Test Hardness Of Metal Or Ceramic Materials Directly In
High-Temperature Vickers Hardness Tester
1.Scope of application:
Given that materials such as metals, ceramics, and agate are
subjected to varying final working environments, their hardness
undergoes corresponding changes with shifts in environmental
temperature. In order to address the challenge of conducting
consistent hardness tests on the same materials across different
temperature conditions, our company has taken an innovative
approach. We have augmented the conventional hardness tester with a
high-temperature system, enabling the simulation of diverse working
environments characterized by varying temperatures. This
enhancement facilitates the collection of material hardness data,
thereby augmenting the reference value and reliability of our
experimental findings.
2.Host system:
The external computer control system enhances user-friendliness,
allowing for effortless operation. This system facilitates online
testing, enabling the comprehensive acquisition of necessary data
in real-time.
Mainframe Parameters:
| Objective lens/indenter switching | Automatic switching between objective lens and indenter |
| Turret drive type | Stepper motor-driven copper gear drive |
| Test force | Standard equipment:0.5, 1, 2, 2.5, 3, 5, 10 , 20, 30, 50kg
Selectable:0.2, 0.3, 0.5, 1, 2, 2.5, 3, 5,10kg |
| Loading method | Fully automatic loading, holding and unloading program control |
| Load-holding duration. | 5-60 steps with a duration of 5 seconds each. |
| Range of hardness measurement. | 5 HV – 3000 HV or higher |
| High-temperature compression rods. | Silicon nitride (or heat-resistant steel) |
| Objective lens | 10X, 20X |
| X-Y testing platform. | Size: 120 × 120mm Maximum movement: 8 × 8mm Minimum reading: 0.01
mm |
| Method of measurement reading. | Input diagonal length, computer-based online automatic reading. |
| Software automation | The computer can manage the loading, unloading, and holding time of
the hardness tester, as well as automatically detect the test
force. |
| Maximum specimen dimensions. | φ15*10mm |
| Distance from the center of the indenter to the wall. | 135mm |
| Implementation standard (or reference) | GB/T 4340;ISO 6507;ASTM E384;JIS B7734 |
| Power source. | 220 VAC, 50/60 Hz |
3.High-temperature systems:
Heating element: Heating with silicon molybdenum rods is characterized by stable
temperatures and minimal overshoot.
High Temperature Furnaces:The furnace body's heat insulation involves lining it with
polycrystalline mullite ceramic fiber, which yields excellent
insulation, aesthetics, durability, and straightforward
installation and upkeep. Additionally, a thermal barrier coating is
applied to the interior of the stainless steel furnace body,
ensuring optimal heat insulation protection.
Hot plate for specimens:Silicon nitride ceramics are employed due to their notable
attributes, including exceptional high-temperature resistance and a
low coefficient of expansion.
Heating switch:The heating system employs a switching power supply (12V, 200A).
While its individual cost surpasses that of the traditional
transformer, it boasts superior stability, reliability,
compactness, and reduced weight. These attributes outshine those of
the conventional silicon-controlled power supply. The system also
demonstrates advantages such as high power utilization and immunity
to electromagnetic signal interference in the vicinity.
Additionally, it incorporates a floating ground feature within the
switching power supply, thereby maximizing the assurance of user
safety during operation.
Water cooling protection:Incorporating a constant temperature control chiller, the furnace
body's outer wall is constructed with dual-layer stainless steel,
forming a water-filled cavity that enables temperature regulation
up to a maximum of 40°C. This constant temperature control chiller
effectively sustains the furnace body's consistent temperature. It
not only guarantees the stability of the outer furnace surface
temperature but also serves to stabilize and finely adjust the
internal furnace temperature. This refinement ensures greater
precision in furnace temperature, ultimately enhancing the accuracy
of the testing process.
High temperature furnace parameters:
| Temperature range | Normal temperature～1000℃ (specimen temperature) |
| Heating speed | 50℃/min |
| Temperature display accuracy | ±1℃ |
| Furnace size | Configured based on the specimen size, with a maximum specimen size
of 15mm. |
| Temperature setting | Set the target temperature as desired. |
| Thermocouples | PtRh-Pt (Type S), thermal response time <2s |
| Heating element | Silicon molybdenum rod |
4.Image Acquisition System:
The system is designed for processing hardness images in Vickers
indentation measurements, encompassing tasks such as measurement,
statistical analysis, data storage, and result output.
The software automatically generates and displays indentation test
result curves, depth curves, error statistics, and group statistics
for the number of tests.
Technical Parameters:
| Image sensor | CMOS(colorful) |
| Effective pixel | 1.3 million |
| Imaging area | 6.55(H)×4.92(V)mm 1/2 type |
| Scanning method | Line-by-line scanning |
| Mirror Image Inversion Function | Sensor horizontal and vertical flipping |
| Pixel size | 3.2(H)×3.2(V)μm |
| Shutter mode | Roll-up curtain |
| Color scheme | RGB bayar arrangement |
| Frame rate | 12fps |
| Electronic shutter | 1/19688～0.832s ※24MHz drive clock |
| Connector | USB 2.0 Bulk Transfer |
| Synchronization method | Internal synchronization |
| Lens mount | C bayonet |
5.Purification Circulation System:
A closed working environment is established through a box and gas
purification system. Inert gas, such as argon or nitrogen, is
introduced into the box to displace and cycle out active
substances. This process ensures the maintenance of a highly clean
and pure inert gas environment, with levels of water and oxygen
reaching below 0.1 ppm in the equipment. This setup doesn't
compromise the hardness tester's force value or measurement
accuracy. Moreover, it serves to safeguard specimens from oxidation
during the heating process.
1)Product Features and Benefits
Very low system leakage rate:
The glove box adheres to a factory standard leakage rate of
<0.005 VOL%/H, with the measured leakage rate falling below
<0.001 VOL%/H—significantly surpassing the international
benchmark of <0.05 VOL%/H. The system employs an oxygen method,
equipped with automatic leakage rate detection functionality.
Three testing programs are employed to thoroughly assess the
complete system after assembly:
- Positive and negative pressure change detection；
- Helium Mass Spectrometer Leak Detector for Gas Tightness Testing；
- Oxygen Method Leak Rate Detection.
2)Main parameters
- Water content standard <1ppm, measured value <0.1ppm
- Oxygen content standard <1ppm, measured value <0.1ppm
- The glove box is equipped with an automatic detection function for
leakage rate using the oxygen method. The factory-standard leakage
rate is <0.005VOL%/H, and the measured value is <0.001VOL/H.
It's worth noting that this measured value is substantially below
the internationally accepted glove box leakage rate standard of
<0.05VOL/H.
