EN36 Case Hardening Steel | AISI 3310 | 15NiCr13

EN36 steel is actually divided into EN36A, EN36B and EN36C, which belong to the Ni-Cr-Mo series of alloy steels as per BS970 standard.

As case hardening steel,EN36 series steel are characterized by high surface hardness,high strength,and soft core without loss of strength. EN36 series steel can also be quenched and tempered to obtain high strength and hardness.

In the field of mechanical engineering, EN36 steel is often used to manufacture mechanical parts with high wear resistance, such as gears, screws, shafts, rollers, etc. In addition, it is often used in aircraft engineering, shipbuilding, railway industry, oil industry and other fields.

Available Types & Range

Form of Supply Size(mm) Length(mm)
Round bar Φ 16 -Φ 140 Standard or As your request
Forged Rounds Φ 140  – Φ 650 Standard or As your request
Forged Flats Thickness : 65 – 450
Width: 130 – 650		 Standard or As your request

EN 36 – ROLLED

Size – 16 mm to 150 mm Dia

Brand – LSRM , JAILAXMI

EN 36 – FORGED ROUND

Size – 140 mm to 670 mm Dia

Brand – Kolkatta& Punjab Main Make

Chemical Composition & Technical Specification EN 36

Grade C Si Mn P S Cr Ni Mo
EN36A ≤0.15 0.1-0.35 0.3-0.6 ≤0.05 ≤0.05 0.6-1.1 3.0-3.75 –
EN36B 0.12-0.18 0.1-0.35 0.3-0.6 ≤0.05 ≤0.05 0.6-1.1 3.0-3.75 –
EN36C 0.12-0.18 0.1-0.35 0.3-0.6 ≤0.05 ≤0.05 0.6-1.1 3.0-3.75 0.10-0.25

EN36 Steel Mechanical Property As Per BS970

Property EN36A EN36B EN36C
Tensile Strength Mpa ≥850 ≥1004 ≥1004
Elongation, % ≥15 ≥13 ≥13
impact,J ≥35 ≥30 ≥30
Forging
Heat to 1150oC and hold until temperature is uniform throughout the section. Soaking time at forging temperature should be as short as possible to avoid heavy scaling and excessive grain growth. This will vary depending on furnace conditions but 15 minutes per 25 mm of section may be used as a guide.Do not forge below 850oC.

Following completion of forging operation, work piece should be cooled as slowly as possible in sand or dry lime etc.
Note: Case hardening steels due to their low carbon content are less susceptable to cracking than medium or high carbon steels, and may therefore be heated and cooled more rapidly.
Heat Treatment
Annealing
Heat to 830oC – 850oC, hold until temperature is uniform throughout the section and cool in furnace.
Carburizing
Pack, salt or gas carburize at 900oC – 950oC, holding for sufficient time to develop the required case depth and carbon content, followed by a suitable hardening and tempering cycle to optimise case and core properties.
Hardening
Refer Refining & Hardening.
Nitriding
EN36A suitably hardened and tempered (uncarburised) will respond to nitriding giving a surface hardness up to Rc 60.Nitriding is carried out at 490oC – 530oC followed by slow cooling (no quench), reducing the problem of distortion.

N.B. The fairly high nickel content in EN36A will result in a lower case hardness, or a longer nitriding cycle than with other alloy grades containing less nickel.
Normalizing – For Improved Machinability
Heat to 880oC – 920oC, hold until temperature is uniform throughout the section. Soak for 10 – 15 minutes and cool in still air.Temper immediately at 650oC – 660oC and air cool.
Refining & Hardening
Core Refine
Slow cool from carburizing temperature and re-heat to 830oC – 880oC, hold until temperature is uniform throughout the section, quench as required in water, oil or air cool. Alternatively quench in salt bath held at 150oC – 250oC, followed by air cool.
Case Hardening
Following core refining, re-heat to 760oC – 800oC, hold until temperature is uniform throughout the section, and quench in oil.Temper immediately while still hand warm.
Single Refine*
Direct Quench: Cool from carburizing temperature to 810 oC – 830 oC, hold until temperature is uniform throughout the section. Quench as required in water, oil or air cool. Alternatively quench in salt bath held at 150 oC – 250 oC, followed by air cool and temper immediately.

Or: Cool from carburizing temperature to room temperature, re-heat to 810 oC – 830 oC and hold until temperature is uniform throughout the section and quench or air cool as previous. Temper immediately.
Note: When air cooling large sections a uniform fan cooling is recommended, especially when direct cooling from carburizing temperature.
*Suitable for fine grained steels only.
Stress Relieving
Heat to 600oC – 650oC, hold until temperature is uniform throughout the section, soak for 1 hour per 25 mm section, and cool in still air.
 
Tempering
Heat to 150oC – 200oC as required, hold until temperature is uniform throughout the section, soak for 1 – 2 hours per 25 mm of section, and cool in still air.N.B.Tempering will improve the toughness of both case and core, with only a slight reduction in core strength and case hardness. It will also reduce the susceptibility of the case to grinding cracks.
Notes on Heat Treatment
Heating temperatures, rate of heating, cooling 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
EN36A in the annealed as supplied condition has very good machinability and all operations such as turning, drilling, milling and tapping etc. can be carried out satisfactorily as per machine manufacturers recommendations for suitable tool type – feeds and speeds.
Welding
EN36A is readily weldable in the annealed as supplied condition. Following welding, the work piece immediately upon cooling to hand warm should be stress relieved at 600oC – 650oC if possible. N.B. Welding in the carburized and heat treated conditions not recommended.
Welding Procedure
Welding of EN36A should always be carried out using low hydrogen electrodes – please consult your welding consumables supplier.
Suggested Pre-heat Temperature
Section 25mm 50mm 75mm 150mm
oC 250 300 350 400
Post Welding
Maximum cooling rate 100oC per hour down to 100oC, followed by cooling in still air.
It is recommended that the work piece if possible is buried in sand or dry lime etc..