N9E, U9A, C85W, 1.1830, У9А - Carbon tool steel for deep and low hardening
Table of content:
| Standard | Grade | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chemical composition % | |||||||||||||||
| C: | Si: | Mn: | P: | S: | Cr: | Ni: | Cu: | ||||||||
| ISO | C90U - 1.1535 | ||||||||||||||
| 0.85-0.95 | 0.15-0.3 | 0.15-0.4 | <0.030 | <0.030 | - | - | - | ||||||||
| DIN | C85W - 1.1830 | ||||||||||||||
| 0.8-0.9 | 0.1-0.3 | 0.1-0.35 | <0.030 | <0.030 | - | - | - | ||||||||
| PN | N9 | ||||||||||||||
| 0.85-0.94 | 0.15-0.35 | 0.15-0.35 | <0.030 | <0.030 | <0.2 | <0.25 | <0.25 | ||||||||
| STAS | OSC 8M | ||||||||||||||
| 0.8-0.9 | 0.15-0.35 | 0.35-0.80 | <0.030 | <0.025 | <0.2 | <0.25 | <0.25 | ||||||||
| GOST | U9A - У9А | ||||||||||||||
| 0.85-0.94 | 0.17-0.33 | 0.17-0.28 | <0.025 | <0.018 | <0.2 | <0.25 | <0.25 | ||||||||
| BS | BW1 | ||||||||||||||
| 0.85-0.95 | <0.3 | <0.35 | <0.15 | - | <0.15 | <0.2 | - | ||||||||
| PN | N9E | ||||||||||||||
| 0.85-0.94 | 0.15-0.3 | 0.15-0.3 | <0.025 | <0.025 | <0.15 | <0.2 | <0.2 | ||||||||
U9A / / C85W steels – description
Steel with carbon content slightly above eutectoid point. It is the steel grade with the lowest alloy content of all tool steels used for machining. Although it has a hardness similar to steel with a higher carbon content, has a lower abrasion resistance and a worse cutting edge.
N9E has a higher impact and shock resistance than N9, so it is recommended to use N9E steel for applications requiring higher quality.
Applications
This alloy is widely used for:
- Chisels
- Punches
- Cutters
- Wood tools
- Screw taps
Mechanical and physical properties
Hardness is in this case the most important feature.
| Norm | Grade | Max HB hardness as soft annealed | Max HB hardness as quenched |
|---|---|---|---|
| ISO | TC90 | 207 | - |
| GOST | U9 | 192 | 62 |
| GOST | U9A | 192 | 62 |
| PN | N9 | 197 | 62 |
| PN | N9E | 197 | 62 |
| UNI | C90KU | 207 | 60 |
| BS | BW1 | 207 | - |
Other properties:
| Grade: | N9 | N9E | U9A |
|---|---|---|---|
| Electrical resistivity: | 1.76 μΩ*m | 1.76 μΩ*m | - |
| Density: | 7.851g/cm3 | 7.851g/cm3 | 7.81g/cm3 |
| Specific heat capacity: | 498 J/kg*K | 498 J/kg*K | - |
| Linear expansion coefficient: | 10.84 (10^6)/OC | 10.84 (10^6)/OC | - |
Quenching
N9 differs from N9E in it’s hardening capacity, similarly to U9 and U9A. U9 and N9 are deep hardening steels, and U9A as well as N9E are shallow hardening ones.
In this case shallow-hardening steel exhibit better impact resistance than it's deep hardening counterpart.
| Temperature [℃] | ||||||
|---|---|---|---|---|---|---|
| Largest grain size on a fracture / hardening depth on rode fracture, mm | 760 | 800 | 840 | 880 | ||
| Deep hardening steel N9 | 7 / 5 | 7 / 6 | 6 / 8 | 5 / 12* | ||
| Shallow-hardening steel N9E | 7 / 3 | 7 / 4 | 7 / 4 | 7 / 5 | ||
* ATTENTION! Hardening cracks on a fracture are likely.
Heat treatment and plastic working
Following parameters are recommended for working and heat treatment
| N9E heat treatment and forging | ||
|---|---|---|
| Process | Cooling | Temperature [℃] |
| Forging | ash or sand | 1000–800℃ |
| Soft annealing | any | 680–710℃ |
| Stress relief | slow | 600-700℃ |
| Quenching | water | 760-780℃ |
| Tempering | air | 180-300℃ |
Welding
Tool steel of this kind is not easy to weld, thus welding should be considered only for repairs.
Following coated electrodes can be used: ENS 50 B, ENS 15CrB, ENS 18, EN 450 B, EN 600 B, WBEN 280 MoB, EN 350 B.
We deliver this steel alloy as:
Replacements, equivalents and other designations:
T9A, U9A, C90E2U, 1.1535, C90U, 1.1625, BW1A, N9, OSC8M, TC90, 43962, 43961, SK5, 19192, W1-8½, C90KU