The Developing History for Tungsten Carbide Drawing Dies in China
Tungsten carbide drawing dies are the mainly consumable tools in metal drawing field, which have experienced cast-iron mould, alloy-steel mould, diamond mould, tungsten carbide mould and PCD mould etc stages.
The tungsten carbide was invented by German to make drawing dies at first,we can say drawing die is the direct incentive for the emerge of the tungsten carbide .
In 1950s ,China has set up its own tungsten carbide industry ,and the tungsten carbide drawing dies has been used widely since then .Meanwhile the carbide drawing dies are WC-Co series in China ,Sweden and Italy.however there are some countries who add rare-earth elements into the material with totally different producing process.
The Cobalt content in our carbide drawing dies is similar to Soviet Union .The traditional grade in domestic is YG8 ,and also a few of grade YG15 and YG6X .Later ,in order to improve its wear-resistance,the Co in grade YG8 has been reduced to 7%,6% and 3% from original 8%,on the contrary ,its anti-shock and T,R,S performance also are decreased with the reduction of Co compostion.In recent years ,the Co content is same as Sandvik of Sweden who is head in this area.Meanwhile ,the Co content of the grades from Japan and Itay are also closed to Sandvik’s
Form 1 as below shows the tungsten carbide drawing dies grades in these countries .
Our carbide wire drawing dies are rarely added the rare-metal carbides such as TiC,TaC ,NbC etc,but some grades of foreign manufacturers have taken them.If these elements existed in the grades ,they are helpful to improve the carbide dies’ hardness and wear-resistance,also harmful to its transverse rupture strength.Of course ,we have studied to add the carbide and rare-earth elements to improve the drawing dies performance .For instance
1) To add rare-earth elements into grade YG8 to help improve its performance
2) To add 1% TaC in grade Yg8 to restrain grain grow up in sintering process so as to refine grain-size and get longer service life
3) To reduce Co content of grade Yg8 to 6% and add a few amount of TaC in order to increase output by1 time when drawing steel A3,#2,YIF and copper .
Nevertheless,we still have not deviated from the old drawing dies’ grade as Yg8 and Yg6,consequently ,we can say it is not any meaning to make innovation on the common grades.We all know the content of the grades ,but the most important is to produce the tungsten carbide complying with the chemical compositon and maintain the stable quality .
Form 1
|
Country
|
Grade
|
Chemical Composition
|
Hardness
(HRA)
|
Density
(g/cm3)
|
TRS
N/mm2
|
|
WC
|
Co
|
Others.
|
|
China
|
YG3
|
97
|
3
|
N/A
|
91
|
15.0~15.3
|
1176
|
|
YG6
|
94
|
6
|
N/A
|
89.5
|
14.6~15.0
|
1421
|
|
YG8
|
92
|
8
|
N/A
|
89
|
14.8~14.9
|
1470
|
|
Soviet
Union
|
BK3
|
97
|
3
|
N/A
|
89
|
15.0~15.3
|
980
|
|
BK6
|
94
|
6
|
N/A
|
88.5
|
14.6~15.0
|
1420
|
|
BK8
|
92
|
8
|
N/A
|
87.5
|
14.8~14.9
|
1570
|
|
Germany
|
G10
|
94
|
6
|
N/A
|
HV1550
|
14.6
|
1670
|
|
G15
|
91
|
9
|
N/A
|
1450
|
14.4
|
1860
|
|
G20
|
88
|
12
|
N/A
|
1300
|
14.2
|
2060
|
|
Italy
|
-
|
94.12
|
5.4
|
Mo0.08Ti0.11Ta0.48
|
-
|
-
|
-
|
|
-
|
93.32
|
6.0
|
Mo0.11Ti0.03Ta0.54
|
-
|
-
|
-
|
|
Japan
|
D1
|
94
|
6
|
Available
|
92
|
15.1
|
1765
|
|
D2
|
93
|
7
|
N/A
|
90.5
|
14.8
|
2060
|
|
D3
|
90
|
10
|
N/A
|
90
|
14.6
|
2450
|
