Defects. Types of product defects. Types of welded defects. Types of defects in goods and fabrics

A defect, it is an industrial marriage, can be practically for all products. Briefly speaking, these are products that are not allowed to the consumer because of inconsistency with the requirements put forward. For example, leaky packing, insufficient strength of the welded seam and so on. Let's talk in more detail about what defects are, and also look at the types of defects in various materials.

General information

Any industry produces defective products, to some extent, defective ones. As a rule, the marriage is determined after the shipment to the warehouse or to the consumer. In this case, the manufacturer can both recall its products and leave it. For example, the defect of packages for household sponges can not be considered critical, but the marriage in the brake system of the car can lead to the death of the driver. Therefore, one must understand that defects are different: some are permissible, others are not. It can be said that any product that has at least one deviation from the established norms is considered defective, while the rest is classified as suitable. And then it does not matter which industry is involved. As you already understood, any production has its own defects. Types of defects are divided into correctable and incorrigible. Products belonging to the first group can be made suitable (if it is economically feasible), to the second - it is impossible.

Types of defects in construction

Sometimes on news we hear information that the house collapsed somewhere, brickwork collapsed, etc. Often the fault is some defect that was not revealed during the control check. So, in the construction industry, any mismatch with the technical task (TOR) or the established rules is called a constructive defect. If it is a question of non-compliance of technical documentation for manufacturing products, this is called a production defect. But this is not the whole list. The fact is that in construction there are other defects. The types of defects here are classified as follows:

• An obvious defect is determined by external examination, that is, visually;
• The latent defect does not provide for the norm of control. It usually comes to light after the goods are shipped to the consumer.

It can be said that an obvious defect is less dangerous for a consumer, since it is much easier to detect and eliminate. However, not always obvious defects are eliminated by the manufacturer. Often you can buy products that do not visually match the norm, for example, having chipped on its surface, leaking packaging, etc.

Critical, significant and minor defect

All these types of marriage can be conditionally placed in one group, since they are interrelated. The fact is that such inconsistencies, one way or another, affect the efficiency of product use, but in varying degrees. For example, a critical marriage indicates that the effectiveness of the product, depending on the scope, will be much lower. Usually, the use of products for their intended purpose is impossible or forbidden in this case. An example is a broken kitchen knife, an unpressurized compressor for supplying compressed air, and so on.

A significant defect is one that is not critical, but has a significant impact on the durability and efficiency of product use as intended. For example, a microcrack in a metal sheet is considered a significant defect. Such a defective product can be used, but not for so long and not under such a heavy load. A minor defect is one that practically does not affect the durability and efficiency of product use. For example, shabby paint on the radiator is considered a minor defect.

Types of welded defects

It is difficult to underestimate the importance of welded joints. Agree, they determine the quality of the product as a whole. For example, a well-welded body of solid fuel boiler looks much better than the one on which defects are detected. Types of welding defects are divided into internal and external marriages. The first one is determined visually, and the second one can be detected only during flaw detection.

In addition, in this case we can talk about permissible and unacceptable defects. A group of goods with a tolerable marriage can be used with an efficiency of less than 100%, the second group to the consumer is not allowed. However, the defect in itself is already something abnormal, requiring elimination. Today defects of welded joints are eliminated using modern welding techniques and allowing only qualified masters to work. In addition, add special filler materials, use welding equipment and much more. Let's take a closer look at the types of product defects (welded) and how they affect the efficiency of product use and safety for the consumer.

Outdoor marriage

Any violation of the geometry of the structure is called an external defect. These include the influx, neprovar, undercut, etc. Almost all this is determined by eye. For example, the main reason for the failure is a small penetration into the metal arc. This happens because of insufficient current. Fix such a defect is extremely simple: try to increase the dynamics and reduce the length of the welding arc. In addition, this marriage is often met because of too fast work, so sometimes it makes sense to make a weld seam more measured.

Another typical and often encountered defect is undercut. This is a marriage, which is a groove (groove) in the base metal near the welded joint. It is usually formed due to incorrectly selected current and welding speed. In principle, much depends on the human factor.

Burns also occur quite often. This defect is a through hole in the weld. There is a marriage due to too slow welding and high current. As a result, there is a leakage of the welding bath.

An inflow occurs as a result of the appearance of scale on the surface with an incorrectly selected welding mode. Such a marriage is a leakage of an additive on a base metal without fusion.

