The main reason for the decline in the quality of the bent pipe
sunnysteel
In pure bending, under the action of external force distance M, the outer arm wall of the seamless steel pipe is thinned by the tensile stress &1 of the neutral layer, and the inner side is subjected to compressive stress. Thickening due to the action, the resultant force N1 and N2 changes the cross-section of the tube. Based on this factor, the main reason for the decline in the quality of the elbow is RX and SX. Therefore, in GBJ235-82, the RX value and the thinning amount of the outer side under various pressure levels are clearly stipulated, the purpose is to control RX with the value of SX, thus ensuring the quality.
As mentioned in the previous article, when the pipe is bent, the outside of the material is pulled, and the position of the neutral axis under pressure on the inside is different from the bending method. When the top bending (compression bending) works, the neutral axis is about 1/ from the outer wall At 3 places, the neutral axis is 2/3 away from the outer wall when the turning (bending) works. Therefore, when thin-walled pipes are bent, it is beneficial to use the swivel method.
The precision of the bent tire is also one of the factors affecting the quality of the bent pipe. In the manufacture of bent tires, in addition to the specifications and dimensions required to be controlled within a certain tolerance range, we also require users to select the corresponding bent tires according to the bent pipe diameter during use.
The bendability and surface corrosion of the pipe itself may also affect the quality of the bend. During on-site construction, the operator also needs to understand the material of the processed pipe, its processing performance and make judgments on the surface corrosion.
Now provide R. (bending radius/pipe outer diameter) relationship graph, for users to refer to when selecting the relationship between pipe diameter and wall thickness. Reflecting the influence of relative bending radius and relative wall thickness on the quality of elbow pipes, according to the acceptance specifications for pipe processing: cold-formed steel pipes are 4D for medium and low pressure, and 5D for high pressure. Therefore, our bending tire design is R=4D (determined in special cases), so as far as the pipe bending machine produced by our factory is concerned, it is mainly to choose the relative wall thickness SX. The upper part of the figure is the no mandrel area, and the middle part It is the common mandrel area, and the lower part of the figure is the special mandrel area. Because the design and manufacture of special mandrels are very difficult, and the operation is not convenient, so our factory generally does not supply them. Special circumstances can be negotiated separately.
The influence of lubrication on product quality during the forming process:In the traditional pipe bending production process, enterprises will adopt many methods to obtain better pipe bending surface quality, including: adopting more advanced and high-grade pipe bending machines, using higher strength molds, or using lubricating products, etc. Method. Enterprises often need to invest a lot of money to complete the use of high-end pipe bending machines and high-strength molds. Only the use of pipe bending lubricating products is relatively cheap and quickly meets the requirements of enterprise product quality.
However, in the traditional production process: oil-based elbow lubricating products can meet the quality requirements of enterprises in elbow production, but the oil-based elbow lubricating products are not easy to clean and pollute the environment. , In this way, enterprises must use more means to eliminate the impact of oil-based elbow lubrication products on the quality of the final product, and invest more energy and funds for this. The arrival of IRMCO elbow water-based lubricating grease not only meets the requirements of enterprises for the quality of elbow products, but also can avoid and reduce the increased investment of enterprises due to the use of oil-based elbow lubricating products, and completely optimize the production process of enterprises.
In the application process of traditional oil-based lubricating products, the production efficiency of enterprises is greatly restricted, because the fluidity and extremely difficult cleaning of oil-based lubricating products have caused pollution to the production environment and working conditions of workers. These pollutions often cost a lot of money, manpower and material resources. Adoption can reduce or even avoid the human and material resources of the above-mentioned cleaning pollution for the enterprise, and its characteristics of no-cleaning and direct welding can greatly improve the production efficiency and product quality of the enterprise. The amount of IRMCO water-based elbow grease can usually be reduced by 50%-80% compared with traditional lubricating oil, which can save more costs for enterprises.
