1.Application
These standards regulates high speed tool steels (hereafter steels) made through either hot rolling or forging.
2.Types
There are 13 types of steel and their symbols are as shown in table 1.
*[table1]
|
Types |
Symbols |
1 Types
2 Types
3 Types
4 Types
5 Types
6 Types
7 Types |
STC 1
STC 2
STC 3
STC 4
STC 5
STC 6
STC 7 |
3.Production method
- Steel is produced from Killed steel.
- The steel, unless specifically designated, must be rolled or forged at the temper rate of over 4S.
However, for cases where the rate is below 4S. upsetting forging can make up for the lower rate.
- The steel, unless specifically designated must be annealed. however, steel plates and steel beams should remain as they are unless specifically mentioned.
4.Chemical component
Chemical component of steel is defined by ladle analysis. in accordance to table2.
*[table 2]
|
Symbols |
Chemical component% |
Reference Usage |
C |
Si |
Mn |
P |
S |
STC1 |
1.30~1.50 |
0.35 under |
0.50 under |
0.030 under |
0.030 under |
files |
STC2 |
1.10~1.30 |
0.35 under |
0.50 under |
0.030 under |
0.030 under |
drill,metal work file, small puncher, razor blade, windup spring, metal saw |
STC3 |
1.00~1.10 |
0.35 under |
0.50 under |
0.030 under |
0.030 under |
Dies for making screws, metal saw, press mould, gauge, windup spring, chisel |
STC4 |
0.90~1.00 |
0.35 under |
0.50 under |
0.030 under |
0.030 under |
Windup spring, woodwork drill, ax,chisel, needles, razor blade, woodwork belt saw,pen tip, press mould, gauge |
STC5 |
0.80~0.90 |
0.35 under |
0.50 under |
0.030 under |
0.030 under |
Marking press, press mould, windup spring, belt saw, round saw, pen tip,gile, gauge
|
STC6 |
0.70~0.80 |
0.35 under |
0.50 under |
0.030 under |
0.030 under |
Marking press, snap, round saw, windup spring, press mould, file |
STC7 |
0.60~0.70 |
0.35 under |
0.50 under |
0.030 under |
0.030 under |
Marking press, snap, press mould, knife
|
Note : For steel that are not annealed, annealing in table3 will take place, followed by hardened tempering. |
5. Annealing hardness
Annealing hardness of steel is as seen in table3. But for cases where it is difficult to use .
Brinnel hardness, it is possible to use Rockwell B hardness or Vickers hardness,
depending on the agreement by the manufacturer and the buyer.
*[table 3]
|
Symbols for types |
Annealing temperature C |
Annealing hardness HB |
STC 1
STC 2
STC 3
STC 4
STC 5
STC 6
STC 7 |
750~780 slow cooling
750~780 slow cooling
750~780 slow cooling
740~760 slow cooling
730~760 slow cooling
730~760 slow cooling
730~760 slow cooling |
217 under
212 under
212 under
207 under
207 under
201 under
201 under |
6. hardening tempering hardness
For the tests that represents hardening and tempering hardness, the hardness of tempering and hardening after taking an appropriate temperature given in table 4, the hardness of hardening and tempering will be as seen in table4.
*[table 4] Tested hardening tempering hardness
|
symbol |
Heat treatment °C |
Hardening, tempering hardnessHRC |
Hardening |
Tempering |
STC 1
STC 2
STC 3
STC 4
STC 5
STC 6
STC 7 |
760~820 water-cooled
760~820 water-cooled
760~820 water-cooled
760~820 water-cooled
760~820 water-cooled
760~820 water-cooled
760~820 water-cooled
|
150~200 air-cooled
150~200 air-cooled
150~200 air-cooled
150~200 air-cooled
150~200 air-cooled
150~200 air-cooled
150~200 air-cooled
|
63 over
63 over
63 over
61 over
59 over
57 over
56 over |
Note: For steel that are not annealed, annealing should be done as seen in table3, followed by hardening tempering. |
7. Appearance, shape, size and their allowance
1 Hot rolled rounded steel
- In appearance, hot rolled rounded steel should have good finishing and must have
no hazard for use.
|