UR Series
Dezincification corrosion resistance alloy

If brass alloy is used as a member being in contact with tap water or seawater, "zinc-free corrosion" that zinc selectively elutes from the surface of the brass alloy may occur.
The UR series are copper alloy materials with excellent dezincification corrosion resistance, and is possible to provide optimum materials depending on the application.

Main features

  • 1) Good dezincification resistance to corrosion.
  • 2) Good Machinability (UR31, 34)
  • 3) Good hot forgeability (UR34)
  • 4) Good seawater resistance (UR30ST)
  • 5) Good antifouling property (UR30ST)

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Main purposes of use

  • 1) Faucet fittings · Hot water supply piping parts · Heat exchanging parts (UR31,34)
  • 2) Aquaculture fish preservation (UR30ST)

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Chemical composition

The chemical components of UR series are as follows.

Chemical components(Weight %)
  Cu Sn Ni Al Pb Zn
UR30ST 67 0.7   0.6   Rem.
UR31 64 0.8 <0.1   1.9 Rem.
UR34 62 0.8 <0.1   1.7 Rem.

* Including inevitable impurities and trace additive elements

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Physical properties

The physical properties of UR series are as follows.

Physical properties
Property Representative Value
Alloy UR31 UR34 UR30ST
Specific Gravity 8.5 8.5 8.5
Electrical Conductivity%
IACS
26 26 20
Coefficient of Thermal Expansion
10—6 /℃
21 21 21
Modulus of Elasticity
kN/mm2
103 103 103

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Mechanical properties (Actual example: LD direction)

The mechanical properties of UR series are as follows.

Mechanical properties (Representative value)
Alloy Shape Ø Temper HRB Tensile Strength
(N/mm2)
Elongation
(%)
Yield strength
(N/mm2)
UR30ST Wire Ø4 1/4H 52 420 23
UR31 Rod/Bar Ø20 D 73 415 35 280
Ø35 D 50 350 50 140
UR34 Rod/Bar Ø28 E 44 380 42
Ø58 E 38 360 45
Mechanical properties (Representative value)
Alloy UR30ST
Shape Wire
Ø Ø4
Temper 1/4H
HRB 52
Tensile Strength
(N/mm2)
420
Elongation
(%)
23
Yield strength
(N/mm2)
-
Alloy UR31
Shape Rod/Bar
Ø Ø20 Ø35
Temper D D
HRB 73 50
Tensile Strength
(N/mm2)
415 350
Elongation
(%)
35 50
Yield strength
(N/mm2)
280 140
Alloy UR34
Shape Rod/Bar
Ø Ø28 Ø58
Temper E E
HRB 44 38
Tensile Strength
(N/mm2)
380 360
Elongation
(%)
42 45
Yield strength
(N/mm2)
- -

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Corrosion resistance

It shows corrosion resistance of UR series.
UR series have excellent dezincification corrosion resistance.

Dezincification test
Alloy Ø ISO 6509 test JBMA T-303 test
maximum
corrosion depth
(μm)
average
corrosion
(μm)
corrosion form maximum
corrosion depth
(μm)
evaluation
UR30ST Ø4 <10 <10 no dezincification 60 type Ⅰ
UR31 Ø20 20 <10 no dezincification 65 type Ⅰ
Ø35 20 <10 no dezincification 65 type Ⅰ
UR34 Ø28 330 180 preferential corrosion
of β phase
forging* 30 <10 preferential corrosion
of γ phase
70 type Ⅰ
C3604 Ø26 1000 900 general corrosion 400 N/A
C3771 forging 900 800 general corrosion 250 N/A

* annealing

Dezincification test
Alloy UR30ST
Ø Ø4
ISO 6509 test maximum corrosion depth(µm) <10
average corrosion(µm) <10
corrosion form no dezincification
JBMA T-303 test maximum corrosion depth(µm) 60
evaluation type Ⅰ
Alloy UR31
Ø Ø20 Ø35
ISO 6509 test maximum corrosion depth(µm) 20 20
average corrosion(µm) <10 <10
corrosion form no dezincification no dezincification
JBMA T-303 test maximum corrosion depth(µm) 65 65
evaluation type Ⅰ type Ⅰ
Alloy UR34
Ø Ø28 forging*
ISO 6509 test maximum corrosion depth(µm) 330 30
average corrosion(µm) 180 <10
corrosion form preferential corrosion of β phase preferential corrosion of γ phase
JBMA T-303 test maximum corrosion depth(µm) - 70
evaluation - type Ⅰ
Alloy C3604
Ø Ø26
ISO 6509 test maximum corrosion depth(µm) 1000
average corrosion(µm) 900
corrosion form general corrosion
JBMA T-303 test maximum corrosion depth(µm) 400
evaluation N/A
Alloy C3771
Ø forging
ISO 6509 test maximum corrosion depth(µm) 900
average corrosion(µm) 800
corrosion form general corrosion
JBMA T-303 test maximum corrosion depth(µm) 250
evaluation N/A

* annealing

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Stress corrosion cracking resistance

It satisfies the stress corrosion cracking test by JIS method and ASTM method (both conducted in ammonia atmosphere).

Stress corrosion crack test result
  JIS A ASTM
UR30ST
UR31

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Machinability

Machinability of UR 31 is almost equal to C 3604 and has excellent machinability.

Cutting resistance and triple force measurement result of UR 31
  Drill test Three force components
Torque
N・m
Thrust
N
Main force
N
Feed force
N
Thrust force
N
Resultant force
N
UR31 0.40 214 107 31 13 112
C3604 0.37 224 91 61 22 112

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Hot workability

Deformation resistance of UR 34 at high temperature

graph

The hot forging temperature of UR 34 is preferable in a range of 700℃ to 820℃ so as to be equivalent hot deformation resistance to C3771 by raising 50℃ higher than 650℃ to 770 ℃ which is the hot forging temperature of C3771.

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Antifouling properties

UR30ST has excellent antifouling properties (properties that prevent the adherence of marine organisms such as algae and shellfish), and it is used as a wire of crawls for sea surface culturing.

Sea farming picture

photo Galvanized steel wire crawl (4 months passed after installation)
photo UR30ST crawl (2 years passed after installation)

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Inquiry

  • Business Development Group+81-3-6629-5857 (UR30ST)
  • Osaka Sales Group+81-72-233-2954 (UR31,34)

Please inquire here for any questions.

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