Sichuan Liaofu Special Steel Company is one of the most experienced manufacturers and suppliers of din en 20crmo4 1.7321 alloy steel bar in China. With over 20 years' experience, our factory offer high quality products made in China with competitive price. Welcome to contact us for wholesale service.
DIN EN 20CrMo4 1.7321 / AISI 8620 Alloy Steel Bar / Rod
One of the most popular and widely used carborizing steels available. 20MoCr4 is a hardenable chromium, molybdenum, nickel low steelalloy steel often used for carburizing to develop a case-hardened part. This case-hardening will result in good wear characteristics.
Applications
Gears, shafts and other applications where a hard carborized case and a tough core are desired.
SUPPLY RANGE OF 20CrMo4
Dimension: Diameter 4-1600 mm, any length below 16 meters
Delivery Conditions:
- Cold drawn: 4-100 mm
- Peeled: 30-160 mm
- Grinded: 4-600 mm
- Turned: 130-1200 mm
- Hot rolled: 12-320 mm
- Hot forged: 130-1600 mm
Surface: Black, smooth, turned, peeled, grind, polished, oiled and painted surface or other anti-corrosive treatment per customers' requests
End: Beveled, plain end, vanished or plastic caps can be provided if necessary
Annealed or Quenched and tempered provided BK (+C)/ BKW (+LC)/ BKS (+SR)/ GBK (+A)/ NBK (+N)
Standard
ASTM A213; ASTM A335; ASTM A519; ASTM A106; ASTM A29; JIS G3462; JIS G3458; JIS G3444; JIS G4053; DIN17175; DIN1629; DIN2391; GB/9948, GB/6479; GB/T8162; GB/T8163; GB/T 3077; EN 10297; EN 10084; EN 10083; ISO 683/11; IOS 683/10; IOS 683/1
Chemical Requirements, Composition, %
| C | Si | Mn | P | S | Cr | Mo |
| 0.17-0.23 | max 0.4 | 0.7-1.0 | max 0.035 | max 0.035 | 0.3-0.6 | 0.4-0.5 |
Heat Treatment
| Treatment | Temperature | Cooling |
| Case hardening | 880-980oC | Oil (water), hot bath 160-250oC |
| Carburising | 880-980oC | Oil (water), hot bath 160-250oC |
| Direct hardening | 860-900oC | Oil, hot bath 160-250oC |
| Core refining | 860-900oC | Oil, hot bath 160-250oC |
| Core refining | 780-820oC | Oil, hot bath 160-250oC |
| Tempering | 150-200oC | Air |
Machinability
Machining is done prior to carburizing to within as close a tolerance as possible. Finish machining, after heat treatment and/or carburizing, should be at a minimum so as not to impair the hardened case of the part. Machining may be done by conventional means prior to heat treatment - after carburizing machining is usually limited to grinding.
Welding
The alloy may be welded by conventional methods, usually gas or arc welding. Preheating at 200oC is beneficial and subsequent heating after welding is recommended - consult the approved weld procedure for the method used.
Cold working
The alloy may be cold worked in the annealed condition by conventional methods. Cold working, as with machining, should be done to as close a tolerance as possible before heat treatment or carburizing.
| C | Si | Mn | P | S | Cr | Mo |
| 0.17-0.23 | max 0.4 | 0.7-1.0 | max 0.035 | max 0.035 | 0.3-0.6 | 0.4-0.5 |
20CrMo4 - General Mechanical Properties
| Yield Rp0.2 (MPa) |
Tensile Rm (MPa) |
Impact KV/Ku (J) |
Elongation A (%) |
Reduction in cross section on fracture Z (%) |
As-Heat-Treated Condition | Brinell hardness (HBW) |
|---|---|---|---|---|---|---|
| 481 (≥) | 945 (≥) | 33 | 11 | 11 | Solution and Aging, Annealing, Ausaging, Q+T,etc | 443 |
Soft Annealing
Heat to 650-700oC, cool slowly. This will produce a maximum Brinell hardness of 207.
Heat Treatment
| Treatment | Temperature | Cooling |
| Case hardening | 880-980oC | Oil (water), hot bath 160-250oC |
| Carburising | 880-980oC | Oil (water), hot bath 160-250oC |
| Direct hardening | 860-900oC | Oil, hot bath 160-250oC |
| Core refining | 860-900oC | Oil, hot bath 160-250oC |
| Core refining | 780-820oC | Oil, hot bath 160-250oC |
| Tempering | 150-200oC | Air |
Hardenability Diagram
Forging
Hot forming temperature: 1050-850oC.
Machinability
Machining is done prior to carburizing to within as close a tolerance as possible. Finish machining, after heat treatment and/or carburizing, should be at a minimum so as not to impair the hardened case of the part. Machining may be done by conventional means prior to heat treatment - after carburizing machining is usually limited to grinding.
Welding
The alloy may be welded by conventional methods, usually gas or arc welding. Preheating at 200oC is beneficial and subsequent heating after welding is recommended - consult the approved weld procedure for the method used.
Cold working
The alloy may be cold worked in the annealed condition by conventional methods. Cold working, as with machining, should be done to as close a tolerance as possible before heat treatment or carburizing.
Payment & Delivery
1. Both T/T and L/C will be acceptable
2. Trade Terms: FOB, CIF, CFR
3. The delivery will be in 10-15 days if have stock; For customized items, the delivery will be negotiated by both parties
4. Shipping by sea freight from Shanghai Port (PRC) for Bulk orders, by airfreight or express for samples
Our Services
What we can offer?
- We offer a wide range of steel products in a wide variety of dimensions and executions, according to the common international specifications or customize.
- Machining and heat treatment are available.
- Also, we advise you in choosing the right materials.
FAQ
Q: What is your minimum order quantity for 20CrMo4 steel bar? Can I order just one bar for a trial?
A: For standard sizes in stock, we can supply a single bar or cut a short piece. For custom sizes or forged material, the minimum is usually 500 kg. Tell us the diameter and length you need, and we will confirm the smallest practical order.
Q: Is 20CrMo4 equivalent to AISI 8620? Can I use them interchangeably?
A: They are similar carburizing steels, but not identical. 8620 contains nickel, while 20CrMo4 does not. For many gears and shafts, they can be substituted, but you should check hardenability and core properties for your section size. We supply both grades and can provide comparison data if needed.
Q: Are you a factory or a trading company? Where does the material come from?
A: We are a trading company working with qualified mills. We source from producers that meet DIN, ASTM, and GB standards, and we keep regular stock in our warehouse. Every shipment comes with a mill test certificate showing the actual heat number and chemistry.
Q: What is the length tolerance if you cut the bars to my size?
A: Our standard cut length tolerance is +5/-0 mm. If you need tighter, we can discuss. Deburring is included. For bars longer than 6 meters, we recommend a small allowance for handling. Please include your length and quantity in the inquiry.
Q: What surface hardness can I expect after carburizing and hardening?
A: After carburizing at 880–980°C and quenching, surface hardness typically reaches 58–62 HRC, depending on case depth and tempering. Core hardness depends on section size and quench speed. We can share reference data from the mill for your specific diameter.
Q: Do you provide samples? Are they free or charged?
A: We can provide small samples free of charge, but you pay the freight. For larger pieces or custom cuts, we charge the material cost. Tell us your required size and quantity, and we will quote the sample cost and lead time.
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