Detailed explanation of the operational differences between plastic high-temperature creep testing machine and metal high-temperature creep testing machine

Although both are high-temperature creep testing equipment, due to the different material characteristics of plastic flexibility, low heat resistance, and easy deformation compared to metal rigidity, high heat resistance, and slight deformation, there are significant differences in the experimental operation process, parameter settings, equipment matching, and experimental logic. The specific differences are as follows:

1、 Experimental temperature operation difference (the most intuitive difference)

Plastic high temperature creep testing machine: low testing temperature, narrow temperature range, mild temperature rise. The standard testing range is from room temperature to 300 ℃, without the need for special high temperatures. The heating rate is slow, and sudden temperature changes are avoided throughout the entire process. Plastic has high thermal sensitivity, and rapid temperature rise can easily cause sample softening, warping, and premature aging, resulting in test failure. Moreover, the insulation time is short, and only the surface temperature of the sample needs to be uniform.

Metal high-temperature creep testing machine: high testing temperature, wide temperature range, strict temperature control. Conventional testing can reach 300-1200 ℃, suitable for high-temperature conditions such as alloys and steels. Long term constant temperature preheating is required for operation, with a holding time of more than 1 hour. It is required that the temperature in the entire furnace is uniform, and the temperature control accuracy and temperature field calibration standards are much higher than plastic testing. It is necessary to calibrate the furnace temperature field in advance.

2、 Differences in clamping and centering operations

Plastic high-temperature creep testing machine: Plastic materials are soft and prone to deformation due to pinching. Flexible anti slip fixtures should be used for operation, with gentle clamping force, and excessive clamping and squeezing of the sample are strictly prohibited; Simultaneously supporting multi-mode clamping of tension, compression, and bending, without the need for high coaxiality accuracy, with a focus on protecting the sample from mechanical damage.

Metal high-temperature creep testing machine: Metal has high hardness and strong rigidity. Hard high-temperature resistant fixtures must be used, with high axial centering accuracy required for clamping. Eccentricity deviation must be strictly controlled to avoid bending stress during loading, which affects the detection accuracy of small creep variables. The clamping calibration steps are cumbersome and the standards are more stringent.

3、 Differences in loading methods and load control operations

Plastic high temperature creep testing machine: Plastic has a large creep deformation and fast response. The operation adopts a small load, smooth and slow loading, with a smaller load value and a smoother loading speed to prevent direct fracture and plastic deformation of the plastic sample caused by excessive instantaneous stress. The focus is on observing large deformation and stress relaxation phenomena.

Metal high-temperature creep testing machine: The metal creep deformation is extremely small and changes slowly. Adopting constant high load long-term loading, high load accuracy requirements, zero load drift throughout the entire process, mainly observing micro scale deformation of metals. After loading is completed, it needs to be stabilized for a long time to adapt to metal ultra long term creep and persistent fracture tests.

4、 Differences in experimental duration and data collection operations

Plastic high temperature creep testing machine: Plastic creep speed is fast, the testing cycle is short, and the test can be completed in several hours to tens of hours. Data collection focuses on deformation trends and relaxation rates, with intuitive curve fluctuations that do not require ultra-high resolution data collection.

Metal high-temperature creep testing machine: Metal high-temperature creep is extremely slow, and the testing cycle is extremely long, reaching hundreds or even tens of thousands of hours. The operation requires uninterrupted monitoring throughout the entire process, equipped with ultra-high precision extensometers to continuously capture trace deformation data, with higher requirements for data acquisition density and stability.

5、 Test termination determination difference

Plastic testing: If the sample shows obvious tensile, bending, or softening deformation, it can be terminated, with a focus on determining the material's heat resistance, durability, and deformation resistance.

Metal testing: Continuous testing is required until the specimen fractures or reaches the ultimate creep strain, with a focus on determining high-temperature endurance strength and service life.