The sickle shape of a metal tape is the deviation of its shape from a straight line, in which the tape bends in the form of an arc or sickle. This defect significantly affects the performance characteristics of the final product, creating problems when using it and reducing the quality of the products. Sickle formation can occur at all stages of working with the tape, from production to transportation and storage. Understanding the nature of this phenomenon helps to minimize risks and improve the quality of finished metal products.
The effect of sickle shape on product quality
Sickle deformation has a negative impact on the performance properties of products in various industries:
- Packaging industry. Sickle shape leads to violations of the packaging geometry, reducing dimensional accuracy, strength and reliability of final products. Deformed tape can cause errors in the operation of packaging machines, which will worsen the tightness of the package and increase the risk of damage to the goods.
- Construction. Curved tape makes installation difficult and reduces the strength and reliability of the load-bearing elements, which leads to the weakening of structures and their destruction or deformation under load. In conditions of high requirements for dimensional accuracy, for example, when constructing bridges and high-rise buildings, sickle formation is particularly dangerous.
- Mechanical engineering. The crescent band causes machinery to malfunction, increasing the risk of downtime and financial losses due to the need for repairs. For example, in the production of automotive parts, improper tape geometry can disrupt the cutting or stamping process, leading to defects.
- Production of welded structures. The bending of the sickle tape can cause a low-quality weld, which, in turn, will reduce the strength and reliability of the entire metal structure.
Causes of sickle formation
To better understand the problem, let's look at the main factors that cause sickle formation.
Technological factors
- Hardware configuration errors:
- the misalignment of the rolling mill rolls leads to an uneven distribution of forces on the belt, which causes it to lose shape;
- incorrect selection of rolling parameters (for example, too high speed or pressure) creates internal stresses.
- Uneven cooling:
- metal that cools at different rates in different areas undergoes structural changes that can cause bending.
Logistical factors
- Improper transportation:
- mechanical damage, shocks or pressure during transportation deform the belt.
For example, if rolls of tape are stacked on top of each other without protective pads, this may cause the lower layers to bend.
- Storage errors:
- failure to comply with storage conditions, an increase in the allowable humidity or improper placement of rolls can lead to deformation.
For example, excessive pressure from improper placement of coils causes the metal to gradually bend.
Equipment wear
- Outdated or worn out elements of production lines, for example, rolling mill rolls, create uneven loads on the metal, causing deformation.
The human factor
- Inadequate staff qualifications, violation or absence of technological regulations exacerbate the problem.
For example, errors in the installation and configuration of rolling equipment or improper handling of the belt during transportation can lead to sickle formation.
During production, internal stresses may occur in the cold-rolled strip, leading to sickle deformation. The reasons for this are often uneven cooling after rolling or welding, or structural changes caused by plastic deformation and recrystallization. To effectively solve the problem, it is important to pay attention to every stage — from production to transportation and storage.
Methods for controlling sickle
Various types of sickle deformation are used to prevent and minimize sickle deformation control methods:
- Visual control. The method is used for preliminary assessment of defects. For example, an operator can roll a tape on a flat surface and visually detect the presence of a bend. However, visual examination does not always accurately determine the degree of sickle formation, especially with minor deviations.
- Using special tools. For more accurate control of sickle shape, you can use micrometers, calipers and other measuring instruments. These tools allow you to measure the distance between two points on the tape and determine the presence and extent of sickle shape.
- The use of machine vision technologies. Modern automated monitoring systems make it possible to automatically identify defects in real time, increasing the accuracy of control. For example, high-resolution cameras and specialized software capture even minimal deviations from the norm.
Sickle formation is a serious problem that can lead to significant losses. Therefore, it is important to control the production and storage process of metal tape to prevent the occurrence of sickle deformation.
Ways to eliminate and prevent sickle formation
The St. Petersburg Precision Alloy Plant uses an integrated approach to eliminating sickle shape. Here are the key measures:
- Optimization of production processes:
- adjusting the settings of the rental equipment: regular maintenance and accurate adjustment of machines, including timely alignment of the rolling mill rollers and adjusting the rolling speed, make it possible to eliminate the causes of bending;
- temperature control: the use of modern cooling systems ensures an even distribution of temperature over the entire surface of the belt.
- Straightening and straightening the tape:
- specialized devices such as rolling and bending machines, presses and other tools are used to correct existing defects.
- Improving logistics:
- use of specialized packaging: for example, rolls of metal tape are packed in strong frames that protect them from external influences;
- ensuring proper storage conditions: rolls are stored on a flat surface; protective gaskets are used when laying them.
- Staff development:
- staff training working with new equipment and complying with technological regulations significantly reduces the likelihood of defects;
- conducting regular trainings configuring equipment helps to minimize human errors.
The problem of sickle formation has been known since the first rolling mills appeared in the 19th century. At that time, sickle correction was done manually. Today, machine vision systems are able to detect defects with an accuracy of fractions of a millimeter, which significantly improves product quality. Eliminating bends at the early stages of production can reduce the number of defects and improve the quality of the finished product.
Cold-rolled strip produced by PZPS
The sickle shape of a metal tape is a serious manufacturing defect that can adversely affect product quality, reliability and performance. To eliminate it, we use an integrated approach that includes improving production processes, analyzing transportation and storage conditions, as well as introducing modern control and editing technologies.
At PZPS, you can buy cold-rolled strip in accordance with GOST 21996-76 made of grade alloys 60S2A, 65G, 70S2HA, as well as precision alloys that meet the highest quality standards. Thanks to the use of modern equipment and technologies, we guarantee minimum sickle shape and impeccable performance characteristics of our products. Contact usto learn more about our products!
