Impact toughness characterises how well tungsten carbide withstands sudden shock loading and resists chipping or catastrophic fracture.
For drilling tools, mining wear parts, valve trims and other components exposed to dynamic loads, Langsun Carbide evaluates impact toughness to ensure robust, real-world performance.
Pendulum Impact Test Method
We use pendulum-type impact tests, conceptually similar to Charpy or Izod methods, adapted for cemented carbides:
1.Specimen preparation
Standardised notched or un-notched specimens are prepared from the tungsten carbide grade being evaluated.
2.Impact loading
A pendulum of known mass and length strikes the specimen at a defined velocity, causing it to fracture.
3.Energy measurement
The energy absorbed during fracture is recorded and expressed as impact energy, often normalised to specimen cross-section.
Impact energies obtained from different grades and batches are compared to evaluate relative toughness and to verify improvements in grade design.
Why Impact Toughness Matters
In real applications, tungsten carbide components frequently experience non-ideal conditions:
● Hard inclusions or foreign objects in the workpiece or process medium.
● Vibration, misalignment or intermittent contact during operation.
● Pressure spikes, water hammer or dynamic flow effects in valves and pumps.
Without adequate impact toughness, even very hard and wear-resistant carbides can fail prematurely through:
● Edge chipping or local spalling.
● Crack initiation from minor defects and rapid crack propagation.
● Sudden catastrophic breakage under shock loads.
Impact toughness data helps us optimise the hardness–toughness balance so that components survive realistic dynamic loading conditions.
Impact Toughness Optimisation at Langsun Carbide
Langsun Carbide uses impact testing as part of grade design and application engineering:
● Application-driven grade design
For drilling, mining and severe-service valves, we adjust grain size and binder content to enhance toughness while maintaining sufficient hardness.
● Combined evaluation
Impact toughness is analysed together with TRS, hardness, coercivity and microstructure to achieve the best overall performance balance.
● Continuous improvement
Field feedback and laboratory impact results are used to refine grades and processing routes over time.
● Transparent reporting
Impact test data can be provided in qualification documents for critical projects where shock resistance is a key requirement.
Through dedicated impact toughness optimisation, Langsun Carbide ensures that its tungsten carbide products deliver both high wear resistance and reliable shock resistance in harsh environments.
Relative Impact Toughness of Representative Grades
The table below shows relative impact toughness levels and indicative impact energy ranges for representative WC–Co grades. These values illustrate general trends; detailed data is available for specific grades and projects.
|
Grade |
wCo/% |
Relative Impact Toughness |
Indicative Impact Energy (J) |
Typical Applications |
|
WC-6Co |
6 |
Low to medium |
~1 – 3 |
High-wear parts with limited shock loading: nozzles, wear plates |
|
WC-11.5Co |
11.5 |
Medium |
~2 – 4 |
General wear parts, bushings and sleeves subjected to some impact |
|
WC-15Co |
15 |
Medium to high |
~3 – 6 |
Mining inserts, drilling tools, severe-service valve components |