Cast iron is a commonly used metal material, and its strength and hardness are important indicators for evaluating its quality and performance. Accurate determination of the strength and hardness of iron castings is essential to ensure their safety and durability. The following is a detailed description of the strength evaluation and hardness testing methods of cast iron.

Method for evaluating the strength of 1. iron castings

There are various methods for evaluating the strength of iron castings, and the commonly used methods are as follows:

1. Tensile test method: Tensile test is a common method for evaluating the strength of cast iron materials. The strength of a material is determined by applying a tensile force on the material and measuring strain and stress under specific conditions. The tensile test can obtain the yield strength, tensile strength, breaking strength, elongation at break and other strength indicators of the cast iron material.

2. Compression test method: Compression test is a test method that applies pressure to cast iron to measure its compressive strength and deformation capacity. By measuring the strain and stress, the compressive properties and buckling pressure of the material can be evaluated.

3. Impact test method: Impact test is to evaluate the strength of cast iron materials by applying impact load to cast iron parts, and then observing and measuring the material failure behavior and performance under this load. The commonly used impact test methods are impact toughness test and impact hardness test.

4. Notch sensitivity test method: Because the defects in cast iron will greatly reduce its strength, it is also an effective method to evaluate the strength of cast iron through notch sensitivity test. Common notch sensitivity tests include Pap impact test, parallel notch tensile test, etc.

Test method for hardness of 2. iron castings

The hardness test of cast iron is to evaluate its resistance to cutting and wear resistance. The commonly used hardness test methods are as follows:

1. Brinell hardness test method: Brinell hardness test is to press a fixed pressure diamond, hard alloy or hard spherical object into the surface of the material, and then calculate the hardness value by measuring the size of the impression. The Brinell hardness test method is simple and fast, and is widely used in the hardness test of cast iron and other materials.

2. Rockwell hardness test method: Rockwell hardness test is to press the diamond cone head or steel ball into the surface of the material, and then calculate the hardness value by measuring the depth of the press. The Rockwell hardness test method is suitable for metal materials with high hardness such as cast iron.

3. Vickers hardness test method: Vickers hardness test is to evaluate the hardness of a material by pressing an indenter into the surface of the material and measuring the depth of the indentation. The Vickers hardness test method is suitable for materials to which Brinell and Rockwell hardness tests cannot be applied.

4. Ultrasonic hardness test method: Ultrasonic hardness test is to evaluate the hardness of materials by using the speed and amplitude difference of ultrasonic wave in materials. The ultrasonic hardness test method has high accuracy and is suitable for measuring the hardness of large-size materials such as cast iron.

The above are the common methods for strength evaluation and hardness testing of cast iron parts. According to the specific situation and needs, the appropriate method is selected for testing to ensure the quality and performance of cast iron parts.