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Better formability with same strength

25 Alloy Mill hardened ”Type B” and “Type S”

Features

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.

Tensile Strength

Comparison of bending formability test of 25HM(Usual) and 25-TypeB("New Grade")

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(Usual)

25HM-TypeB

25HM-TypeB

Spec

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

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