Analysis of the hottest material and process probl

2022-09-27
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Analysis of material and process problems affecting the quality of steel barrels (I)

the quality problem of steel barrels has always been one of the eternal topics in the steel barrel industry, and it is also one of the problems that have plagued barrel makers for a long time. Most of the reasons for this are that we have not carried out scientific and systematic research and management on relevant technologies and processes. The establishment of ISO9000 quality system provides a strong guarantee for the improvement and stability of steel barrel quality. With the support of this powerful system, we can adopt a scientific attitude to systematically study the real quality problems inside the steel barrel. Through the seamless quality assurance of ISO9000, we can realize the powerful combination of advanced technology and scientific process. The main quality problem of the steel barrel is the leakage of the steel barrel, which is the key to whether the steel barrel is qualified or not, and also the key to technology and process, which is the focus of this study. There are many technological problems that affect the quality of steel barrels. If you search and analyze them separately, you will see only trees and not forests, which is not conducive to the solution of the problem. Through our long-term practice and research in the steel barrel industry from technology to production, we found that these technologies and processes have an internal relationship, mutual influence, mutual unity and mutual connection. Therefore, we should conduct a comprehensive interactive analysis. Only in this way can we find the essence of quality problems and achieve the unification of technology, process and quality. Using the process interaction analysis method, we can see the impact of each process on the quality in the steel barrel production process, how to affect it, and how to have no or less impact. At first glance, most of the process problems do not seem to directly affect the final quality, but after using the interaction analysis, it will be found that it will have a certain impact on other processes, thus affecting the final product quality. Steel barrel production technology is actually a comprehensive technology. Production seems simple, but it involves a wide range of technical fields. For example, the uncoiling and leveling of coil belongs to steel rolling and shaping technology; Edging (or milling) of barrel material belongs to metal cutting technology; Barrel body rolling, etc. belong to sheet metal processing technology; Spot welding and seam welding belong to welding technology; The essence of sealing technology is permeated in the sealing; The production process of barrel bottom, top and mouth belongs to cold stamping technology; Oil and rust removal of barrel body belongs to chemical surface treatment technology; The painting of steel barrels by various methods belongs to metal surface painting technology; The drying process of various coatings belongs to far-infrared heating technology and other heating technologies; The pattern making on the finished steel barrel belongs to the category of printing technology, etc., which also uses such technologies as rolling technology, forging technology, hydraulic transmission technology, pneumatic transmission technology, bulging technology, automatic control technology, etc. Therefore, barrel making technology is not a separate discipline, and we must broaden our horizons and study it carefully. Now, let's use the interaction analysis method to analyze the main process. Due to the length, we can't elaborate the process in more detail. We pay attention to the analysis method and the analysis of the relationship, in order to play a role of throwing bricks and attracting jade. 1、 In order to ensure the product quality, we must first ensure the process quality, and to meet the process quality requirements, the quality assurance of raw materials is the first to bear the brunt. The main raw material of the steel barrel is steel plate, and the auxiliary materials include sealant, gasket, barrel mouth parts, paint and so on. The main material that affects the process quality is steel plate. The requirements of barrel making process for steel plates are generally flat surface, low hardness (small rigidity), small carbon content and uniform thickness. Of course, how to be the most appropriate is also related to the equipment conditions of various manufacturers. In addition, there is a problem of quality and cost, so we can't blindly seek high. As long as the minimum process requirements are met. Next, we will analyze the problems that often occur in the production practice when the raw material steel plate is not suitable for the barrel making process requirements. 1. The surface of the steel plate is uneven. When the surface of the steel plate is warped unevenly, the barrel body may be out of tolerance when it is unexpected. After seam welding, the diameters of both ends may be inconsistent or the overlap of seam welding may be misplaced. When the diameter of the barrel body is too small, it will affect the connection with the top of the barrel bottom when it is wrapped, and the top of the barrel bottom cannot be pressed into the barrel body in place, resulting in quality problems such as insufficient crimping materials and inaccurate crimping. When the barrel diameter is too large, the matching with the bottom and top of the barrel is too loose during sealing, and the gap is too large, resulting in loose sealing and wrinkle of the barrel. As a result, a total of 413 extruders imported from Thailand from China from January to October this year have leakage or surface quality problems. The dislocation of seam welding lap makes the lap position appear the phenomenon of stepped flanging such as PPR pipe ring stiffness testing machine in the flanging process. The flanging size at the short lap is insufficient, and the materials and layers that affect the flanging in the sealing process are insufficient, resulting in the quality problem of false flanging. When the surface of the steel plate is warped irregularly, the quality of the barrel bottom and top is difficult to guarantee during blanking and forming, and the warpage of the barrel bottom and top may occur, which may affect the degree of crimping in the sealing. Warping is unusual for the lid of an open top barrel, causing assembly problems. Due to the influence of the roundness of the blanking, uneven flanging around may also occur, which will also affect the sealing quality of the closed barrel and the sealing joint degree of the open barrel cover, which will cause the leakage of the steel barrel. 