of 60-62HRc.

• If it is necessary to soften the EN36 for machining between the carburising and subsequent heat treatment stages, heat to 640-650°C. Soak at this temperature for 1 to 2 hours and cool slowly in the furnace or in air.

• Heat treatment temperatures, including rate of heating, cooling and soaking times will vary due to factors such as the shape and size of each EN36 steel component. Other considerations during the heat treatment process include the type of furnace, quenching medium and work piece transfer facilities. Please consult your heat treatment provider for full guidance on heat treatment of EN36 case hardening steel.