MITSUBISHI MATERIALSCopper & Copper Alloy Business

MITSUBISHI MATERIALSCopper & Copper Alloy Business


Products information

UR SeriesDezincification corrosion resistance alloy

Standard No.
C3531(UR31,34)CDA: C45470(UR30ST)

If brass alloy contacts to water or seawater, zinc may salectively elutes from the brass allow surface, which is called "zinc-free corrosion".

The UR series are copper alloy materials with excellent dezincification corrosion resistance. We can provide optimum materials accordingly to the application. UR30ST is suitable alloy especially for the wire of Aquaculture.

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)

Main applications

Faucet fittings · Hot water supply piping parts · Heat exchanging parts (UR31,34)
Wire for Aquaculture (UR30ST)

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

Physical properties

The physical properties of UR series are as follows.

Physical properties
Property Representative Value
UR31 UR34 UR30ST
Specific Gravity (293K) 8.5 8.5 8.5
coeffcient of thermal Expansion
21 21 21
electrical conductivity
26 26 20
Modulus of Elasticity
103 103 103

Mechanical properties (Actual example: LD direction)

The mechanical properties of UR series are as follows.

Mechanical properties (Representative value)
alloy UR30ST UR31 UR34
Shape wire bar bar
size Ø4 Ø20 Ø35 Ø28 Ø58
Temper 1/4H D D E E
Tensile Strength
420 415 350 380 360
Yield Strength
- 280 140 - -
23 35 50 42 45
52 73 50 44 38
D: 引抜棒  E:押出棒

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
average corrosion
corrosion form maximum corrosion depth
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

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


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
Main force
Feed force
Thrust force
Resultant force
UR31 0.40 214 107 31 13 112
C3604 0.37 224 91 61 22 112

Hot workability

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.

Deformation resistance of UR 34 at high temperature

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

Galvanized steel wire crawl (4 months passed after installation)

UR30ST crawl (2 years passed after installation)


Group Ⅲ, Extruded Product & Wire Rod Sales Dept.