Dezincification-resistant brass bars for forging and for free-cutting FZ Metal
▼ Types and features
FZ Metal-1: Dezincification-resistant brass bars for forging This is material developed as dezincification-resistant brass bars for forging. This has superior hot workability and erosion-corrosion resistance. With the specified heat treatment after forging, this material shows superior dezincification corrosion resistance.
FZ Metal-2: Dezincification-resistant brass bars for cutting This is material developed based on FZ Metal-1 as dezincification-resistant brass bars for cutting and has superior machinability. This is material that complies with "C3531" regulated by JIS H 3250.
▼ Specifications comparison
Properties
FZ Metal
KZ Metal
Free-cutting brass bars
Brass bars for forging
Bronze casting
FZ Metal-1 (forged products) (heat treated)
FZ Metal-2 (bars)
KZ
C3604
C3771
CAC406
Dezincification corrosion resistance
Erosion-corrosion resistance
Stress corrosion cracking resistance
Mechanical properties
Cutting properties
Machinability
Surface roughness
* Hot forgeability
-
-
* For the hot forgeability of FZ Metal-2, it has the same chemical composition as FZ Metal-1 and the hot workability is equivalent.
▼ Chemical composition (representative example) (%)
Material
Cu
Sn
Fe
Pb
Special elements
*Cd
Zn
FZ Metal
61.0
1.2
0.2
2.2
0.5
General spec.
Residual
Less than 75 ppm
C3771
59.0
Sn+Fe 1.0
2.2
-
General spec.
Residual
Less than 75 ppm
C3604
59.0
Sn+Fe 1.0
3.2
-
General spec.
Residual
Less than 75 ppm
CAC406 CAC406C
85.0
5.0
-
5.0
-
-
5.0
▼ Mechanical properties (representative example)
Material
Manufacturing method (size)
Properties
Tensile strength (N/mm²)
0.2% yield strength (N/mm²)
Elongation (%)
Hardness (HV)
FZ Metal-1
Extruded (ø28)
400
185
36
105
C3771
Extruded (ø30)
350
140
45
90
CAC406
Sand casting tension test piece
235
-
28
67
FZ Metal-2
Drawn (ø34)
410
240
35
110
C3604
Drawn (ø24)
450
340
26
140
CAC406C
Continuous cast bar (ø30)
286
-
33
65
* Even if material is the same, the extrusion, drawing, and heat treatment conditions make the mechanical properties different. * JIS Z 2201 #4 test pieces were used for the tension test.
▼ Dezincification corrosion resistance
Test method
ISO 6509 / JIS H 3250 Annex A
Evaluation standard
Maximum depth of erosion: 200μｍ
Test results and photographs of dezincification-resistant test microscope metal structure
FZ Metal-1 (forged products)
FZ Metal-2 (bars)
C3771 (forged products)
C3604
CAC406C
×200
×200
×200
×200
×200
Maximum depth of erosion：30μm
Maximum depth of erosion：50μm
Maximum depth of erosion：1380μm
Maximum depth of erosion：1450μm
Maximum depth of erosion：10μm
β, γ phase column type corrosion
β, γ phase column type corrosion
Layer corrosion
Layer corrosion
-
* FZ Metal-1 forged products are subject to the specified heat treatment after forging.
Evaluation results
FZ Metal-1 (forged products) and FZ Metal-2 (bars) comply with the evaluation (maximum depth of erosion: 200μm) .
▼ Erosion-corrosion resistance
Test method
Gap jet corrosion test method
Test results
Material
FZ Metal-1 (forged products)
FZ Metal-2 (bars)
C3771 (forged products)
C3604 (bars)
CAC406C (bars)
Photograph of surface after 5 hours
Corrosion form
Layer corrosion
Layer corrosion
Ring corrosion
Ring corrosion
Layer corrosion
Depth of erosion (μm)
46
64
620
430
56
Mass loss (mg)
360
270
480
500
240
Evaluation results
FZ Metals are materials that have superior erosion-corrosion resistance. They corrode uniformly overall with the same kind of layer corrosion as CAC406 and CAC406C.
▼ 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 (photograph)
Bars
Forged products
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
Visually observe whether or not there are cracks. ○: No cracks observed ×: Cracks observed (visual judgment)
Test results
Material
Corrosion duration
4H
8H
12H
24H
36H
48H
FZ Metal-2 (bars)
KZ Metal (bars)
C3604 (bars)
FZ Metal-1 (forged products)
C3771 (forged products)
Evaluation results
Compared to our KZ Metal and C3604, FZ Metal-2 (bars) has about the same or better stress corrosion cracking resistance. Compared to C3771 (forged products), FZ Metal-1 (forged products) has about the same or better stress corrosion cracking resistance.
▼ 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
FZ Metal-1
C3771
Photograph
Temperature (ºC)
670
700
730
760
790
670
700
730
760
790
Upset ratio (%)
45
50
55
60
Proper forging temperature (ºC)
720 to 780
680 to 740
* For the forgeability evaluation, products with no cracking were judged O and those on which cracks were visible were judged X.
Evaluation results
FZ Metal-1 (forged products) can provide good forging with the forging temperature set slightly higher than for C3771. The proper forging temperature is a rough yardstick. 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 dezincification corrosion resistance and to eliminate residual stress, after forging, it is necessary to heat treat FZ Metal-1at 460 to 480ºC for the actual metal for 2 hours or longer.
▼ Machinability
Turning and drilling conditions
Method
Machining conditions
Cutting speed (m/min)
Rotation speed (rpm)
Feed (mm/rev.)
Cutting depth (mm)
Drill radius (ø)
Cutting conditions
Turning
113
1,800
0.06
1.0
-
Dry
Drilling
28
1,800
0.06
-
8.0
Dry
Test results and cutting chip observation results
Method
C3604
KZ Metal
FZ Metal-2
CAC406C
Turning
Machinability Rating: 100
Machinability Rating: 92
Machinability Rating: 92
Machinability Rating: 87
Drilling
Machinability Rating: 100
Machinability Rating: 97
Machinability Rating: 94
Machinability Rating: 89
* The cutting chip collection conditions are the same conditions as for cutting resistance measurement. * Machinability Rating = ([C3604 cutting resistance value]/[Cutting resistance value for each material]) × 100
Evaluation results
The machinability rating of FZ Metal are good and are about the same as for CAC406C.
