25 Alloy Mill hardened ”Type B” and “Type S”
New grade "Type B" and "Type S" mill-hardened Alloy-25 have been developed by refinement of the manufacturing process for improved formability.
The bend radius ratio(R/t) of Type B is half that of the usual mill-hardened alloy.
The bend radius ratio(R/t) of Type S is one quarter that of usual due to crystal-grain-size-control.
* Mill-hardened alloy is pre-aged(hardened) in the mill. Using mill-hardened alloy frees us from the troublesome aging process.
These photos show the 90ºbending test results (Bad Way, R/t = 1.0, thickness 0.2mm). There are micro cracks on the usual product ‘25HM’, but new grade ‘25HM-TypeB’ has no cracks. Good Formability was achieved in new grade “Type B” and “Type S”.
Tensile Strength: 1000 N/mm2
25HM(Usual)
25HM-TypeB
Chemical Composition
| Alloy (NGK) | JIS No. (H3130) | Chemical Composition (wt%) | |
|---|---|---|---|
| 25 | C1720 | Be | 1.80 - 2.00 |
| Ni+Co | min. 0.20 | ||
| Ni+C+Fe | max. 0.60 | ||
| Cu+Be+Ni+C+Fe | min. 99.5 | ||
Physical Properties
| Item | NGK Alloy 25 (C1720) | |
|---|---|---|
| Melting Point (slidus) | °C | 865 |
| Melting Point (liquidas) | °C | 980 |
| Density | g/cm3at 20°C | 8.26 |
| Specific Heat | J/(kg⋅K) at 20°C | 419 |
| Thermal Expansion Coefficient | /°C at 20 - 300°C | 17.8 x 10-6 |
| Thermal Conductivity | W/(m⋅K) at 20°C | 83.7 - 130 |
| Electrical Conductivity | %IACS at 20°C | 20 |
| Modulus of Elasticity | kN/mm2 | 127 |
| Modulus of Rigidity | kN/mm2 | 49 |
| Poison's Ratio | 0.3 | |
Properties of Strip
| Alloy (JIS No.) |
Temper | Tensile Strength (N/mm2) | Yield Strength 0.2% offset (N/mm2) | Elognation (%) | Vickers hardness (Hv) | Electrical Conductivity (%IACS) |
|---|---|---|---|---|---|---|
| Alloy 25 (C1720) Type B | 1/2HMB | 830 - 930 | 660 - 860 | min. 12 | 255 - 310 | min. 16 |
| HMB | 930 - 1030 | 760 - 930 | min. 9 | 280 - 340 | min. 17 | |
| XHMB | 1070 - 1210 | 930 - 1170 | min. 4 | 330 - 390 | min. 17 | |
| XHMSB | 1210 - 1310 | 1030 - 1240 | min. 3 | 360 - 410 | min. 20 | |
| Alloy 25 (C1720) Type S | HM-TypeS | min. 960 | 790 - 940 | min. 9 | 285 - 370 | min. 17 |
| XHM-TypeS | min. 1060 | 930 - 1070 | min. 6 | 315 - 395 | min. 17 |
Formability (Ratio of the Bend Radius; R/t)
| Alloy (JIS No.) | Type | 90° bending | |
|---|---|---|---|
| Long. | Trans. | ||
| 25 (C1720) Type B | 1/2HMB | 0.0 | 0.0 |
| HMB | 1.0 | 1.0 | |
| XHMB | 2.5 | 2.0 | |
| XHMSB | 3.5 | 6.0 | |
| 25 (C1720) Type S | HM-TypeS | 0.5 | 0.5 |
| XHM-TypeS | 1.0 | 1.0 | |
* Typical R/t of 0.15mm thickness samples
