The Identification of Cracks Formed by Forge Pressing
Forge pressing is a common manufacturing process used to form various parts of products and equipment as well as reconstruct existing materials to increase their strength and durability. This uses a press machine to press the material between two dies. The press force is typically between 8 and 11 tonnes per cm of die width so the pressure and heat effectively forge the material into the required shape. However, this process can also result in the formation of various types of cracks in the forged material. These may be visible as thin lines on the surface of the material or may be embedded within its interior.
In order to prevent part failure as a result of crack propagation, it is important to identify these defects accuratel and in a timely manner. This requires a thorough visual inspection and destructive testing where applicable. For example, ultrasonic testing enables the detection of subsurface cracking by sending high frequency sound waves through the material.
Visual inspection is done to detect surface cracks, which often appear as dark lines on the materials surface. Magnifying instruments or non-destructive testing equipment such as a penetrant or dye-penetrant test may also be used. For example, a dye-penetrant test introduces a colored dye into various areas of the material and then is inspected under a black light.
In some cases, destructive testing may also be used depending on the material and configuration of the part being analyzed. A hardness test is sometimes used to detect surface cracks in steel parts. Other tests such as tapping and drilling are also used to identify depth and size of embedded defects.
Finally, metallographic examination is another technique used to identify cracks in forge pressed metals. This involves the microscope examination of fine polished and etched samples of the material in order to identify any flaws or microstructure irregularities.
It is important to recognize the type of defect present in the material, as different cracks require different remedial action. If surface cracks are present, it may be possible to repair them by a welding and/or surface grinding procedure. If the cracking is localized to one or several diem, the die may need to be replaced or repaired. Embedded cracks require the material to be heat treated in order to induce further stress at the location of the crack and promote further cracking.
In conclusion, identify the type and location of cracks form by forge pressing is an important step in avoiding failure in products and equipment. The process should include thorough visual inspection and destructive testing if necessary, to determine the type and location of the cracks and take corrective action accordingly. Understanding the nature of the crack and the methods used to identify them is vital in ensuring the safety and durability of the forged part.
