1. Introduction of experimental equipment
Impact sample broaching machine
Purpose: After the impact sample is processed, it is necessary to prepare the "V" groove by rotating the steering wheel on this equipment.
Impact testing machine
Purpose: Used to determine the impact toughness of materials under certain temperature conditions, in order to understand the performance of materials under impact load, with the use of impact sample broaching machine.
Metallographic structure analyzer
Purpose: It is used to observe the internal structure of the material or the weld to determine whether the material or the weld is defective, so as to determine whether it can meet the requirements of use.
Metallographic sample grinding and polishing machine
Thoroughfare: Used for fine grinding and polishing of test blocks to make them meet the experimental requirements.
Rockwell hardness machine (left)
Brinell hardness machine (right)
Purpose: Determine the Rockwell hardness or Brinell hardness of materials respectively.
Universal testing machine
Purpose: Used to measure the mechanical properties of materials, such as tensile stress, tensile strength, yield point stress, yield strength, elongation or elongation, pressure test, bending test, etc., and can analyze the elastic deformation of the material through the test curve To the broken state, the elastic modulus can be measured.
2. Test introduction
Jiangsu Runhong Materials Laboratory was established in August 2019 with a total investment of more than 1 million yuan. The equipment includes universal testing machines, impact testing machines, metallographic structure analyzers, Rockwell hardness machines, Brinell hardness machines, metallographic grinding and polishing machines, Metallographic sample cutting machine, portable metallographic analyzer, portable hardness machine, 3D SCAN scanner, etc., 2 certified laboratory personnel.
Main equipment and test introduction:
(1) Universal testing machine
The universal testing machine mainly performs tensile, compression and bending tests on materials. It is used to measure the mechanical properties of materials, such as tensile stress, tensile strength, yield point stress, yield strength, elongation or elongation, pressure test, bending test, etc. The test curve can be used to analyze the elastic deformation of the material to fracture State, the elastic modulus can be measured.
1. Start: press "power on" "oil pump start button", the indicator light is on;
2. After waiting for about 5 seconds, open the software and set the test plan (such as the shape and size of the sample, the entrance force of the test, the control speed and other common parameters);
3. Choose suitable fixtures: use "V" type fixtures for round bar samples, and use "flat plate" fixtures for plate samples (note: the selected fixture must be within the sample size range);
4. Enter the sample size, sample gauge length and related experimental parameters. You can enter the size of one test bar at a time, or you can enter the size of all test bars at one time;
5. Put one end of the sample into the upper clamp and clamp it (note: the clamping position of the sample should exceed 3/4 of the clamp), and clear the force value; adjust the lower beam to the appropriate position to clamp the sample;
6. Click "start" in the test window to enter the test state until the sample breaks;
7. Remove the sample and measure the gauge length and cross-section after the fracture, enter the corresponding position in the program, and the program automatically calculates the result;
9. Print the experiment report;
10. Close the software and turn off the main power supply of the test machine.
(2) Impact testing machine
The impact testing machine mainly applies impact load to the material to determine the impact toughness of the material at a certain temperature, and is equipped with an impact sample broaching machine.
1. Sample preparation
Specimen specifications: length 55±0.60, width 10±0.10, height 10±0.05, and notch processing is performed on the notch machine.
2. Operation steps:
(1) Turn on the power of the testing machine, start the swing, and ensure that the pendulum has been placed in the pre-raising hook position;
(2) The empty machine test is to check whether the energy loss is too large;
(3) Place the sample, place the sample horizontally on the support, and subject the back of the sample notch to impact load;
(4) Manually dial the pointer of the instrument panel to the maximum scale value;
(5) Press the eject button and the impact button in turn to let the pendulum fall freely, so that the test is subjected to impact load;
(6) Return the pendulum to the pre-raising hook position;
(7) Read the value and record the test data;
(8) Prepare for the next impact;
(9) After the test, long press the pendulum button to release the pendulum to the lowest point;
(10) Turn off the power and clean the scene.
(3) Metallographic structure analyzer
The metallographic structure analyzer magnifies the surface of the material to observe the internal metallographic structure, and is used to observe the internal structure of the material or weld to determine whether the material or weld is defective, and to determine whether it can meet the requirements of use.
Test process: Take ductile iron as an example
1. Choose a plane as the sampling point on the processing surface and the non-cold iron placement surface of the lower molding surface of the casting;
2. Use an angle grinder to install the grinding wheel to polish the sample points, the diameter is about 40mm, and the depth is 3-5mm (if the metallographic display effect is not good, the grinding depth can be deepened appropriately, but it should not exceed 3/5 of the casting processing volume) ;
3. The angle grinder is replaced with 200# or 400# polishing wheels for polishing, and polishing until there are no traces of the grinding wheel, and if necessary, replaced with wool polishing velvet polishing;
4. Take off the gloves, take the microscope out, install the 10X eyepiece, tighten the fastening screw to fix the eyepiece, install the 10X objective lens, and tighten the objective lens in place;
5. Place the microscope on the sample point to be tested (make the base fit the casting), turn on the lighting switch, rotate the lighting lamp to make the lighting in the best position, and tighten the lighting lock nut;
6. Observe the eyepiece, rotate the fine-tuning knob to make the metallography in the field of view in the best state, move the microscope to observe the metallographic structure of the sample point;
7. Adjust the field of view to a clear position, use the camera to point the eyepiece to take the metallographic picture and save it, compare the standard metallographic atlas to evaluate the spheroidization rate;
8. Turn off the lighting switch after use, remove the eyepiece and objective lens and put them in the protective box.
(4) Brinell hardness machine
The Brinell hardness machine is specially used to determine the Brinell hardness of materials.
1. Preparation of the sample:
(1) The surface of the sample is smooth and flat, and there should be no oxide scale, decarburized layer, carburized layer, electroplated layer and other dirt, especially grease;
(2) The edge of the indentation of the sample should be clear enough, and polishing treatment should be carried out if necessary to accurately read the indentation diameter.
2. Selection and installation of test bench: Choose a suitable workbench according to the shape and size of the sample, and place the workbench in the screw mounting hole.
3. Pre-selection of total test force: The pre-selection of test force must be completed before the test.
4. Calibration of testing machine: Calibrate the testing machine with a standard hardness test block.
5. Place the test piece on the workbench and wipe its supporting surface clean. Rotate the handwheel to slowly rise the workbench until the specimen touches the indenter until the pressure is automatically applied.
6. Wait for the load to be automatically applied to the set force value until it is automatically released.
7. Remove the sample and read the indentation using a reading microscope.
8. Look up the table "Metal Brinell Hardness Numerical Table" or perform computer analysis to get the Brinell hardness of the tested material.
9. Clean up the scene.