Internal defects

This kind of marriage is revealed somewhat less often, since not everyone can find it with the naked eye. That is why there is often a breakdown of the welded structure, which can be very dangerous for a person. One of the most common and dangerous defects is hot cracks. They can be either longitudinal or transverse. Occur during the intermediate period of melting and solidification of the metal, and also because of an error in the choice of filler material and its chemical composition. The responsibility for such a defect lies entirely on the shoulders of the welder. There are also cold cracks. They arise even after the metal solidifies and the joint cools. Usually appear due to excess loads on the seam.

Pores are a defect that appears in all types of welding work. It is possible to say with confidence that every welder faced with such problems. If we list all the main types of defects in welded joints, then this will be in the first place. It arises because of insufficient protection of the bath with welding gas. As a result, pores are formed, which differ in size and chaotic distribution.

About tissue defects

In the process of manufacturing any product, a marriage occurs. Weaving is no exception. There are a variety of types of tissue defects that we will now try to consider. The most common marriage is close. It implies the absence of one or more threads in a certain length. Often, this defect occurs due to the breakage of the thread during the work. This happens because of a faulty lamella device or as a result of an operator error that stopped the machine later than necessary. It is interesting that such a defect is not taken into account if it is on the closed parts of the product. At the same time, products with close to 10-20 cm in two strands are not allowed for sale.

Often there is also a podletyna. Such a vice is a breakage of one or two threads and sealing them into the fabric. As a result, the product in the place of attachment becomes irregular in shape. Such a defect is unacceptable in products of the 1st and 2nd grade. A defect called "non-working of threads" affects the quality of the product in the same way as the subweaving. The vice lies in the fact that the main threads do not intertwine with the weft threads, as a result of which they appear on the surface of the tissue, changing its shape. Marriage, associated solely with the malfunctioning of the weaving unit, is called nedosek. It is in the presence of a duck of permitted bands.

Other tissue defects

There are other types of defects in goods made from fabric. But first it should be noted that the vice is local (local) and common. The first is usually small and is only on a certain section of the product. To such defects it is possible to carry twin, podletiny. But the vices that propagate along the entire length of a piece of tissue are called widespread. These are usually referred to as weediness, banding, etc. Another interesting point is that all these defects can occur at different stages of production. So, the defect can appear even during spinning because of insufficient quality of the raw material or even when finishing. All this suggests that careful monitoring is required at all stages. In addition, it is necessary to purchase only quality raw materials. The same applies to weaving equipment and, in fact, the skills of employees.

For example, the presence of contaminants and oily stains depends on the abundance of lubrication machine. And since the modern equipment is smeared automatically, then the operator has no sense to blame. The same applies to holes, perforations, as well as holes on the product, which appear due to incorrect work of the machine. Such goods do not pass quality control and are immediately rejected. It is worthwhile to draw your attention to the fact that in the weaving business there are eliminated defects. Local defects in any case, reduce the grade, but when cutting the fabric they can be circumvented, carrying out the delivery of premium quality products.

Defects of metal and metal products

To date, there are no defect-free metal samples. This suggests that, to some extent, marriage is present. But it is interesting that as a result of certain processes and the performance of mechanical operations, the quality of the metal can be significantly reduced, resulting in complete inadequacy of the product for further operation.

The most common defects are those that occur when a metal is in a solid state. The smaller the deformation, the less defects will appear. Some steel grades have good elasticity, this allows them to assume their former shape after a slight deformation. However, if you constantly increase the load, then there will be a turning point, when it will be impossible to restore the metal. In any case, it makes sense to say that here, as in weaving, some types of metal defects occur even during casting, while others are already at the final processing of the product.

For example, found defects are very common. In the metallurgical industry, they are constantly struggling with them, developing new ways of casting. Uneven cooling and solidification of liquid metal leads to the formation of pores and shifts of internal layers. There are also various types of defects in parts that undergo secondary mechanical and thermal processing. There is also a marriage arising during the transportation or storage of a metal product.

Conclusion

As you can see, there are various defects. We examined the types of metal defects, welded joints and fabrics. But you must understand that marriage is present in both the food and chemical industries. You can not even talk about the human factor here, since the machines also sometimes fail, which leads to a similar result. Nevertheless, some types of product defects can be excluded by partial or complete automation of the technological process, which is currently being done.

As for the buyer as the end user, then do not buy defective products. Often they are offered with a discount and other tempting offers. This makes sense only when the purpose of the product is not of a responsible nature, in other cases any defects can lead to the most unexpected and even sad consequences. Therefore, before you buy something, make sure the quality of the goods, as well as in its serviceability. After all, even a slight error in the production process can cost you health, and often life.