2. High hardness and rigidity of steel plates are mostly caused by high carbon content and inadequate heat treatment. For barrel making technology, it directly affects the quality of process molding. When the hardness is too large, the steel plate will rebound greatly, and the curvature radius of the barrel body will be too large, which will affect the seam welding positioning of the next process; In flanging process, because the springback is too large, the flanging angle is too large and the size is reduced; In the sealing process, there will also be cracks in the crimping due to the springback problem, resulting in the quality problem of false crimping. Due to the large rebound, the locking quality of the barrel opening parts on the steel barrel cover will also be affected, which may lead to gaps and leakage. 3. High carbon content of steel will lead to high hardness and rigidity of steel plate. In addition, the high carbon content will have a great impact on the seam welding quality of the barrel body, making the welding materials brittle and causing cracks in the subsequent flanging and expansion processes, which is the biggest hidden danger of the leakage quality problem of the steel barrel. 4. Uneven thickness of steel plates is a taboo in barrel production. The thickness of the steel plate is uneven, and the seam welding machine will be at a loss, because the various parameters adjusted by the seam welding machine before production have been determined. When the steel plate is suddenly thick and thin in production, its parameters will not automatically adapt, so there are welding quality problems, do not burn through, do not weld firmly. The thickness of the steel plate is uneven, and the problem in crimping assembly is even greater, because a shaped crimping forming roller can only adapt to the steel plate of one thickness. For the ultra thick steel plate, it cannot be loaded because the roll groove is small; For the ultra-thin steel plate, because the roll groove is large and the loading is insufficient, these two cases will certainly cause more leakage. Uneven thickness of steel plate can cause out of tolerance or deformation of workpiece size for the stamping process of barrel parts. 1 Making samples according to gb/t 19536 (2) 004 plywood for container floor can also cause damage to tools and dies or reduce their service life. 5. Influence of auxiliary materials on process quality inappropriate auxiliary materials are sometimes important links that affect the process quality of steel barrels. Curling sealant requires good elasticity, large adhesive force, more curing components, good chemical resistance, good process performance, etc. Good elasticity means that it can be compressed to a certain extent under the action of the sealing force during sealing. Due to its good elasticity, it has a certain resilience. With the help of this resilience, it can fill the curling gap and improve its sealing performance. The adhesive force is strong, which can make the rubber ring pre sprayed on the top edge of the barrel bottom firmly adhere to the crimping, and it is not easy to fall off when there is external friction with the barrel flanging in the crimping. There are many curing ingredients to truly fill the curling gap. Some adhesives have too few curing ingredients, and a lot of wet glue is sprayed. The oil delivery valve makes a lot of noise, but it is very little after curing, which cannot achieve the filling effect. Good chemical resistance is to prevent the sealant from having adverse reactions with the contents of the steel barrel. Some reactions may invalidate the sealant, and some reactions may deteriorate the contents. Good process performance mainly refers to the construction process. Some sealants and other properties are good, but the construction performance is not good, such as difficult to spray, brush, dry, etc., which will cause difficulties in construction and affect the use; When some glue is put into the drying furnace in the steel barrel to dry the paint film, there are phenomena such as scorching, thinning and flowing, which affect the sealing performance of crimping. The sealing gasket on the barrel mouth part has a certain elasticity, which can make the sealing performance better. Besides, the chemical resistance of the material is also quite important, which is the same as the requirements of the sealant, mainly to prevent the gasket from being corroded due to chemical reaction with the contents, thereby affecting its sealing performance or polluting the contents. The quality of the barrel mouth itself will also affect the sealing performance and interchangeability of the steel barrel. The external coating of steel barrel only affects the quality of appearance, but for the internal coating of internal barrel, it has the greatest impact on the safety of contents. The adhesion and chemical corrosion resistance of the coating are the most important. The process determines the difficulty of construction and the effect of coating. If it fails to meet the quality requirements of internal coating, it will undoubtedly cause damage to the contents. 2、 The uncoiling and leveling of sheet metal and the blanking process. The uncoiling and leveling of sheet metal should be said to be the first pass in the production of steel barrels, but its impact is from beginning to end. 1. During the uncoiling and leveling of the warped sheet metal, if the sheet metal is not leveled and warped unevenly, the result will be the same as the raw material unevenness mentioned in the previous part, which will affect the subsequent process. Generally speaking, the quality of raw steel plates can be easily realized in this uncoiling and leveling process. For example, in the normal uncoiling and leveling, the equipment has been adjusted as usual, but it is found that the steel plate does not meet the process requirements of leveling, and the plate still has warping, which indicates that the material may have high hardness, high rigidity or uneven thickness. Therefore, when this happens, we can immediately carry out some necessary tests on the materials, and timely prevent the unqualified materials from entering the production process. 2. The blanking size of barrel body is out of tolerance. At present, many uncoiling and leveling processes are connected with blanking and produced as a process. The quality of blanking process directly affects the quality of subsequent production process. When the blanking size of the barrel body exceeds the tolerance, various unqualified products may be caused. For example, parallelogram material, trapezoid material, width is too large or too small, length is too large or too small, and various conditions have different effects on the subsequent process. During seam welding, parallelogram material will cause overlapping dislocation, forming trapezoidal notch after flanging, and insufficient flanging size at the notch will also cause insufficient flanging material in the flanging process, insufficient number of flanging layers, hollow flanging, etc., resulting in leakage of unqualified products is inevitable. Trapezoidal materials may cause two kinds of results: one is the overlap dislocation after seam welding, which belongs to the same position dislocation; The other is the barrel body after seam welding

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