Low-lead, cadmium-free, high-corrosion-resistance | KEEPALLOY Ⅱ XC Metal
This material is a low-lead and cadmium-free high-corrosion-resistant brass bar for cutting and registered with the U.S. Copper Development Association (CDA) as "No. C46750". And this material is standardized by B21 and B249 of ASTM, respectively.
▼ Features
XC Metal is a dezincification-resistant brass bar for cutting with superior mechanical properties and dezincification corrosion resistance.
This dezincification-resistant brass bar for cutting also has superior erosion-corrosion resistance and stress corrosion cracking resistance.
▼ Specifications comparison
Properties
KEEPALLOY Ⅱ XC Metal
Brass bars for cutting JIS C3604
Dezincification corrosion resistance
-
Erosion-corrosion resistance
-
Stress corrosion resistance
Mechanical properties
Cutting properties
Machinability
Surface roughness
◎=Superior, ○=Equal, ×=Inferior
▼ Chemical composition (representative example) (%)
Material
Cu
Sn
Fe
Sb
P
Ni
Pb
Cd
Si
Bi
Zn
XC metal
61.2
1.2
0.10 max.
0.09
0.09
0.20 max.
0.20 max.
75ppm max.
-
-
Rem.
JIS C3604
59.0
Sn+Fe: Less than 1.0
-
-
-
3.2
General spec.
-
-
Rem.
CD75
▼ Mechanical properties (representative example)
Material
Manufacturing method (size)
Properties
Tensile strength (N/mm²)
0.2% yield strength (N/mm²)
Elongation (%)
Hardness (HV)
Charpy impact value (J) (at 20ºC)
XC metal
Drawn (ø35)
408
238
37
105
28.7
JIS C3604
Drawn (ø24)
450
340
26
140
28.5
▼ Dezincification corrosion resistance
Test method
ISO 6509
Evaluation standard
Maximum depth of erosion: 200μm
Test result
XC Metal (bars)
JIS C3604 (bars)
×200
×50
Maximum depth of erosion: 30μm
Maximum depth of erosion: 1,450μm
β, γ phase column type corrosion
Layer corrosion
Evaluation results
XC Metal complies with the evaluation standard of 200μm maximum depth of dezincification corrosion.
▼ Erosion-corrosion resistance
Test method
Gap jet corrosion test method
Test results
Material
XC Metal (bars)
JIS C3604 (bars)
JIS CAC406C (bronze continuous cast bar)
Photograph of surface after 5 hours
Corrosion form
Layer corrosion
Ring corrosion
Layer corrosion
Depth of erosion (μm)
62
430
56
Mass loss (mg)
310
500
240
Evaluation results
XC Metal is a material that has much more superior erosion-corrosion resistance compared to JIS C3604 material. It corrodes uniformly overall with the same kind of layer corrosion as JIS CAC406C material.
▼ Stress corrosion cracking resistance
Test method
Apply a threading tensile stress to a joint for evaluation that has been machined to add a tapered female pipe thread, by applying a certain torque to a bushing that has been machined to add a male thread. Observe how many hours it takes before cracks occur on the surface in an atmosphere of 14% ammonia. By testing under the same conditions, it is possible to make relative evaluations between the material being evaluated and the comparison material.
The photograph below shows an example in which a stainless steel bushing is mounted on the brass material being evaluated.
Test conditions and judgment standard
Samples
Test material that has been machined to add Rc1/2 pipe tapered thread (See photograph.)
Partner material
Bushing SCS13A 1/2×3/8 ... PB(1)1/2
Tightening torque
9.8 N･m
Atmosphere
Normal temperature ammonia atmosphere (14% NH3 solution)
Judgment standard
Observe visually and with stereoscopic microscope to see whether or not there are cracks. ○: No cracks observed △: Cracks observed (Cannot be judged visually, judge with stereoscopic microscope) ×: Cracks observed (visual judgment)
Test results
Material
Judgment results for each corrosion duration
4H
8H
16H
24H
48H
XC Metal (bars)
JIS C3604 (bars)
Evaluation results
XC Metal has more superior stress corrosion cracking resistance compared to JIS C3604 material.
▼ Hot forgeability
Test method
Upset test After a test piece in the figure below was heated to the test temperature, it was compressed with a press machine to the pre-determined upset ratio, then the material was evaluated by checking visually for cracks in the surface of the test piece.
Test results
Material
XA Metal
JIS C3771
Photograph
Temperature (ºC)
670
700
730
760
790
670
700
730
760
790
Upset ratio (%)
45
50
55
60
Metal structure
Granulated
Acicular
Proper forging temperature (ºC)
730~780
680~740
* After the upset test, forged products with no visible cracking were judged ○ and those on which cracks were visible were judged ×.
Evaluation results
XA metal shows good forgeability over wide ranges of upset ratios and forging temperatures equivalent to those for JIS C3771. The recommended forging temperature shown here is a rough yardstick. The product shapes and forging conditions vary for each forging operation. We recommend that you run test forging with actual work pieces to check the optimum forging temperature first.
Heat treatment conditions for forged products
In order to ensure stable dezincification corrosion resistance and to eliminate residual stress, after forging, it is necessary to heat treat XA Metal at 450 to 480ºC (actual metal temperature) for 2 hours or longer.
However, if the forged product does not require the dezincification corrosion resistance, this heat treatment is not necessary.
▼ Machinability
Turning and drilling conditions
Method
Material diameter (mm)
Cutting speed (m/min)
Rotation speed (rpm)
Feed (mm/rev.)
Cutting depth (mm)
Drill radius (mm)
Cutting conditions
Turning
Φ18
150
2,810
0.2
2.0
-
Dry/Wet
Drilling
-
40
1,500
0.1
-
Φ8.5
Dry/Wet
Test result and cutting chip observation
Material
Turning
Drilling
Dry
Wet
Dry
Wet
XC Metal
Machinability Rating: 42
Machinability Rating: 42
Machinability Rating: 30
Machinability Rating: 56
JIS C3604
Machinability Rating: 100
* Machinability Rating (%) = [(JIS C3604 cutting resistance)/(Cutting resistance value for each material)] x 100
Evaluation results
As for the cutting property of XC Metal, the cutting performance is lower than JIS C3604 material with the conditions shown here and there is a tendency that cutting chips are generated somewhat continuously. However, by changing from dry machining to wet machining , the cutting resistance of the drilling can be reduced.
