Ordinary Q235 steel can achieve it, and the effect is even better for processed and hardened ordinary steel plates. Materials that require no deformation under external forces simply do not exist. Usually, a maximum degree of deformation, known as deflection, is required. National standards specify this requirement, so you cannot request no deformation, only that the degree of deformation should not exceed a certain limit, such as 0.001 millimeters.
Once the deflection is determined, suitable materials can be selected. For example, the tensile strength of ordinary Q235 steel is 235 MPa, which is equivalent to 23.5 kg/mm^2. If your thin plate is 2 mm thick and 50 mm wide, with an effective cross-sectional area of 100 square millimeters, the tensile strength can be calculated as 100 mm^2 × 23.5 kg/mm^2 = 235 kg without fracturing.
If it undergoes processing and hardening, its tensile strength will be higher. Assuming a discount of one percent, the bending strength would reach one percent of the tensile strength. The bending strength of Q235 thin plates can reach 2.35 kg or 2350 grams, which can support a weight of 20 grams without breaking. Martensitic stainless steel can also be used, such as 4Cr13 and 9Cr18, which are commonly used in medical instruments, but they are more expensive. If cost is a concern, GCr15 bearing steel can also be used.
Testing requirements:
The cross-section of the test specimen can be circular or rectangular, and the span during the test is generally ten times the diameter. For brittle materials, a small amount of plastic deformation is sufficient to cause failure in the bending test. For ductile materials, the bending fracture strength cannot be measured, but the ductility and uniformity can be evaluated. The bending test of ductile materials is called cold bending test. During the test, the specimen is loaded to a certain degree of bending, and cracks on the surface of the specimen are observed.
Testing characteristics:
Compared to tensile tests, bending tests have several distinctive characteristics: bending test specimens are simple in shape (circular, square, and rectangular), making them suitable for measuring brittle materials that are difficult to process. When conducting tensile tests on brittle materials, the deformation is minimal, while bending tests can indicate the plasticity of brittle materials through deflection. During the bending test, the stress distribution on the cross-section is highest at the surface, making it sensitive to surface defects. For highly ductile materials, the bending test usually does not reach the point of failure, so bending strength tests are generally not performed. Bending tests are simpler and more convenient than tensile tests in terms of operation.
Bending curve:
The bending curve, also known as the M-f curve or F-f curve, represents the relationship between the bending moment M (or load F) as the vertical coordinate and the deflection f of the specimen as the horizontal coordinate, indicating the deviation of the bending moment or load from the original position of the specimen's centerline.
Applications:
Bending tests can be used to measure the bending strength of gray cast iron, which is an important mechanical property indicator. It can also be used to measure the bending strength of hard alloys, as these materials are difficult to process into tensile specimens, but simple bending specimens can be easily made. Bending tests can also be used to measure the bending strength of ceramic materials and tool steel. These brittle materials are difficult to measure their tensile strength, and preparing specimens is also challenging, hence the use of bending tests. Bending tests can be used to assess and compare the quality and performance of surface heat treatment layers, as they are sensitive to surface defects.
During sample processing, the grinding direction on the surface should be consistent with the length direction of the specimen. The process includes rough grinding and fine grinding. The depth of rough grinding should not exceed 0.03 mm per pass. Fine grinding is carried out using diamond wheels with grit sizes of 320 to 800, with a depth of no more than 0.002 mm per pass. Mechanical properties include stress, strain, tensile stress, compressive stress, and shear stress.
Once the deflection is determined, suitable materials can be selected. For example, the tensile strength of ordinary Q235 steel is 235 MPa, which is equivalent to 23.5 kg/mm^2. If your thin plate is 2 mm thick and 50 mm wide, with an effective cross-sectional area of 100 square millimeters, the tensile strength can be calculated as 100 mm^2 × 23.5 kg/mm^2 = 235 kg without fracturing.
If it undergoes processing and hardening, its tensile strength will be higher. Assuming a discount of one percent, the bending strength would reach one percent of the tensile strength. The bending strength of Q235 thin plates can reach 2.35 kg or 2350 grams, which can support a weight of 20 grams without breaking. Martensitic stainless steel can also be used, such as 4Cr13 and 9Cr18, which are commonly used in medical instruments, but they are more expensive. If cost is a concern, GCr15 bearing steel can also be used.
Testing requirements:
The cross-section of the test specimen can be circular or rectangular, and the span during the test is generally ten times the diameter. For brittle materials, a small amount of plastic deformation is sufficient to cause failure in the bending test. For ductile materials, the bending fracture strength cannot be measured, but the ductility and uniformity can be evaluated. The bending test of ductile materials is called cold bending test. During the test, the specimen is loaded to a certain degree of bending, and cracks on the surface of the specimen are observed.
Testing characteristics:
Compared to tensile tests, bending tests have several distinctive characteristics: bending test specimens are simple in shape (circular, square, and rectangular), making them suitable for measuring brittle materials that are difficult to process. When conducting tensile tests on brittle materials, the deformation is minimal, while bending tests can indicate the plasticity of brittle materials through deflection. During the bending test, the stress distribution on the cross-section is highest at the surface, making it sensitive to surface defects. For highly ductile materials, the bending test usually does not reach the point of failure, so bending strength tests are generally not performed. Bending tests are simpler and more convenient than tensile tests in terms of operation.
Bending curve:
The bending curve, also known as the M-f curve or F-f curve, represents the relationship between the bending moment M (or load F) as the vertical coordinate and the deflection f of the specimen as the horizontal coordinate, indicating the deviation of the bending moment or load from the original position of the specimen's centerline.
Applications:
Bending tests can be used to measure the bending strength of gray cast iron, which is an important mechanical property indicator. It can also be used to measure the bending strength of hard alloys, as these materials are difficult to process into tensile specimens, but simple bending specimens can be easily made. Bending tests can also be used to measure the bending strength of ceramic materials and tool steel. These brittle materials are difficult to measure their tensile strength, and preparing specimens is also challenging, hence the use of bending tests. Bending tests can be used to assess and compare the quality and performance of surface heat treatment layers, as they are sensitive to surface defects.
During sample processing, the grinding direction on the surface should be consistent with the length direction of the specimen. The process includes rough grinding and fine grinding. The depth of rough grinding should not exceed 0.03 mm per pass. Fine grinding is carried out using diamond wheels with grit sizes of 320 to 800, with a depth of no more than 0.002 mm per pass. Mechanical properties include stress, strain, tensile stress, compressive stress, and shear stress.
