20NiCrMo2-2 Alloy Steel DIN 1.6523

Description

20NiCrMo2-2 Alloy Steel is a low carbon nickel chromium molybdenum alloy steel. And it is low-cost steel with good carburized properties. 20NiCrMo2-2 steel has half of the Nickel content and added a small amount of Molybdenum element. DIN 1.6523 steel also improves the content of Manganese, so it has better hardenability and strength than 18NiCr5-4. 20NiCrMo2-2 is suitable for parts which require good toughness and wear resistance.
The nickel content contributes to case toughness at high strength with above average core toughness. The chromium and molybdenum support the proper formation of carbides resulting in good surface hardness and wear. It is the most widely used carburizing alloy.

20NiCrMo2-2 Alloy Steel

Equivalent Grade of 20NiCrMo2-2 Alloy Steel

DIN ASTM JIS EN
1.6523 8620 SNCM220 20NiCrMo2-2

20NiCrMo2-2 Alloy Steel Chemical Composition

Steel Grade C Mn Si P S Cr Ni Mo
8620 0.18-0.23 0.70-0.90 0.15-0.35 0.030 max 0.040 max 0.40-0.60 0.40-0.70 0.15-0.25
20NiCrMo2-2 0.17-0.23 0.65-0.95 0.40 max 0.030 max 0.030 max 0.35-0.70 0.40-0.70 0.15-0.25
SNCM220 0.18-0.23 0.60-0.90 0.15-0.35 0.030 max 0.040 max 0.40-0.65 0.40-0.70 0.15-0.30

Mechanical Property

Typical Mechanical Properties For Core – Carburised and Oil Quenched at 840 °C

Section Size 11mm 30mm 63mm
Tensile Strength Mpa 980-1270 780-1080 690-930
Yield Strength Mpa ≥785 ≥590 ≥490
Elongation % ≥9 ≥10 ≥11
Charpy Impact J ≥41 ≥41 ≥41
Hardness HB 290-375 235-320 205-275
Hardness HRC 31-41 23-35 16-29

Heat Treatment

This 20NiCrMo2-2 Alloy Steel may be hardened by heating to 1500F followed by a water quench. Carburize at 1650F to 1700F in an appropriate carburizing medium and oil quench to harden. Improved carburized case and core properties can be obtained by furnace cooling from carburizing at 1650F-1700F and then reheating to 1575F

Annealing:
8620 gear steel may be given a full anneal at 1550F and slow cooling at not more than 50F per hour down to 850F. From there it may be air cooled.

Hardening:
Hardening is done by oil quench from 1675F. Carburizing is accomplished at the same 1650F-1700F range in a carburizing “pack” or environment, followed by oil quench for thin sections or a furnace cool for heavier (over 3/4″) sections. Following carburizing of heavy sections a reheat at 1575F will enhance both case and core properties of the alloy.

Tempering:
Tempering is usually carried out to relieve stresses from the hardening process,it will improve the toughness of both case and core, with only a little reduction in core strength and case hardness.Heat the AISI 8620 steel to 150oC – 200oC as required, hold enough time until temperature is uniform throughout the section, soak for 1 – 2 hours per 25 mm of section, and cool in still air.

Application

20NiCrMo2-2 Alloy Steel is a good choice for a variety of applications. Carburized 20NiCrMo2-2 Alloy Steel is strong and durable and as a result is preferred in certain manufacturing applications. It is used to make a wide range of gears, crankshafts, gear rings, pinions, piston pins, cams, gauges, tie bars, collets, bushings and bolts as well as hand tools and a multitude of machinery parts and components. Structural parts such as gears, pinions, spline shafts, pins and a variety of other important applications requiring a hard wear surface and a ductile core.

Contact

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