• Categories:Company News
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• Time of issue:2020-12-10 15:43
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(Summary description)The effect of material modification of cold heading machine on product quality The adjustment of material structure has a great impact on product quality. The head defects of anchor rod parts and the crack defects of cold head machine parts are the main waste phenomena in the production process of cold heading machines. Part of the reason for these defects is the material preparation process. According to the theory of metal plastic deformation, the bolt cold heading machine applies a certain pressure to the metal blank at room temperature to cause plastic deformation in the mold cavity and form it according to the specified shape and size. A pair of bevel gears are installed on one end of the crankshaft for standard parts machinery, a cam device is installed on the driven bevel gear shaft, and a scissors slider is installed vertically on the roller shaft of the driven roller of the cam device. The utility model overcomes the shortcomings of the prior art, and the running friction coefficient and impact force between the various parts of the feeding and cutting mechanism are small, so that the equipment runs smoothly, the running noise is effectively reduced, and the product quality and productivity are greatly improved. The cold heading machine is a special equipment mainly used for mass production of fasteners such as nuts and bolts. Reasons and control of bolt fracture According to the national standard GB3098.1, the bolts of the cold heading machine should undergo a head hardness test without heat treatment. In the test, the fracture of the bolt head is called fracture. There are two types of broken ends: cracks caused by the interlayer of the head and the joints or adjacent parts of the head and the rod fracture. The reason for the cracking caused by the interlayer of the workpiece head is relatively simple, and it is generally caused by improper cold forging machine technology. When the center position of the punching method and the concave shape of the front punching process are improperly adjusted, the head and the rod of the front punch have different shafts, and the head forms an obvious tilt, which will produce waste during formation. If the diameter of the wire is small, the forging ratio is increased. Vertical bending is prone to occur during fracturing, leading to metal streamline turbulence, separation of organic connections between crystal grains, and breakage. For the head caused by improper processing of the cold heading machine, as long as the process design can be improved. The fracture of the head joint is partly due to the fidelity of the material reforming process. Production practice and experimental research show that the cold deformation properties of steel play a decisive role in the quality of the workpiece. The quality of steel consists of two aspects: First, the steel performance of the steel mill must meet the requirements of the steel for the cold heading machine; on the other hand, the steel must help protect or improve the performance of the steel cold heading machine during the reforming process. The common defects in the original structure of steel are: there is a serious segregation zone in the steel, and the concentration of non-metallic elements such as carbon, phosphorus, and sulfur in the segregation zone reduces the cold deformation performance of the steel and causes deformation of the workpiece. actual. Generally speaking, rimmed steel is prone to segregation. There are defects such as shrinkage cavities, pores, and inclusions in the steel, or the superheated structure with coarse grains, which shows brittleness. In the process of material reorganization, due to improper process management, the factors that cause steel defects include: hydrogen embrittlement of steel during the pickling process and brittle fracture caused by overheating during the annealing process. When the tensile deformation in the material structure is within the critical deformation degree, when the crystal annealing results in a larger grain thickness, the head phenomenon will also occur. When the deformation of the head and the workpiece rod are greatly different, the degree of work hardening caused by the difference is large, and the joint of the head may be broken when the strength of the head joint is low. For example, the thick tracking process of the grooved hexagonal bolt is less damaged than the fine tracking process, and the process of the cold drilling machine of the groove is smaller than that of the cold drilling machine. This is due to the poor strength of the original head rod and fewer interruptions in the production of small and medium products. This is because the properties of the materials used in small-sized products are improved after repeated rolling and drawing.