D3 |
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BS4659 BD3 is a high carbon high chromium, air hardening alloy tool steel with excellent resistance to wear and abrasion. D3 tool steel has good through hardening properties and dimensional stability combined with high resistance to tempering.
| Typical Analysis |
C. |
Si. |
Mn. |
Cr. |
2.10% |
0.30% |
0.30% |
11.50% |
Forging:
Heat slowly and uniformly to 700°C then more rapidly to 900/1050°C. After forging cool slowly, preferably in a furnace.
Annealing:
Anneal at 900°C and slow furnace cool. Hardness after annealing will be approx. 225 brinell.
Stress Relieving:
If machining operations have been heavy or if the tool has an unbalanced section, remove stresses before hardening by heating up to 700°C, equalise, then cool slowly.
Hardening:
Pre heat slowly to 750/800°C and thoroughly soak. Continue heating to the final hardening temperature of 950/1000°C and allow the component to be heated through. Cool in air or quench in oil.
Tempering:
Heat uniformly and thoroughly at the selected tempering temperature and hold for at least one hour per inch of total thickness. Double tempering should be carried out with intermediate cooling to room temperature.
| Tempering °C |
150 |
200 |
250 |
300 |
350 |
400 |
| HRc |
64/63 |
63/61 |
62/60 |
61/60 |
60/59 |
59/58 |
Hard Chrome Plating:
After hard chromium plating tempering of D3 tool steel is recommended at 180°C for 4 hours to avoid hydrogen embrittlement. Tempering is to be performed immediately after chromium plating.
Welding:
Due to the high risk of crack formation welding of D3 tool steel should be avoided, if possible. When, however welding is essential, the following serves as a guide:
A. Welding of soft annealed D3 tool steel
· Preheat to 300 - 500°C
· Weld at 300-500°C
· Immediately stress relieve
Electrode: Cr-Mo alloy electrode for welding structural steel.
B. Welding in connection with hardening of soft annealed D3 tool steel.
· Heat to austenitizing temperature.
· Cool to approx. 500°C
· Weld at approx. 500°C
· Cool to approx. 100°C in the same way as at normal hardening, then temper to desired hardness. Double tempering will reduce the risk of crack formation.
Electrode: Hard facing electrode.
C. Repair welding of D3 tool steel in hardened and tempered condition.
· Preheat to the tempering temperature (min. 200°C) previously used.
· Weld at tempering temperature.
· Heat immediately to tempering temperature, but max. 300°C. Soaking time 3 hours.
· Cool in air to approx. 80°C.
· Heat to tempering temperature. Soaking time 2 hours.
Electrode: Hard facing electrode.
| Physical Properties: |
Temperature: |
|
|
| | 20°C | 200°C | 400°C |
| Density (Kg/dm³) |
7.70 |
7.65 |
7.60 |
| Coefficient of thermal expansion (per °C from 0°C) |
- |
11.0 x 10-6 |
10.8 x 10-6 |
| Thermal conductivity (cal/cm.s °C) |
49.0 x 10-3 |
51.3 x 10-3 |
54.9 x 10-3 |
| Specific heat (cal/g °C) |
0.110 |
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| Modulus of elasticity: |
|
|
|
| Kp/mm² |
19 790 |
19 280 |
17 645 |
| N/mm² |
194 000 |
189 000 |
173 000 |
BS4659 BD3 available in:-
   
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