Commercially, they are usually divided into: cutting blades, mining alloys, and wear-resistant alloys according to the use of the products. The classification and uses of cemented carbide are not very standardized in relevant domestic books, magazines, and materials. They are usually classified according to alloy composition, and the descriptions of uses are relatively scattered.
According to the composition and structure of the alloy, it can be divided into the following 8 categories.
This type of alloy is called YG type alloy. The normal structure of WC-Co alloy is a two-phase alloy composed of polygonal WC phase and bonding phase Co. Sometimes less than 2% of other (tantalum, niobium, chromium, vanadium) carbides are added as additives to the cutting blade or drawing die to increase the service life of the tool. However, this does not change the basic performance of the alloy, and it still belongs to the WC-Co alloy. Compared with other cemented carbides with the same cobalt content, this type of alloy has the highest flexural strength, compressive strength, impact toughness and elastic modulus, as well as a smaller linear expansion coefficient.
According to tungsten carbide grains, this type of alloy is usually divided into three categories: coarse grain, medium grain and fine grain. With the development of processed materials and cemented carbide production processes, the WC grains of WC-Co alloys have developed greatly towards the ultra-coarse and ultra-fine ends.
According to the cemented carbide grain size classification standard being studied by the German Powder Metallurgy Association and the ISO/TC190 Technical Committee, the WC grain size of medium-crystalline alloys is 1.3~2.5μm. According to the cobalt content, this type of alloy can be divided into three types: low cobalt, medium cobalt and high cobalt alloy. Low-cobalt alloys usually contain 3% to 8% cobalt and are mainly used to make cutting inserts for processing cast iron, non-ferrous metals, non-metals and some heat-resistant alloys, titanium alloys, stainless steel and other difficult-to-machine materials. It is also used to manufacture various drawing dies, compression dies, ordinary and special wear-resistant parts (such as top hammers), as well as drill bits and coal cutting teeth for rotary drilling in geological drilling. Among them, coarse-grained alloys with higher cobalt content can also be used in drill bits for impact rotary drilling of soft rock formations. Medium cobalt alloys (containing 10% to 15% cobalt) are mainly used for drill bits for impact rotary drilling of medium-hard and hard rock formations, some stamping dies with low impact loads, and special wear-resistant parts. High-cobalt alloys (cobalt content greater than 15%) are mainly used for cold heading dies, cold forging dies, stamping dies and rolls with large impact loads.
Post time: Jan-01-2024
