Needle Roller Bearings · ISO 1206 / DIN 617 / GB/T 5801
Case-Hardened 20CrMnTi NA49 Series Machined Ring Needle Roller Bearings
Grade, hardness, corrosion behavior, service temperature and the full bore range for this material.
Case-Hardened 20CrMnTi NA49 Series Machined Ring Needle Roller Bearings are made from 20CrMnTi (GB/T 3077), of the same class as 20MnCr5 and SAE 8620 — carburized to a hard case over a tough, unhardened core. Corrosion behavior: none of its own; protected in service exactly as through-hardened bearing steel is. The material is magnetic, and the usable service range is similar to through-hardened rings — about +120 °C without special stabilization. In practice this material is chosen for shock loading and for heavy ring sections, where a tough core resists the cracking a fully through-hardened section would not survive.
Material
20CrMnTi (GB/T 3077), of the same class as 20MnCr5 and SAE 8620 — carburized to a hard case over a tough, unhardened core
Corrosion resistance
None of its own; protected in service exactly as through-hardened bearing steel is
Magnetic response
Magnetic
Service temperature
similar to through-hardened rings — about +120 °C without special stabilization
Property figures are typical for the material. In an assembled bearing the lubricant, the seals and the cage frequently reach their limits before the material does, so check all four against the duty. Material certification is available on request for production orders.
Case-Hardened 20CrMnTi NA49 Series Machined Ring Needle Roller Bearings: Chosen for shock loading and for heavy ring sections, where a tough core resists the cracking a fully through-hardened section would not survive. The material decides the corrosion behavior — none of its own; protected in service exactly as through-hardened bearing steel is and the temperature the part will stand (similar to through-hardened rings — about +120 °C without special stabilization), and it is the reason the alternatives below exist. Properties, limits and the full size table follow.
Why Case-Hardened 20CrMnTi for NA49 Series Machined Ring Needle Roller Bearings
Chosen for shock loading and for heavy ring sections, where a tough core resists the cracking a fully through-hardened section would not survive. In a na49 series machined ring needle roller bearings it is the steel of the rings and, in most designs, of the rolling elements.
Carburizing puts the hardness where the rolling contact is and leaves the core tough, so the ring can absorb shock and heavy section stresses that would crack a through-hardened ring. It is the usual choice for large roller bearing rings and for anything that gets hit rather than merely loaded.
Material Properties
Grade designation
20CrMnTi (GB/T 3077), of the same class as 20MnCr5 and SAE 8620 — carburized to a hard case over a tough, unhardened core
Magnetic response
Magnetic
Service temperature
Similar to through-hardened rings — about +120 °C without special stabilization
Corrosion characteristic
None of its own; protected in service exactly as through-hardened bearing steel is
Service Limits
The case has a depth, and that depth is a design limit: load high enough and the maximum shear stress moves below the hardened case into the softer core, where the surface then collapses. That is why case depth is specified against the rolling element size and the load, and why a case-hardened ring is not simply a tougher version of a through-hardened one.
Alternatives and When to Switch
Through-hardened GCr15 is the alternative and the default: it is used wherever the section is modest and the load is steady, which is most of the catalog. Case-hardened rings earn their place under shock and in large sections.
Sizes of NA49 Series Machined Ring Needle Roller Bearings Available in Case-Hardened 20CrMnTi
Designation
Bore d (mm)
Outer diameter D (mm)
Width B (mm)
NA4900
10
22
13
NA4901
12
24
13
NA4902
15
28
13
NA4903
17
30
13
NA4904
20
37
17
NA4905
25
42
17
NA4906
30
47
17
NA4907
35
55
20
NA4908
40
62
22
NA4909
45
68
22
NA4910
50
72
22
NA4911
55
80
25
NA4912
60
85
25
NA4913
65
90
25
NA4914
70
100
30
NA4915
75
105
30
NA4916
80
110
30
NA4917
85
120
35
NA4918
90
125
35
NA4919
95
130
35
NA4920
100
140
40
NA4922
110
150
40
NA4924
120
165
45
NA4926
130
180
50
Other ways to specify the NA49 Series Machined Ring Needle Roller Bearings
Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the designation snaps the other fields to that size's standard values; you can then override any individual value.
Sends the selected values to the quote form below.
Our facility
Where these dimensions are actually made
Ring forging, heat treatment, raceway grinding and superfinishing all happen under one roof, so a bore tolerance and a clearance group are set by processes we control and can evidence, not by whichever supplier had stock.
Request a Quote
The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.
Dimensions & Specifications (ISO 1206 / DIN 617 / GB/T 5801)
Designation
Bore d (mm)
Outer diameter D (mm)
Width B (mm)
NA4900
10
22
13
NA4901
12
24
13
NA4902
15
28
13
NA4903
17
30
13
NA4904
20
37
17
NA4905
25
42
17
NA4906
30
47
17
NA4907
35
55
20
NA4908
40
62
22
NA4909
45
68
22
NA4910
50
72
22
NA4911
55
80
25
NA4912
60
85
25
NA4913
65
90
25
NA4914
70
100
30
NA4915
75
105
30
NA4916
80
110
30
NA4917
85
120
35
NA4918
90
125
35
NA4919
95
130
35
NA4920
100
140
40
NA4922
110
150
40
NA4924
120
165
45
NA4926
130
180
50
Video: Case-Hardened 20CrMnTi NA49 Series Machined Ring Needle Roller Bearings
Third-party video, selected automatically for this topic. It is not produced by Bushing Bearings and is not a specification source — use the tables on this page for dimensional data.
Frequently Asked Questions
Can a standard bearing run above 120 °C?
Not without being ordered for it. Standard rings are heat stabilized for use to about +120 °C; above that they grow and lose their fit unless a stabilized version is specified. The grease, the seals and a polymer cage usually reach their limits at or below that temperature too.
Are Case-Hardened 20CrMnTi NA49 Series Machined Ring Needle Roller Bearings magnetic?
Case-Hardened 20CrMnTi is magnetic.
What temperature can Case-Hardened 20CrMnTi NA49 Series Machined Ring Needle Roller Bearings run at?
The usable range for the material is similar to through-hardened rings — about +120 °C without special stabilization. In an assembled bearing the lubricant, the seals and the cage frequently give out before the material does, so check all four against the duty.
What corrosion resistance does Case-Hardened 20CrMnTi give?
Corrosion behavior: none of its own; protected in service exactly as through-hardened bearing steel is.
How do I request a quotation?
Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.
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